TWI426701B - Inductor and capacitor-based clock generator and timing/frequency reference - Google Patents

Description

Inductor and capacitor based clock generators and timing/frequency reference Cross-references to related applications

U.S. Patent Application Serial No. 11/232,407, filed on Sep. 20, 2005, to the name of "Single-Way Clock Generator and Timing/Frequency Referencer Frequency Control" by McCorquodale, Michael S., et al. The U.S. Patent Application Serial No. 11/084,962, filed on Mar. 21, 2005, to the name of Part of the "single-chip clock generator and timing/frequency reference" is a continuation of the priority of the U.S. Patent Application Serial No. (11/084,962), which is incorporated by reference to McCorquodale, Michael. U.S. Provisional Patent Application Serial No. 60/555,193, filed on March 22, 2004, entitled "Single-chip and micro-mechanical RF reference monolithic and top-down clock synthesis" priority, It is hereby incorporated by reference in its entirety, the entire content of which is hereby incorporated by reference in its entirety in the entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire disclosure

This application is also a continuation of the U.S. Patent Application Serial No. 11/084,962, filed on March 21, 2005, to the name of the "single-chip clock generator and timing/frequency reference device" by McCorquodale, Michael S. et al. And claiming the priority of the U.S. Patent Application, the U.S. Patent Application Serial No. 60/555,193, filed on Mar. 22, 2004, to The priority of the mechanical RF reference monolithic and top-down clock synthesis method ("Second Related Application") is given in conjunction with this case, all of which are included here. For reference, and for all commonly disclosed subject matter claims priority.

This application is also related to U.S. Patent Application Serial No. 11/085,372, filed on March 21, 2005, to the name of <RTI ID=0.0>> And claiming the priority of the U.S. Patent Application, which claims the priority of U.S. Provisional Patent Application Serial No. 60/555,193, which is assigned to the present application, all of which is incorporated herein by reference. It is incorporated herein by reference and claims the priority of all commonly disclosed subject matter.

The present invention relates generally to the generation of an oscillating or clock signal, and more particularly to a clock signal generator and a timing/frequency reference, which are free-running, self-referencing, in terms of process, voltage and temperature. Accurate, low jitter, and monolithically integrated with other circuits to form a single integrated circuit.

An accurate clock generator or timing reference system typically relies on a crystal oscillator, such as a quartz oscillator, which provides a mechanical, resonant vibration at a particular frequency. The difficulty with such a crystal oscillator is that it cannot be fabricated as part of the same integrated circuit ("IC") driven by its clock signal. For example, a microprocessor such as the Intel Pentium processor requires a separate clock IC. As a result, almost all circuits that require accurate clock signals require an off-chip clock generator.

There are several consequences for this non-integrated solution. For example, because such processors must be connected through external circuitry, such as over a printed circuit board (PCB), the power consumption is relatively increased. In applications that rely on limited power sources, such as battery power for mobile communications, such additional power consumption is disadvantageous.

In addition, this non-integrated solution that requires additional ICs increases the space and area requirements on the PCB or in the finished product, which is also detrimental to the mobile environment. Moreover, such additional components add manufacturing and manufacturing costs because additional ICs must be fabricated and assembled in a primary circuit such as a microprocessor.

Other clock generators that are formed as integrated circuits with other circuits are often not accurate enough, especially through process, voltage and temperature (PVT) variations. For example, ring, relaxation, and phase shift oscillators provide clock signals for certain low sensitivity applications, but are not available in some of the more complex electronic circuits (eg, High accuracy required for applications that require considerable processing power or data communication. Moreover, such clock generators or oscillators often exhibit considerable frequency drift, jitter, have a relatively low Q value, and are subject to other distortions from noise or other interference.

Therefore, there is still a need for a clock generator or timing reference that can be monolithically integrated with other circuits (as a single IC) and that is highly accurate to PVT variations. Such a clock generator or timing reference system should be free-running and self-referential and should not require locking or reference to another reference signal. Such a clock generator or timing reference system should exhibit minimal frequency drift and have relatively low jitter and should be suitable for applications requiring a highly accurate system clock. Such a clock generator or timing reference should also provide a plurality of modes of operation including: a clock mode, a reference mode, a power save mode, and a pulse mode. Finally, such a clock generator or timing reference should provide control over the output frequency in response to changes in ambient or junction temperature, or changes in other parameters such as voltage, process, frequency, and aging, To provide a stable and desired frequency.

In various exemplary embodiments, the present invention provides an apparatus for generating a frequency reference signal. The device includes a resonator that can be implemented using one or more inductors and capacitors (as an "LC-resonator"), a transconductance amplifier, a frequency controller, and a temperature compensator. Used to provide open loop frequency control and to select a low jitter, free running and self-referencing clock generator and/or timing and frequency reference, which is highly accurate in terms of PVT and aging (time) changes, And it can be monolithically integrated with other circuits to form a single integrated circuit. It does not require a separate reference oscillator, and embodiments of these examples are not phase locked, delayed locked, or locked to any other frequency reference. Rather, embodiments of these examples can be utilized as such a reference oscillator that generates a frequency reference signal that can then be locked to one or more phase locked or delayed locked loops. Embodiments of various examples of the invention include features for producing highly accurate frequencies under variations in process, voltage, and temperature (PVT). These characteristics include frequency tuning and selection, and compensation for frequency variations due to temperature and/or voltage variations and process variations, as well as variations due to aging of the integrated circuit.

For applications that may require high Q, low jitter, and low phase noise, the resonator typically includes one or more inductors and capacitors that form one or more LC-resonant circuits or LC resonators. In the first embodiment, a double balanced differential LC oscillator topology is utilized. In other example embodiments, a differential or single-ended LC oscillator topology may be utilized, such as a differential n-MOS cross-coupling topology; a differential p-MOS cross-coupling topology; single-ended Colpitts LC oscillations , single-ended Hartley LC oscillator, differential Colpitts LC oscillator (both base and common collector), differential Hartley LC oscillator (also in two forms of common base and common collector) A single-ended Pierce LC oscillator, a quadrature oscillator (eg, consisting of at least two double balanced differential LC oscillators). In any of these embodiments, the active inductor can be utilized in an LC oscillator or in other reactive components. Any of these LC topologies can be implemented as balanced, cross-coupled, differential, or single-ended, and any type of transistor can be utilized, such as n-MOS, p-MOS, or BJT. Other LC oscillator topologies now known or to become known are considered equivalent and are within the scope of the present invention.

Exemplary embodiments of the present invention also provide for varying degrees and types of control. For example, both discontinuous and continuous control are provided on-the-fly to control the output frequency of the free-running oscillator in accordance with such variations. Moreover, such control is typically provided in an open loop without the need for (or necessarily) a feedback connection, and there is no need to continuously lock the oscillator to another reference signal.

Furthermore, exemplary embodiments of the present invention provide a clock generator and/or timing and frequency reference having a plurality of modes of operation including modes such as a power save mode, a clock mode, a reference mode, and a pulse mode. . Moreover, various embodiments provide multiple output signals at different frequencies and provide low latency and glitch-free switching between such various signals.

Importantly, embodiments of the various exemplary embodiments of the present invention produce significant and relatively high frequencies, such as in the range of hundreds of MHz and GHz, which are then divided into a plurality of lower frequencies. Each of these divisions divided by "N" (a rational number of integers) causes significant noise reduction, where phase noise is reduced by a factor of N and phase noise power is reduced by a factor of ^two . Thus, exemplary embodiments of the present invention result in significantly lower relative period jitter than oscillators that produce their output directly or through frequency multiplication.

Various device embodiments include a resonator, an amplifier, and a frequency controller, which can include various components or modules, such as: a temperature compensator, a process variation compensator, a voltage isolator, and/or voltage. A compensator, an aging (time) change compensator, a frequency divider, and a frequency selector. The resonator is provided with a first signal having a resonant frequency. A temperature compensator adjusts the resonant frequency in response to temperature, and the process variation compensator adjusts the resonant frequency in response to a process change. In addition, various embodiments may further include: a frequency divider to divide the first signal having the resonant frequency into a plurality of second signals having a corresponding plurality of frequencies, the plurality of frequencies being substantially equal to or lower And the frequency selector; and a frequency selector for providing an output signal from one of the plurality of second signals. The frequency selector can further include a surge suppressor. The output signal can be provided in any of a variety of forms, such as differential or single-ended, and substantially square or sinusoidal, or in the form of a spread-spectrum.

Exemplary embodiments of the present invention provide a frequency control device for an integrated free-running harmonic oscillator that includes a resonator adapted to provide a resonant frequency a first signal; a sensor adapted to provide a second signal, such as a control voltage, in response to at least one of a plurality of parameters; and a frequency controller coupled to the sensor And coupled to the resonator, wherein the frequency controller is adapted to modify a reactance element coupled to the resonator to modify the resonant frequency in response to the second signal. The plurality of parameters are variable and include at least one of the following parameters: temperature, process, voltage, frequency, and aging (ie, elapsed time).

In an exemplary embodiment, the frequency controller is further adapted to modify an effective reactance or impedance element coupled to the resonator in response to the second signal, for example, modifying the total of the resonator in response to the second signal Capacitor, coupling a fixed or variable capacitance to or decoupled from the resonator, modifying or modifying a resonator by changing or switching a varactor to a selected control voltage Effective reactance, or equivalently modifying the inductance or resistance of the resonator in response to the second signal, for example, by coupling a fixed or variable inductance or resistance to the resonator or from the resonance The device is decoupled. In other embodiments, a differentially weighted reactance or a differentially sized reactance (eg, a variable capacitor (varactor)) can be switched to or removed from the resonator. Switched to a plurality of different selectable control voltages or removed from a plurality of different selectable control voltages, or both. For example, in selected embodiments, the reactance of one or more variable capacitors coupled to the resonator can be controlled by switching the one or more variable capacitors to one of a plurality of control voltages. To change, this results in a different or differentially weighted effective reactance coupled to the resonator.

For example, a plurality of fixed capacitors (having different binary weighted or differentially weighted capacitors) can be coupled to the resonator to provide discrete level frequency control, and one coupled to The varactor of the resonator can be provided with a control voltage selected by one of a plurality of control voltages that are responsive to temperature, which can be utilized to maintain a fixed temperature variation Frequency, and it provides continuous level frequency control. Moreover, any such control voltage may vary in response to a selected parameter (e.g., temperature) or may be fixed relative to the one parameter. The different weights of the various reactances utilized may be embodied in a plurality of forms, for example, binary weighted, linearly weighted, or weighted in any other desired manner, all of which are considered equal and in the present invention. Within the scope of the category.

It should be noted that the terms "fixed" and "variable" are used in the senses known in the art, wherein "fixed" is understood to mean that it is generally configured to be relative to one The selected parameters are not changed, while the "variable" representation is generally configured to vary with respect to the selected parameters. For example, a fixed capacitor generally means that its capacitance does not change as a function of the applied voltage, and a variable capacitor (varactor) will have a capacitance that does vary as a function of the applied voltage. However, both capacitors may have and generally have capacitances that vary as a function of process variation. Furthermore, a fixed capacitor can be formed, for example, as a varactor coupled to a fixed voltage. Similarly, components may be coupled to one another, directly or indirectly, in other words, operatively coupled or coupled via signal transmission. For example, a component can be coupled to a second component via a third component, such as through a switching configuration, a frequency divider, a multiplier, and the like. Those skilled in the art will appreciate the various scenarios and contexts depicted and discussed below, as well as the meanings that are used when such terms are used.

In an exemplary embodiment, the frequency controller may further include: a coefficient register adapted to store the first plurality of coefficients; and a first array having a plurality of couplings to the coefficient register And a switchable capacitive module coupled to the resonator, each switchable capacitive module has a fixed capacitance and a variable capacitance, and each switchable capacitive module is responsive A coefficient corresponding to one of the first plurality of coefficients is switched between the fixed capacitance and the variable capacitance, and each variable capacitance is switched to a control voltage. The plurality of switchable capacitive modules can be binary weighted. The frequency controller may further include a second array having a plurality of switchable resistive modules coupled to the coefficient register, and further having a capacitive module, the capacitive module and the A plurality of switchable resistive modules are further coupled to a node to provide the control voltage, wherein each switchable resistive module is responsive to a second plurality of coefficients stored in the coefficient register A corresponding coefficient to switch the switchable resistive module to the control voltage node. In selected embodiments, the sensor further includes a current source responsive to temperature, wherein the current source is coupled to the second array through a current mirror to span the plurality of switchable resistors The control voltage is generated on at least one switchable resistive module of the module. Also in selected embodiments, the current source has at least one complementary to absolute temperature ("CTAT") configuration, proportional to absolute temperature ("PTAT") configuration, proportional to absolute temperature squared ("PTAT ² ") configuration, or a combination of these configurations. In addition, each of the switchable resistive modules of the plurality of switchable resistive modules has a different temperature response for a selected current.

In other exemplary embodiments, the sensor is a parameter (temperature, process, voltage, aging, etc.) sensor and changes the second signal in response to changes in the selected parameter; for example, The sensor can be a temperature or voltage sensor and change the second signal in response to a change in temperature or voltage. The selected embodiment can also include an analog to digital converter coupled to the sensor to provide a digital output signal in response to the second signal and including a control logic block to convert the digital output signal Become the first plurality of coefficients.

In other exemplary embodiments, the frequency controller further includes a process variation compensator coupled to the resonator and adapted to modify the resonant frequency in response to one of the plurality of parameters. The process variation compensator can further include a coefficient register adapted to store a plurality of coefficients; and an array having a plurality of binary weighted switchable coupled to the coefficient register and the resonator a capacitive module, each switchable capacitive module having a first fixed capacitance and a second fixed capacitance, wherein each switchable capacitive module is responsive to one of the plurality of coefficients Corresponding coefficients are switched between the first fixed capacitance and the second fixed capacitance. In other exemplary embodiments, the process variation compensator can further include a coefficient register adapted to store a plurality of coefficients; and an array having a plurality of couplings to the coefficient register and the resonance The switchable variable capacitive module, each switchable variable capacitive module is responsive to a corresponding one of the plurality of coefficients to be at a first voltage and a second voltage Switch between, for example, switching to a selected control voltage.

In other exemplary embodiments, the frequency controller further includes a coefficient register adapted to store the first plurality of coefficients; and a first array having a plurality of coupled to the coefficient register and a switchable capacitive module coupled to the resonator, each switchable capacitive module having a variable capacitance, each switchable capacitive module responsive to the first plurality of A coefficient corresponding to one of the coefficients to switch the variable capacitance to a selected one of the plurality of control voltages. In other exemplary embodiments, the process variation compensator can further include a coefficient register adapted to store at least one coefficient; and at least one switchable to the coefficient register and the resonator The variable capacitive module is responsive to the at least one coefficient to switch to a selected control voltage. The sensor may include a current source responsive to temperature, and the frequency controller may further include a second array having a plurality of resistive modules coupled to the current source through a current mirror, the plurality Each of the resistive modules is adapted to provide the plurality of control voltages, and wherein each of the plurality of resistive modules has a different response to temperature and is adapted to respond to a current from the current The source current provides a corresponding control voltage for the one of the plurality of control voltages.

In other exemplary embodiments, an apparatus for frequency control of a resonator includes a coefficient register adapted to store a first plurality of coefficients; and a first array having a plurality of couplings Up to the coefficient temporary device and the switchable reactance or impedance module of the resonator, each switchable reactance module is responsive to a corresponding one of the first plurality of coefficients to switch a corresponding reactance Modify the resonant frequency. The corresponding reactance or impedance can be a fixed or variable inductance, a fixed or variable capacitance, a fixed or variable resistance, or any combination thereof. The corresponding reactance can be switched to the resonator or, when coupled to the resonator, can be switched to a control voltage, a supply voltage or a ground potential, and the control voltage can be responsive to temperature The current source is used to decide. For example, the corresponding reactance is variable and coupled to the resonator and switched to a selected one of a plurality of control voltages. In selected embodiments, the first plurality of coefficients are calibrated by a sensor responsive to at least one of a plurality of variable parameters (eg, temperature, process, voltage, frequency, and aging) Or decide.

In other exemplary embodiments, a frequency control device for an integrated free-running harmonic oscillator includes: a plurality of resistive modules adapted to generate a plurality of control voltages; a plurality of coupled to a controlled reactance module of the harmonic oscillator; and a plurality of switches coupled to the plurality of resistive modules and the plurality of controlled reactance modules, wherein the plurality of open relationships are coupled in response to a control signal And connecting a first control voltage of the plurality of control voltages to one of the plurality of controlled reactance modules to modify a resonant frequency of the harmonic oscillator.

As described above, the device can also include a current source coupled to the plurality of resistive modules, wherein the current source is adapted to provide a parameter dependent current to at least one of the plurality of resistive modules The resistive module generates at least one of the plurality of control voltages, the control voltage being parameter dependent. In other embodiments, the current source is adapted to provide a substantially parameter-independent current to at least one of the plurality of resistive modules to generate at least one of the plurality of control voltages The control voltage is substantially independent of the parameters. According to this exemplary embodiment, each of the switchable resistive modules of the plurality of switchable resistive modules can have a different temperature response for a selected current. Thus, when the parameter is temperature, at least one of the plurality of control voltages is temperature dependent, and at least one of the plurality of control voltages is substantially temperature independent.

The apparatus of the example may also include a coefficient register coupled to the plurality of switches and adapted to store the first plurality of coefficients, wherein the control signal is by at least one of the first plurality of coefficients Provide it. The plurality of controlled reactance modules may further include a plurality of differential (eg, binary) weighted fixed capacitances and variable capacitances, and wherein the plurality of open relationships are coupled to the first plurality of coefficients in response to the fixed one Capacitance to the harmonic oscillator and coupling one of the plurality of control voltages to a variable capacitance coupled to the harmonic oscillator. The plurality of resistive modules may further include a plurality of switchable resistive modules coupled to the coefficient register and a capacitive module, the capacitive module and the plurality of switchable resistive modes The group is further coupled to a node to provide the first control voltage, wherein each switchable resistive module is responsive to a corresponding one of a first plurality of coefficients stored in the coefficient temporary Switching the switchable resistive module to the control voltage node.

In an exemplary embodiment, an analog to digital converter can be coupled to the plurality of switchable resistive modules to provide a digital output signal in response to the first control voltage, for example, to convert a temperature dependent The current (as a sensor) becomes a digital form; and a control logic block converts the digital output signal into the first plurality of coefficients or the control signal.

In addition, in the exemplary embodiment, the plurality of controlled reactance modules further includes: a plurality of switchable capacitive modules coupled to the coefficient register, and the plurality of switchable capacitive modules Relatably coupled to the harmonic oscillator, wherein each switchable capacitive module has a variable capacitance, and wherein each switchable capacitive module is responsive to the first plurality of coefficients A corresponding coefficient to switch the variable capacitance to a selected one of the plurality of control voltages. According to this embodiment, a current source responsive to one of the plurality of variable parameters is coupled to the plurality of resistive modules through a current mirror; wherein each of the plurality of resistive modules The resistive module has a different response to the parameter and is adapted to provide a corresponding one of the plurality of control voltages in response to a current from the current source. According to this embodiment, at least one of the plurality of control voltages is substantially parameter dependent, and at least one of the plurality of control voltages is substantially parameter independent.

In addition, in an exemplary embodiment, the plurality of controlled reactance modules further includes: a plurality of differentially weighted switchable capacitive modules coupled to the coefficient register and the harmonic oscillator, each Each of the switchable capacitive modules has a first fixed capacitance and a second fixed capacitance, and each switchable capacitive module is responsive to a corresponding one of the plurality of coefficients to Switching between the first fixed capacitor and the second fixed capacitor. In other embodiments, the plurality of controlled reactance modules further includes: a plurality of switchable variable capacitive modules coupled to the coefficient register and the harmonic oscillator, each switchable The variable capacitive modules are each responsive to a corresponding one of the plurality of coefficients to switch between a first voltage and a second voltage of the plurality of control voltages. In other embodiments, the plurality of controlled reactance modules further includes: a plurality of switchable variable capacitive modules coupled to the coefficient register and the harmonic oscillator, each switchable The variable capacitive modules are each responsive to a corresponding one of the plurality of coefficients to switch to a selected one of a plurality of control voltages, the plurality of control voltages comprising a plurality of different sizes The voltage, and wherein the selected control voltage is substantially fixed under temperature changes.

Moreover, in an exemplary embodiment, the apparatus can further include: a plurality of switchable resistors responsive to a control signal to switch a corresponding resistance to the harmonic oscillator to modify the resonant frequency. The apparatus can include a voltage divider coupled to the plurality of controlled reactance modules and adapted to provide a selected control voltage in response to a voltage change. Additionally, an aging change compensator can be coupled to the resonator and adapted to compare a current value of a selected one of the plurality of parameters with an initial value of the selected parameter, and responsive to the The difference between the current value of the selected parameter and the initial value modifies the resonant frequency.

Many other example embodiments are depicted and described in detail below, and include additional modulators and compensators for voltage variations and aging (IC life) changes.

The present invention can also include a mode selector coupled to the frequency selector, wherein the mode selector is adapted to provide a plurality of modes of operation, which can be selected from the group consisting of a clock mode, a timing and frequency reference mode, A group of power saving modes and a pulse mode.

