JP6540942B2 - Oscillator circuit, oscillator, electronic device and moving body - Google Patents

Description

  The present invention relates to an oscillator circuit, an oscillator, an electronic device, and a movable body.

  Patent Document 1 discloses an oscillation circuit having a circuit for outputting a pulse signal for shortening the start time of an oscillation circuit for oscillating a vibrator.

JP, 2011-188313, A

  However, in the oscillation circuit described in Patent Document 1, the relationship between the input of the pulse signal to the oscillation circuit and the operation of the power supply circuit for operating the oscillation circuit is not defined. Depending on the rising characteristics of the circuit, the oscillation circuit may not start at high speed even if a pulse signal is input to the oscillation circuit.

  The present invention has been made in view of the above problems, and according to some aspects of the present invention, it is possible to provide an oscillation circuit capable of shortening the start-up time as compared with the prior art. . Further, according to some aspects of the present invention, it is possible to provide an oscillator, an electronic device and a mobile using the oscillation circuit.

  The present invention has been made to solve at least a part of the above-described problems, and can be realized as the following aspects or application examples.

Application Example 1
An oscillation circuit according to this application example includes an oscillation circuit that has a first terminal connected to one end of a vibrator and a second terminal connected to the other end of the vibrator, and causes the vibrator to oscillate; An activation circuit electrically connected to the oscillation circuit and outputting an activation signal for activating the oscillation circuit; and a power supply circuit for supplying power to the oscillation circuit, the activation circuit including: The start signal is output to the oscillation circuit in conjunction with the rise of the power supply circuit.

  The oscillation circuit may be part or all of various oscillation circuits such as, for example, a pierce oscillation circuit, an inverter type oscillation circuit, a Colpitts oscillation circuit, and a Hartley oscillation circuit.

  According to the oscillation circuit of this application example, when the oscillation circuit starts to operate by linking the activation of the oscillation circuit to the rise of the power supply circuit, power is supplied from the power supply circuit. The start-up time can be shortened as compared with the conventional oscillator circuit in which the circuit for oscillation starts simultaneously.

Application Example 2
In the oscillation circuit according to the application example, a first DC voltage is applied to the first terminal and a second DC voltage is applied to the second terminal before the oscillation circuit starts to start. The start signal may be a signal for stopping application of the first DC voltage to the first terminal and application of the second DC voltage to the second terminal.

  According to the oscillation circuit of this application example, before the oscillation circuit starts to start, the potential difference between both ends of the vibrator is held at the potential difference between the first DC voltage and the second DC voltage, and the oscillation circuit Since the desired potential difference is obtained after the start of the start, it is possible to change the potential difference between both ends of the vibrator before and after the start of the oscillation circuit starts. As a result, since the initial excitation current at which the oscillator starts oscillation becomes large, the start-up time can be shortened compared to the conventional oscillation circuit in which the initial excitation current is almost zero.

Application Example 3
In the oscillation circuit according to the application example, the first direct current voltage is higher than the second direct current voltage, and the voltage of the first terminal after the oscillation circuit starts to start is the first direct current voltage. The voltage of the second terminal, which is lower than the DC voltage and after the oscillation circuit starts to start, may be higher than the second DC voltage.

  For example, the first DC voltage may be a power supply voltage and the second DC voltage may be a ground voltage.

  According to the oscillation circuit of this application example, when the oscillation circuit starts to start, the voltage of the first terminal falls from the first DC voltage, and the voltage of the second terminal rises from the second DC voltage Therefore, before and after the oscillation circuit starts to start, the potential difference between both ends of the vibrator can be sharply changed. As a result, since the initial excitation current at which the oscillator starts oscillation becomes larger, the start-up time can be further shortened.

Application Example 4
In the oscillation circuit according to the application example, the power supply circuit receives a first signal and generates a second signal that follows the first signal, and the voltage of the first signal and the second signal are generated. The start-up circuit has a comparator circuit that compares the voltage of the first signal with the voltage of the second signal when the voltage rises with the voltage of the signal, and the output signal of the comparator circuit The activation signal may be generated on the basis of this.

  According to the oscillation circuit of this application example, even if the rise time of the power supply circuit fluctuates due to the temperature or the fluctuation of the power supply voltage, the start of the oscillation circuit can be linked to the rise of the power supply circuit.

Application Example 5
In the oscillation circuit according to the application example, the comparator circuit increases the voltage of the first signal, and the sum of the voltage of the second signal and a positive offset voltage corresponds to the voltage of the first signal. The polarity of the output signal may be inverted when they coincide.

  According to the oscillation circuit of this application example, since the polarity of the output signal of the comparator circuit can be reversed slightly before the power supply circuit rises, activation of the oscillation circuit is more reliably interlocked with the rise of the power supply circuit. be able to.

Application Example 6
In the oscillation circuit according to the application example, the start-up circuit may increase the offset voltage after the voltage of the first signal rises and the polarity of the output signal of the comparator circuit is inverted. .

According to the oscillation circuit of this application example, the polarity of the output signal of the comparator circuit is not reversed unless the voltage of the first signal is reduced by the offset voltage on the input side of the second signal (the oscillation circuit The polarity of the output signal of the comparator circuit is less likely to be restored by increasing the offset voltage after the oscillation circuit starts to start, because the polarity does not return to the polarity before starting to start. Can be oscillated stably.

Application Example 7
The oscillator according to this application example includes any of the above-described oscillation circuits, the vibrator, and a container in which the oscillation circuit and the vibrator are disposed.

