CN1926494A

CN1926494A - Programmable clock generation

Info

Publication number: CN1926494A
Application number: CNA2005800066366A
Authority: CN
Inventors: 弗朗切斯科·佩索拉诺
Original assignee: Koninklijke Philips Electronics NV
Current assignee: Koninklijke Philips NV
Priority date: 2004-03-04
Filing date: 2005-02-28
Publication date: 2007-03-07
Anticipated expiration: 2025-02-28
Also published as: WO2005088421A3; EP1728139A2; WO2005088421A2; JP2007526575A; CN100422901C

Abstract

A mechanism for generating a clock signal for an integrated circuit, or part of one, so that the frequency thereof can be safely changed continuously (i.e. with a gradual frequency change) without spurious signals or glitches being created on the clock output line. A electronic device according to an exemplary embodiment, comprises a multiplexer (10) having two input signals, the second of which is a delayed version of the first, created by feeding the input to the multiplexer (10) via a set of generic combinatorial delay elements (12) and the multiplexer output id fed to the output (Out) via an inverter (14). The element further comprises a D-type flip-flop (16) having as its 'D' input a programming signal (Fk), and the two outputs 'Q' and 'Qn' from the D-type flip-flop provided respective drive signals to the multiplexer (10). The delay of the output signal (Out) with respect to the input signal (In) depends on the value of the programming signal (Fk), which is synchronized on the rising edge of the local clock (sync_ck).

Description

Programmable clock generates

Technical field

The present invention relates to programmable up/down clock generator, its manufacture method, programmable clock signal generation method and by clock signal that this method generated.

Background technology

Need to change the frequency of the work clock signal in the integrated circuit under many circumstances, so that power or performance management.For example, many semiconductor equipments have operation and stand-by operation pattern.With respect to the power consumption in operational mode, the power consumption in standby mode has reduced, thereby has still increased efficient the period of free time in device power-on.A method that in standby mode, reduces power consumption be reduce a plurality of must be when device power-on the frequency of operation of the circuit of continuous working.This can realize by the double oscillator frequency is provided: upper frequency is duration of work driving circuit at full speed in operational mode, and lower frequency has reduced the power consumption of duration of work circuit in standby mode thus with than the low velocity driving circuit.

Similarly,, caused various progress, comprised higher clock frequency and simpler instruction set usually to computing machine, especially to microprocessor and the higher performance need of microcontroller.As a result, for all integrated circuit, it is very crucial that the control of clock speed and frequency and dirigibility have become.

Summary of the invention

We have invented a kind of improved device now, the purpose of this invention is to provide a kind of method and apparatus, be used to generate integrated circuit or its a part of clock signal, so that can change its frequency in fact continuously (promptly, by the frequency gradual change, when the clock signal changes, keep its continuity simultaneously between different frequency), and can on clock output line, not produce any spurious signal (spurious signal) or disturb (glitch).

According to the present invention, the electronic equipment of the clock signal that is used to generate integrated circuit is provided, this equipment comprises: the module that is used to generate first clock signal of first frequency; Be used to rely on controlled variable signal to postpone the module of described first clock signal, described controlled variable signal is synchronized to the local clock signal; With the module that is used to generate by second clock signal of the second frequency of described controlled variable signal definition.

The present invention expands to the method for making electronic equipment as defined above and relies on the clock signal that electronic equipment generated as defined above.

According to the present invention, a kind of method that is used to generate the clock signal of integrated circuit also is provided, this method comprises: first clock signal that generates first frequency; Rely on controlled variable signal to postpone described first clock signal; Described controlled variable signal is synchronized to the local clock signal; And generation is by second clock signal of the second frequency of described controlled variable signal definition.

This electronic device design can be become switch between at least two frequencies, and the module that is used to postpone first clock signal can comprise two-way or multipath delay element, for example D flip-flop etc.This delay element has the input as it of controlled variable signal and local clock signal in the preferred case.The output of this delay element can be used as drive signal and presents to multiplexer between the input and output of this equipment etc.

The present invention can expand to the device that generates clock signal, and it comprises a plurality of as defined above electronic equipments.Described electronic equipment can be connected in the loop, and each equipment has controlled variable signal and output separately, and wherein the frequency of the clock signal that is generated by oscillator can change by the output that changes electronic equipment separately.This oscillator can also comprise and adding/subtract FIFO etc., and be used for receiving the signal that has defined in the desired change of frequency of clock signal, and be used for correspondingly changing the output of electronic equipment, to realize desired change in the clock signal frequency.

According to embodiment described here, these and other aspects of the present invention will become clear, and with reference to this embodiment these and other aspects of the present invention will be described.