For a reference mode, the present invention may further include: a synchronization circuit coupled to the mode selector; and a controlled oscillator coupled to the synchronization circuit and adapted to provide a third signal; wherein In the timing and reference modes, the mode selector is further adapted to couple the output signal to the synchronization circuit to control the timing and frequency of the third signal. The synchronization circuit can be a delay locked loop, a phase locked loop, or an injection locking circuit.

These and other embodiments are discussed in further detail below. Numerous additional advantages and features of the present invention will become apparent from the Detailed Description of the Drawings.

While the present invention is susceptible to various embodiments of the various embodiments of the embodiments of the present invention The specific examples and embodiments of the invention are not intended to be limited.

As indicated above, various embodiments of the present invention provide a number of advantages, including the ability to integrate a highly accurate (under PVT and aging), low jitter, free running, and self-referencing clock generators and/or timing and The frequency reference is connected to other circuits, such as those shown in FIG. 1 is a block diagram depicting a system embodiment 150 in accordance with one example of the teachings of the present invention. As shown in FIG. 1, system 150 is a single integrated circuit having a single chip with another (or second) circuit 180 and an interface (I/F) (or input/output (I/O) circuit) 120. A clock generator and/or timing/frequency reference 100 of the present invention is integrated. The interface 120 will typically provide power (such as from a power supply (not shown), ground, and other lines or busses to the clock generator 100, such as for calibration and frequency selection. As shown, one or more output clock signals are provided on the bus bar 125 as a plurality of frequencies, such as: a first frequency ( f ₀ ), a second frequency ( f ₁ ), etc. Up to an (n+1) _th frequency ( f _n ). In addition, a power saving mode (or low power mode (LP)) is also provided (again, above bus bar 125). The second circuit 180 (or I / F 120) can also provide input to clock generator 100 when, for example, through the selection signal (S _0, S ₁ to S _n) and one or more calibration signal (C _0, C ₁ To C _n ). Alternatively, the selection signals (S ₀ , S ₁ to S _n ) and the one or more calibration signals (C ₀ , C ₁ to C _n ) are permeable to the interface 120 (such as above the bus bar 135) and together with the power supply ( Directly above line 140) and ground (above line 145) are provided directly to clock generator 100.

In addition to the low power mode, the clock generator and/or timing/frequency reference 100 has additional modes as further detailed below. For example, in a clock mode, device 100 will provide one or more clock signals (as output signals) to second circuit 180. The second circuit 180 can be any type or type of circuit, such as a microprocessor, digital signal processor (DSP), radio frequency circuit, or any other circuit that can utilize, for example, one or more output clock signals. Moreover, for example, in a timing or frequency reference mode, the output signal from device 100 can be a reference signal, such as a reference signal for synchronization of a second oscillator. Thus, the term "clock generator and/or timing/frequency reference" will be used interchangeably herein, and it is understood that the clock generator will also typically provide a square wave signal, which may A timing/frequency reference is provided or not, which can instead utilize a substantially sinusoidal signal. Moreover, as further detailed below, various embodiments of the present invention also provide a pulse mode in which the output signals from the clock generator and/or the timing/frequency reference device 100 are bursts or intervals. (interval) is provided, for example, to improve the processing efficiency of instructions and lower power consumption.

It should be noted that, for example, various signals, voltages, parameter-independent current sources, and the like, are referred to as "substantially" sinusoidal or square wave signals, substantially fixed control voltages, or substantial Voltage or current independent of parameters. This is a consideration of various introduced variations, sources of noise, and other distortions that may cause such signals, voltages, or currents to be substantially different from the preferred depictions seen in textbooks. For example, as discussed in further detail below, exemplary "substantial" square wave signals are depicted in Figures 15A and 15B and exhibit various distortions such as undershoot, overshoot, and others. The change, but still regarded as a very high quality square wave.

Several important features of the present invention are in system 150. First, a highly accurate, low jitter, free running and self-referencing clock generator 100 is monolithically integrated with other (second) circuits 180 to form a single integrated circuit (system 150). This is a significant contrast to conventional techniques because the reference oscillator in the prior art is used to provide a clock signal, such as a crystal reference oscillator, which cannot be integrated with other circuits and is off-chip (off) -chip), which is a second and separate component that must be connected to any other circuit through a circuit board. For example, in accordance with the present invention, system 150 (including clock generator 100) can be fabricated with other second circuits using conventional CMOS (Complementary Metal Oxide Semiconductor), BJT (dual-carrier connection) Surface transistors), BiCMOS (dual-carrier and CMOS), or other manufacturing technologies used in modern IC manufacturing.

Second, the present invention does not require a separate reference oscillator. Rather, in accordance with the present invention, the clock generator 100 is self-referential and free-running such that it is not referenced or locked to another signal. For example, conventional techniques are typically synchronized to a phase locked loop (PLL), delay. Lock the loop (DLL) or lock to a reference signal via injection. However, embodiments of such examples can be utilized as such a reference oscillator that generates a frequency reference signal, for example, which can then be locked by one or more phase locked loops or delay locked loops.

Third, the clock generator 100 provides a plurality of output frequencies and a power saving mode so that the frequency system can be switched at a low delay and in a non-surge manner. For example, the second circuit 180 can be switched to a power saving mode, such as: a battery or a lower frequency mode, and request (via the selection signal) a lower clock frequency to minimize power consumption, or A low power clock signal is requested to enter a sleep mode. As discussed in more detail, such frequency switching is provided at a substantially negligible delay with low delay introduced to prevent glitch (proportional to the number of glitch prevention stages utilized) ), which uses only a few clock cycles, rather than the thousands of clock cycles required to change the output frequency from the PLL/DLL.

Additional embodiments are also provided for generating a plurality of frequency reference signals (whether sinusoidal or square), such as one or more clock signals or a reference frequency source. In an exemplary embodiment, the clock/frequency reference of the present invention is coupled to one or more phase locked loops ("PLLs") or delay locked loops ("DLLs") to provide the selected frequencies. The corresponding multiple output reference signals. Embodiments of these examples are typically programmable via control signals or stored coefficients, for example, to adjust the frequency-division factor of the PLL or DLL for corresponding frequency selection.

In addition, new operational modes are available under the extremely high output frequencies provided by the clock generator and/or timing/frequency reference 100 discussed below. For example, the start-up time of the clock is actually or substantially negligible, and the allowable clock generator and/or the timing/frequency reference 100 can be started and stopped repeatedly, for example, completely shut down for power saving or Pulsed. For example, it is not a continuous operation, and the clock generator and/or timing/frequency reference device 100 can operate in a relatively short, discrete interval or burst of periodic or aperiodic (also That is, pulsed) for processing by instructions made by the second circuit 180, such as a processor. As discussed in more detail, this pulsed operation provides power savings under fast start-up times because each microwatt (mW) of power consumption processes more instructions (millions of instructions per second or MIPS). Moreover, such pulse modes can be utilized, among other uses, to periodically synchronize a second clock or oscillator. Accordingly, the clock generator and/or timing/frequency reference 100 (and other embodiments discussed below) have a plurality of modes of operation including: a clock mode, a timing and/or frequency reference mode , a power saving mode, and a pulse mode.

Fourth, as discussed in more detail later, the clock generator and/or timing/frequency reference 100 includes highly accurate features characterized by variations in process, voltage, temperature ("PVT") and aging. Frequency is generated. These characteristics include frequency tuning and selection, as well as compensation for frequency variations that can be attributed to temperature and/or voltage variations, process variations, and IC aging.

Fifth, the clock generator and/or timing/frequency reference 100 produces a significant and relatively high frequency, such as in the range of hundreds of MHz and GHz, which is then divised to a plurality of lower frequencies. . Each such division by "N" (a rational number in the ratio of integers) results in significant noise reduction, where the phase noise is reduced by a factor of N and the phase noise power is reduced by a factor of ^two . Thus, the clock generator of the present invention results in significantly lower relative period jitter than is available to other oscillators that produce their output either directly or through frequency multiplication.

These features are described in more detail in FIG. 2, which is a block diagram depicting an embodiment of an apparatus 200 including a frequency controller 215 in accordance with a first example of the teachings of the present invention. As shown in FIG. 2, apparatus 200 is a clock generator and/or a timing/frequency reference that provides one or more output signals, such as: one having a plurality of frequencies (using frequency selector 205) The selected clock or reference signal. The apparatus (or clock generator) 200 includes an oscillator 210 (having a resonant element), a frequency controller 215, a frequency divider 220, a mode selector 225, and the frequency selector 205 described above. According to the present invention, based oscillator 210 generates a signal having the relatively high frequency f _0. Due to the above-described changes in PVT or aging, the frequency controller 215 is utilized to frequency select or tune the oscillator 210 such that the oscillating frequency f _{0 can be} selected from a plurality of potential oscillating frequencies, that is, the frequency controller 215 Provides an output signal with an accurate frequency at PVT and aging changes.

For example, given these PVT variations, the output frequency from an oscillator (such as oscillator 210) can vary by ±5%. For some applications, such as those utilizing a ring oscillator, such frequency variability may be acceptable. However, in accordance with the present invention, greater accuracy of the clock generator 200 is desirable, especially for more sensitive or complex applications, such as providing microprocessors for integration, micro-control Clock signal of the device, digital signal processor, communication controller, etc. Thus, the frequency controller 215 is utilized to adjust for such PVT variations such that the output frequency from the oscillator is the selected or desired frequency f ₀ having a variation size that is reduced by several orders of magnitude, Such as: ±0.25% or lower, and has a relatively low jitter.

Various exemplary embodiments of frequency controller 215 in accordance with the teachings of the present invention are depicted in detail below. For example, please refer to FIG. 21, which is a block diagram depicting a frequency controller 1415 and apparatus 1400 in accordance with an exemplary embodiment of the present invention. An oscillator (resonator 310 and continuous amplifier 305) provides a resonant frequency f _{0 .} The first output signal. The frequency controller 1415 of the example is coupled to the oscillator and modifies the resonant frequency f ₀ in response to a second signal (eg, a second signal provided by the one or more sensors 1440). The example frequency controller 1415 includes one or more of the following components: a transconductance modulator 1420, a variable parameter modulator (or controller) 1425 (eg, one or more of the following controlled The capacitor module or the controlled reactance module), the process (or other parameter) modulator (or compensator) 1430, the voltage compensator 1455, the coefficient register 1435, and may also include an aging change compensator 1460. The frequency controller 1415 may also include one or more sensors 1440, an analog to digital (A/D) converter ("ADC") 1445, and a control logic block 1450, in accordance with selected embodiments. For example, the temperature dependent current source I(T) (or more generally yI(x)) generator 415 depicted in FIG. 4 effectively functions as a temperature sensor in accordance with the present invention, which provides A corresponding output current is changed as a function of the ambient or junction temperature. Such temperature dependent output current can be converted to a digital signal by an A/D converter (ADC) 1445 and utilized to provide corresponding coefficients (stored in register 1435) for the frequency controller Various modulators or compensators 1420, 1425, 1430, 1455, and 1460 of 1415 are utilized to control the resonance in accordance with various parameters (eg, a variable operating temperature or a variable process) (or Output) frequency f ₀ . In other embodiments, such temperature dependent output currents are provided directly (as a second signal without intermediate A/D conversion) to various modulators, for example, being provided to each other. A modulator 1420 and a variable parameter modulator (or controller) 1425. Thus, the modulators are, for example, by modifying the current through the resonator 310 and the sustain amplifier 305, or by modifying the effective reactance or impedance (eg, capacitance) that is coupled to the resonator 310 and effectively forms part of the resonator 310. , inductance or resistance) to modify the resonant frequency f ₀ . For example, the effective reactance (or impedance) can be modified by coupling a fixed or variable capacitance to the resonator 310, or decoupling a fixed or variable capacitor from the resonator 310, or The magnitude of one or more reactances coupled to the resonator is modified, for example, by modifying a control voltage or other continuous control parameter.

In various embodiments described below, the transconductance modulator 1420 and the variable parameter modulator (or controller) 1425 are typically implemented to utilize a temperature parameter such that changes in operating temperature next to provide a substantially stable resonance frequency f _0. Those skilled in the art will appreciate that these modulators can be implemented as a function of other variable parameters (e.g., due to process-induced changes, voltage changes, aging, and other frequency changes) or in response to The variable parameters provide a substantially stable resonant frequency f ₀ .

Referring again to Figure 2, in order to improve performance and reduce jitter (noise) and other interference, the present invention does not use to generate a low frequency output and multiply it to a higher frequency (as with PLL and DLL). The present invention produces a relatively high frequency output f ₀ which is then divised to one or more lower frequencies ( f ₁ to f _n ) using the frequency divider 220. A clock signal having one or more frequencies from a plurality of frequencies of the frequency divider 220 can then be selected using the frequency selector 205. As noted above, such frequency selection is provided without surge and low delay, which provides extremely fast and surge free frequency switching. In addition, a plurality of modes of operation are also provided using mode selector 225.

3 is a block diagram showing in greater detail a device embodiment in accordance with a second example of the teachings of the present invention as a clock generator and/or timing/frequency reference 300. Referring to FIG. 3, the clock generator and/or the timing/frequency reference device 300 includes a resonator 310 and a continuous amplifier 305 (constituting an oscillator 395), a temperature compensator (or modulator) 315, and a a process variation compensator (or modulator) 320, a frequency calibration module 325, a voltage variation compensator (or modulator) 380, an aging (time) variation compensator (or modulator) 365, one or A plurality of coefficient registers 340, and depending on the selected embodiment, may also include: a sensor 385, an analog to digital converter ("ADC") 390, a frequency divider and a square wave generator 330. A voltage isolator 355, a resonant frequency selector 360, an output frequency selector 335, a mode selector 345, and a low delay start module 399. The continuous amplifier 305, the temperature compensator 315, the process variation compensator 320, the voltage isolator 355, the voltage variation compensator 380, the aging change compensator 365, the resonant frequency selector 360, and the frequency calibration module 325 are often included in Among a frequency controllers, such as: frequency controller 349 (or 215 or 1415). Alternatively, the sustain amplifier 305 and the resonator 310 can be considered to constitute an oscillator 395, and various controller components (eg, temperature compensator 315, process variation compensator 320, voltage isolator 355, voltage variation compensation) One or more of the 380, the aging change compensator 365, the resonant frequency selector 360, the sensor 385, the ADC 390, and the frequency calibration module 325 are included in a frequency controller 349 (or 215 or 1415). )within. It should also be noted that a square wave generator (block 330) may not be required in a timing or frequency reference embodiment.

The resonator 310 can be any type of resonator that stores energy, for example, coupled to form an inductor (L) and a capacitor (C), one of the LC resonant circuits, wherein the LC resonant circuit has a plurality of LCs A selected configuration of the resonant circuit configuration, either electrically or electromechanically equivalent to an inductor coupled to a capacitor, or the art is typically represented as an inductor coupled to a capacitor. Such an LC resonator is depicted as resonator 405 in FIG. Other resonators are considered equivalent except for LC resonators, and are within the scope of the present invention; for example, resonator 310 can be a ceramic resonator, a mechanical resonator (eg, XTAL), A microelectromechanical ("MEMS") resonator, or a film bulk acoustic resonator. In other examples, various resonators may be represented by electrical or electromechanical analogy to LC resonators and are also within the scope of the present invention. In the exemplary embodiment, the LC resonant circuit has been utilized as a resonator to provide a high Q value for a complete integrated solution.

The sustain amplifier 305 provides startup and continued amplification for the resonator 310. Temperature compensator 315 provides frequency control for resonator 310 to adjust the oscillating frequency based on changes due to temperature, and in selected embodiments, depending on the degree of control desired or required, temperature compensator 315 may Control over current and frequency is included, as described below for the selected embodiment. For example, the temperature compensator 315 can include one or both of the transconductance modulator 1420 of FIG. 21 and the variable parameter modulator 1425, wherein the modulators 1420 and 1425 are both implemented to respond to temperature changes. . Similarly, process variation compensator 320 provides frequency control for resonator 310 to vary process variations inherent to semiconductor fabrication techniques: process variations within a particular plant (eg, batch or operational variations, for a particular Variations in the wafer, as well as grain-to-grain changes in the same wafer) and process variations between different plant-to-factor processes (eg, 130 nm and 90 nm processes), To adjust the oscillation frequency. Voltage variation compensator 380 can be utilized to maintain a stable output frequency under supply voltage variations as well as other voltage variations. The aging change compensator 365 can be utilized to maintain a stable output frequency as the circuit component undergoes corresponding changes over a period of time as the IC ages. Based frequency calibration module 325 may be utilized to occur from between the resonator 310 in a plurality of oscillation frequency fine tuning, and selecting a desired output frequency f _0, that is: from the plurality of available frequency selection potential or Output frequency f ₀ . In selected embodiments, coefficient register 340 is utilized to store coefficient values for use in various examples of compensator and calibration embodiments, i.e., as described in greater detail below.

As noted above, the frequency controller 349 can also include one of the plurality of sensors 385 and an analog to digital converter (ADC) 390 in selected embodiments. In addition, many other compensators and modulators in the frequency controller also include components that function as sensors, such as temperature dependent current sources and other voltage change detectors. In addition to being utilized to generate a plurality of various coefficients stored to provide control over various switching elements, switching a controlled reactance module (described below) to the resonator 310 (as a discrete form of control), and In addition to the effective amount of reactance (a continuous form of control) provided by the coupling or switching to the reactance of the resonator 310, various sensors, compensators, and modulators can also be utilized for the resonator 310. The resonant frequency provides other forms of continuous control. As depicted and described below, various continuous outputs from sensors, current generators, control voltages, etc., function as control signals within the scope of the present invention. For example, various control voltages (which may vary with a selected parameter (eg, temperature) or may be fixed relative to a selected parameter) act as control signals that are used to modify utilization The corresponding size of the controlled capacitor module made of the container.

In addition to temperature and process compensation, voltage isolator 355 provides isolation from changes in voltage (such as from a power supply) and can be implemented independently or as part of other components, such as temperature compensator 315. Part of it. In addition to frequency adjustments for such changes in PVT and aging, the resonant frequency can also be independently selected by resonant frequency selector 360 for obtaining a selected frequency from one of the available frequency ranges.

For the generation of the clock signal, the clock generator 300 uses a frequency divider (in the module 330) to convert the output oscillation frequency f ₀ into a plurality of lower frequencies ( f ₁ to f _n ), and uses one side. The wave generator (also in module 330) converts a substantially sinusoidal oscillating signal into a signal for a substantial square wave of the clock application. The frequency selector 335 then provides a selection of one or more of the plurality of available output signals, and the mode selector 345 can also provide a selection of modes of operation, such as providing a low power mode, a pulse mode, A reference mode, and so on. Using these components, the clock generator 300 provides a plurality of highly accurate (under PVT), low jitter, and stable output frequencies f ₀ , f ₁ to f _n , which are caused by such PVT variations. Minimize to negligible frequency drift, thus providing sufficient accuracy and stability for sensitive or complex applications, as described above.

4 is a schematic block diagram depicting a higher order of a frequency controller, oscillator, and frequency calibration embodiment in accordance with an example of the teachings of the present invention. As shown in FIG. 4, the resonator is implemented as a resonant LC resonant circuit 405, and the frequency controller is implemented as a plurality of components, namely: a negative transconductance amplifier 410 (used to implement the sustaining amplifier), a temperature responsive (or temperature dependent) current generator (I(T)) (or more generally yI(x)) 415 in response to any such parameter "x", a temperature responsive (or The temperature dependent (f ₀ (T)) compensation module 420, a process variation compensation module 425, and a frequency calibration module 430. The various temperature responsive or temperature dependent modules 415 and 420 are either temperature sensitive or responsive to temperature variations and provide corresponding adjustments such that the resonant frequency is such a PVT and aging change. Stable and accurate.

The resonant LC resonant circuit 405 and a continuous amplifier are equally described as a harmonic oscillator or harmonic core, and all such variations are within the scope of the present invention. It should be noted that although the resonant LC resonant circuit 405 is an inductor 435 connected in parallel with a capacitor 440, other circuit topologies are known and equivalent to the foregoing, such as: an inductor in series with a capacitor. . Another such equivalent topology is illustrated in FIG. Moreover, as noted above, other types of resonators can also be utilized and are each considered to be equivalent to the resonant LC resonant circuit described herein. Furthermore, as discussed in more detail below, additional capacitors and/or inductors (both fixed and variable (and more generally referred to as impedance or reactance (or reactive components)) are distributed across various modules. It is part of the LC resonant circuit 405 that effectively forms resonance and is utilized as part of the frequency controller of the present invention. In addition, the corresponding resistors (resistive components of various impedances) R _L 445 and R _C 450 are individually shown, but it should be understood that they are inherently within the inductor 435 and the capacitor 440, respectively, which is attributed to The portion of the fabrication, rather than the individual components of the individual inductor 435 and capacitor 440 or separate components. Instead, such additional or inherent (parasitic) resistances may also be included as part of the compensation for PVT variations, as depicted and described below with reference to FIG.