  According to the oscillator of this application example, when the oscillation circuit starts the oscillation circuit interlocking with the rising of the power supply circuit, power is supplied from the power supply circuit when the oscillation circuit starts the activation. The start-up time can be shorter than that of a conventional oscillator in which the power supply circuit and the oscillation circuit start simultaneously.

Application Example 8
An electronic device according to this application example includes any of the above-described oscillation circuits or the above-described oscillator.

Application Example 9
A mobile according to this application example includes any of the above-described oscillation circuits or the above-described oscillator.

  According to these applications, since the oscillation circuit or the oscillator which can reduce the start-up time is used as compared with the prior art, highly reliable electronic devices and mobile objects can be realized.

The perspective view of the oscillator of this embodiment. FIG. 2A is a cross-sectional view of the oscillator, and FIG. 2B is a bottom view of the oscillator. The functional block diagram of the oscillator of this embodiment. FIG. 2 is a view showing an example of the configuration of an output circuit in the oscillator of the present embodiment. FIG. 2 is a diagram showing an example of the configuration of an amplitude control circuit in the oscillator of the present embodiment. The figure which shows an example of the relationship between the setting value of an output level adjustment register | resistor, the output voltage of D / A converter, and clip voltage. The figure which shows an example of the output waveform of a clipped sine wave. FIG. 2 is a diagram showing an example of the configuration of an oscillator circuit in the oscillator of the present embodiment. FIG. 6 is a diagram showing an example of waveforms of the respective signals of the oscillation circuit in the present embodiment when the power is turned on. The figure which shows an example of the waveform from the time of the power activation of each signal of the oscillation circuit in a comparative example. FIG. 2 is a functional block diagram showing an example of the configuration of the electronic device of the embodiment. The figure which shows an example of the external appearance of the electronic device of this embodiment. The figure which shows an example of the mobile body of this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. In addition, not all of the configurations described below are necessarily essential configuration requirements of the present invention.

1. Oscillator FIG. 1 and FIG. 2 show the structure of the oscillator of this embodiment. FIG. 1 is a perspective view of the oscillator according to the present embodiment, and FIG. 2 (A) is a cross-sectional view taken along the line AA 'of FIG. FIG. 2B is a bottom view of the oscillator of this embodiment.

  As shown in FIGS. 1 and 2A, the oscillator 1 according to this embodiment includes an electronic component 9 including an oscillation circuit 2 of FIG. 3 described later, a vibrator 3, a package 4, a lid 5, an external terminal (external electrode 6) and the sealing member 8 are comprised.

  The vibrator 3 may be, for example, a SAW (Surface Acoustic Wave) resonator, an AT-cut quartz vibrator, an SC-cut quartz vibrator, a tuning fork-type quartz vibrator, other piezoelectric vibrators, or a MEMS (Micro Electro Mechanical Systems) vibrator. Etc. can be used. As a substrate material of the vibrator 3, a piezoelectric material such as quartz, a piezoelectric single crystal such as lithium tantalate or lithium niobate, a piezoelectric ceramic such as lead zirconate titanate, or a silicon semiconductor material can be used. As an excitation means of the vibrator 3, one based on the piezoelectric effect may be used, or electrostatic drive based on coulomb force may be used. In addition, although the vibrator 3 of this embodiment is a chip-shaped element in which the substrate material is singulated, the present invention is not limited to this, and a vibrating device in which a chip-shaped element is sealed in a container may be used. .

  The package 4 is a container for housing the electronic component 9 and the vibrator 3. Specifically, the package 4 is provided with two concave portions on opposite surfaces, and the lid 5 covers one concave portion to form the storage chamber 7a, and the sealing member 8 covers the other concave portion. It becomes a storage room 7b. The vibrator 3 is accommodated in the accommodation chamber 7a, and the electronic component 9 is accommodated in the accommodation chamber 7b. Not shown for electrically connecting the two terminals (XO terminal and XI terminal of FIG. 3 described later) and the two terminals of the vibrator 3 to the inside of the package 4 or the surface of the recess. Wiring is provided. Further, on the surface of the interior of the package 4 or the recess, not shown wiring is provided for electrically connecting the terminals of the oscillation circuit 2 to the corresponding external terminals 6.

  As shown in FIG. 2B, the oscillator 1 of this embodiment controls the external terminal VCC as a power supply terminal, the external terminal GND1 as a ground terminal, the test terminal or the electronic component 9 on the bottom surface (the back surface of the package 4). An external terminal TP1 which is a terminal to which a signal to be input is input, and four external terminals 6 of an external terminal OUT1 which is an output terminal are provided. A power supply voltage is supplied to the external terminal VCC1, and the external terminal GND1 is grounded.

  FIG. 3 is a functional block diagram of the oscillator of this embodiment. As shown in FIG. 3, the oscillator 1 of the present embodiment is a temperature compensation type oscillator including an oscillator circuit 2 and a vibrator 3, and the oscillator circuit 2 and the vibrator 3 are accommodated in a package 4.

  The oscillation circuit 2 includes a VCC terminal as a power supply terminal, a GND terminal as a ground terminal, an OUT terminal as an output terminal, a TP terminal as a test terminal or a terminal to which a signal for controlling the electronic component 9 is input The terminal XI and the terminal XO are provided. The VCC terminal, the GND terminal, the OUT terminal, and the TP terminal are exposed on the surface of the electronic component 9 (see FIG. 1) which is an IC chip, and the external terminals VCC1, GND1, TP1, and OUT1 provided in the package 4 are provided. And connected. Further, the XI terminal is connected to one end (one terminal) of the vibrator 3, and the XO terminal is connected to the other end (other terminal) of the vibrator 3.