Description of drawings

Now, with the mode by example only and describe embodiments of the invention with reference to the accompanying drawings, wherein:

Fig. 1 is the schematic circuit diagram of the two-way delay element that uses in the clock generating device of the exemplary embodiments according to the present invention;

Fig. 2 is the schematic circuit diagram of the element of Fig. 1, has wherein omitted D flip-flop in order to clearly demonstrate;

Fig. 3 is the schematic block diagram of explanation topological structure of the oscillator of exemplary embodiments according to the present invention;

Fig. 4 is the schematic circuit diagram of the oscillator of exemplary embodiments according to the present invention; And

Fig. 5 is to use the picture specification of the obtainable clock waveform of device of the exemplary embodiments according to the present invention.

Embodiment

In known solutions, clock generates needs reference clock, this reference clock can be used to produce the clock signal that frequency is the multiple of reference clock frequency then usually.Yet the major defect of these known arrangement is that the frequency that only is the reference clock frequency multiple is available, and the solution of standard is easy to introduce interference on clock line.

U.S. Patent No. 5,808,486 have described a kind of clock enable circuits, and when having enable signal, this clock enable circuits generates the clock signal that has with input clock signal same frequency, same duty cycle and fixed phase relationship.First d type flip flop that the positive edge that comprises this circuit triggers, marginal AND door along second d type flip flop that triggers and two inputs.This clock enable circuits is intended to generate clock signal, makes enabling output signal when changing into logical falsehood, and this clock signal turns back to its steady-state value in the mode that does not produce any interference, and keeps the dutycycle of input clock.

U.S. Patent No. 6,275,546 are usually directed to a kind of commutation circuit, be used for two independent, switch between input clock signal free-running operation, that can have identical or different frequency and phase place usually, so that produce glitch-free clock signal, this clock signal is synchronized in the input clock signal.

U.S. Patent Application Publication No.2003/0074595 A1 has described a kind of circuit, it comprises the dynamically changeable output clock value that generates according to the input clock value and as the sample period output of rising edge alignment enable signal, maintain that the sample period is determined and rising edge alignment incident between one-one relationship, and no matter the dynamic change in the round values.This circuit provides according to input clock and has exported clock based on integer-valued dynamically changeable, and wherein this integer can be revised continuously.

As mentioned above, the present invention aims to provide a kind of mechanism, generates integrated circuit or wherein a part of clock signal, makes its frequency to be changed (that is, by the frequency gradual change) safely continuously.

Fig. 1 with reference to the accompanying drawings, the programmable up/down clock generator of exemplary embodiments comprises the synchronous double-way element according to the present invention, this synchronous double-way element is constructed to single unit under the best circumstances.Be appreciated that circuit realization of the present invention can change, although its basic function does not change.

In illustrated example, described element comprises the multiplexer 10 with two input signals, second delay form that input signal is first input signal, second input signal produces by importing to present to multiplexer 10 via one group of common combination delay element 12, and the output of multiplexer is presented to output (Out promptly " goes out ") via phase inverter 14.This element also comprises D flip-flop 16, and this D flip-flop has programming signal (Fk) and imports as its " D ".Usually, D flip-flop is a digital logic device, when certain conversion (that is, low to height or high to low) is made in its clock input (CP), this digital logic device is just stored the state of its " D " input, and (a plurality of) outputs " Q " show the value of current storage.Under the situation of this exemplary embodiments of the present invention, provide separately drive signal to multiplexer 10 from two outputs " Q " of D flip-flop and " Qn ", and output signal (Out) depends on the value of programming signal Fk with respect to the delay of input signal (In promptly " goes into ").This signal is carried out at the rising edge of local clock (sync_ck) synchronously.Just the latter this make this circuit can reach purpose of the present invention on the one hand.

Fig. 2 has with reference to the accompanying drawings illustrated and the typical element of Fig. 1 has wherein omitted synchronous rising edge trigger 16, so that more clearly illustrate the whole operation of this circuit.Therefore, as the professional and technical personnel will be clear, the output signal (Out) that basic operation in a circuit according to the invention is to use controlled variable signal Fk to come delay clock generator wherein uses the D flip-flop 16 in the circuit that for example is included in Fig. 1 that this controlled variable signal Fk is synchronized to local clock.

Fig. 3 with reference to the accompanying drawings can create oscillator by a plurality of such elements 20 are connected in series in the loop, each element has control signal F separately.The driving circuit that is used for oscillator illustrated in fig. 3 is schematically illustrated in Fig. 4 of accompanying drawing.This driving circuit comprises and adding/subtract FIFO 22, and the frequency of oscillator can change by the value that changes on the R1-R9 signal.In order to change the frequency of oscillator, the pattern on the R1-R9 signal must be such, promptly once has only a delay element 24 to be reprogrammed.This can use and add/subtract FIFO22 and realize that this adds/subtract FIFO 22 can make pattern 0000001 become 1111111 (vice versa) by simple logical shift.Under the situation of this exemplary embodiments, moving to left increases oscillator frequency (" adding " signal) and moves to right and reduce frequency (" subtracting " signal).