The size of the inductor 435 and capacitor 440 of the resonant LC resonant circuit or oscillator 405 is set to substantially or approximately provide the selected oscillating frequency f ₀ , or an oscillating frequency range around f ₀ . In addition, inductor 435 and capacitor 440 may be sized to have or conform to the area requirements of the IC layout, with higher frequencies requiring less area. Those who are familiar with this technology will recognize that: , but only as a first-order approximation, as discussed below, such as impedances R _L and R _C , any additional resistors, and other factors such as temperature and process variations and other distortions affect f ₀ , and may It is included in the approximation of the second and third orders. For example, inductor 435 and capacitor 440 may be sized to produce a resonant frequency in the range of 1 to 5 GHz; in other embodiments, higher or lower frequencies may be desirable, and all These frequencies are all within the scope of the invention. In addition, inductor 435 and capacitor 440 can be fabricated using any semiconductor or other circuit processing technique and can be, for example, CMOS compatible, bipolar junction transistor compatible, while in other embodiments, inductor 435 and capacitor 440 can use silicon-on-insulator (SOI), metal-insulator-metal (MiM), polysilicon-insulator-polysilicon (PiP), gallium arsenide (GaAs), strained-silicon, semiconductor Bonding techniques, or fabrication based on MEMS-based techniques, are also by way of example and not limitation. It should be understood that all such embodiments and embodiments are within the scope of the invention. Furthermore, other resonator and/or oscillator embodiments may be utilized in addition to or in place of the resonant LC resonant circuit 405 and are also within the scope of the present invention. As used herein, "LC resonant circuit" shall mean and refer to any and all circuit arrangements, configurations or topologies of inductors and capacitors that may provide oscillation, regardless of how they are implemented. It should be noted that the ability to fabricate the oscillator 405 using conventional processes such as CMOS technology allows the clock generator to be integrated with other circuits, such as the second circuit 180, and fabricated monolithically, thus providing the present invention. A significant advantage.

In addition, the capacitor 440 shown in FIG. 4 is only a part of the overall capacitance determined by the resonance and frequency of the resonant LC resonant circuit 405, and is a fixed capacitor. In selected embodiments, for example, the fixed capacitance can represent approximately 10% to 90% of the total capacitance of the oscillator. Alternatively, if desired, the capacitor 440 can also be implemented as a variable capacitor. As discussed in more detail, the overall capacitance is dispersed such that additional fixed and variable capacitances are selectively incorporated within the clock generator and/or timing/frequency reference 300, and for example by frequency The components of the controller (215, 1415) (eg, temperature responsive frequency ( f ₀ (T)) compensation module 420 and process variation compensation module 425) are provided to provide a selected resonant frequency f ₀ and allow resonant frequency f ₀ is no substantial changes with respect to temperature and process.

In the selected embodiment, the inductor 435 has been fixed, but may be implemented in a variable manner or as a combination of one of a fixed and a variable inductor. Therefore, those skilled in the art will recognize that the detailed discussion of fixed and variable capacitance is similarly related to the choice of inductance for frequency tuning and temperature and process non-dependency. For example, different inductive systems can be switched in and out of the oscillator to similarly provide tuning. In addition, the inductance of a single inductor can also be modulated. Accordingly, all such inductance and capacitance variations are within the scope of the present invention and are depicted as switchable of the controlled impedance module 1305 of the example of FIG. 20 and the controlled reactance module 1805 of FIGS. 25-27. Variable and/or fixed reactive components or components.

As also shown in FIG. 4, the resonant LC resonant circuit 405 and the resulting output signal (referred to as the first (output) signal at nodes or lines 470 and 475) are differential signals and provide common mode rejection. (common-mode rejection). Other configurations, including: non-differential or other single-ended configurations, are also within the scope of the present invention. For example, in a single-ended configuration, various modules (eg, 485, 460) would only require one of the entities, rather than two entities for a balanced configuration as shown. Similarly, other components and features discussed below, such as frequency dividers, will also have a single-ended configuration rather than a differential configuration. In addition to the differential LC oscillators shown in Figures 6 and 8, these additional exemplary LC oscillators (differential and single-ended) are discussed below with reference to Figures 31-37. Moreover, the various embodiments illustrated are MOSFET transistors (metal oxide semiconductors) that utilize various forms (eg, CMOS, accumulation mode MOSFET ("AMOS"), inversion mode MOSFET ("IMOS"), etc.) Field effect transistors); other embodiments are also available, such as the use of dual carrier junction transistors ("BJT"), BiCMOS, and the like. All such embodiments are considered equivalent and are within the scope of the invention.

The negative-based transconductance amplifier 410 is selected to ON resistance through the transconductance (g _m) of the modulator and its resistor to provide temperature compensation. The mutual conductance ( g _m ) modulation can also be used independently for frequency selection. Another significant advantage of the present invention is the choice of negative transconductance amplifier 410 to provide both start-up and continuous amplification because the amplitude and frequency of the oscillation are both affected by the mutual conductance of the sustain amplifier, providing amplitude in addition to providing temperature compensation. Modulation and frequency fine tuning (or tuning). The negative transconductance amplifier 410 will inject current into the resonant LC resonant circuit 405 in response to a voltage "v" across the resonant LC resonant circuit 405 (as shown across nodes 470 and 475) (and more specifically Above capacitor 440). Next, this current injection will change (and distortion) voltage waveform (because the voltage of the current of integration), which leads to a change or a change in the frequency, which is approximately inversely proportional to the transconductance g size _m of, i.e., as in FIG. 5A Shower. It should be noted that this mutual conductance is a negative value because the gain is provided to counteract the inherent loss of the resonant element. Therefore, whenever a "transimpedance amplifier" is used in this document, it should be understood to mean and is only an abbreviation for "negative transconductance amplifier". Next, the mutual conductance is also a function of the bias current, substantially (probably) proportional to the square root of the current through the amplifier 410 (yI(x)) (for the MOSFET), and is substantially (probably) proportional to The current of amplifier 410 (yI(x)) (for BJT) is temperature dependent, causing it to be a waveform distortion dependent on temperature and bias current, as shown in Figure 5B. Furthermore, as shown in FIG. 5C, the oscillation frequency is also a function of the mutual conductance of the continuous negative transconductance amplifier 410 and provides a selection of the oscillation frequency. Furthermore, in addition to temperature dependence (eg, I(T)), the current can also be changed to a function of other parameters or variables (and thus more generally referred to as I(x)), such as: voltage or external Tuning, and may also be such as being amplified by a factor "y" (as described later); therefore, the current is referred to as "yI(x)".

As noted above, more generally, the variable current yI(x) can be utilized as a sensor or as part of a sensor, such as one or more sensors 1440 or transconductance of FIG. The modulator 1420 is also the sensor 1815 of FIG. For example, when this variable current is provided by I(T) generator 415 such that the supplied current is a function of temperature (parameter or variable "x" = temperature parameter "T"), I(T) Generator 415 acts thereby as a temperature sensor and can be utilized in the exemplary embodiment, for example, by the frequency controller (215, 349, 1415) to adjust the resonance in response to temperature variations. Frequency f ₀ . For example, the transconductance modulator 1420 of FIG. 21 can include such a temperature (or other parameter) responsive current source 415 (which also functions as a sensor 1440) that provides current to a continuous amplifier 305.

Breakthrough based important innovations of the present invention comprises: advantageously utilize the potential of such distortion, the value for f ₀ to generate the selected oscillator to provide frequency compensation, frequency modulation, and continuously through the transconductance amplifier of the modulation . Thus, as will be discussed in more detail later, first, the mutual conductance can be modified or changed for frequency selection, and second, the current yI(x) can be modified by substantially instantaneous or near instantaneous. To compensate for such frequency changes due to temperature, voltage, process or aging. In accordance with the present invention, the selected frequency f ₀ and its stability with respect to temperature variations can be determined by the appropriate choice of transconductance g _{m and} the choice of I(T). In other words, according to the present invention, the bias current is made temperature dependent system, such as I (T) (or, more generally are yI (x)), which then influence the transconductance g _m, and thus affect the oscillation frequency f _0. This method can also be utilized for other variables such as voltage variations, process variations, or aging changes.

6 is a circuit diagram depicting a negative transconductance amplifier (410), a temperature responsive current generator (I(T) 415), and a resonator (405) embodiment of an LC resonant circuit, in accordance with an example of the teachings of the present invention. As shown in FIG. 6, the resonant LC resonant circuit 500 is coupled to a negative transconductance amplifier that is implemented as a complementary cross-coupled pair of amplifiers 505 (by transistors M1, M2, M3). And M4), then coupled to a temperature responsive current generator (I(x) by a voltage isolator 510 (implemented as a current mirror (transistors 525A and 525B) and interchangeably referred to herein) )) 515. Current mirror 510 (voltage isolator) can also be implemented in a cascade topology (520A and 520B), such as to provide improved stability with respect to variations in the power supply and to isolate the oscillator from the power supply (voltage isolation ). The temperature responsive current generator 515 can be implemented to utilize CTAT (complementary to absolute temperature), PTAT (proportional to absolute temperature), or PTAT ² (such as shown in Figures 7A, 7B, and 7C, respectively). The topology is proportional to the absolute temperature squared, and the combination of CTAT, PTAT, and PTAT ² shown in Figure 7D. In various examples, the current I(T) (or yI(x)) injected into the negative transconductance amplifier (the amplifier of the complementary cross-coupled pair) 505 is temperature dependent, such as increasing the current (PTAT or PTAT ^2). Or reduce the current (CTAT) as a function of the increased temperature, as shown. For example, as shown in FIG. 7D, one or more combinations of such temperature responsive current generators can also be implemented such as CTAT in parallel with PTAT.

The choice of a particular temperature responsive or temperature dependent current generator is also a function of the process utilized; for example, CTAT can be used in the TSMC process. More generally, since different manufacturers utilize different materials, such as aluminum or copper, R _L will generally be different, resulting in different temperature coefficients, which are then used to change the temperature coefficient of the oscillator. There is a need to differ in I(T) compensation. Correspondingly, providing a effectively flat frequency response as a function of temperature may require different ratios of CTAT, PTAT, and PTAT ² compensation. Not separately shown, the various temperature responsive current generators shown in Figures 7A, 7B, 7C, and 7D can include a companion circuit. In addition, the cell system including the selected temperature responsive current generator configuration can be biased differently, such as for the illustrated example topology, for CTAT (M7 and M8) and PTAT ² (M13 and M14) It is biased to the strong reversal zone, while for PTAT (M9 and M10) and PTAT ² (M11 and M12) it is in the subthreshold.

8 is an illustration of another example of a negative transconductance amplifier, a temperature responsive (or temperature dependent) current generator (I(T) or I(x)) and an LC resonant circuit oscillator in accordance with the teachings of the present invention. Circuit block diagram. As shown in FIG. 8, the resonant LC resonant circuit 550 has a different topology than the foregoing, but is also coupled to a negative transconductance amplifier that is implemented as a complementary The cross-coupled pair of amplifiers 505 (transistors M1, M2, M3, and M4) are then coupled to a temperature responsive (or temperature dependent) current generator through a plurality of current mirrors 510 (or 520) and 530 (I(T) or I(x)) 515. As shown, a plurality of current mirrors are utilized to continuously provide gain and increase the current I(T) entering the negative transconductance amplifier 505 and the resonant LC resonant circuit 550. A tail element (eg, transistor M6 in FIG. 6) in the current mirror that supplies current to node B and drives the negative transconductance amplifier is often selected as a PMOS element, and thus may require several stages mirror (as illustrated) to provide an input to the PMOS current mirror g _m amplifier. PMOS systems are often chosen because in modern CMOS processes, PMOS components are often buried channel components, which are known to exhibit less flicker than NMOS components that are equally sized and similarly biased. Noise. The reduced flicker noise in the tail-end component reduces the phase noise and jitter of the oscillator because the flicker noise is upconverted to near the oscillation frequency due to the nonlinear active components in the circuit.

As indicated above, the portion of current mirror 510 or 520 (or other circuitry) that supplies current to negative transconductance amplifier 505 should have a high impedance at its output to reduce the frequency drift of the power supply, such as by using long electrical current. Crystal geometry and cascode configuration to increase output resistance and provide significant stability to Node B. In addition, a shunt capacitor 570 can also be utilized to filter and thereby reduce flicker noise from various tail end components.

Depending on the application chosen, the use of a negative transconductance amplifier 505 with its I(T) (or yI(x)) bias provides sufficient frequency stability for additional frequency control in this application. The components may not be necessary or desirable. However, in other embodiments, additional accuracy and smaller frequency drift may be provided using one or more of the components discussed in greater detail below.

In addition to providing a temperature dependent current yI(x) (or I(T)), the various transistors M1, M2, M3, and M4 each have a resistance associated with one of the on periods, which may also tend to oscillate. Causes frequency distortion and frequency drift during the period. In each half cycle, not M1 and M4 are turned on, that is, M2 and M3 are turned on. This resistance is also temperature dependent. Therefore, the transistors M1, M2, M3 and M4 should be sized (width and length) to compensate for these frequency effects simultaneously. It should be noted that the current flowing into the resonant LC resonant circuit 405 must be sufficient to sustain oscillation (as shown in Figure 5C), and the result will have a minimum which may limit the permeable transconductance amplifier 410 (or 505) The degree or ability of frequency control that is easily implemented by the temperature dependent current generator 415 (or 515). Therefore, the size decisions of I(T) and transistors (M1, M2, M3, and M4) should be selected together to provide an oscillating start to account for the maximum current under power consumption constraints, in conjunction with the selected IC area and layout. . For example, choose to provide a transconductance g _m is substantially sufficient current to ensure the start and continues to oscillate, which has a frequency characteristic of the frequency reduced with increasing temperature, followed by a decision transistors M1, M2, M3 and M4 The size is large enough so that the frequency is independent of temperature or increases with temperature, and then the frequency-temperature relationship is fine-tuned by the appropriate choice of I(T). In the selected exemplary embodiment, under PVT, this results in a frequency accuracy of about ±0.25% to 0.5%, which may be quite sufficient for many applications.

Refer again to FIG 4, additional compensation module was also used as a frequency controller (215,349,1415) portion, in order to provide greater control and accuracy of the resonance frequency f _0, such as: which may be used Applications requiring greater accuracy and less variation (or frequency drift), or some techniques that do not allow the aforementioned techniques to provide sufficient accuracy under PVT or aging changes, such as: providing approximately ±0.25% Or better frequency accuracy. In such cases, a temperature dependent (or temperature responsive) frequency ( f ₀ (T)) compensation module 420 can be utilized, such as: the example temperature responsive frequency ( f ₀ (T)) compensation mode Group 420. For example, the module 420 can be implemented using a controlled (or controllable) capacitive module 485 coupled to respective sides or tracks of the resonant LC resonant circuit 405 (line 470). And 475), and respectively under common control, the common control system is composed of a first complex number ("w") switching coefficients ( p ₀ to p _{(w - 1)} ) (storage 495) and a voltage the controller (V _{C T R L)} 480 is provided, the voltage controller 440 to provide system ( "x") a switching coefficient (q ₀ to q _{(x - 1))} by a second complex (register 455) is determined A representative example of a control voltage is illustrated in Figures 9 and 10. (The terms "controlled" and "controllable" are used interchangeably herein). Additional exemplary embodiments are depicted in FIG. 20, which depicts an example of a controlled impedance module 1300 that is utilized in a frequency-temperature compensation module, for example, instead of being controlled in module 420. (or controllable) capacitor module 485, or an additional module in addition to the capacitor module 485; in Figure 22, another variant of the controlled capacitor module 485 is controlled The capacitor module 1500 has a plurality of temperature-dependent control voltages or other parameter-dependent control voltages (generated as shown in FIG. 23 or 26); in FIG. 25, it depicts a plurality of controlled reactance modules. 1805, the controlled reactance module 1805 is switched in and out (coupled to or from the resonator) in response to a control signal from the control logic 1810 and the sensor 1815 (including feedback from the oscillator) Resonator decoupling; in Figure 26, it depicts a plurality of controlled reactance modules 1805 that are switched in response to control signals (continuous) or coefficients (discrete) In and out and/or switched to a control voltage; and in Figure 27, A plurality of controlled reactance module 1805, the plurality of line controlled reactor module 1805 in response to the control signal is switched to compensate for voltage variations. There are several different types of switching that can be utilized, for example, coupling or decoupling a reactance or impedance to the resonator, or for example switching the reacted reactance or impedance to a selected control voltage or other control signal.

9 is a circuit diagram depicting a first controllable capacitive module 635, which may be utilized as a controlled (or controllable) capacitive mode in a frequency-temperature compensation module 420, in accordance with one example of the teachings of the present invention. Group 485 (and attached to each side of the resonant LC resonant circuit 405 (node or lines 470 and 475)). , The fixed binary weighted capacitive capacitor module 640 of the controlled (or controllable) capacitor module 635 by a complex system or a row of the array (w) a switchable (C _f) 620 binary FIG. Or other differentially weighted variable capacitor (varactor) (C _v ) 615. Any type of fixed capacitor 620 and variable capacitor (varactor) 615 can be utilized; in selected embodiments, varactor 615 is an AMOS (accumulated mode MOSFET), IMOS (reverse mode MOSFET), and/or Face/diode varactor. Each switchable capacitive module 640 has the same circuit layout, and each difference is a binary weighted capacitor, wherein the switchable capacitive module 640 ₀ is a capacitive, switchable capacitive module having one unit. 640 ₁ is a capacitor with two units, and so on, the switchable capacitive module 640 _{( w - 1 )} is a capacitor having 2 ^{( w - 1 )} units, and each unit represents a specific capacitance Or value (typically in femtofarad (fF) or picofarad (pF)). As noted above, other methods of differential weighting are equally applicable, such as linear or binary, and may also be provided by switching the reactance to a selected control voltage to provide such differential weighting. Thereby increasing or decreasing its effective reactance.

Within each switchable module 640, each fixed and variable capacitance system is initially equal, wherein the variable capacitance is allowed to change in response to the control voltage provided to node 625. The control voltage is then changed with temperature or another selected variable parameter, which results in that the overall capacitance or total capacitance provided by the controlled capacitance module 635 also changes to temperature (or Is one of the other parameters) and it is then utilized to change the resonant frequency f ₀ . In other selected embodiments, any of a plurality of control voltages (including static control voltages) can be utilized to provide other types of compensation, as described below. Further, in the respective capacitive switchable module 640, the fixed capacitance C _f or a variable capacitance C _v (not both) lines using switching coefficient p ₀ to P _{(w - 1)} is switched into the circuit. For example, in the embodiment chosen, for a particular or selected module 640, when the corresponding "p" coefficient of a logic high (or high voltage), the corresponding fixed capacitance C _f Is switched into the circuit, and the corresponding variable capacitor C _v is switched away from the circuit (and depending on whether the component is AMOS or IMOS, respectively coupled to a power rail voltage V _{D D} or ground (GND), avoid a floating node contact, and so presents to the capacitance of the resonant circuit is minimized), when its corresponding "p" coefficient is a logic low (or low voltage), the corresponding fixed capacitance C _f system is switched away from the The circuit, and the corresponding variable capacitor _Cv , is switched into the circuit and coupled to the control voltage provided to node 625.

In an exemplary embodiment, a total of eight switchable capacitive modules 640 (and corresponding first plurality of eight switching coefficients p ₀ to p ₇ ) have been implemented to provide 256 combinations of fixed and Variable capacitance. Therefore, an important control over the oscillation frequency as a function of temperature variation is provided.

In this exemplary embodiment, it should be noted that by switching in and out of the fixed capacitor C _f or the variable capacitor C _v , the ratio of the fixed capacitor to the variable capacitor is changed, and the controllable capacitive mode is changed. The amount or degree of temperature response of group 635 is correspondingly changed. For example, under an increased amount of the variable capacitance C _v, the line capacitance module 635 may be controlled in response to temperature (or other parameter) to provide a larger capacitance variability, thereby adjusting the resonant oscillating circuit or other The frequency response of the device.

10 is a circuit diagram depicting a temperature dependent voltage control module 650 that is utilized to provide a controllable capacitive mode (of the frequency temperature compensation module 420) in accordance with an example of the teachings of the present invention. The control voltage in group 635 is taken as V _{C T R L} 480 (in Figure 4). As shown, voltage control module 650 utilizes current generator 655 to generate a temperature dependent current I(T) (or more generally a current I(x)) as previously described for use of PTAT, PTAT ² And/or one or more combinations of CTAT current generators, and may share the I(T) generator 415 utilized by the negative transconductance amplifier 410, rather than providing a separate generator 655. The temperature-dependent current I(T) (or I(x)) is mirrored through the current mirror 670 to an array or array of switchable resistive modules or branches 675 and a fixed capacitive module or Branch 680, all modules or branches are configured in parallel. In other exemplary embodiments, other control voltage generators described below may also be utilized depending on the parameter variations to be compensated.

In other combinations, a temperature independent current can also be generated depending on the selection and weighting of the PTAT, PTAT ² and/or CTAT current generators. For example, a PTAT generator sized to have equal magnitudes and opposite slopes and a CTAT generator can be combined to produce a current generator that provides a fixed current under temperature variations. For example, such a current generator can be utilized to provide a fixed current source in the aging change compensator shown in FIG. Those skilled in the art will recognize that other current sources can also be utilized, such as those that vary with supply voltage, and can be utilized as corresponding voltage sensors.