  In the present embodiment, the oscillation circuit 2 includes an oscillation circuit 10, an amplitude control circuit 20, an output circuit 30, a temperature compensation circuit 40, a temperature sensor 42, a regulator circuit 50, a memory 60, a switch circuit 70, and a serial interface (I / F). A circuit 80 is included. In the oscillation circuit 2 of the present embodiment, some of these elements may be omitted or changed, or other elements may be added.

The oscillation circuit 10 is a circuit for oscillating the vibrator 3, amplifies an output signal of the vibrator 3, and feeds it back to the vibrator 3. The oscillation circuit 10 outputs an oscillation signal based on the oscillation of the oscillator 3.

  The temperature sensor 42 is a temperature sensitive element that outputs a signal (for example, a voltage corresponding to the temperature) corresponding to the temperature around it.

  The temperature compensation circuit 40 is temperature-compensated according to the temperature characteristic of the vibrator 3 with temperature as a variable so that the output signal from the temperature sensor 42 is input and the oscillation frequency of the oscillation circuit 10 becomes constant regardless of temperature. Generate a voltage. The temperature compensation voltage is applied to one end of a variable capacitance element (not shown) that functions as a load capacitance of the oscillation circuit 10, and the oscillation frequency is controlled.

  The output circuit 30 receives an oscillation signal from the oscillation circuit 10, and generates and outputs an oscillation signal for external output.

  The amplitude control circuit 20 is a circuit for controlling the amplitude of the oscillation signal output from the output circuit 30. The amplitude control circuit 20 includes an amplitude control unit that controls the amplitude of the oscillation signal output by the output circuit 30 and a heat generating unit. As described later, in the heat generating unit, the input direct current is controlled based on the operating state of the oscillation circuit 10 and the amplitude control unit of the amplitude control circuit 20.

  The regulator circuit 50 generates a constant voltage Vreg serving as a power supply voltage or a reference voltage of the oscillation circuit 10, the temperature compensation circuit 40, and the output circuit 30, based on the power supply voltage VCC (positive voltage) supplied from the VCC terminal.

  The memory 60 has a non-volatile memory and a register (not shown), and can read / write to the non-volatile memory or the register from the external terminal through the serial interface circuit 80. In this embodiment, since the terminal of the oscillation circuit 2 connected to the external terminal of the oscillator 1 is only four of VCC, GND, OUT, and TP, the serial interface circuit 80 has, for example, the voltage of the VCC terminal is higher than the threshold value. When it is high, the clock signal SCLK input from the TP terminal and the data signal DATA input from the OUT terminal may be received to read / write data from / to the nonvolatile memory or the internal register.

  The switch circuit 70 is a circuit for switching the electrical connection between the temperature compensation circuit 40 and the OUT terminal connected to the output side of the output circuit 30 and electricity.

  In the present embodiment, when the signal input to the TP terminal is at a low level, the switch circuit 70 is controlled so as not to electrically connect the temperature compensation circuit 40 and the OUT terminal, and the oscillation output from the output circuit 30 A signal is output to the OUT terminal. Further, as described later, when the signal input to the TP terminal is at the low level, the operation of the heat generating portion of the amplitude control circuit 20 is stopped.

  On the other hand, when the signal input to the TP terminal is at high level, the switch circuit 70 is controlled to electrically connect the temperature compensation circuit 40 and the OUT terminal, and the output of the oscillation signal from the output circuit 30 is stopped. The output signal (temperature compensation voltage) from the temperature compensation circuit 40 is output to the OUT terminal. Further, as described later, when the signal input to the TP terminal is at the high level, the heat generating unit of the amplitude control circuit 20 is based on the operation state of the oscillation circuit 10 and the amplitude control unit of the amplitude control circuit 20. The input direct current is controlled.

When used as a Temperature Compensated Crystal Oscillator (TCXO) for GPS applications used for cellular etc., a high frequency temperature compensation accuracy such as ± 0.5 ppm is required. Therefore, in the present embodiment, the output voltage amplitude of the output circuit 30 is stabilized by the regulator circuit 50, and the output circuit 30 outputs a clipped sine waveform whose output amplitude is suppressed from the viewpoint of reducing current consumption. In this embodiment, the amplitude control circuit 20 can adjust the output amplitude of the output circuit 30 in a range of, for example, 0.8 to 1.2 Vpp, and the amplitude control circuit 20 is smaller than in the prior art. The circuit has a built-in heating circuit. Further, in the present embodiment, the memory 60 includes a division switching register DIV for selecting whether or not the oscillation signal is divided by the division circuit provided inside the output circuit 30, and the output circuit An output level adjustment register VOUT_ADJ is provided to adjust the amplitude level of the clipped sine wave oscillation signal output by the H.30. An amplitude control is interlocked with a setting state based on data stored in these registers. The amount of current supplied to the heat generating circuit inside the circuit 20 is controlled.

  The set values of these registers are stored, for example, in the non-volatile memory of the memory 60 when the oscillator circuit 2 is manufactured, and set values from the non-volatile memory to each register when the power is turned on after assembling the oscillator 1 Is written. Further, for example, at the time of manufacturing the oscillation circuit 2, temperature compensation data (0th order, 1st order, and 3rd order according to the frequency temperature characteristics of the vibrator 3) are input to the non-volatile memory. Also stored are numerical values (the fourth and fifth order coefficient values may be included) or a correspondence table between temperature and temperature compensation voltage.