In order to guarantee correctly to work and avoid problem, be necessary to use the D flip-flop 26 that for example in Fig. 4, has only illustrated that the clock signal (CK) of above-mentioned pattern and generation is kept synchronously.Just because of this reason, the trigger 16 in the circuit of Fig. 1 is necessary, and wherein trigger must be positioned at the vicinity of its respective delay element to avoid competition (race).This trigger exist (perhaps its equivalent) implies in the circuit of Fig. 2, and when using the circuit of Fig. 1, this circuit should be contained in the delay element in oscillator loop.

Device of the present invention allows to change clock frequency continuously and without any looking genuine conversion, and typical waveform has been described among Fig. 5 of accompanying drawing, has wherein illustrated with respect to clock frequency is changed into the performed test of about 100MHz from 2GHz.Control to the frequency of the clock that generated is relatively very simple, because do not need such a clock work.On the contrary, only use the control that two signals " add " and " subtracting " realizes expecting.

Therefore, the invention provides a kind of mechanism and generate integrated circuit or wherein a part of clock signal, this makes its frequency to be changed (that is, by the frequency gradual change) safely in fact continuously, and without any the conversion of looking genuine.The present invention does not require the use external oscillator, and with the such normal structure test Solution compatibility of for example scan chain.As discussed above, device according to the present invention finds its application in the system that changes frequency for performance and power management.

Embodiments of the invention only are described by example in front, and those skilled in the art will be clear, under the situation of not leaving the scope of the present invention that defines by claims, can make numerous modifications and variations to described embodiment.For example, in exemplary embodiments shown in Fig. 1 and that be described with reference to Figure 1, use D flip-flop to dispose the two-way delay element.Yet, in the embodiment that replaces, can adopt the multipath delay element.The professional and technical personnel will be understood that, what the topological structure of this oscillator can be with accompanying drawing is illustrated in fig. 3 different.The sync cap of need of work of the present invention can realize by the mode different with the illustrated sync cap of embodiment, and can conceive for adding in Fig. 4 circuit/subtract multiple design of FIFO.

In addition, in the claims, place any reference marker between the parenthesis will not be interpreted as limiting claim.Term " comprises " does not get rid of the element do not listed in the claims or the existence of step.A plurality of meanings do not got rid of in term " ".The present invention can rely on the hardware that comprises multiple resolution element and rely on the computing machine of programming suitably to realize.Enumerated a plurality of modules in the device claim, the part in these modules can be implemented by same hardware component.In different mutually independent claims, carefully stated this fact of multiple measure and do not represented that the use of the combination of these measures does not have advantage.

Claims

1, a kind of electronic equipment that is used to generate the clock signal (Out) of integrated circuit, described equipment comprises the module of first clock signal (Out) that is used to generate first frequency, be used to rely on controlled variable signal (Fk) to postpone the module of described first clock signal, described controlled variable signal (Fk) is synchronized to local clock signal (sync_ck), and is used for the module of generation by second clock signal (Out) of the second frequency of described controlled variable signal (Fk) definition.

2, electronic equipment according to claim 1 is set between at least two kinds of frequencies and switches.

3, according to claim 1 or the described electronic equipment of claim 2, the module (16) that wherein is used to postpone described first clock signal comprises two-way or multipath delay element.

4, electronic equipment according to claim 3, wherein said delay element comprise D flip-flop (16).

5, according to claim 3 or the described electronic equipment of claim 4, wherein said delay element (16) has described controlled variable signal (Fk) and described local clock signal (sync_ck) as its input.

6, according to any one described electronic equipment in the claim 3 to 5, output (the Q of wherein said delay element (16), Qn) (S0 S1) presents to the multiplexer (10) between input that is positioned at described electronic equipment (In) and the output (Out) to be used as drive signal.

7, be used to generate the device of clock signal, comprise according to any one described a plurality of electronic equipment (24) in the claim 1 to 6.

8, device according to claim 7, wherein said a plurality of electronic equipments (24) are connected in the loop, and each equipment (24) has controlled variable signal (F1-F9) and output separately.

9, device according to claim 8, wherein the frequency of the described clock signal that is generated by described device can change by the output (R1-R9) of each electronic equipment of change (24).

10, according to any one described device in the claim 7 to 9, also comprise and add/subtract FIFO (22), be used for receiving the signal of the desired change of frequency that has defined described clock signal (Out), and be used for correspondingly changing the described output (R1-R9) of electronic equipment (24), to realize desired change in the clock signal frequency.

11, a kind of method that is used to generate the clock signal of integrated circuit, described method comprises first clock signal (Out) that generates first frequency, rely on controlled variable signal (Fk) to postpone described first clock signal, described controlled variable signal is synchronized to local clock signal (sync_ck), and generates second clock signal (Out) by the second frequency of described controlled variable signal (Fk) definition.

12, a kind of method of making according to any one described electronic equipment in the claim 1 to 6.

13, a kind of method of making according to any one described device in the claim 7 to 10.

14, by generate according to any one described electronic equipment in the claim 1 to 6, by the clock signal that generate or that rely on method according to claim 11 to generate of the arbitrary described device according to claim 7 to 10.