Resistor 685 can be any type or combination of different types, such as: diffusion resistors (p or n), polysilicon, metal resistors, self-aligned metal salicide or non-self-aligned metal deuteration (unsalicide) polysilicon resistors, or well resistors (p or n wells). Depending on the type of resistor selected or a combination of multiple types, the resistor 685 will typically also have a corresponding temperature dependence (or response) for a particular current through the selected resistor 685, This provides a corresponding voltage change across the selected resistor 685 as a function of temperature. For example, a diffusion resistor will generally have a high temperature coefficient (providing a larger voltage change with temperature), while a polysilicon resistor will generally have a lower temperature coefficient (provided with temperature) A smaller voltage change), and a mixture of these multiple different resistor types in series for a selected module 675 will provide a corresponding response between these high and low response levels. Alternatively, the size or weighting of the resistor 685 can be determined to provide a different voltage level as a function of a particular current, such as a temperature dependent current (eg, I(T)), thereby For such a temperature-dependent current, a corresponding voltage change is provided as a function of temperature.

Each switchable resistive module 675 is switched into the voltage control module 650 by a corresponding "q" coefficient of the second complex number ("x") of the switching coefficients q ₀ to q _{(x - 1)} . . When the switchable resistive module 675 is switched to the circuit (such as when its corresponding coefficient is a logic high or high voltage), the resulting voltage across its corresponding resistor 685 is also temperature dependent. This is because of the temperature dependent current I(T). In one selected embodiment, three switchable resistive modules 675 are utilized that provide eight branch combinations. Thus, the control voltage provided to node 625 is also a function of temperature (or other parameter), thereby providing a dependency on a temperature or other parameter of variable capacitor 615 in controllable capacitive module 635 or Sensitivity. Other parametric or temperature independent resistive modules are described below with reference to Figures 23 and 26 and Figure 28, respectively.

A first plurality of switching coefficients p ₀ to p _{(w - 1)} and the second plurality of switching the coefficients q ₀ q _{(x - 1)} may be tested by having a clock generator according to the present invention in a representative IC Manufacturing was later decided. Once a resonant frequency f ₀ has been selected and/or calibrated for a particular process (described below with reference to Figures 11 and 12), the temperature (or other parameter) response of the oscillator is determined and adjusted. A substantially fixed selected resonant frequency f _{0 is} provided for such changes in ambient or operating temperature (or other variable parameters). In an exemplary embodiment, the first plurality of switching coefficients p ₀ to p _{(w - 1)} are first determined by testing various combinations of coefficients to provide a coarse degree of adjustment resulting in a varying ambient temperature. The essence of a function or almost a flat frequency response. As shown in FIG. 24, somewhat fixed or variable capacitance C _f of the capacitor C _v is switched out of the oscillator. For example, when the frequency of the oscillator is uncompensated for temperature variations of the response is indicated by a line 1705 or 1710, additional variable capacitance C _v may be switched to enter, this system the frequency response of the oscillator for providing a rough Adjust to the position of line 1715. Conversely, the same example, when the frequency of the oscillator is uncompensated for temperature variations of the response is indicated by a line 1725 or 1730, additional fixed capacitors can be switched into the C _f, of the oscillator for this system The frequency response provides a rough adjustment to approximately the position of line 1720.

The second plurality of switching coefficients q ₀ to q _{(x - 1)} is the line followed by the same test various combinations of coefficients is determined to provide a more refined level of the adjustment, as a change caused by a function of ambient temperature The substantial or significantly flat frequency response is depicted in FIG. 24 as the selection of the temperature response through various resistors 685 to adjust the partially compensated frequency response (line 1715 or 1720) to be substantially flat for line 1700. response. The first and second plurality of coefficients are then loaded into individual registers 495 and 455 of all ICs fabricated in the selected processing job (or batch). Depending on the process, in other cases, individual ICs can be individually calibrated in order to achieve higher accuracy. Thus, in combination with the temperature compensation provided by the negative transconductance amplifier 410 and the I(T) generator 415, the overall frequency response of the clock generator is substantially independent of temperature variations.

In other exemplary embodiments, the first plurality of switching coefficients p ₀ to p _{(w - 1)} and the second plurality of switching coefficients q ₀ to q _{(x - 1)} may also be used during the operation of the oscillator. Deciding and dynamically changing, for example, through the sensor 1440 and A/D converter 1445 shown in FIG. 21, or through the sensor 1815 and control logic (or control loop) 1810 shown in FIG. . In these alternative embodiments, the stored first and second plurality of coefficients may be omitted or bypassed, and the corresponding voltages applied directly to the individual switching members as shown in Figures 9 and 10 as The control signal (and, this similarly extends to other complex coefficients as described below).

For example, as shown in FIG. 26, as described in more detail below, any of a plurality of current sources 1955 can be provided to a plurality of resistive modules in various combinations to respond to a selected one. The parameter "P" generates a plurality of control voltages, and the control voltages can be switched to each of the plurality of controlled reactance modules 1805 in any combination, and the controlled reactance modules 1805 can be, for example, Implemented as a controlled capacitor module 1505 (Fig. 22) to control the effective reactance of the resonator. Further, as shown in FIG. 28, any of a plurality of fixed (temperature independent) control voltages can be generated. Furthermore, other or additional types of current sources can also be utilized which generate the control voltage or provide the functions of the sensors 385, 1440, for example, those that can vary with the supply voltage VDD, or with the supply voltage, temperature And other parameter-independent sensors. In addition to discrete control, any of these control voltages can be utilized to provide instantaneous continuous control of parameter changes such as temperature changes.

Therefore, the capacitance of the LC resonant circuit 405 provided to the resonance is distributed as a fixed portion combined with one of the variable portions, wherein the variable portion is responsive to provide temperature compensation, and thus the resonant frequency f ₀ . Is switched to a circuit (control capacitor module 635) of the variable capacitance C _v is larger, the variation of the frequency response of greater ambient temperature. As noted above, both fixed and variable capacitors can be implemented with variable capacitors (varactors) that are respectively coupled or switched to a substantially fixed or variable voltage.

In addition to providing temperature compensation, it should be noted that a switched or controlled (or controllable) capacitive module 635 can also be utilized to select or tune the resonant frequency f ₀ . It will also be apparent to those skilled in the art that a switched or controllable capacitive module 635 can also be utilized to provide a frequency response to other parameter variations (e.g., process variations, frequency and voltage variations). Furthermore, as described below with reference to Figures 20 and 25 through 27, a capacitor, an inductor, a resistor or any other reactance or impedance element can be utilized in these various exemplary embodiments, which provide a controlled A reactance or impedance module provides a selected frequency response for any of a plurality of variable parameters, such as temperature, voltage, process, or frequency.

Figure 22 is a diagram depicting the use of (in conjunction with the module 1600 of Figure 23) in a frequency-temperature compensation module 420, or more generally as a frequency controller 215, 349, 1415, in accordance with the teachings of the present invention. A circuit diagram of an exemplary second controlled capacitor module 1500 (instead of modules 485 and 480 or as a module other than the modules). The second controlled capacitor module 1500 operates similarly to the first controlled capacitor module 635, but utilizes a variable capacitor, rather than both fixed and variable capacitors, and utilizes a plurality of different Control voltage, not a single control voltage. Moreover, such a variable capacitor is not coupled to or decoupled from the resonator (ie, the variable capacitors are always coupled to the resonator), but are switched to different control voltages. A function that controls the frequency response to a selected parameter (eg, temperature). Moreover, the selected embodiment can utilize as few as one module, and the differential weighting can be achieved by switching to a selected one of a plurality of control voltages.

Referring to FIG. 22, the second controlled capacitor module 1500 utilizes at least one of a plurality of ("g") variable capacitor modules 1505, each of which includes a variable capacitor. (C _v) 1515 _{a 0} to 1515 _{B (g - 1) (depicted} by a and B in pairs, to the corresponding coupling node 475 or 470 of the balance, and is depicted as having binary weighted), the plurality of variable The capacitor can be switched (through a plurality of transistors or other switches 1520 ₀ to 1520 _{( g - 1 )} ) to one of a plurality of control voltages V ₀ , V ₁ (x) to V _{( k - 1 )} (x) The selected control voltage, wherein the control voltage V ₀ is substantially static (substantially non-responsive to the selected parameter "x", such as temperature), while the remaining control voltages V ₁ (x) to V _{( k - 1 )} (x) is generally responsive to the selected parameter "x" (eg temperature) or sensitive thereto. As shown, the backplanes of each corresponding pair of variable capacitors 1515 (A and B) are coupled to each other (short-circuited together) and then connected to a selected control voltage via a switch. Each such pair of variable capacitors 1515 is permeable to a corresponding coefficient (depicted as a fourth plurality of coefficients d ₀ , d ₁ , ..., d _{(k - 1)} to h ₀ , h ₁ , ..., h _{(k - 1)} ) are switched so that each module 1505 can be individually and independently switched to the plurality of control voltages V ₀ , V ₁ (x) to V _{( k - 1 )} Any of (x). Thus, the switchable modules can remain coupled to the resonator, wherein the effective impedance (eg, reactance) is varied by switching to one or more control voltages.

23 is a circuit diagram depicting a second voltage control module 1600 that is utilized in an example of a frequency-temperature compensation module in accordance with the teachings of the present invention. As depicted in Figure 23, a parameter sensitive or responsive current source 655 (e.g., any of the various CTAT, PTAT, and PTAT ² temperature sensitive current sources previously described and illustrated in Figures 7A through 7D) One and a combination thereof (through one or more current mirrors (eg, 670, 510, 520)) is provided to an array or row of plural "k-1" resistive modules 1605 (depicted as modules 1605 ₀ , 1605 ₁ to 1605 _{( k - 1 )} ), each resistive module 1605 provides a separate or independent control voltage V ₁ (x), V ₂ (x) to V _{( k - 1 )} (x The control voltage is provided to the module 1505 (of FIG. 22). The various corresponding resistors 1620 ₀ , 1620 ₁ through 1620 _{( k - 1 )} may be of any type, size or weight previously described with reference to FIG. 10 to provide any selected voltage for a selected parameter (eg, temperature). response. As shown, a static control voltage V ₀ can be generated using any voltage divider coupled between the voltage source rail V _{D D} and ground, where the corresponding resistor size or values 1605 ₀ and 1605 _y are selected. Provide the desired static voltage level. In addition, the generation of a plurality of different static or fixed (i.e., temperature independent) voltages is depicted in Figure 28 by combining currents having different shapes in response to temperature (or other parameters). The different current sources and the different temperature dependent resistors having complementary or opposite temperature responses produce a plurality of substantially constant and substantially fixed control voltages under temperature variations. Any of these various voltages can be utilized as desired, as any of the various control voltages.

In an exemplary embodiment, each such control voltage of the plurality of control voltages is different to provide a plurality of control voltages, each control voltage being differently responsive or shaped (ie, providing a different response) (Response curve) is a function of the change in the selected parameter (eg, temperature), which may be responsive to different parameters, while other control voltages may be substantially fixed relative to a selected parameter. Depending on the embodiment selected, the array or row of resistive modules 1605 can be switchable through corresponding transistors 1610 (depicted as transistors 1610 ₀ , 1610 ₁ through 1610 _{( k - 1 )} ), And thereby being switched into and out of the array 1600, or may be statically included (fixed connection 1615, depicted as a dashed line in FIG. 23) to automatically generate a predetermined number of control voltages V ₀ , V ₁ (x) to V _{( k - 1 )} (x). Depending on the choice of resistor 1620 (and/or transistor 1610, if included), the various control voltages V ₀ , V ₁ (x) through V _{( k - 1 )} (x) will be different, respectively. Or provide a different response to the selected parameter or variable, for example, a different temperature response.

Similarly, FIG. 26 depicts a circuit block diagram of a third voltage control module 1900 that can be utilized to provide control voltage to any of the various modules in accordance with the teachings of the present invention. As depicted in Figure 26, a plurality of current sources 1955 that are sensitive or responsive to the parameters (e.g., various CTAT, PTAT, and PTAT ² temperature sensitive current sources previously described and illustrated in Figures 7A through 7D) Any one or a combination thereof (through one or more current mirrors (eg, 670, 510, 520)) is provided to an array or row of plural "n-1" resistive modules 1905 (depicted as a mode Group 1905 ₀ , 1905 ₁ to 1905 _{( n - 1 )} ). Each resistive module 1905 provides a separate or independent control voltage V ₀ (P), V ₁ (P), V ₂ (P) to V _{( n - 1 )} (P), which produces a plurality of responses Or a control voltage according to the selected parameter "P", and the control voltages are provided to the controlled reactance module 1805, the controlled capacitor module 1505 (of FIG. 22), or any utilization One or more other modules that control the voltage. Corresponding to the various resistors _{19200, 19201} to 1920 _{(n - 1)} previously described may be of any type, size or weight, a selected voltage to provide any response to a selected parameter. The choice of current source (or combination of current sources) and resistor size and type allows for the shaping of the response of any desired control voltage to the selected parameter. Moreover, any of a plurality of different static or fixed (i.e., temperature independent) voltages shown in Figure 28 can be utilized as desired for use in any of the modules discussed. Any of a variety of control voltages.

Depending on the embodiment selected, the array or row of resistive modules 1905 can be switchable through corresponding transistors 1915 (depicted as transistors 1915 ₀ , 1915 ₁ through 1915 _{( n - 1 )} ), And thereby switching in and out of the array dynamically or statically to automatically generate a plurality of control voltages V ₀ (P), V ₁ (P), V ₂ (P) to V _{( n - 1 )} (P). Each of these different control voltages can then be switched (using switch 1930, for example, a full crossbar switch) in any combination, statically or dynamically, under control of the control signal and/or coefficient 1950. To the controlled reactance module 1805, the controlled reactance modules 1805 can be coupled to the resonator or can be switched into and out of the resonant circuit. Thus, any of these control voltages can be utilized to control the effective reactance of the resonator (oscillator), providing discrete and continuous control of the resulting resonant frequency. For example, any of these parameter dependent control voltages V ₀ (P), V ₁ (P), V ₂ (P) to V _{( n - 1 )} (P), or the substantially parameter-independent control Any of the voltages (Fig. 28) can be provided to the controlled impedance module 1305 or the controlled capacitance module 1505 or 1805 to vary the effective capacitance supplied to the resonator, for from a plurality of A change in any of the parameters provides frequency control.

Referring again to Figure 22, when these different control voltages V ₀ , V ₁ (x) to V _{( k - 1 )} (x), or more generally V ₀ (P), V ₁ (P), V ₂ Any one of (P) to V _{( n - 1 )} (P) and a substantially fixed control voltage is available, respectively, and is permeable to the fourth plurality of coefficients d ₀ , d ₁ , ... d _{(k - 1)} to h ₀ , h ₁ , ... h _{(k - 1)} to switch to the variable capacitance C _v 1515 in the variable capacitance module 1505, one for the selected parameter ( e.g. temperature) of highly flexible, and highly controlled fine-tuning the frequency response of the system is provided to the resonator 405, so that the height of this system resonance frequency f ₀ of an accurate frequency control becomes possible. For example, the variable capacitances 1515 _{A ( g - 1 )} and 1515 _{B ( g - 1 )} in module 1505 _{( g - 1 )} can pass the parameter h ₁ (or a corresponding dynamic applied voltage as a control signal is set to logic high (or high voltage) and the remaining h parameters of the fourth plurality of parameters are set to logic low (or low voltage) to be switched to control voltage V ₁ (x), providing a first line frequency response function of a selected temperature or other parameters, and in the ₁₅₀₅₀ in the variable capacitance module 1515 _{a 0} and 1515 _{B 0} permeable parameter d _{(k - 1) (or} A corresponding dynamic applied voltage, as another control signal, is set to a logic high (or high voltage) and the remaining d parameters of the fourth plurality of parameters are set to a logic low (or low voltage), To be switched to the control voltage V _{( k - 1 )} (x), this provides a function of the second frequency response as a temperature or other selected parameter, and so on. As described above, the fourth plurality of coefficients d ₀ , d ₁ , ..., d _{(k - 1)} to h ₀ , h ₁ , ..., h _{(k - 1)} can also pass the test one or more The ICs are determined after fabrication, or may also be during operation of the oscillator, such as through sensor 1440 and A/D converter 1445 as depicted in FIG. 21 or through FIG. The depicted sensor 1815 and control logic (or control loop) 1810 dynamically determine and change. More generally, such a transmission coefficient or control of the control signal is depicted in Figure 26 and can be utilized to provide either or both of discrete or continuous frequency control for any selected parameter (e.g. , a function of temperature, voltage, process, aging, or frequency.

Furthermore, instead of the coefficients stored for the first, second or fourth plurality of coefficients, in particular when the corresponding value will be dynamically determined as described above, the corresponding voltage can be directly as described above It is applied to the various switches (eg, transistor 1520 or switching transistors of modules 640 and 650) as control signals.

Referring again to Figure 4, another compensation module is also utilized to provide greater control and accuracy for the resonant frequency f ₀ , as well as for greater accuracy and less variation (or frequency drift). The application is, for example, a frequency accuracy of about ±0.25% or better for PVT. And the like in this case, a process variation compensation module 425 (such as the example in FIG. 11 and the module 12 shown) may be utilized to provide a system for controlling the resonance frequency f _0, without regard to process variation. As noted above, any of these various modules can include any impedance, reactance, or resistance and be configured to respond to any selected parameter, such as temperature, process variation, voltage variation, and frequency variation.

11 is a circuit diagram depicting a first process variation compensation module 760 in accordance with one example of the teachings of the present invention. The first process variation compensation module 760 can be utilized as the process compensation module 460 of FIG. 4, wherein each module is one of the tracks or sides of the LC resonant circuit 405 attached to the resonance (the line or node 470 and 475). In addition, each of the first process variation compensation modules 760 is controlled by a third complex number ("y") of switching coefficients r ₀ to r _{(y - 1)} stored in the register 465. The first process variation compensation module 760 provides an array of switchable capacitive modules having differentially weighted (eg, binary weighted) first fixed capacitance 750 for adjustment of the resonant frequency f ₀ and Alternatively, it is switched in and out of a plurality of fixed capacitors 750 by a corresponding plurality of switching transistors 740 (controlled by a corresponding "r" coefficient). Similarly, when each capacitor branch is switched in and out of the array or circuit 760, the corresponding first fixed capacitance is added to or subtracted from the total available capacitance of the oscillations added to the resonant LC resonant circuit. Thereby changing the effective reactance and modulating the resonant frequency. The third plurality of switching coefficients r ₀ to r _{(y - 1) are} also determined after manufacture by using the test IC, and the determination of the first and second (or fourth) plurality of switching coefficients is substantially A repetitive process. This calibration is achieved using a frequency calibration module (325 or 430) and a reference oscillator known to have a predetermined frequency. The determined "r" coefficient is then stored in the corresponding register 465 of the IC of the production or processing lot. Or, for example, individual IC systems can be individually calibrated.

In addition to such a calibration method, the third plurality of switching coefficients r ₀ to r _{(y - 1)} can also be determined by other methods described below, for example, using various voltage and current sensors. The measurement reflects, for example, a process parameter of the transistor threshold voltage, a magnitude or value of the resistance of the resonant circuit, or a parameter or variable of the absolute current level produced by the various current sources. Such measured values can then be utilized to provide corresponding coefficients (the third plurality of switching coefficients r ₀ to r _{(y - 1)} ) and/or control signals for corresponding frequency adjustments. For example, such measured or sensed values can be converted to digital values, which are then indexed to a lookup table in memory, which is then based on known values or other Calibrate or model to provide the stored values.

In order to avoid additional frequency distortion, several additional features may be implemented using the first process variation compensation module 760. First, in order to avoid additional frequency distortion, the on-resistance of the MOS transistor 740 should be small, and thus the width/length ratio of the transistor is large. Second, the large capacitance can be divided into two branches, and the two corresponding transistors 740 are controlled by the same "r" coefficient. Third, in order to provide the resonant LC resonant circuit with a similar load under all conditions, when a first fixed capacitor 750 is switched in and out of the circuit 760, it acts as a "dummy" capacitor (with significant A corresponding second fixed capacitor 720 of a smaller capacitance or a minimum size allowed by the design rules of the process is switched in and out of the circuit in accordance with the reciprocal of the corresponding "r" coefficient. Therefore, approximately or substantially the same on-resistance of the transistor 740 is always present, only the amount of capacitance is changed.

As an alternative to the use of "dummy" capacitors, metal fuses or the like can be utilized in place of transistor 740. The metal fuse system will remain intact to contain the corresponding fixed capacitance 750, and can be "fuse" (open) to remove the corresponding fixed capacitance 750 from the self-resonant LC resonance 405.

12 is a circuit diagram depicting a second process variation compensation module 860 in accordance with one example of the teachings of the present invention. The second process variation compensation module 860 can be utilized as the process compensation module 460 of FIG. 4, wherein each module is attached to one of the tracks or sides of the resonant LC resonant circuit 405 (lines 470 and 475). Not module 760. More generally, the second process variation compensation module 860 is utilized as part of a frequency controller (215, 349, or 1415), such as a process (or other parameter) modulator or compensator 1430 (FIG. 21) ). In addition, each of the second process variation compensation modules 860 is also controlled by a third plurality of switching coefficients r ₀ to r _{(y - 1)} stored in the buffer 465. (However, since different circuits are applied to the process variation compensation modules 760 or 860 of the respective examples, the corresponding third plurality of switching coefficients r ₀ to r _{(y - 1)} will of course be different from each other.) Such switching can be controlled by the use of any control signals as described above.