[Configuration of output circuit]
FIG. 4 is a diagram showing a configuration example of the output circuit 30 of FIG. As shown in FIG. 4, in the output circuit 30, the output voltage Vreg of the regulator circuit 50 is applied to the Vreg terminal, and a clip for obtaining a clipped sine wave output generated by the amplitude control circuit 20 is provided to the Vclip terminal. A voltage Vclip is applied. The output circuit 30 includes a divider circuit, and can select whether to divide the signal (oscillation signal output from the oscillation circuit 10) input to the IN terminal into two or not according to the voltage level of the DIV terminal. It is done. In the present embodiment, when the setting value of the division switching register DIV is 0, the DIV terminal is set to low level, the input signal is not divided, and the polarity is inverted by the inverter formed of the MOS transistors M1 to M4. , And the signal of node VBUF1 is transmitted to NOR circuit NOR1. On the other hand, when the setting value of the division switching register DIV is 1, the DIV terminal is set to the high level, the input signal is divided into half by the dividing circuit, and the signal of the node VBUF1 is input to the NOR circuit NOR1. introduce.

  The output circuit 30 is enabled when the TP terminal is at low level, and is deactivated when the TP terminal is at high level. In normal operation, the TP terminal is set to low level, the input signal from the input terminal IN is clipped at a voltage amplitude level determined by Vclip, and is output from the OUT terminal. When adjusting (testing) the temperature compensation circuit 40 of FIG. 3, the TP terminal is set to the high level, the MOS transistors M2 and M3 are turned off, and the output node VBUF2 of the NOR circuit NOR1 and the output node of the NOR circuit NOR2 Both VBUF3 are at the ground potential, and both NMOS transistors M5 and M6 are turned off. As a result, the output circuit 30 is in the operation stop state.

[Configuration of amplitude control circuit]
FIG. 5 is a diagram showing a configuration example of the amplitude control circuit 20 of FIG. In FIG. 5, NMOS transistors M1, M2 and M3 are depletion type MOS transistors, and the other MOS transistors are normal type (enhancement type) MOS transistors. The amplitude control circuit 20 shown in FIG. 5 generates static heat (direct current) Iht at the time of adjustment of the temperature compensation circuit 40 to generate heat corresponding to the heat generated by the output circuit 30 at the time of normal operation. Thereby, the fluctuation of the heat generation amount between the normal operation time and the adjustment time of the temperature compensation circuit 40 can be suppressed.

As shown in the following equation (1), the clip voltage Vclip for determining the output amplitude level of the output circuit 30 is a voltage obtained by subtracting the gate-source voltage Vgs _M2 of the MOS transistor M2 from the output voltage Vg of the differential amplifier AMP. .

  Vg is obtained from the analog voltage Vdac D / A converted by the D / A converter DAC based on the data given by the output level adjustment register VOUT_ADJ by the following equation (2).

  By substituting equation (2) into equation (1), the following equation (3) holds. That is, the clip voltage Vclip is determined by Vdac · (R1 / R2 + 1) which is a voltage obtained by amplifying the output voltage Vdac of the D / A converter DAC by the differential amplifier AMP.

  During normal operation, the TP terminal is set to low level, the switch circuit SW1 is on, the NMOS switch SW2 is off, the MOS transistor M3B is off, and the heating circuit 21 is in the operation stop state. On the other hand, when adjusting the temperature compensation circuit 40, the TP terminal is set to the high level, the switch circuit SW1 is turned off, and the NMOS switch SW2 is turned on, whereby the NMOS transistor M2 is turned off and the NMOS transistor M3 is turned on. The heating circuit 21 including the above becomes an operating state.

The waveforms output from the output circuit 30 are clipped sine waves as shown in FIG. 7A and FIG. 7B, and the peak value (amplitude) of the clipped sine wave decreases as the output frequency increases. Therefore, the set value of the output level adjustment register VOUT_ADJ is selected in accordance with the output frequency. Normally, the set value of the output level adjustment register VOUT_ADJ is selected so that the amplitude of the clipped sine wave can be maintained at 0.8 Vpp or more. FIG. 6 shows an example of the relationship between the set value of the output level adjustment register VOUT_ADJ, the output voltage Vdac of the D / A converter DAC, and the clip voltage Vclip. FIG. 6 is an example in the case where the gain of the replica circuit 22 including the differential amplifier AMP is set to about 1.2 times, and the clip voltage Vclip shows a DC-like voltage value. FIGS. 7A and 7B are diagrams showing an example of the output waveform of the clipped sine wave when the output frequency is 26 MHz and 52 MHz, respectively, and both VOUT_ADJ are set to “01”. It is done. As shown in FIG. 6, when VOUT_ADJ is set to "01", the clip voltage Vclip is 0.9 V, and as shown in FIG. 7A, when the output frequency is 26 MHz, the clipped sine wave is The amplitude is about 0.9 Vpp, and as shown in FIG. 7B, even when the output frequency is 52 MHz, the amplitude of the clipped sine wave can be secured to about 0.82 Vpp. When the output frequency is 52 MHz, the amplitude of the clipped sine wave may decrease slightly, and VOUT_ADJ can be set to "10" to raise the amplitude by 0.1 V to 0.92 Vpp. is there.