It should be noted that Fig. 12 provides a varactor legend different from that used by other figures, wherein a varactor 850 is represented by a MOS transistor rather than a capacitor having an arrow therethrough. . It will be appreciated by those skilled in the art that the varactor is typically an AMOS or IMOS transistor, or more generally a MOS transistor, such as that shown in Figure 12, and by shorting the source of the transistor. It is composed with bungee jumping. Thus, other illustrated varactors can be considered to include (as a potential embodiment) an AMOS or IMOS transistor as constructed in FIG. In addition, varactors 850 may also be binary weighted with respect to each other, or other differential weighting methods may be used.

The second process variation compensation module 860 has a similar structural concept but has another significant difference from the first process variation compensation module 760. The second process variation compensation module 860 provides an array or a plurality of switchable variable capacitance modules 865 without MOS switches/transistors, and thus is eliminated by loss or load of the MOS transistors. Instead, the load presents a low loss capacitance; this low loss also means that the oscillator starting power is small. In the second process variation compensation module 860, a MOS varactor 850 is switched to Vin (which may be any of the various plurality of control voltages described above) to provide a corresponding capacitance level to the resonant LC resonant circuit 405. Alternatively, it can be switched to a ground or power rail (voltage V _{D D} ) to provide a minimum capacitance or maximum capacitance to resonant LC resonant circuit 405 depending on the geometry of varactor 850. For AMOS, switching to voltage V _{D D} will provide the least capacitance and switching to ground will provide the maximum capacitance, and the opposite is true for IMOS. Similarly, the second process variation compensation module 860 is composed of an array of variable capacitors (such as varactor 850) for adjustment and selection of the resonant frequency f ₀ by transmitting a corresponding " The r" coefficient is either coupled or switched by a corresponding control signal application or switching a selected varactor 850 to any of a plurality of control voltages ( Vin ) or ground or V _{D D} , for example, switching in a Between the first voltage and a second voltage. In another alternative, instead of a plurality or an array of varactors, a varactor 850 can be utilized that is provided to the resonant circuit with an effective reactance that is controlled by a selected control voltage. .

When each capacitor branch is switched to a corresponding control voltage, ground or V _{D D} , the corresponding variable capacitance is added or not included in the resonance of the LC resonant circuit, the total available capacitance of the oscillation, thereby changing its effective Reacts and modulates the resonant frequency. More specifically, for an AMOS implementation, coupling to V _{D D} (as V _{i n} ) provides a smaller capacitance, and coupling to ground (V _{i n} =0) provides a larger capacitance, However, for an IMOS implementation, the opposite is true, where coupling to V _{D D} (as V _{i n} ) provides a larger capacitance, and coupling to ground (V _{i n} =0) provides a smaller Capacitor, which assumes that the voltage on the track of the LC resonant circuit (nodes of Figure 4 or lines 470 and 475) is between zero volts and voltage V _{D D} and is significantly or substantially farther away from the voltage Level. The voltage coupled between V _{D D} and ground, for example, is a plurality of control voltages of the various control voltages as Vin , which will provide a corresponding intermediate level of capacitance to the resonant circuit. The third plurality of switching coefficients r ₀ to r _{(y - 1)} are also determined after manufacture using the test IC, and this is also a process of repeating the determination of the first and second plurality of switching coefficients. The determined "r" coefficient is then stored in the corresponding register 465 of the IC of the production or processing lot. Similarly, individual ICs can be individually calibrated and tested. In addition, any selected number of modules 850 can also be dynamically controlled to provide continuous frequency control during oscillator operation.

As indicated above, depending on the type of varactor (AMOS or IMOS), any variable capacitive modules 865 to V _{D D} or ground are switched to serve as the first and second voltage levels, which produces corresponding The maximum capacitance or no (negligible) capacitance is included as an effective capacitance for the resonator (LC resonant circuit). However, as discussed above, other capacitance levels intermediate between the maximum and minimum values can also be generated by switching the variable capacitive module 865 to a corresponding control voltage. Using a plurality of control voltage systems having different sizes, the corresponding capacitance of the variable capacitive module 865 is added to (or subtracted from) the LC resonant circuit, thereby changing its effective reactance and modulating the resonant frequency. .

28 is a circuit diagram depicting a fourth voltage control module 2050 that is utilized in an example of frequency, process, and other parameter compensation modules in accordance with the teachings of the present invention. Referring to FIG. 28, a plurality of substantially fixed voltage modules 2060 (depicted as 2060 _A , 2060 _B , 2060 _C to 2060 _K ) are utilized to generate a corresponding plurality of control voltages relative to one The selected parameters (e.g., temperature) are substantially fixed and have a corresponding plurality of different sizes, which produces a plurality of control voltages V _A , V _B , V _C to V _K having different sizes. As shown, the plurality of different substantially static or fixed (i.e., temperature independent) voltages are combined by different current sources 2055 (depicted as current sources 2055 _A , 2055 _B , 2055 _C to 2055 _K ) is generated, each current source having a different response to temperature or other parameters (ie, a current shaped in response to temperature (or other parameter)) and having one of a plurality of resistors 2040 Corresponding resistors (depicted as corresponding resistors 2040 _A , 2040 _B , 2040 _C to 2040 _K ), each resistor having a temperature or other parameter dependent response that is opposite or complementary to the particular A corresponding current source 2055 of module 2060. Each corresponding current source 2055 and resistor 2040 is selected to have such a reverse or complementary response to each other to effectively cancel the other party's response to the selected parameter. For example, a current source 2055 is selected to have a particular combination of a particular PTAT, CTAT, or CTAT ² current source, and a resistor 2040 is selected based on size, type, etc., such that The voltage is substantially fixed under this parameter change (eg, temperature change). Any of these various voltages can be utilized as desired to serve as any of the various control voltages, for example, to provide a corresponding Vin of the variable capacitive module 865 shown in FIG. To adjust the effective capacitance (reactance) of the resonator and the resulting resonant frequency.

It should also be noted that the described embodiments of modules such as temperature compensator 315 (or 410, 415 and/or 420) and process variation compensator 320 (or 425 and 460) are such as those illustrated in Figures 6-12. The presenter can be utilized for other purposes. For example, the various embodiments of compensator 315 (or 410, 415, and/or 420) can be made dependent on process variations rather than temperature. Similarly, the various embodiments of compensator 320 (or 425 and 460) can be made dependent on temperature rather than process variation. Therefore, embodiments of such modules and other modules should not be considered to be limited to the example circuits and structures described, as those skilled in the art will recognize other equivalent circuits and applications. All are within the scope of the invention.

As noted above, the various controlled capacitor modules (485, 635, 460, 760, 860, 1501) can be generalized to any reactance or impedance component, whether a capacitor, inductor, resistor, or A combination of capacitors, inductors, or resistors. Such a complex ("a") switchable controlled impedance (or reactance) module 1305 of an array or bank 1300 is depicted in FIG. 20 and can be utilized in the frequency controller of the present invention (215, Within 349, 1400), it is any of various modulators or compensators (315, 320, 355, 1420, 1425, 1430). Each of the different weighted controlled reactance or impedance modules 1305 (depicted as 1305 ₀ , 1305 ₁ to 1305 _{( a - 1 )} ) is composed of one or more fixed reactances Z _f 1315, variable reactance Z _v 1310 Or a "dummy" reactance 1320, which is switchable in response to a corresponding coefficient "s" of the fifth plurality of coefficients ( s ₀ , s ₁ to s _{(a - 1)} ). The array of controlled reactance or impedance modules 1305 can generally be implemented to operate as described above with respect to any of the various modules of the various controlled capacitive modules of any of the various embodiments. As described above for the coefficients of the other groups, the fifth plurality of coefficients can be determined after manufacture or dynamically. Moreover, in accordance with this embodiment, various reactances or impedances can be switched into and out of the array 1300 as previously described or switched to various control voltages or grounds, and can be utilized in response to any of a plurality of parameters, For example, temperature changes, voltage variations, processes, or frequencies to provide a selected frequency response of the oscillator.

Similarly, referring to FIG. 25, an array or a plurality of "n" switchable controlled reactance modules 1805 are depicted (for the controlled reactance modules 1805 ₀ to 1805 _{( n - 1 )} ), and It can also be utilized within the frequency controller (215, 1415) of the present invention as any of a variety of modulators or compensators (315, 320, 355, 1420, 1425, 1430). The controlled reactance modules 1805 can also be binary, linear, or differently weighted and switched into and out of various circuits, switched to one or more control voltages, or any combination of the control voltages, and can be responsive For any selected parameters. The array of controlled reactance modules 1805 can generally be implemented to operate as described above with respect to any of the various modules of the various controlled capacitive modules of any of the various embodiments. In this exemplary embodiment, instead of being switched to the oscillator through a plurality of coefficients, the controlled reactance module 1805 is provided under feedback (line or node 1820) through the sensor 1815. The voltage or current directly supplied by the control logic 1810 is dynamically switched, and the feedback can be implemented as known in the art or as described above, all of which are considered to be in the present invention. Within the scope of the category. In addition, the reactance module can be more generally regarded as an impedance module having resistive and/or reactive characteristics, for example, using various resistors shown in FIG.

For example, such changes in selected parameters can be determined using any of the previously described plurality of modes, for example, by a temperature sensitive current source, other temperature sensors, or in response. Any other type of sensor for the selected parameter. For example, a sensor can include a voltage across a diode that provides a voltage output that is responsive to temperature. Referring to FIG. 21, the output of such a sensor 1440 can be provided to an A/D converter 1445, which provides a digital output indicating the level of the sensed parameter, the digit The output can then be utilized as a corresponding coefficient (any of the above plurality of coefficients) or used to dynamically switch between various controlled reactance or impedance modules (eg, 1305, 1805) or various Any one of the two controlled capacitor modules. Similarly, the output of sensor 1815 can be provided to control logic 1810, which can also adjust various reactances either statically or dynamically, with or without feedback from the resonator.

27 is a circuit block diagram depicting a voltage variation compensation module 2000 in accordance with an example of the teachings of the present invention, and may be utilized as the voltage variation compensators 380, 1455 shown in FIGS. 3 and 21. Referring to Figure 27, a switchable resistive module 1650 utilizes resistors 1620 ₀ and 1620 _y to form a voltage divider that provides a voltage V ₀ . In the case where the supply voltage (power rail) V _{D D} fluctuates, the voltage V ₀ is correspondingly changed. Since the voltage V ₀ can be switched (switch 1930) (as described above) to any of the controlled reactance modules 1805 under control of the control signal or coefficient 1950, the effective capacitance coupled to the resonant circuit is also changed, thereby Modulate the resonant frequency. Thus, the resonant frequency can be controlled under such voltage variations. Other embodiments will be apparent from the following examples, and are therefore within the scope of the invention.

As noted above, in addition to the inherent or parasitic resistances R _L 445 and R _C 450 of Figure 4, the resonant frequency of the resonant circuit can also be modified by varying the resistance coupled to the resonant circuit. 29 is a circuit diagram depicting a resistive control module 2100 in accordance with an example of the teachings of the present invention that can be utilized as all or part of any of a variety of frequency control modules and various frequency controllers. Such a resistive control module 2100 can be inserted into node Q in resonator 405 of FIG. 4, in series with inductors 435 and _RL 445 or in series with capacitors 440 and R _C 450, or both. Each switchable resistive module 2115 (depicted as the plurality of switchable resistive modules 2115 _M , 2115 _N , 2115 _O to 2115 _U ) has a different weighted (eg, binary weighted) resistance 2105 (depicted as corresponding resistors 2105 _M , 2105 _N , 2105 _O to 2105 _U ), and can be transmitted through a corresponding transistor or switch 2110 under control of a control signal and/or coefficient 1950 (depicted as electricity) The crystals 2110 _M , 2110 _N , 2110 _O to 2110 _U ) are switched in and out of the array or module 2100. As noted above, such switching also provides another mechanism to control or modulate the resonant frequency of the resonator 405, and can be a function of any selected parameter, or can be parameter independent, for example, The choice of resonant frequency.

30 is a block diagram depicting an aging variation compensator 2200 in accordance with an example of the teachings of the present invention. As depicted in Figure 30, various sensors are utilized to measure a related parameter that is (or may be) affected by time elapsed or that varies with the life of the IC, for example, The voltage sensor 2205 measures the threshold voltage of the transistor, the resistance sensor 2210 measures the magnitude or value of one or more resistors of the resonant circuit, and/or the current sensor measures the current by various currents. The absolute current level produced by the source. A selected measurement system (via multiplexer 2220) at a particular point in time is provided to ADC 2225 for conversion to a digital value that is stored in a register or other non-status In the electrical memory 2230. When the IC is powered or initialized for the first time, an initial measurement is stored in the register 2230 to provide a basis for comparison for subsequent measurements. Additional measurements can then be made, the resulting values being stored in the register 2230 as corresponding current values, which are depicted as current and initial values of voltage, resistance, and current. For a particular parameter (eg, voltage), the current value can be read and compared to the initial value, and then comparator 2235 provides a ratio proportional to any difference between the two values. Aging compensation signal. Such differences provided by the aging compensation signal can then be utilized to provide corresponding coefficients and/or control signals for corresponding frequency adjustments. For example, such an aging compensation signal can be indexed to a lookup table in memory 2240, which then provides the stored value based on a known value or other calibration or model of aging effects and is provided for The corresponding frequency adjustments of any of the various modulators and compensators described above are utilized.

As described above, the clock generator and timing/frequency reference (100, 200, 300) of the present invention can utilize a wide variety of oscillators. In an exemplary embodiment, a resonant LC oscillator is utilized to provide an output signal (as a first reference signal) having a relatively high Q value, low jitter, and reduced phase mismatch. News. Exemplary first and second differential LC oscillators have been discussed above with reference to Figures 4, 6 and 8. Other types of resonant oscillators are also within the scope of the present invention, and exemplary LC oscillators are depicted in Figures 31-37 and are discussed below with reference to the figures, wherein an active inductor is depicted In Figure 38. These other examples of LC oscillator and inductor types (passive or active) can be utilized equivalent to the previously described LC oscillator, and to describe their equivalent actions, they are also described in connection with FIG. 4 previously. Examples of frequency controller components, namely, compensation modules 420 and 425, are described. It should be understood that any other controller reactance module, control voltage generator, frequency control, calibration, frequency selection, frequency division, and other components may equally be identical to the components explicitly depicted in Figures 31-37. Be exploited.

It should also be noted that the active inductor of the example shown in Figure 38, or any other active inductor, can be used instead of the topology shown in any of Figures 1-37. Any of the passive inductors. Similarly, various topologies utilizing n-MOS or p-MOS transistors are depicted; any type of transistor can be utilized equally. Thus, the use of any passive or active inductor, or any type of transistor, is considered equivalent and within the scope of the present invention.

The various LC oscillators described below can provide a differential or single-ended first reference signal. The various compensation modules 420 and 425, which can be implemented as a controlled reactance module in a wide variety of ways as described above, can be combined with various oscillators in a number of ways. First, the controlled reactance modules (depicted as compensation modules 420 and 425) can be coupled in parallel with any of one or more of the depicted capacitors. In many examples, examples of multiple controlled reactance modules can be coupled to the depicted LC oscillator. Accordingly, the corresponding nodes for coupling are labeled as node "A" and node "B" to indicate the corresponding node for coupling to a given LC oscillator topology, which can be utilized for coupling Further examples are described as corresponding nodes "A'" (A-single) and node "B'" (B-single) and/or corresponding nodes "A" (A-double) and Node "B"" (B-double). Second, although the controlled reactance modules (depicted as compensation modules 420 and 425) are not individually depicted in each of Figures 31-37, they can be utilized in place of one or more of the depicted capacitors. Any one. Those skilled in the art will appreciate that there are numerous other variations, all of which are considered equivalent and are within the scope of the present invention.

31 is a circuit diagram depicting an LC oscillator 2260 of a third example that can be utilized in accordance with the teachings of the present invention, which is constructed using a differential n-MOS cross-coupling topology and is tied to A variation of one of the LC oscillators shown in FIG. As shown, the device 2250 includes an LC oscillator 2260 having a third example of a differential n-MOS cross-coupled topology, and a frequency controller previously discussed in the dual balanced configuration of FIG. Frequency calibration module (compensation modules 420 and 425). The output frequency f ₀ is obtained between nodes 470 _A and 475 _A , which is equivalent to nodes 470 and 475 previously discussed, and thus may be used in place of all references to nodes 470 and 475 in the drawings and in this specification.

The cross-coupled n-MOS transistors 2251 and 2252 are coupled to a bias current through a current mirror 530A (or 530B), such as using a parameter responsive current I (also discussed previously) ( x) Generator 515 (or 415), or other fixed or variable current source. The frequency controller module (480, 485, which has coefficient registers 455 and 495) and the frequency calibration module (460, which has a coefficient register 465) are shown across the nodes A and B as shown. It is coupled to the oscillator and also operates as previously discussed. As shown, inductors 2253 and 2254 (and the depicted resistors) can be replaced by a centrally tapped inductor 2257 (with its center tap coupled to V _{D D} ) and plugged into node A. Between B and can be fixed or variable. Moreover, as previously discussed, various capacitors can be implemented as fixed or variable and are depicted as both fixed and variable capacitors. In an exemplary embodiment, the resistance can also be fixed or variable.

It will be apparent to those skilled in the art that a similar cross-coupled n-MOS version of the oscillator shown in Figure 6 can be similarly implemented (by eliminating (replaced by a short circuit) Cross-coupled p-MOS transistors M1 and M2).

32 is a circuit diagram depicting an LC oscillator 2280 of a fourth example that can be utilized in accordance with the teachings of the present invention, which is constructed using a differential p-MOS cross-coupled topology and is A variation of one of the LC oscillators shown in FIG. As shown, the device 2270 includes an LC oscillator 2280 having a fourth example of a differential p-MOS cross-coupled topology, and a frequency controller previously discussed in the dual balanced configuration of FIG. Frequency calibration module (compensation modules 420 and 425). The output frequency f ₀ is obtained between nodes 470 _B and 475 _B , which is equivalent to nodes 470 and 475 previously discussed, and thus may be used in place of all references to nodes 470 and 475 in the drawings and in this specification.

The cross-coupled p-MOS transistors 2271 and 2272 are coupled to a bias current through a current mirror 510 (or 520), such as a responsive current I (also referred to as previously discussed). x) Generator 515 (or 415), or other fixed or variable current source. The frequency controller module (480, 485, which has coefficient registers 455 and 495) and the frequency calibration module (460, which has a coefficient register 465) are shown across the node A as shown B is coupled to the oscillator and also operates as previously discussed. As shown, inductors 2273 and 2274 (and the depicted resistors) can be replaced by a centrally tapped inductor 2277 (whose center tap is coupled to ground) and interposed at nodes A and B. Between, and can be fixed or variable. Moreover, as previously discussed, various capacitors can be implemented as fixed or variable and are depicted as both fixed and variable capacitors. In an exemplary embodiment, the resistance can also be fixed or variable.

Again, it will be apparent to those skilled in the art that a similar cross-coupled p-MOS version of the oscillator shown in Figure 6 can be similarly implemented (by elimination (replaced by a short circuit)) The depicted cross-coupled n-MOS transistors M3 and M4).

33 is a circuit diagram depicting a fifth example LC oscillator 2305 that can be utilized in accordance with the teachings of the present invention, having a single-ended Colpitts configuration (or topology). As shown, the apparatus 2300 includes the LC oscillator 2305 of the third example having a single-ended Colpitts configuration (or topology) and a previously discussed frequency controller and frequency calibration module (compensation module 420). Part of the single-ended version with 425). The frequency controller and the frequency calibration module (485, 460) are coupled in parallel across the nodes A and B as shown in the figure to the capacitor 2310, or in parallel across the nodes A' and B' as shown. To capacitor 2315, or both (single capacitor 2310 is connected in parallel across nodes A and B and capacitors 2315 are connected in parallel across nodes A' and B'). The output frequency f ₀ is obtained between nodes 470 _C and 475 _C , which is equivalent to nodes 470 and 475 previously discussed, and thus may be used instead of all references to nodes 470 and 475 in the drawings and in this specification. .

The transistor 2325 can be coupled to a fixed or variable bias voltage or other circuit node (not individually drawn). In addition, a bias current is also provided, which utilizes, for example, a parameter responsive current I(x) generator 515, also discussed previously, or other fixed or variable current source. The frequency controller module (480, 485, which has coefficient registers 455 and 495) and the frequency calibration module (460, which has a coefficient register 465) also operate as previously discussed. In addition, various reactances (inductor 2320, capacitors 2310 and 2315) can also be implemented as fixed or variable as previously discussed. In an exemplary embodiment, the resistor 2330 can also be fixed or variable.

Figure 34 is a circuit diagram depicting an LC oscillator of a sixth example that may be utilized in accordance with the teachings of the present invention, having a differential, common base Colpitts configuration (or topology). As shown, the apparatus 2400 includes a sixth example LC oscillator 2405 having a differential, common base Colpitts configuration (or topology) and previously described in the dual balanced configuration of FIG. Frequency controller and frequency calibration module. Based on the output frequency f ₀ between nodes _D 470 and _D 475 obtained, also goes to the previously discussed equivalent to the node 470 and 475, which may thus be used to replace in the drawings with reference to this specification for all of the nodes 470 and 475 .

Transistors 2425 and 2426 can be coupled to a fixed or variable bias voltage. Although depicted as utilizing an n-MOS transistor, transistors 2425 and 2426 also provide an example of a dual-contact junction transistor that is equivalent in the present invention. In addition, one or more bias currents are also provided, such as utilizing a parameter responsive current I(x) generator 515, also discussed previously, or one or more other fixed or variable current sources. The frequency controller module (480, 485, which has coefficient registers 455 and 495) and the frequency calibration module (460, which has a coefficient register 465) are shown across the nodes A and B as shown. Parallelly coupled to capacitor 2415, or coupled in parallel across node A' and B' to capacitor 2410 as shown, or coupled in parallel across node A" and B" to capacitor 2430 as shown Or any combination of these three configurations, and it also operates as previously discussed. In addition, various reactances (inductor 2420, capacitors 2410, 2415, and 2430) can also be implemented as fixed or variable as previously discussed.

35 is a circuit diagram depicting an LC oscillator 2505 of a seventh example that may be utilized in accordance with the teachings of the present invention, having a Colpitts configuration (or topology) of differential, common collectors. As shown, the apparatus 2500 includes an LC oscillator 2505 of the seventh example having a differential, common collector Colpitts configuration (or topology) and previously described in the dual balanced configuration of FIG. Frequency controller and frequency calibration module. The output frequency f ₀ is obtained between nodes 470 _E and 475 _E , which is also equivalent to nodes 470 and 475 previously discussed, and thus may be used in place of all references to nodes 470 and 475 in the drawings and in this specification.

One or more bias currents are provided, for example, using a parameter responsive current I(x) generator 515, also discussed previously, or one or more other fixed or variable current sources. The frequency controller module (480, 485, which has coefficient registers 455 and 495) and the frequency calibration module (460, which has a coefficient register 465) are shown across the nodes A and B as shown. Parallelly coupled to capacitor 2515, or coupled in parallel across node A' and B' to capacitor 2510 as shown, or coupled in parallel across node A" and B" to capacitor 2530 as shown Or any combination of these three configurations, and it also operates as previously discussed. In addition, various reactances (inductor 2520, capacitors 2510, 2515, and 2530) can also be implemented as fixed or variable as previously discussed.

36 is a circuit diagram depicting an LC oscillator 2605 of an eighth example that can be utilized in accordance with the teachings of the present invention, having a single-ended Hartley configuration (or topology). As shown, the apparatus 2600 includes an LC oscillator 2605 of the eighth example having a single-ended Hartley configuration (or topology) and portions of the frequency controller and frequency calibration module discussed previously. Also because the oscillator 2605 is single-ended rather than differential, the frequency controller and frequency calibration module (485, 460) are only coupled to one rail (node 470 _F ), rather than having the double balance of FIG. Configuration. As shown, the output frequency f ₀ is obtained between nodes 470 _F and 475 _F , which is also equivalent to nodes 470 and 475 previously discussed, and thus may be used in place of all of the nodes 470 in the drawings and in this specification. With reference to 475. (Furthermore, although the frequency controller and frequency calibration module (485, 460) are depicted between node 470 _F and the ground potential at node 475 _F , the frequency controller and frequency calibration module (485, 460) It is also considered to be parallel across capacitor 2610 between nodes 470 _F and V _{D D} because V _{D D is} also equivalent to AC ground.)

The transistor 2625 can be coupled to a fixed or variable bias voltage. In addition, a bias current is also set, for example, using a parameter responsive current I(x) generator 515, also discussed previously, or other fixed or variable current source. The frequency controller modules (480, 485, which have coefficient registers 455 and 495) and the frequency calibration module (460, which has coefficient registers 465) also operate as previously discussed. In addition, various reactances (inductors 2615 and 2620, capacitor 2610) can also be implemented as fixed or variable as previously discussed. In an exemplary embodiment, resistor 2630 can also be fixed or variable.

Comparing Figures 33 and 36, it will be apparent that the Hartley configuration can be derived from the Colpitts configuration by replacing the inductor with a capacitor and replacing the capacitor with an inductor. Referring again to Figures 34 and 35, it will be apparent to those skilled in the art that the common base and common collector differential Hartley oscillator configurations can be exchanged by the described Colpitts in the differential. Capacitors and inductors in the configuration are formed. Thus, the two differential Hartley oscillator configurations are not individually described.

37 is a circuit diagram depicting an LC oscillator of a ninth example that can be utilized in accordance with the teachings of the present invention, having a single-ended Pierce configuration (or topology). As shown, the apparatus 2700 includes a LC oscillator 2705 of the ninth example having a single-ended Pierce configuration (or topology) and portions of the frequency controller and frequency calibration module discussed previously. Also because the oscillator 2705 is single-ended rather than differential, the frequency controller and frequency calibration module (485, 460) are only coupled to one rail (node 470 _G ) instead of having the double balance of FIG. Configuration. As shown, the output frequency f ₀ is obtained between nodes 470 _G and 475 _G , which is also equivalent to nodes 470 and 475 previously discussed, and thus may be used in place of all of the nodes 470 in the drawings and in this specification. With reference to 475. In addition, the frequency controller and frequency calibration module (485, 460) are coupled in parallel to the capacitor 2710 across nodes A and B as shown, or across nodes A' and B' as shown. Parallel coupling to capacitor 2715, or both (individually across node A and B in parallel to capacitor 2710 and across nodes A' and B' in parallel to capacitor 2715).

The oscillator 2705 includes an inductive load 2720, which may be, for example, an inductor or an inductor in parallel with a capacitor (presenting an integral inductance) and, as previously discussed, may be implemented as Fixed or variable. The inductive load 2705 is connected in parallel with an inverter 2725 and a resistor 2730. The frequency controller module (480, 485, which has coefficient registers 455 and 495) and the frequency calibration module (460, which has a coefficient register 465) also operate as previously discussed. In addition, various capacitors 2710 and 2715 can also be implemented as fixed or variable as previously discussed. In an exemplary embodiment, the resistor 2730 can also be fixed or variable.

It should be noted that any of a variety of LC oscillator topologies can be implemented to provide an orthogonal configuration (or topology) that can be compensated with frequency (for temperature, process variations, in accordance with the teachings of the present invention). And other parameter changes) are used together. For example, two LC oscillators can be cross-coupled to each other and suitably to the frequency controller module (480, 485, which has coefficient registers 455 and 495) and a frequency calibration module (460, which has coefficients for the time being The registers 465) are configured together to provide a plurality of first reference signals (at 0°, 90°, 180°, and/or 270°) having a phase relationship of 90°.

38 is a circuit diagram depicting a configuration of an active inductor 2910 that can be utilized in accordance with the teachings of the present invention. Although the active inductor 2910 is depicted as utilizing a bipolar junction transistor, any type of CMOS transistor can be utilized to obtain an equivalent circuit. The active inductor 2910 can be utilized in any of the LC oscillators or their equivalent oscillator inductors or inductive loads described herein, and can provide the savings in IC area. The depicted active inductor 2910 will typically be coupled to other portions of the oscillator at node D. A bias current is also set, for example, using a parametric responsive current I(x) generator 515, also discussed previously, or other fixed or variable current source. Moreover, the active inductor 2910 is exemplified as an example without limitation - other active inductor circuits can equally be utilized, including active inductors utilizing other types of transistors and circuit configurations. Circuit.

Those skilled in the art will recognize that numerous variations are available for the LC oscillator embodiments of the various examples described above. For example, various amplifiers can be implemented in a wide variety of ways, for example, using only p-channel transistors, using only n-channel transistors, or using a combination of p- and n-channel transistors, as shown. In addition, various amplifiers and current mirrors can have various circuit positions and configurations with respect to various resonators. Variations in single or multiple inductors or abrupt devices can be utilized equally. For example, various topologies may be symmetric or asymmetric, complementary or non-complementary, or cross-coupled or non-cross-coupled. All such variations are considered equivalent and are within the scope of the invention.

Please refer to Figures 2, 3, 18 and 25-27 again, and the spread spectrum function can also be implemented. In accordance with the present invention, for example and without limitation, the spread spectrum function can be implemented in the clock/frequency reference (100, 200, 300), for example, via control logic 1810 and/or control logic or control coefficients 1950. Changing the first frequency of the first reference signal over time, or may be implemented in various frequency dividers, frequency selectors, or mode selectors (220, 205, 225, 330, 335, 345, Within 1000, 1050) or any of the locking circuits (eg, PLL/DLL 1205), the second frequency of the corresponding second reference signal is varied over time. For example, a control circuit (of control logic and/or storage coefficient register 1950) can be coupled to a plurality of switchable controlled reactance modules and adapted to provide the plurality of switchable controlled reactance modes The group of time dependent switchings modifies the first frequency and provides a first reference signal having a spread of a plurality of different first frequencies over time. Also by way of example, control circuitry (of control logic and/or storage coefficient register 1950) can be coupled to one or more lockout circuits (PLL/DLL 1205), wherein the control circuitry is adapted to provide The time dependent variation of the frequency multiple can be used to provide a second reference signal having a spread of a plurality of different second frequencies over time. Continuing with this example, any of the various frequency dividers (of a locking circuit (PLL/DLL 1205), or other frequency dividing circuit, can be implemented as a counter, wherein the control circuit is adapted to Modify the terminal or final count, which provides an output signal at the terminal or at the end of the count.

Referring again to FIG. 21, the frequency controllers 215, 349, 1415 of the present invention may include one or more of the following components: (1) a transconductance modulator 1410 (eg, 410, 415 and shown in FIGS. 6-8) Embodiments), in an exemplary embodiment, may also include or be coupled to a continuous amplifier 305; (2) a variable parameter modulator 1425 responsive to any selected parameter (eg, temperature, Process variation, voltage change, or frequency) to modulate the resonant frequency f ₀ , such as various controlled capacitor modules 485, 635, 1505 or controlled reactance modules 1305, 1805; (3) process (or other Parameter) modulator or compensator 1430, for example, process variation compensator 425, 760, 860 or controlled reactance module 1305, 1805; (4) voltage change compensator 380, 1455; and / or (5) aging (Time) variation compensator (or modulator) 365, 1460. Those skilled in the art will observe a transconductance modulator 1410, a variable parameter modulator 1425, or a process (or other parameter) modulator or compensator 1430 or other compensators and modulators. The various divisions between them are arbitrary and do not limit the scope of the invention, as each division can be made to respond to any of the above parameters and can be utilized for any of the above purposes, respectively (eg, The variable parameter modulator 1425 can be utilized to compensate for process variations, etc., rather than, for example, temperature changes. Moreover, depending on the selected implementation, one or more coefficient registers 1435 (e.g., 455, 465, 495) can be utilized to store any of the plurality of coefficients described above. In an alternative embodiment, such a factor may be undesirable, but the switching voltage or current is applied directly and statically or dynamically as a control signal.

Likewise, in the exemplary embodiment, the various components may include a sensor 1440, 1815 (eg, yI(x) (or I(T)) generator 415, 515), or for example, sensing The device can be configured as a separate component, such as the current source coupled to the diode. Again, in accordance with selected embodiments, A/D converter 1445 and control logic 1450, 1810 can also be used to provide selected frequency control.

In summary, an exemplary embodiment of the present invention provides an apparatus for frequency control of a resonator, wherein the resonator is adapted to provide a first signal having a resonant frequency. The apparatus includes a sensor (1440, 1815) adapted to provide a second signal (eg, a control voltage) in response to at least one of a plurality of parameters; and a frequency controller (215) , 1415), coupled to the sensor and coupled to the resonator, wherein the frequency controller is adapted to modify the resonant frequency in response to the second signal. The plurality of parameters are variable and include at least one of the following parameters: temperature, process, voltage, frequency, and aging.

In an exemplary embodiment, the frequency controller is further adapted to modify a reactance or impedance component coupled to the resonator in response to the second signal, for example, modifying the total of the resonator in response to the second signal Capacitor (Fig. 9), coupling a fixed or variable capacitor (635) to the resonator or decoupling from the resonator, modifying one by switching the varactor to a selected control voltage An effective reactance of the varactor coupled to the resonator, or equivalently modifying an inductance of the resonator in response to the second signal, for example, by coupling a fixed or variable inductance to the The resonator is either decoupled from the resonator or modifies a resistance (or other impedance) of the resonator in response to the second signal, for example, by coupling a resistor to the resonator or from the The resonator is decoupled.

In an exemplary embodiment, the frequency controller may further include: a coefficient register adapted to store the first plurality of coefficients; and a first array (635) having a plurality of couplings to the coefficient a register and a switchable capacitive module coupled to the resonator, each switchable capacitive module having a fixed capacitor 615 and a variable capacitor 620, each switchable capacitor The module is responsive to a corresponding one of the first plurality of coefficients to switch between the fixed capacitance and the variable capacitance, and switches each variable capacitance to a control voltage. The plurality of switchable capacitive modules can be binary weighted. The frequency controller may further include a second array 650 having a plurality of switchable resistive modules coupled to the coefficient register and further having a capacitive module, the capacitive module and the A plurality of switchable resistive modules are further coupled to a node 625 to provide the control voltage, wherein each switchable resistive module is responsive to a second plurality of coefficients stored in the coefficient register A corresponding coefficient is used to switch the switchable resistive module to the control voltage node 625. In selected embodiments, the sensor further includes a current source 655 responsive to temperature, wherein the current source is coupled to the second array via a current mirror 670 to span the plurality of The control voltage is generated on at least one of the switchable resistive modules of the switchable resistive module. Also in selected embodiments, the current source has at least one CTAT, PTAT or PTAT ² configuration (Figs. 7A through 7D). In addition, each switchable resistive module of the plurality of switchable resistive modules has a different temperature response for a selected current system.

In other exemplary embodiments, the sensor is a temperature sensor and changes the second signal in response to a change in temperature. The selected embodiment can also include an analog to digital converter 1445 coupled to the temperature sensor to provide a digital output signal in response to the second signal and including a control logic block 1450 for conversion The digital output signal becomes the first plurality of coefficients.

In other exemplary embodiments, the frequency controller further includes a process variation compensator 320, 425, 760 or 860, the process variation compensator can be coupled to the resonator and adapted to respond to the plurality of parameters One of the process parameters to modify the resonant frequency. The process variation compensator can further include a coefficient register adapted to store a plurality of coefficients; and an array 760 having a plurality of switchable capacitive modules coupled to the coefficient register and the resonator Each switchable capacitive module has a first fixed capacitor 750 and a second fixed capacitor 720, and each switchable capacitive module is responsive to a corresponding one of the plurality of coefficients Switching between the first fixed capacitance and the second fixed capacitance. In other exemplary embodiments, the process variation compensator can further include a coefficient register adapted to store a plurality of coefficients; and an array 860 having a plurality of couplings to the coefficient register and the a binary weighted switchable variable capacitive module 865 of the resonator, each switchable variable capacitive module responsive to a corresponding one of the plurality of coefficients to be at a first voltage and Switch between a second voltage.

In other exemplary embodiments, a frequency controller further includes a coefficient register adapted to store the first plurality of coefficients; and a first array 1500 having a plurality of couplings to the coefficient temporary storage And a switchable binary-weighted capacitive module 1505 coupled to the resonator, each switchable capacitive module having a variable capacitor 1515, each switchable capacitive module Resisting (1520) the variable capacitance to a selected one of the plurality of control voltages in response to a corresponding one of the first plurality of coefficients. The sensor can include a current source responsive to temperature, and the frequency controller can also include a second array 1600 having a plurality of resistive modules 1605 that pass through a current mirror ( 670, 510, 520) coupled to the current source (655), the plurality of resistive modules are adapted to provide the plurality of control voltages, and wherein each resistive mode of the plurality of resistive modules The set has a different response to the temperature system and is adapted to provide a corresponding one of the plurality of control voltages in response to a current from the current source.

In other exemplary embodiments, an apparatus for frequency control of a resonator includes a coefficient register adapted to store a first plurality of coefficients; and a first array (1300, 1800) Having a plurality of switchable reactance modules (1305, 1805) coupled to the coefficient register and the resonator, each switchable reactance module responsive to one of the first plurality of coefficients The coefficient modifies the resonant frequency by switching a corresponding reactance to the resonator. The corresponding reactance can be a fixed or variable inductance, a fixed or variable capacitance, or any combination of the two. The corresponding reactance can be switched between the resonator and a control voltage or a ground potential, and the control voltage can be determined by a current source responsive to temperature. For example, the corresponding reactance is variable and switched between the resonator and a selected one of a plurality of control voltages. In selected embodiments, the first plurality of coefficients are calibrated or determined by a sensor responsive to at least one of a plurality of variable parameters (eg, temperature, process, voltage, and frequency).

In an exemplary embodiment, the plurality of switchable reactive modules may further include a plurality of binary weighted switchable capacitive modules 640 (of the reactance module 635), each switchable capacitive module Having a fixed capacitance and a variable capacitance, each switchable capacitive module is responsive to a corresponding one of the first plurality of coefficients to be between the fixed capacitance and the variable capacitance Switch and switch each variable capacitor to a control voltage. The device can also include a current source 655 responsive to temperature; and a second array having a plurality of switchable resistives coupled to the coefficient register and selectively coupled to the current source The module 675 further includes a capacitive module 680. The capacitive module and the plurality of switchable resistive modules are further coupled to a node 625 to provide the control voltage. Switching the resistive module to switch the switchable resistive module to the control voltage node in response to a corresponding one of a second plurality of coefficients stored in the coefficient register, and wherein the plurality Each switchable resistive module of each of the switchable resistive modules has a different temperature response to a selected current system from the current source.

In other exemplary embodiments, the plurality of switchable reactive modules further includes a plurality of binary weighted switchable capacitive modules 1505 (of the controllable capacitor module 1500), each switchable capacitive module The group has a variable capacitance 1515, and each switchable capacitive module is responsive to a corresponding one of the first plurality of coefficients to switch (1520) the variable capacitance to the plurality of control voltages One of the selected control voltages. The device can also include a current source 655 responsive to temperature; and a second array having a plurality of resistive modules 1605 coupled by a current mirror (670, 510, 520) Connected to the current source, the plurality of resistive modules are adapted to provide the plurality of control voltages, and wherein each of the plurality of resistive modules has a different response to the temperature system, and Is adapted to respond to a current from the current source to provide a corresponding one of the plurality of control voltages.

In other exemplary embodiments, the plurality of switchable reactive modules may further include (a plurality of process variation compensators 760) coupled to the coefficient register and binary weighted switchable capacitors of the resonator Each of the switchable capacitive modules has a first fixed capacitor 750 and a second fixed capacitor 720, and each switchable capacitive module is responsive to one of the plurality of coefficients Corresponding coefficients are switched between the first fixed capacitance and the second fixed capacitance. In other exemplary embodiments, the plurality of switchable reactance modules may further include (a plurality of process variation compensation modules 860) coupled to the coefficient register and binary weighted switchable of the resonator A variable capacitive module 865, each switchable variable capacitive module is responsive to a corresponding one of the plurality of coefficients to switch between a first voltage and a second voltage.

In an exemplary embodiment, an apparatus in accordance with the teachings of the present invention includes a resonator 310, 405 adapted to provide a first signal having a resonant frequency; and a temperature compensator 315 coupled to The resonator is also adapted to modify the resonant frequency in response to a change in temperature. The resonator is at least one of the following resonators: an inductor (L) and a capacitor (C) configured to form a resonator of an LC-resonant circuit; a ceramic resonator, a mechanical resonator, and a The microelectromechanical resonator is either a film bulk acoustic resonator. The apparatus can further include a negative transconductance amplifier 410 coupled to the resonator and the temperature compensator, wherein the temperature compensator is further adapted to modify a current through the negative transconductance amplifier in response to a change in temperature. The temperature compensator can further include a current source 415, 515, 655 responsive to temperature changes.

In other exemplary embodiments, the temperature compensator further includes: a current source 415, 515, 655 adapted to provide a current responsive to a change in temperature; and a second adapted to store the first plurality of coefficients a coefficient register; a plurality of resistive modules 675, 1605 coupled to the resonator and the current source, at least one of the plurality of resistive modules being adapted to provide a control voltage or a plurality of controllable voltages; and a plurality of switchable reactive modules (1305, 1805, 635, 1505) coupled to the resonator and the current source and selectively coupled to the plurality of resistive At least one resistive module in the module.

In other exemplary embodiments, the present invention provides a frequency controller for frequency control of a resonator, comprising: a coefficient temporary storage adapted to store a first plurality of coefficients and a second plurality of coefficients a current source 415, 515, 655 adapted to provide a current corresponding to a temperature; a plurality of switchable resistive modules 675, 1605 having a plurality of coupled to the coefficient register An array, and further having a capacitive module, the first array being further coupled to the current source through a current mirror to be switchable across at least one of the plurality of switchable resistive modules Generating at least one control voltage on the resistive module, each switchable resistive module is responsive to a corresponding coefficient of the second plurality of coefficients to switch the switchable resistive module to provide the control voltage To a control voltage node; and a second array having a plurality of binary weighted switchable capacitive modules 640 coupled to the coefficient register and the resonator, each The switchable capacitive module has a fixed capacitance and a variable capacitance, and each switchable capacitive module is responsive to a corresponding one of the first plurality of coefficients to be at the fixed capacitance And switching between the variable capacitors and switching each variable capacitor to the control voltage node.