  In the present embodiment, the current Iht flowing through the heating circuit 21 when the TP terminal is set to the high level changes in conjunction with the setting value of the division switching register DIV and the setting value of the output level adjustment register VOUT_ADJ, When the TP terminal is set to the low level, the current equivalent to the current consumed by the output circuit 30 is approached. Thereby, the difference current which is a difference current between the consumption current of the oscillator 1 when the TP terminal is set to the low level and the consumption current of the oscillator 1 when the TP terminal is set to the high level is reduced. . That is, the difference between the current when the output circuit 30 is in the operation state and the current when the output circuit 30 is in the stop state is reduced to suppress the fluctuation of the heat generation amount of the oscillation circuit 10.

[Configuration of oscillation circuit]
FIG. 8 is a diagram showing a configuration example of the oscillation circuit 10 of FIG. As shown in FIG. 8, the oscillation circuit 10 includes an oscillation circuit 11, a power supply circuit 12, and a start circuit 13.

  The oscillator circuit 11 has an XO terminal (an example of a first terminal) connected to one end of the vibrator 3 and an XI terminal (an example of a second terminal) connected to the other end of the vibrator 3. Make 3 oscillate. In the example of FIG. 8, the oscillation circuit 11 forms a Pierce type oscillation circuit by connecting the collector terminal and the base terminal of the bipolar transistor Q1 to both ends of the vibrator 3, and the oscillation supplied from the power supply circuit 12 The oscillator 3 is oscillated by the stage current Iosc. In the oscillation circuit 11, varicap diodes VCDD1 and VCD2 as variable capacitance elements are connected in series in parallel with the vibrator 3, and a temperature compensation voltage is applied to the varicap diodes VCD1 and VCD2 to obtain a temperature. On the other hand, the capacitance value of the oscillation circuit 11 changes, and an oscillation signal whose frequency temperature characteristic of the oscillator 3 is compensated is output.

  The power supply circuit 12 (current source circuit) is a circuit for supplying power to the oscillation circuit 11. In the example of FIG. 8, the power supply circuit 12 generates a current Iref serving as a reference of the oscillation stage current Iosc by the differential amplifier AMP1, the PMOS transistor M2, the bipolar transistor Q2, and the resistor R1. The size of the gate width of the PMOS transistor M1 and the size of the gate width of the PMOS transistor M2 have, for example, a ratio of 10: 1. The size of the gate width of the PMOS transistor M3 and the size of the gate width of the PMOS transistor M4 have the same size ratio. For example, assuming that Iref = 20 μA, 200 μA which is 10 times larger is supplied to the oscillation circuit 11 as the oscillation stage current Iosc.

  In the power supply circuit 12, a voltage signal Vreg (an example of a first signal) output from the regulator circuit 50 is input to the inverting input terminal (-terminal) of the differential amplifier AMP1, and the voltage signal Vref follows the voltage signal Vreg. (An example of a second signal) is generated, and rises when the voltage of the voltage signal Vreg matches the voltage signal Vref (that is, the oscillation stage current Iosc becomes a desired current).

The circuit constituted by the differential amplifier AMP2, the PMOS transistor M4, the current source IB1 for flowing the bias current Ibias, and the PMOS transistors M5 and M6 further depends on the power supply dependency of the oscillation stage current Iosc flowing to the cascode-connected PMOS transistors M1 and M3. It is a circuit for suppressing. This circuit is a gain-enhanced cascode circuit that further reduces the power supply dependency of the current output from the current source compared to the cascode circuit in TCXO, which requires a high frequency accuracy. This cascode circuit monitors the source voltage of the PMOS transistor M4 on the reference side, and controls the gate voltage of the PMOS transistors M3 and M4 by the differential amplifier AMP2 when the power supply voltage VCC (voltage of the VCC terminal) fluctuates. , PM
The change of the potential difference between the source and the drain of the OS transistors M1 and M2 is further suppressed. The output resistance of the power supply circuit 12 is further increased by the gain multiple of the differential amplifier AMP2. The oscillation stage current Iosc is stabilized against the fluctuation of the power supply voltage, and the oscillation frequency fluctuation of the oscillation circuit 11 can be suppressed.

  The start circuit 13 is electrically connected to the oscillation circuit 11 and outputs a start signal for starting the oscillation circuit 11 in conjunction with the rising of the power supply circuit 12. In the example of FIG. 8, the start circuit 13 includes a comparator circuit including PMOS transistors M9, M10, M15 and M16, NMOS transistors M11, M12, M13 and M14, and current sources IB2 and IB3, and an output of the comparator circuit. It is configured to include CMOS inverters INV1 and INV2 that generate activation signals INV1out and INV2out based on the signals. This comparator circuit includes the voltage of the voltage signal Vreg input to the inverting input terminal (− terminal) (gate terminal of the NMOS transistor M11) and the non-inverting input terminal (+ terminal) (gate terminals of the NMOS transistors M12 and M13) And the voltage of the voltage signal Vref input to the Here, for example, the NMOS transistor M11 is formed by connecting two basic NMOS transistors in parallel, while the NMOS transistor M12 is connected by three basic NMOS transistors in parallel. It is configured. That is, the ratio of the size of the gate width of the NMOS transistor M11 to the size of the gate width of the NMOS transistor M12 is 2 to 3, and an offset is given to the non-inversion input terminal (+ terminal) of the comparator circuit. . Therefore, when the voltage of the voltage signal Vreg rises and the voltage of the voltage signal Vref rises and reaches a voltage lower than the voltage of the voltage signal Vreg by the offset voltage (the power supply circuit 12 The polarity of the output signal COMPout is inverted (a low level (near 0 V) is inverted to a high level (near VCC)) a little before the rise of.

  When the polarity of the output signal COMPout of the comparator circuit is inverted from low level to high level, the polarity of the output signal INV1out of the CMOS inverter INV1 is inverted from high level to low level, and the polarity of the output signal INV2out of the CMOS inverter INV2 is low level Reverse to high level.

  The output signal (start signal) INV1out of the CMOS inverter INV1 is input to the gate terminal of the NMOS transistor M8, and the output signal (start signal) INV2out of the CMOS inverter INV2 is input to the gate terminal of the PMOS transistor M7. Therefore, when the polarity of the output signal COMPout of the comparator circuit is at low level (before the oscillation circuit 11 starts to start), both the NMOS transistor M8 and the PMOS transistor M7 are in the ON state. The voltage VCC (an example of a first direct current voltage) is applied, and the ground voltage (0 V) (an example of a second direct current voltage) is applied to the terminal XI. Then, when the polarity of the output signal COMPout of the comparator circuit is inverted from low level to high level, the NMOS transistor M8 and the PMOS transistor M7 are both turned off by the start signals INV1out and INV2out. And the application of the ground voltage (0 V) to the terminal XI, the oscillation circuit 11 starts to start. As described above, by providing an offset to the non-inversion input terminal (+ terminal) of the comparator circuit, the oscillation circuit 11 reliably starts to operate in conjunction with the rising of the power supply circuit 12.

Then, the voltage of the XO terminal after the oscillation circuit 11 starts to start is lower than VCC, and the voltage of the XI terminal after the oscillation circuit 11 starts to start is higher than the ground voltage (0 V). As a result, since the potential difference between both ends of the vibrator 3 changes sharply before and after the oscillation circuit 11 starts to start, the initial excitation current supplied to the vibrator 3 becomes large, and the vibrator 3 Since the power supply circuit 12 substantially rises when the oscillation is started, a sufficient excitation current is continuously supplied to the vibrator 3 even after the oscillation starts, so that the time until the oscillation is stabilized is shortened.

  When the polarity of the output signal INV1out of the CMOS inverter INV1 is low and the polarity of the output signal INV2out of the CMOS inverter INV2 is high, both the NMOS transistor 14 and the PMOS transistor 15 are turned on, and the NMOS transistor M13 is connected in parallel to the NMOS transistor M12. Connected The NMOS transistor M13 is configured, for example, by connecting six basic NMOS transistors in parallel, and the size of the gate width of the NMOS transistor M13 is twice the size of the gate width of the NMOS transistor M12 (NMOS transistor M11 3 times the size of the gate width of That is, after the voltage of the voltage signal Vreg rises and the polarity of the output signal COMPout of the comparator circuit is inverted from the low level to the high level, the start circuit 13 starts the non-inversion input terminal (+ terminal) of the comparator circuit (+ The offset amount (positive offset voltage) of the gate terminals of the NMOS transistors M12 and M13 is increased. As a result, after the oscillation circuit 11 starts to start, the output signal COMPout of the comparator circuit holds the high level even if the voltage of the voltage signal Vreg decreases a little (both the NMOS transistor M8 and the PMOS transistor M7 are off) Can be maintained, and the oscillation of the oscillation circuit 11 can be stably continued.

  FIG. 9 shows an example of the waveform from when the power of each signal in the oscillation circuit 10 is turned on. Further, FIG. 10 shows an example of waveforms of respective signals in the oscillation circuit of the comparative example in which the start-up circuit 13, the NMOS transistor M8 and the PMOS transistor M7 do not exist. Each numerical value shown in Drawing 9 and Drawing 10 is only an example, and oscillation circuit 10 in this embodiment is not limited to composition which fulfills these numerical values.

The equivalent series resistance of the vibrator 3 is R ₁ , the equivalent series inductance is L ₁ , the Q value is Q, the circuit loss is R _p , the negative resistance is r _n , and the value of the excitation current after the power supply circuit 12 rises. _Where i ₁ and the initial current value supplied to the oscillator 3 are i ₀ , the time t _{l in} the linear region of the quartz current I _xtal and the time t _{nl in the} saturation region shown in FIGS. 4) and calculated by equation (5).

For example, when R ₁ = 24.3 Ω, L ₁ = 16.44 mH, Q = 110 549, R _p = 50 Ω, r _n = 1 kΩ, and i ₁ = 500 μA, i ₀ = 5 μA in the oscillator circuit 10 in this embodiment. there for _{t l} ≒ _50μs, whereas a _{t nl} ≒ _1.01ms, the oscillation circuit of the comparative example _i 0 ^{= 10 -17} _μA ≒ 0 a is for _{t l} ≒ _500μs, at _{t nl} ≒ _1.01ms is there. That is, the oscillation circuit 10 in this embodiment, it is possible to shorten the time t _l of the linear region of the crystal current I _xtal to about 1/10 of the oscillation circuit of the comparative example.

The _start- up time T _start from when the power is turned on to when the oscillation is stabilized is T _start = t ₁ + t _nl 1.51.51 ms in the oscillation circuit of the comparative example, while the oscillation circuit 10 in this embodiment is Then, T _start = t ₀ + t ₁ + t _nl tt ₀ +1.06 ms. Here, t ₀ is the time from when the power is turned on until the polarity of the output signal COMPout of the comparator circuit is inverted from low level to high level (time until the oscillation circuit 11 starts to start), It is time of about several microseconds. Therefore, according to the oscillation circuit 10 in the present embodiment, the start-up time can be shortened compared to the oscillation circuit of the comparative example.