Referring again to FIGS. 3 and 4, the clock generator and/or timing/frequency reference (100, 200 or 300) may also include a frequency calibration module (325 or 430). This frequency calibration module is the subject of an individual patent application, but its high-level functions are outlined below. 13 is a high level block diagram depicting a frequency calibration module 900 (which may be utilized as module 325 or 430) in accordance with one example of the teachings of the present invention. The frequency calibration module 900 includes a digital frequency divider 910, a counter-based frequency detector 915, a digital pulse counter 905, and a calibration register 930 (which can also be utilized as a temporary register 465). ). Under a test IC, the output signal from the clock generator (100, 200 or 300) is frequency divided (910) and compared to a known reference frequency 920 in frequency detector 915. Pulses that are fast or slow, down or up are provided to the pulse counter 905 depending on whether the clock generator (100, 200 or 300) is relatively high relative to the reference. Based on their results, the third plurality of switching coefficients r ₀ to r _{(y - 1)} are determined and the clock generator (100, 200 or 300) is calibrated to a selected reference frequency. Similarly, individual ICs can be individually calibrated and tested.

Referring again to Figures 2, 3 and 4, it will be understood by those skilled in the art that highly accurate, low jitter, free running and self-referential oscillators under PVT have been described and are provided with an option. And one of the tunable resonant frequencies f _{0 is a} differential, substantially sinusoidal signal that can be utilized at nodes 470 and 475. This signal is sufficient for many applications and can be utilized directly (and can be output on bus bar 125 or 135 of FIG. 1, line 250 of FIG. 2, or line 350 of FIG. 3, or The track of Figure 4 or between lines 470 and 475). For example, this signal can be utilized as a timing or frequency reference. Additional applications are available in accordance with the present invention, including: clock generation (substantial square wave), frequency division, low delay frequency switching, and mode selection, ie, as described below.

14 is a block diagram depicting a frequency divider and square wave generator 1000, an exemplary non-synchronous frequency selector 1050, and an exemplary surge suppression module 1080, in accordance with one example of the teachings of the present invention. As noted above, the frequency divider and square wave generator 1000 can incorporate or include modules 220 and/or 330, and the frequency selector 1050 (with or without the surge suppression module 1080) can be incorporated into the module. These modules are included or included in 205 and/or 335.

Referring to FIG. 14, the output signal from the oscillator (ie: and substantially sinusoidal signal, such as one having a frequency f ₀ of the differential: Line 250 in FIG. 2, or on the line 350 of FIG. 3, or The output between the tracks or lines 470 and 475 of FIG. 4 is input to the frequency divider and square wave generator 1000. The frequency of the substantially sinusoidal signal is divided by any one or more arbitrary values "N" to become "m" different frequencies (including f ₀ where appropriate), and converted into a substantial square wave signal, resulting in A plurality of substantial square wave signals having m+1 different available frequencies (becoming frequencies f ₀ , f ₁ , f ₂ to f _n ) are output on the line or bus bar 1020. Any of these substantial square wave signals having m+1 different available frequencies may be selected asynchronously by an exemplary non-synchronous frequency selector 1050, which may be as shown Implemented as a multiplexer. Selecting any one of m + 1 of the system having different frequencies may be utilized such may be substantial square wave signal (the S ₀ S _m) 1055 reached via a plurality of select lines, one of the frequencies while providing a substantial square having a selected The wave signal is output on line 1060.

As part of the non-synchronous frequency selection, the spur suppression is also provided by the spur suppression module 1080. The spur suppression module 1080 can be implemented in a plurality of manners, including: transmitting one or more as shown in FIG. An example of the use of the D-type flip-flop (DFF). The glitch system may occur in an asynchronous frequency transition in which a high state or a low state is not maintained for a sufficient period of time and may cause metastability in the circuit driven by the output clock signal ( Metastability). For example, a non-synchronous frequency transition may cause a low state of a first frequency to transition to a high state of a second frequency, and at a time point, the high state is a low state to be converted back to the second frequency. , causing a voltage spike or glitch. In order to avoid potential bursts being provided as part of an output clock signal, the selected substantial square wave signal (having a selected frequency) is provided over line 1060 to a first DFF 1065, which is a DFF 1065 system. A holding state is provided; if a glitch occurs, it will be saved until the edge of the clock triggers the DFF. In order to prevent glitch from occurring at the edge of the clock, the DFFs can be provided with a clock that is less than the maximum available frequency, or one or more additional DFFs (such as DFF 1070) can be used because While waiting for another clock signal, the Q output from DFF 1065 will have stabilized to a first state (high or low) or a second state (low or high), such as to a power or ground track. The inventors have confirmed that 2 DFFs are sufficient, and the addition of additional DFFs may be desirable, but the additional DFFs cause increased switching delays. Although illustrated with the exemplary DFF, other flip-flops or counters may be utilized, and those skilled in the art will be aware of a variety of other equivalent embodiments that achieve this result, and all such variations are Within the scope of the invention.

This example of low latency frequency switching in accordance with the teachings of the present invention is depicted in FIG. Figure 15 also illustrates the "substantial" square wave of the present invention, which is a typical square wave typical of various techniques, and exhibits reasonable variations, undershoot, and overshoot at its individual heights. With a low state (and thus not a complete "flat" for textbook examples). Figure 15A depicts the unsynchronized bumpless switching from 1 MHz to 33 MHz, while Figure 15B depicts the no-surge switching measured from 4 MHz to 8 MHz, then to 16 MHz, and then to 33 MHz. .

Referring again to Figure 14, the frequency divider and square wave generator 1000 can be implemented in a number of ways, such as differential or single-ended, and the illustrated frequency dividers are merely examples. Since the output from the oscillator shown in Figure 4 is differential (across lines or tracks 470 and 475), the first frequency divider 1005 is also differential and provides a complementary output to present a substantial Fixed load and maintain phase alignment, and fast to support high frequencies such as in the GHz range. Furthermore, it may be necessary or appropriate to reject the oscillation of any relaxation mode of the first frequency divider 1005. The second frequency divider 1010 can also be differential and provide any arbitrary frequency division (divide by "M"), such as by an integer, a multiple of 2, a rational number, or any other amount or number, etc. . Topologies or configurations for such frequency dividers are known in the art, and any such frequency divider can be utilized. By way of example and not limitation, such a frequency divider can be a sequence (multi-stage) counter or flip-flop 1075, such as the ones shown in FIG. 16, which are provided in multiples of two The frequency division, the output of each stage provides a different frequency, and is provided for one of the next level of the clock signal, and is also fed back to its own input, as shown. As shown, a plurality of frequency systems are then available for output over the line or bus bar 1020, such as: f ₀ /2, f ₀ /4, etc., to f ₀ /2 ^N . In addition, as shown, the buffer 1085 can also be utilized between the oscillator and the first frequency divider 1005 to provide sufficient voltage to drive the first frequency divider 1005, and can also be utilized in the second The load variation between the stages of the frequency divider 1010 may also affect the state of the signal rise and fall times.

It should also be noted that the use of various flip-flops has also provided a substantial square wave, since any substantial sinusoidal signal system has been provided as a clock to a flip-flop, the output of which is then pulled to A high or low voltage. Other square wave generators can also be utilized, i.e., those skilled in the art or become known to those skilled in the art. In the illustrated embodiment, to maintain phase alignment, the differential signal is maintained through the final divide. After the final divide, the plurality of signals (each having a different frequency) are then formed into a square (in module 1015) to provide a substantially average split (eg, 50:50) duty cycle, causing the signal to be The time of a (high) state is substantially equal to the time at which the signal is in a second (low) state.

Figure 17 is a block diagram depicting a mode selection module in accordance with one example of the teachings of the present invention. There are some cases where a highly accurate, high performance reference device (such as a clock generator (100, 200 or 300) of the present invention) is not required, such as a low power, standby mode. In such cases, in accordance with the present invention, no clock output is provided, or only a low power, reduced performance clock 1105 output is provided. For example, at relatively low frequencies, a low performance ring oscillator can provide adequate performance at low power consumption. As shown in Figure 17, for these situations, the output of the low power oscillator 1105 can be selected (through the multiplexer 1100) and provided as a clock output to one of the other circuits. However, at higher frequencies, such inefficient oscillators consume a significant amount of power, typically significantly exceeding the oscillator of the present invention. Typically there is a "break-even" point as a function of frequency, after which the clock generator (100, 200 or 300) provides higher performance and lower power consumption, It can be selected (through multiplexer 1100) and provided as a clock output to one of the other circuits. Thus, the clock generator (100, 200 or 300) can also be utilized to provide a low power mode.

In addition, under the mode selector 1110, other modes can be selected, such as: a no power mode, rather than just a low frequency or sleep mode, because the clock generator (100, 200 or 300) can be A fairly quick restart, or such as selecting a pulse mode, wherein the clock generator (100, 200 or 300) is repeatedly stopped and restarted in bursts or intervals, periodic or aperiodic. Various reference modes are discussed later.

Significantly compared to prior art, such a pulsed clock system utilizing the clock generator and/or timing/frequency reference (100, 200 or 300) of the present invention provides power savings or savings. Although more power may be consumed during a particular burst period, because the clock has a relatively high frequency, more commands are processed in the interval and then during the no-pulse or turn-off interval. There is no or limited power consumption, which results in a higher MIPS/mW than a continuously operating clock. Conversely, due to the relatively long start-up time and locking of the prior art clocks, such pulsed clocks have resulted in more power consumption and less efficiency in the prior art.

18 is a block diagram depicting a synchronization module 1200 for an example of a second oscillator in accordance with the teachings of the present invention. As noted above, the clock generator and/or timing/frequency reference (100, 200 or 300) can provide a reference mode to synchronize other oscillators or clocks, which can be low power or no, such as: A second oscillator 1210 (eg, a ring, relaxation, or phase shift oscillator). An output signal from one of the clock generator and/or the timing/frequency reference (100, 200 or 300) is further divided as needed to form a plurality of available reference frequencies, wherein a reference frequency is selected from This multiple frequency. This can be accomplished using the modules described above, such as by using an existing frequency divider (e.g., 220, 330, 1000), and then providing a reference signal from frequency selector 1050 (or 205 or 335). For example, referring to FIG. 3, the mode selector 345 selects a reference mode and provides an output reference signal from the frequency selector 335 to a second oscillator (with a synchronization module) 375. A synchronization module such as a PLL or DLL 1205 is then utilized to synchronize the output signal from the second oscillator 1210 to the clock generator and/or the timing/frequency reference (100, 200 or 300). Reference signal. In addition to the continuous synchronization mode, a pulsed synchronization can also be provided, wherein the clock generator and/or the timing/frequency reference (100, 200 or 300) provides a pulsed output and is synchronized. The system occurs during these pulse intervals as a synchronization interval.

19 is a flow chart depicting a method in accordance with an example of the teachings of the present invention and provides a useful summary. The method begins at an initial step 1220, such as by a start of a clock generator and/or a timing/frequency reference (100, 200 or 300). It should be noted that although successive steps are shown in FIG. 19, the steps may occur in any order and may generally be with a clock generator and/or a timing/frequency reference (100, 200 or 300). ) Operational at the same time. Referring to FIG. 19, a resonant signal having a resonant frequency is generated in step 1225, such as through LC resonant circuit 405 or resonator 310. At step 1230, the resonant frequency is adjusted in response to temperature, such as by a temperature compensator 315 that adjusts current and frequency. At step 1235, the resonant frequency is adjusted in response to a process change, such as through process variation compensator 320. As noted above, step 1235 can be performed as a first calibration step followed by a temperature adjustment at step 1230. In step 1240, the resonant signal having the resonant frequency is divided into a plurality of second signals having a corresponding plurality of frequencies, wherein the plurality of frequencies are substantially equal to or lower than the resonant frequency, such as: a frequency divider. 330 or 1000. At step 1245, an output signal is selected from the plurality of second signals, such as, for example, through frequency selector 335 or 1050. For example, depending on the selected embodiment or mode, the selected output signal can be provided directly as a reference signal.

In other embodiments, such as when the output signal is a differential signal rather than a single-ended signal, and when the resonant signal is a substantially sinusoidal signal, in step 1250, the method continues to convert the differential, The substantially sinusoidal signal becomes a single-ended, substantially square wave signal that, if desired, has substantially equal high and low duty cycles, such as to generate a clock output signal, such as a mode of operation. Group 330 or 1000. In step 1255, an operation mode is also selected from a plurality of operation modes, wherein the plurality of operation modes may be one selected from the group consisting of a clock mode, a timing and frequency reference mode, a power saving mode, and a pulse mode. The group, for example, is the application mode selector 225 or 345. In step 1260, when a reference mode is selected in step 1255, the method proceeds to step 1265 to synchronize a third signal (eg, from a second oscillator) in response to the output signal, such as Figure 18 shows. After step 1260 or 1265, in a return to step 1270, the method may end or repeat (continue) (such as continuous operation by a clock generator and/or a timing/frequency reference (100, 200 or 300)) .

Moreover, in summary, the present invention provides an apparatus comprising: a resonator adapted to provide a first signal having a resonant frequency; an amplifier coupled to the resonator; and a frequency A controller (coupled to the resonator) adapted to select a resonant frequency having a first frequency of one of a plurality of frequencies. The device also includes a frequency divider (coupled to the resonator) adapted to divide the first signal having the first frequency into a plurality of second signals having a corresponding plurality of frequencies, the plurality of frequencies It is substantially equal to or lower than the first frequency, such as by dividing by a rational number.

The first signal can be a differential signal or a single-ended signal. When the first signal is a differential signal, the frequency divider is adapted to convert the differential signal into a single-ended signal. Similarly, when the first signal is a substantially sinusoidal signal, the frequency divider is more adapted to convert the substantially sinusoidal signal into a substantially square wave signal.

In various embodiments, the frequency divider can include a plurality of flip-flops or counters coupled in series, wherein one of the selected flip-flops or one of the counters is a previous flip-flop or counter. Dividing a frequency by two; or more generally, the frequency divider comprises a plurality of frequency dividers coupled in series, wherein the output of one of the subsequent frequency dividers is compared to the previous frequency divider The output is at a lower frequency. The plurality of frequency dividers can be differential, single-ended, or differential and single-ended, such as: differential and then with a final single-ended stage. The frequency divider can also include a square wave generator adapted to convert the first signal into a substantially square wave signal having a substantially equal high and low duty cycle.

The invention can also include a frequency selector coupled to the frequency divider and adapted to provide an output signal from one of the plurality of second signals. The frequency selector can further include a multiplexer and a surge suppressor.

The present invention can also include a mode selector coupled to the frequency selector, wherein the mode selector is adapted to provide a plurality of modes of operation, which can be selected from the group consisting of a clock mode, a timing and frequency reference mode , a power saving mode, and a group of one pulse mode.

For a reference mode, the present invention may also include a synchronization circuit coupled to the mode selector; and a controlled oscillator coupled to the synchronization circuit and adapted to provide a third signal; In the timing and frequency reference mode, the mode selector is further adapted to couple the output signal to the synchronization circuit to control the timing and frequency of the third signal. The synchronization circuit can be a delay locked loop, a phase locked loop, or an injection locking circuit.

In selected embodiments, the amplifier can be a negative transconductance amplifier. The frequency controller is further adapted to modify the current through one of the negative transconductance amplifiers in response to temperature and may include a current source responsive to one of the temperatures. The current source may have one or more configurations selected from a plurality of configurations, such as a plurality of configurations including CTAT, PTAT, and PTAT ² configurations. In addition, the frequency controller is further adapted to modify a current through the negative transconductance amplifier to select the resonant frequency in response to a voltage, modify one of the negative transconductance amplifiers to select the resonant frequency, or modify the pass. One of the negative transconductance amplifier currents. The frequency controller can also include a voltage isolator coupled to the resonator and adapted to substantially isolate the resonator from voltage variations, and can include a current mirror, which can further have a cascade configuration. The frequency controller is further adapted to modify a capacitance or an inductance of the resonator in response to a process change, a temperature change, or a voltage change.

The frequency controller can have various embodiments for such various functions, and can further include: a coefficient register adapted to store the first plurality of coefficients; and a first array coupled Connected to the plurality of switchable capacitive modules of the coefficient register and the resonator, each switchable capacitive module has a fixed capacitor and a variable capacitor, and each switchable capacitive module is responsive A coefficient corresponding to one of the first plurality of coefficients is switched between the fixed capacitor and the variable capacitor, and each variable capacitor is switched to a control voltage. The plurality of switchable capacitive modules can be binary weighted or have another weighting method. The frequency controller may further include: a second array having a plurality of switchable resistive modules coupled to the coefficient register and further comprising a capacitive module, the capacitive module and the plurality The switchable resistive module is further coupled to a node to provide the control voltage, and each switchable resistive module is responsive to a corresponding one of the second plurality of coefficients stored in the coefficient register a coefficient to switch the switchable resistive module to the control voltage node; and a temperature dependent current source coupled to the second array via a current mirror.

The frequency controller can also include a process variation compensator coupled to the resonator and adapted to modify the resonant frequency in response to process variations. In an exemplary embodiment, the process variation compensator can include: a coefficient register adapted to store a plurality of coefficients; and a switchable plurality of coupled to the coefficient register and the resonator An array of capacitive modules, each switchable capacitive module having a first fixed capacitance and a second fixed capacitance, each switchable capacitive module being responsive to the plurality of coefficients A corresponding coefficient is switched between the first fixed capacitance and the second fixed capacitance. The plurality of switchable capacitive modules can be binary weighted or have other weighting methods.

In another exemplary embodiment, the process variation compensator can include: a coefficient register adapted to store a plurality of coefficients; and a plurality of coupled to the coefficient register and the resonator An array of switched variable capacitive modules, each switchable variable capacitive module responsive to a corresponding one of the plurality of coefficients to be between a first voltage and a second voltage Do the switching. The plurality of switchable variable capacitive modules can also be binary weighted or have other weighting methods.

The invention can also include a frequency calibration module coupled to the frequency controller and adapted to modify the resonant frequency in response to a reference signal. For example, the frequency calibration module can include a frequency divider coupled to the frequency controller, the frequency divider being adapted to convert an output signal derived from the first signal having the first frequency to a lower level. Frequency to provide a frequency-divided signal; a frequency detector coupled to the frequency divider, the frequency detector is adapted to compare the reference signal with the frequency-divided signal and provide one or a plurality of upper signals or lower signals; and a pulse counter coupled to the frequency detector, the pulse counter adapted to determine a difference between the one or more upper signals or the lower signals, as One of the difference between the output signal and the reference signal is indicated.

The resonator system used in the present invention may include an inductor (L) coupled to one of an LC resonant circuit and a capacitor (C) having a selected one of a plurality of LC resonant circuit configurations. Configurations such as: series, parallel, etc., and may include other components. In other embodiments, the resonator may be selected from the group consisting of: a ceramic resonator, a mechanical resonator, a microelectromechanical resonator, and a film bulk acoustic resonator, or electrically equivalent to An inductor (L) is coupled to any other resonator of a capacitor (C).

For example, the resonator typically includes one or more inductors and capacitors that form one or more LC-resonant circuits or LC resonators. In the first embodiment, a double balanced differential LC oscillator topology is utilized. In other example embodiments, a differential or single-ended LC oscillator topology can be utilized, such as a single-ended Colpitts LC oscillator, a single-ended Hartley LC oscillator, a differential Colpitts LC oscillator (with a common base and Two forms of common collectors), differential Hartley LC oscillators (also two forms of common base and common collector), single-ended Pierce LC oscillators, quadrature oscillators (for example, by at least two double balances) The differential LC oscillator is constructed, or the active inductor LC oscillator (which can be implemented as differential or single-ended). Other LC oscillator topologies that are currently known or will become known are considered equivalent and within the scope of the present invention.

The apparatus of the present invention can be utilized as a timing and frequency reference, or as a clock generator. In addition, the present invention may also include: a second oscillator (such as a ring, relaxation, or phase shift oscillator) that provides a second oscillator output signal; and a mode selector coupled To the frequency controller and the second oscillator, the mode selector is adapted to switch to the second oscillator output signal to provide a power saving mode. The additional mode of operation may be provided by a mode selector coupled to the frequency controller, the mode selector being adapted to periodically initiate and stop the resonator to provide a pulsed output signal, or A power saving mode is provided adapted to selectively initiate and stop the resonator.

In another selected embodiment, the apparatus of the present invention comprises: a resonator adapted to provide a first signal having a resonant frequency; an amplifier coupled to the resonator; a temperature compensator The system is coupled to the amplifier and the resonator, the temperature compensator is adapted to modify the resonant frequency in response to temperature; a process variation compensator coupled to the resonator, the process variation compensator is adapted And modulating the resonant frequency to modify the resonant frequency; a frequency divider is coupled to the resonator, the frequency divider is adapted to divide the first signal having the resonant frequency to have a corresponding plurality of frequencies a plurality of second signals, the plurality of frequencies being substantially equal to or lower than the resonant frequency; and a frequency selector coupled to the frequency divider, the frequency selector adapted to provide from the One of a plurality of second signals outputs a signal.