As described above, according to the oscillator 1 of the present embodiment, the oscillation circuit 10 links the activation of the oscillation circuit 11 to the rise of the power supply circuit 12 by the activation circuit 13, that is, starts the activation of the oscillation circuit 11. By determining the timing based on the magnitude of the value of the output voltage from the power supply circuit 12, when the oscillation circuit 11 starts to start, the oscillation stage current I _osc is transmitted from the power supply circuit 12 to the oscillation circuit 11. Since it is output and sufficient excitation current is supplied to the vibrator 3, the start time can be shortened compared to the conventional oscillation circuit in which the power supply circuit 12 and the oscillation circuit 11 start simultaneously.

  Furthermore, according to the oscillator 1 of the present embodiment, before the oscillation circuit 10 starts the oscillation circuit 11, the potential difference between both ends of the vibrator 3 is the potential difference between the power supply voltage VCC and the ground voltage (0 V). After the oscillation circuit 11 starts to be activated, a desired potential difference (a potential difference between the collector terminal of the bipolar transistor Q1 and the base terminal) is obtained. The potential difference between both ends of can be changed sharply. As a result, since the initial excitation current at which the vibrator 3 starts oscillation becomes sufficiently large, the start-up time can be further shortened compared to the conventional oscillation circuit in which the initial excitation current is approximately zero.

2. Electronic Device FIG. 11 is a functional block diagram showing an example of the configuration of the electronic device of the present embodiment. Moreover, FIG. 12 is a figure which shows an example of the external appearance of the smart phone which is an example of the electronic device of this embodiment.

  The electronic device 300 according to the present embodiment includes an oscillator 310, a central processing unit (CPU) 320, an operation unit 330, a read only memory (ROM) 340, a random access memory (RAM) 350, a communication unit 360, and a display unit 370. It is configured. Note that the electronic device of this embodiment may have a configuration in which a part of the components (each part) in FIG. 11 is omitted or changed or another component is added.

  The oscillator 310 includes an oscillation circuit 312 and a vibrator 313. The oscillation circuit 312 oscillates the oscillator 313 to generate an oscillation signal. This oscillation signal is output to the CPU 320 from the OUT terminal of the oscillator 310.

  The CPU 320 performs various calculation processing and control processing using the oscillation signal input from the oscillator 310 as a clock signal in accordance with a program stored in the ROM 340 or the like. Specifically, the CPU 320 performs various processes according to the operation signal from the operation unit 330, a process of controlling the communication unit 360 to perform data communication with an external device, and causes the display unit 370 to display various information. A process of transmitting a display signal of

  The operation unit 330 is an input device configured by operation keys, a button switch, and the like, and outputs an operation signal according to an operation by the user to the CPU 320.

  The ROM 340 stores programs, data, and the like for the CPU 320 to perform various calculation processes and control processes.

  The RAM 350 is used as a work area of the CPU 320, and temporarily stores programs and data read from the ROM 340, data input from the operation unit 330, calculation results executed by the CPU 320 according to various programs, and the like.

  The communication unit 360 performs various controls for establishing data communication between the CPU 320 and an external device.

  The display unit 370 is a display device configured by an LCD (Liquid Crystal Display) or the like, and displays various types of information based on a display signal input from the CPU 320. The display unit 370 may be provided with a touch panel functioning as the operation unit 330.

  By applying the oscillator circuit 2 of the above-described embodiment as the oscillator circuit 312 or applying the oscillator 1 of the above-described embodiment as the oscillator 310, a highly reliable electronic device can be realized.

  As such an electronic device 300, various electronic devices can be considered. For example, personal computers (for example, mobile personal computers, laptop personal computers, tablet personal computers), mobile terminals such as smartphones and mobile phones, Digital cameras, inkjet discharge devices (for example, inkjet printers), storage area network devices such as routers and switches, local area network devices, devices for mobile terminal base stations, televisions, video cameras, video recorders, car navigation devices, real time Clock device, pager, electronic organizer (including communication function), electronic dictionary, calculator, electronic game device, game controller, word processor, word processor Station, videophone, TV monitor for crime prevention, electronic binoculars, POS terminal, medical equipment (eg electronic thermometer, sphygmomanometer, blood glucose meter, electrocardiogram measuring device, ultrasonic diagnostic device, electronic endoscope), fish finder, various measurement Devices, instruments (for example, instruments of vehicles, aircraft, ships), flight simulators, head mounted displays, motion traces, motion tracking, motion controllers, PDR (pedestrian position and orientation measurement) and the like can be mentioned.

3. Mobile Body FIG. 13 is a diagram (top view) showing an example of the mobile body of the present embodiment. The moving body 400 shown in FIG. 13 is configured to include an oscillator 410, controllers 420, 430, and 440 that perform various controls such as an engine system, a brake system, and a keyless entry system, a battery 450, and a backup battery 460. In the mobile object of the present embodiment, a part of the components (each part) in FIG. 13 may be omitted, or another component may be added.

  The oscillator 410 includes an oscillating circuit (not shown) and a vibrator, and the oscillating circuit oscillates the vibrator to generate an oscillating signal. The oscillation signal is output from the external terminal of the oscillator 410 to the controllers 420, 430, and 440, and is used as, for example, a clock signal.

  The battery 450 supplies power to the oscillator 410 and the controllers 420, 430 and 440. The backup battery 460 supplies power to the oscillator 410 and the controllers 420, 430 and 440 when the output voltage of the battery 450 falls below a threshold.

A highly reliable mobile object can be realized by applying, for example, the oscillation circuit 2 of the above-described embodiment as the oscillation circuit included in the oscillator 410, or applying, for example, the oscillator 1 of the above-described embodiment as the oscillator 410. it can.

  As such a mobile body 400, various mobile bodies can be considered, for example, an automobile (including an electric car), an aircraft such as a jet plane or a helicopter, a ship, a rocket, a satellite, and the like.

  The present invention is not limited to the present embodiment, and various modifications can be made within the scope of the present invention.

  For example, in the embodiment described above, in the example of FIG. 8, the power supply voltage VCC is applied to the XO terminal via the PMOS transistor M7 and the XI terminal via the NMOS transistor M8 before the start of the oscillation circuit 11 starts. So that the ground voltage (0 V) is applied, but the power supply voltage VCC is applied to the XI terminal through the PMOS transistor M7, and the ground voltage (0 V) is applied to the XO terminal through the NMOS transistor M8. Can also produce the same effect. Although the start-up time is later than in this embodiment, the same voltage (for example, power supply voltage VCC or ground voltage (0 V)) is applied to the XO terminal and the XI terminal before the start of the oscillation circuit 11 starts. Startup time can be quicker than before.

  Further, for example, in the above-described embodiment, a temperature compensation type oscillator (TCXO or the like) having a temperature compensation circuit has been described as an example, but in the present invention, a voltage control type oscillator having a voltage control oscillation circuit is also available. Oscillator (VCXO (Voltage Controlled Crystal Oscillator) etc.), oven controlled oscillator (OCXO (Oven Controlled Crystal Oscillator) etc.), Oscillator with both voltage control function and temperature compensation function (VC-TCXO (Voltage Controlled Temperature Compensated Crystal Oscillator) The present invention can be applied to various oscillators such as an oscillator (SPXO (Simple Packaged Crystal Oscillator)) which does not have a voltage control function or a temperature compensation function.

  The above-mentioned embodiment and modification are an example, and are not necessarily limited to these. For example, it is also possible to combine each embodiment and each modification suitably.

  The present invention includes configurations substantially the same as the configurations described in the embodiments (for example, configurations having the same function, method and result, or configurations having the same purpose and effect). Further, the present invention includes a configuration in which a nonessential part of the configuration described in the embodiment is replaced. The present invention also includes configurations that can achieve the same effects as the configurations described in the embodiments or that can achieve the same purpose. Further, the present invention includes a configuration in which a known technology is added to the configuration described in the embodiment.

Reference Signs List 1 oscillator, 2 oscillation circuit, 3 oscillator, 4 package, 5 lid, 6 external terminal (external electrode), 7a, 7b accommodation chamber, 8 sealing member, 9 electronic components, 10 oscillation circuit, 11 oscillation circuit, 12 Power supply circuit, 13 start circuits, 20 amplitude control circuits, 21 heating circuits, 22 replica circuits, 30 output circuits, 40 temperature compensation circuits, 42 temperature sensors, 50 regulator circuits, 60 memories, 70 switch circuits, 80 serial interface (I / O F) Circuit, 300 electronic devices, 310 oscillator, 312 oscillation circuit, 313
Vibrator, 320 CPU, 330 operation unit, 340 ROM, 350 RAM, 360
Communication unit, 370 display unit, 400 mobile unit, 410 oscillator, 420, 430, 440
Controller, 450 battery, 460 backup battery

Claims (8)

An oscillation circuit having a first terminal connected to one end of a vibrator and a second terminal connected to the other end of the vibrator, and causing the vibrator to oscillate;
A start circuit electrically connected to the oscillation circuit and outputting a start signal for starting the oscillation circuit;
A power supply circuit which receives a first signal, generates a second signal following the first signal, and supplies power to the circuit for oscillation based on the second signal ;
The starting circuit is
And a comparator circuit that compares the voltage of the first signal with the voltage of the second signal, and generating the start signal based on the output signal of the comparator circuit, thereby causing the rise of the power supply circuit. conjunction with outputs the activation signal to the oscillation circuit,
The oscillation circuit is a rising edge of the power supply circuit when the voltage of the first signal matches the voltage of the second signal . Before the oscillation circuit starts up, a first DC voltage is applied to the first terminal, and a second DC voltage is applied to the second terminal,
The oscillation according to claim 1, wherein the start signal is a signal for stopping application of the first DC voltage to the first terminal and application of the second DC voltage to the second terminal. circuit. The first DC voltage is higher than the second DC voltage,
The voltage of the first terminal after the oscillation circuit starts to start is lower than the first DC voltage,
Voltage of the second terminal after the oscillation circuit starts to boot is higher than the second DC voltage, the oscillation circuit according to claim 2. The comparator circuit is
The polarity of the output signal is reversed when the voltage of the first signal rises and the sum of the voltage of the second signal and the positive offset voltage matches the voltage of the first signal. The oscillation circuit according to any one of 1 to 3 . The starting circuit is
5. The oscillator circuit according to claim 4 , wherein the offset voltage is increased after the voltage of the first signal rises and the polarity of the output signal of the comparator circuit is inverted. An oscillator comprising: the oscillator circuit according to any one of claims 1 to 5 ; the vibrator; and a container in which the oscillator circuit and the vibrator are disposed. An electronic device comprising the oscillation circuit according to any one of claims 1 to 5 or the oscillator according to claim 6 . A movable body comprising the oscillation circuit according to any one of claims 1 to 5 or the oscillator according to claim 6 .

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