In another selected embodiment, the apparatus of the present invention generates a clock signal and includes: an LC resonator adapted to provide a first signal having a differential, substantially sinusoidal shape having a resonant frequency; a negative transconductance amplifier coupled to the LC resonator; a temperature compensator coupled to the negative transconductance amplifier and the LC resonator, the temperature compensator adapted to modify the temperature in response to the temperature a current in the transconductance amplifier, and further adapted to modify a capacitance of the LC resonator in response to the temperature; a process variation compensator coupled to the LC resonator, the process variation compensator adapted to Modulating the capacitance of the LC resonator in response to a process change; a frequency divider coupled to the resonator, the frequency divider being adapted to convert and divide the first signal having the resonant frequency to have a corresponding a plurality of single-ended, substantially square-wave second signals of a plurality of frequencies, the plurality of frequencies being substantially equal to or lower than the resonant frequency, and each of the second signals having a substantially equal high and low duty cycle; And a frequency Selector, which line is coupled to the frequency divider, the frequency selector adapted to provide a system the plurality of second signal from one of the output signal.

It will be apparent that various changes and modifications can be made without departing from the spirit and scope of the invention. It will be appreciated that the specific methods and apparatus described herein are not intended to be limiting or should be construed as limiting. Rather, all such modifications as fall within the scope of the appended claims are intended to be

100. . . Clock generator and/or timing/frequency reference

120. . . Interface (I/O circuit)

125, 135. . . Busbar

140, 145. . . line

150. . . system

180. . . Second circuit

200. . . Device

205. . . Frequency selector

210. . . Oscillator

215. . . Frequency controller

220. . . Frequency divider

225. . . Mode selector

250. . . line

300. . . Clock generator and/or timing/frequency reference

305. . . Continuous amplifier

310. . . Resonator

315. . . Temperature compensator

320. . . Process change compensator (modulator)

325. . . Frequency calibration module

330. . . Frequency divider and square wave generator

335. . . Output frequency selector

340. . . Coefficient register

345. . . Mode selector

340. . . Frequency controller

350. . . line

355. . . Voltage isolator

360. . . Resonant frequency selector

365. . . Aging (time) change compensator (modulator)

380. . . Voltage change compensator

385. . . Sensor

390. . . Analog to digital converter

395. . . Oscillator

399. . . Low delay starter module

405. . . Resonator

410. . . Negative transconductance amplifier

415. . . I(T)(yI(x)) generator

420. . . Temperature responsive (temperature dependent) frequency (f ₀ (T)) compensation module

425. . . Process variation compensation module

430. . . Frequency calibration module

435. . . Inductor

440. . . Capacitor

445, 450. . . resistance

455. . . Register

460. . . Module

465. . . Register

470, 475. . . Node (line)

470 _A, 475 _A. . . node

470 _B , 475 _B. . . node

470 _C , 475 _C. . . node

470 _D , 475 _D . . . node

470 _E , 475 _E. . . node

470 _F , 475 _F. . . node

470 _G, 475 _G. . . node

480. . . Voltage controller

485. . . Module

495. . . Register

500. . . LC resonant circuit

505. . . Amplifier

510. . . Voltage isolator (current mirror)

515. . . Temperature responsive current generator (I(x))

520. . . Current mirror

520A, 520B. . . Cascade topology

525A, 525B. . . Transistor

530, 530A, 530B. . . Current mirror

550. . . LC resonant circuit

570. . . Shunt capacitor

615. . . Variable capacitor

620. . . Fixed capacitor

625. . . node

635. . . First controllable (controlled) capacitor module

_{640,640 0, 640 1 ~ 640 (} w - 1). . . Switchable capacitive module

650. . . Voltage control module

655. . . Current generator

670. . . Current mirror

675. . . Switchable resistive module (branch)

680. . . Fixed capacitive module (branch)

685. . . Resistor

720. . . Second fixed capacitor

740. . . Switching transistor

750. . . First fixed capacitance

760. . . First process variation compensation module

850. . . Variable container

860. . . Second process change compensation module

865. . . Switchable variable capacitance module

900. . . Frequency calibration module

905. . . Digital pulse counter

910. . . Digital frequency divider

915. . . Frequency detector

920. . . Reference frequency

930. . . Calibration register

1000. . . Frequency divider and square wave generator

1005. . . First frequency divider

1010. . . Second frequency divider

1020. . . Line (bus bar)

1050. . . Asynchronous frequency selector

1055. . . Select line

1060. . . line

1065, 1070. . . DFF

1075. . . Counter (positive and reverse)

1080. . . Surge suppression module

1085. . . buffer

1100. . . Multiplexer

1105. . . Clock

1200. . . Synchronization module

1205. . . PLL (DLL)

1210. . . Second oscillator

1220, 1225, 1230, 1235, 1240, 1245, 1250, 1255, 1260, 1265, 1270. . . step

1300. . . Array

1305, 1305 ₀ , 1305 ₁ ~ 1305 _{( a - 1 )} . . . Controlled impedance module

1310. . . Variable reactance

1315. . . Fixed reactance

1320. . . Virtual reactance

1400. . . Device

1415. . . Frequency controller

1420. . . Mutual transconductor

1425. . . Variable parameter modulator (controller)

1430. . . Process (other parameters) modulator (compensator)

1435. . . Coefficient register

1440. . . Sensor

1445. . . Analog to digital (A/D) converter

1450. . . Control logic block

1455. . . Voltage compensator

1460. . . Aging change compensator

1500, 1501, 1505. . . Controlled capacitor module

1515, 1515 _{A 0} ~ 1515 _{B ( g - 1 )} . . . Variable capacitance

1520 ₀ ~ 1520 _{( g - 1 )} . . . switch

1600. . . Second voltage control module

1605, 1605 ₀ , 1605 ₁ ~ 1605 _{( k - 1 )} . . . Resistive module

1610, 1610 ₀ , 1610 ₁ ~ 1610 _{( k - 1 )} . . . Transistor

1620 ₀ , 1620 ₁ ~ 1620 _{( k - 1 )} . . . Resistor

1650. . . Switchable resistive module

1700, 1705, 1710, 1715, 1720, 1725, 1730. . . Frequency response

1800. . . Array

1805, 1805 ₀ ~ 1805 _{( n - 1 )} . . . Controlled reactance module

1810. . . Control logic

1815. . . Sensor

1820. . . Line (node)

1900. . . Third voltage control module

1905, 1905 ₀ , 1905 ₁ ~ 1905 _{( n - 1 )} . . . Resistive module

1915, 1915 ₀ , 1915 ₁ ~ 1915 _{( n - 1 )} . . . Transistor

1920 ₀ , 1920 ₁ ~ 1920 _{( n - 1 )} . . . Resistor

1930. . . switch

1950. . . Control signal (coefficient)

1955. . . Battery

2000. . . Voltage variation compensation module

2040, 2040 _A , 2040 _B , 2040 _C ~ 2040 _K. . . Resistor

2050. . . Fourth voltage control module

_{2055,2055 A, 2055 B, 2055 C} ~ 2055 K. . . Battery

2060, 2060 _A , 2060 _B , 2060 _C ~ 2060 _K. . . Fixed voltage module

2100. . . Resistive control module

2105, 2105 _M , 2105 _N , 2105 _O ~ 2105 _U. . . Resistor

_{2110,2110 M, 2110 N, 2110 O} ~ 2110 U. . . Transistor (switch)

2115, 2115 _M , 2115 _N , 2115 _O ~ 2115 _U. . . Resistive module

2200. . . Aging change compensator

2205. . . Voltage sensor

2210. . . Resistance sensor

2220. . . Multiplexer

2225. . . ADC

2230. . . Register (memory)

2235. . . Comparators

2240. . . Memory

2250. . . Device

2251, 2252. . . Transistor

2253, 2254. . . Inductor

2257. . . Inductor

2260. . . LC oscillator

2270. . . Device

2271, 2272. . . Transistor

2273, 2274. . . Inductor

2277. . . Inductor

2280. . . LC oscillator

2300. . . Device

2305. . . LC oscillator

2310, 2315. . . Capacitor

2320. . . Inductor

2325. . . Transistor

2330. . . resistance

2400. . . Device

2405. . . LC oscillator

2410, 2415. . . Capacitor

2420. . . Inductor

2425, 2426. . . Transistor

2430. . . Capacitor

2500. . . Device

2505. . . LC oscillator

2510, 2515. . . Capacitor

2520. . . Inductor

2530. . . Capacitor

2600. . . Device

2605. . . LC oscillator

2610. . . Capacitor

2615. . . Inductor

2625. . . Transistor

2630. . . resistance

2700. . . Device

2705, 2715. . . LC oscillator

2720. . . Inductive load

2725. . . inverter

2730. . . resistance

2910. . . Active inductor

The objects, features, and advantages of the present invention will be more readily understood from the aspects of the appended claims <RTIgt; The same or similar components, wherein: Figure 1 is a block diagram depicting a system embodiment in accordance with a first example of the teachings of the present invention.

2 is a block diagram depicting an embodiment of an apparatus in accordance with a first example of the teachings of the present invention.

3 is a block diagram depicting an embodiment of an apparatus in accordance with a second example of the teachings of the present invention.

4 is a high level schematic block diagram depicting a frequency controller, oscillator, and frequency calibration embodiment in accordance with an example of the teachings of the present invention.

Figure 5A is a diagram showing an exemplary graph of oscillator voltage waveform (frequency) distortion caused by the harmonic content of a current injected into an oscillator having a particular filter response.

Figure 5B is an exemplary graph depicting the oscillator voltage waveform (frequency) shown in Figure 5A as a function of temperature.

Figure 5C is a diagram showing an example of a function of the oscillator frequency as a function of the mutual conductance of the sustain amplifier.

6 is a circuit diagram depicting a negative transconductance amplifier, a temperature responsive current generator (I(T)), and an LC resonant circuit oscillator embodiment in accordance with a first example of the teachings of the present invention.

7A is a circuit diagram depicting a temperature responsive CTAT current generator in accordance with an example of the teachings of the present invention.

7B is a circuit diagram depicting a temperature responsive PTAT current generator in accordance with an example of the teachings of the present invention.

7C is a circuit diagram depicting a temperature responsive PTAT ² current generator in accordance with an example of the teachings of the present invention.

7D is a circuit diagram depicting an alternative and scalable temperature responsive current generator having an example of selected CTAT, PTAT, and PTAT ² configurations in accordance with the teachings of the present invention.

8 is a circuit and block diagram depicting an embodiment of a negative transconductance amplifier, a temperature responsive current generator (I(T)), and an LC resonant circuit oscillator in accordance with a second example of the teachings of the present invention.

9 is a circuit diagram depicting a first controlled (or controllable) capacitive module of an example utilized in a frequency-temperature compensation module in accordance with the teachings of the present invention.

10 is a circuit diagram depicting a first voltage control module that is utilized in an example of a frequency-temperature compensation module in accordance with the teachings of the present invention.

11 is a circuit diagram depicting a first process variation compensation module in accordance with an example of the teachings of the present invention.

12 is a circuit diagram depicting a second process variation compensation module in accordance with an example of the teachings of the present invention.

13 is a block diagram depicting a frequency calibration module in accordance with an example of the teachings of the present invention.

14 is a block diagram depicting a frequency divider, a square wave generator, a non-synchronous frequency selector, and a surge suppression module in accordance with an example of the teachings of the present invention.

15A and 15B are diagrams depicting low latency frequency switching in accordance with an example of the teachings of the present invention.

Figure 16 is a block diagram depicting a frequency divider in accordance with an example of the teachings of the present invention.

17 is a block diagram depicting a power mode selection module in accordance with an example of the teachings of the present invention.

18 is a block diagram depicting a synchronization module for an example of a second oscillator in accordance with the teachings of the present invention.

19 is a flow chart depicting a method in accordance with an example of the teachings of the present invention.

20 is a block and circuit diagram depicting an example of a controlled impedance module utilized in a compensation module in accordance with the teachings of the present invention.

21 is a block diagram depicting a frequency controller and apparatus in accordance with a first example of the teachings of the present invention.

22 is a circuit diagram depicting a second controlled capacitance module of an example utilized in a frequency-temperature compensation module in accordance with the teachings of the present invention.

23 is a circuit diagram depicting a second voltage control module that is utilized in an example of a frequency-temperature compensation module in accordance with the teachings of the present invention.

Figure 24 is a diagram depicting an example of frequency control in response to temperature changes in accordance with the teachings of the present invention.

Figure 25 is a block diagram depicting a frequency controller and apparatus in accordance with a second example of the teachings of the present invention.

26 is a circuit diagram depicting a third controlled capacitance module and an exemplary third voltage control module of an example utilized in a parameter compensation module in accordance with the teachings of the present invention.

27 is a circuit and block diagram depicting a voltage variation compensation module in accordance with an example of the teachings of the present invention.

28 is a circuit diagram depicting a fourth voltage control module that is utilized in an example of a frequency and process compensation module in accordance with the teachings of the present invention.

29 is a circuit diagram depicting a resistive control module in accordance with an example of the teachings of the present invention.

30 is a block diagram depicting an aging change compensator in accordance with an example of the teachings of the present invention.

31 is a circuit diagram depicting an LC oscillator of a third example that can be utilized in accordance with the teachings of the present invention.

32 is a circuit diagram depicting an LC oscillator of a fourth example that can be utilized in accordance with the teachings of the present invention.

Figure 33 is a circuit diagram depicting an LC oscillator of a fifth example that can be utilized in accordance with the teachings of the present invention.

Figure 34 is a circuit diagram depicting an LC oscillator of a sixth example that can be utilized in accordance with the teachings of the present invention.

Figure 35 is a circuit diagram depicting an LC oscillator of a seventh example that can be utilized in accordance with the teachings of the present invention.

36 is a circuit diagram depicting an LC oscillator of an eighth example that can be utilized in accordance with the teachings of the present invention.

37 is a circuit diagram depicting an LC oscillator of a ninth example that can be utilized in accordance with the teachings of the present invention.

38 is a block diagram depicting an embodiment of an active inductor in accordance with the teachings of the present invention.

420. . . Temperature responsive (temperature dependent) frequency (f ₀ (T)) compensation module

425. . . Process variation compensation module

430. . . Frequency calibration module

455, 465. . . Register

460. . . Module

470 _A , 475 _A . . . node

480. . . Voltage controller

485. . . Module

495. . . Register

530A, 530B. . . Current mirror

2250. . . Device

2251, 2252. . . Transistor

2253, 2254. . . Inductor

2257. . . Inductor

2260. . . LC oscillator

Claims (19)

A device for providing a first reference signal, the device comprising: a harmonic oscillator comprising an inductor and a capacitor, the harmonic oscillator being adapted to provide the first frequency a first reference signal and operating without being locked to an external reference signal; a plurality of resistive modules adapted to generate a plurality of voltage control signals; a plurality of switchable controlled reactance modules, The plurality of reactive modules are adapted to respond to a corresponding voltage control signal of the plurality of voltage control signals, Providing a selected reactance to modify the first frequency; a coefficient register coupled to the plurality of switches, the coefficient register being adapted to store a plurality of switching coefficients; and a plurality of couplings to the a plurality of resistive modules and switches of the plurality of controlled reactance modules, each of the plurality of switches being responsive to a corresponding switching coefficient to one of the plurality of control voltages The control voltage is coupled to the controlled reactance corresponding to a module. The apparatus of claim 1, wherein the plurality of open relationships are further responsive to a corresponding switching coefficient to couple a corresponding one of the plurality of controlled reactance modules to the harmonic An oscillator to modify the first frequency. The device of claim 1, wherein the harmonic oscillator system Having at least one of the following configurations: a dual balanced differential LC configuration; a differential n-MOS cross-coupled topology; a differential p-MOS cross-coupled topology; a single-ended Colpitts LC configuration; Hartley LC configuration; Colpitts LC configuration for differential common base; Colpitts LC configuration for differential common collector; Hartley LC configuration for differential common base; Hartley LC configuration for differential common collector; single-ended Pierce LC oscillator Or an orthogonal LC oscillator configuration. The apparatus of claim 1, wherein the plurality of controlled reactance modules further comprises: a plurality of variable capacitors correspondingly coupled to the plurality of switches and voltage controllers, the plurality of variable capacitors Capacitor is adapted to provide a selected capacitance in response to a corresponding control voltage; and a plurality of fixed capacitors correspondingly coupled to the plurality of switches, the plurality of fixed capacitors being adapted to respond to a A corresponding switching factor is provided to provide a selected capacitance. The device of claim 1, wherein the at least one of the plurality of control voltages is responsive to one of a plurality of parameters, wherein the plurality of parameters are variable and include the following parameters At least one: temperature, process, voltage, aging, and frequency. The device of claim 5, further comprising: a current source coupled to the plurality of resistive modules, the current source being adapted to provide a parameter dependent current to the plurality of resistive modules And at least one resistive module to generate a control voltage dependent on at least one of the plurality of control voltages. The device of claim 6, wherein the current source has at least one (CTAT) configuration complementary to absolute temperature, proportional to absolute temperature (PTAT) configuration, or proportional to absolute temperature squared ( PTAT ² ) configuration. The device of claim 1, wherein the plurality of controlled reactance modules further comprise a plurality of fixed weights of fixed capacitance and variable capacitance, and wherein the plurality of open relationships are responsive to the plurality of switching coefficients Coupling a fixed capacitor to the harmonic oscillator, and coupling one of the plurality of control voltages to a variable capacitor coupled to the simple harmonic Device. The device of claim 1, wherein the plurality of controlled reactance modules further comprises: a plurality of switchable capacitive modules coupled to the coefficient register and the harmonic oscillator, each weighted switchable capacitor module The switchable capacitive module has a first fixed capacitance and a second fixed capacitance, and each switchable capacitive module is responsive to a corresponding one of the plurality of coefficients to Switching between the first fixed capacitor and the second fixed capacitor. The apparatus of claim 1, wherein the plurality of controlled reactance modules further comprises: at least one switchable variable capacitive module coupled to the coefficient register and the harmonic oscillator, At least one switchable variable capacitive module is responsive to a corresponding one of the plurality of coefficients to perform between a first voltage and a second voltage of the plurality of control voltages Switch. The apparatus of claim 1, wherein the plurality of controlled reactance modules further comprises: a plurality of switchable variable capacitive modules coupled to the coefficient register and the harmonic oscillator, each The switchable variable capacitive module is responsive to a corresponding one of the plurality of coefficients to switch to a selected one of a plurality of control voltages, the plurality of control voltages comprising a plurality of Different sized voltages, and wherein the selected control voltage is substantially fixed for temperature changes. The device of claim 1, further comprising: a plurality of frequency dividers coupled to the oscillator, the plurality of frequency dividers being adapted to provide a plurality of corresponding numbers having a plurality of corresponding frequencies Two reference signals. The device of claim 1, further comprising: a mode selector coupled to the frequency selector, the mode selector adapted to provide a plurality of modes of operation, the plurality of modes of operation being selected from the group consisting of A group consisting of a clock mode, a timing and frequency reference mode, a power saving mode, and a pulse mode. The apparatus of claim 1, further comprising: a square wave generator coupled to the harmonic oscillator, the square wave generator adapted to convert the frequency reference signal into a substantially equal The square wave clock signal of the duty cycle. The device of claim 14, further comprising: a processor coupled to the square wave generator and coupled to the device Form an integrated circuit. The device of claim 1, further comprising: a plurality of frequency dividers or locking circuits coupled to the harmonic oscillator, the plurality of frequency dividers or locking circuits being adapted to provide a plurality of correspondences The frequency corresponds to a plurality of second reference signals. The device of claim 16, further comprising: a control circuit coupled to the plurality of frequency dividers or locking circuits, the control circuit being adapted to provide a control signal to the plurality of frequency dividers or locks The circuit modifies a divisible multiple to provide a second reference signal of one of the plurality of second reference signals. The device of claim 16, further comprising: a control circuit coupled to the plurality of controlled reactance modules, the control circuit being adapted to provide a control signal to the plurality of controlled reactance modules The plurality of controlled reactance modules are selectively switched to modify the first frequency to provide a first reference signal of the spread spectrum. An integrated circuit for providing a first reference signal and having an integrated processor, the integrated circuit comprising: a harmonic oscillator comprising an inductor and a capacitor, the harmonic oscillator system Configuring to provide the first reference signal having a first frequency; a plurality of resistive modules adapted to generate a plurality of voltage control signals; coupled to the harmonic oscillator and the plurality of resistive modules a plurality of controlled capacitor modules, each capacitor module of the plurality of capacitor modules is adapted Providing a selected capacitor to modify the first frequency in response to a corresponding one of the plurality of voltage control signals; a coefficient register coupled to the plurality of switches, the coefficient register Configuring to store a plurality of switching coefficients; a plurality of switches coupled to the plurality of resistive modules and the plurality of controlled capacitor modules, each open relationship of the plurality of switches being coupled in response to a corresponding switching coefficient Connecting a selected one of the plurality of control voltages to a corresponding controlled capacitor module; a frequency divider circuit coupled to the harmonic oscillator and adapted to convert the first reference signal A clock signal that becomes a substantial square wave having substantially equal duty cycles; and a processor coupled to the frequency divider circuit and adapted to receive the clock signal.