CN103311971B

CN103311971B - Charge pump

Info

Publication number: CN103311971B
Application number: CN201210061729.0A
Authority: CN
Inventors: 邱珦益
Original assignee: Novatek Microelectronics Corp
Current assignee: Novatek Microelectronics Corp
Priority date: 2012-03-09
Filing date: 2012-03-09
Publication date: 2016-05-25
Anticipated expiration: 2032-03-09
Also published as: CN103311971A

Abstract

The present invention discloses a kind of charge pump, includes a charge pump circuit, is used for according to a driving signal, produces an output voltage; One comparison circuit, is used for according to this output voltage and a reference voltage, produces a comparative result; One circuit for detecting, be used for according to this comparative result with detect this output voltage ripple frequency range and produce a detecting result; And a driving stage, be used for producing this driving signal according to this comparative result, and adjust the corresponding driving force of this driving signal according to this detecting result.

Description

Charge pump

Technical field

The present invention relates to a kind of charge pump, espespecially one can be avoided audio-frequency noise and guarantee not have stabilityThe charge pump of problem.

Background technology

In general, charge pump (chargepump) can be used to provide regulated output voltage to different loads,And known control mode to charge pump has two kinds, is respectively with operational amplifier and with comparator and controlsSystem. Under the framework of controlling with operational amplifier, output voltage has less output ripple, butUnder different loads and external module, have the consideration of stability; And the framework of controlling with comparatorUnder, although there is no stability problem, there is output voltage to there is larger periodicity output ripple, andUnder some load, may produce audio-frequency noise.

For instance, please refer to Figure 1A, Figure 1A is the schematic diagram of a known charge pump 10. Charge pumpThe 10th, the framework of controlling with operational amplifier (operationalamplifier), includes a charge pump circuit102, an operational amplifier 104, adjustment transistor 106 and a driving stage 108. In simple terms,The driving signal DRVP that charge pump circuit 102 can produce according to driving stage 108, produces an outputVoltage VGH. For example charge pump circuit 102 can be the gloomy charge pump of a Dick, and it is driving signal DRVPDuring for low level, an input voltage AVDD can be to the electric capacity that goes at express speed (flyingcapacitor) CF1, CF2Charging, making driving signal DRVP is high levle and lifting while going at express speed capacitor C F1, CF2 current potential,The stored electric charge of the capacitor C of going at express speed F1, CF2 can transfer to an output capacitance CS1, with by output voltageVGH side Pu is to want level.

Aspect the driving signal DRVP controlling in generation, divider resistance R1, R2 can be by output electricityPress VGH dividing potential drop to give operational amplifier 104 to produce a feedback voltage FBP. Operational amplifier 104 is comparableCompared with feedback voltage FBP and a reference voltage VREF to provide an output signal OP_OUT to give adjustment crystalPipe 106 is adjusted, and, in the time that output voltage V GH is higher, feedback voltage FBP is also higher, and drawsHigh output signal OP_OUT, makes to adjust the electric conduction resistive large (gate voltage is higher) of transistor 106;In the time that output voltage V GH is lower, feedback voltage FBP is also lower, and drags down output signal OP_OUT,The conducting resistance that makes to adjust transistor 106 diminish (being that gate voltage is lower). Then, driving stage 108Produce driving signal DRVP according to adjusting transistor 106 and a frequency signal CLK, to control charge pumpCircuit 102 produces desired output voltage V GH.

Specifically, please refer to Figure 1B, Figure 1B is the signal schematic representation of the charge pump 10 shown in Figure 1A.As shown in Figure 1B, due to driving stage 108 when the high levle of frequency signal CLK constantly by producedDrive signal DRVP to be toggled to high levle, and the conducting resistance of adjustment transistor 106 can be because of output voltageVGH adjusts, therefore the output voltage V GH of last charge pump circuit 102 to output capacitance CS1Charging current to equaling the discharge current of external load. Due to the ripple size direct ratio of output voltage V GHIn charging and discharging currents, therefore there is less output ripple (the driving signal of the framework of operational amplifier controlThe high levle of DRVP is compared with less under the framework of comparator control, and this part is explained after a while).

But, because the framework of charge pump 10 has (the external load of 2 π * CS1* of a limit 1/ in outputValue), therefore in the time of the external load of difference and output capacitance CS1, can change this limit, thereby have stabilityConsider.

On the other hand, please refer to Fig. 2 A, Fig. 2 A is the schematic diagram of a known charge pump 20. Charge pump20 similar to charge pump 10 parts, therefore the similar person of the effect of assembly and signal represents with same-sign.Charge pump 20 is the frameworks with comparator control, include a charge pump circuit 102, a comparison circuit 204,One driving stage 206 and divider resistance R1, R2, and comparison circuit 204 include a comparator 208,One flip-flop (flip-flop) 210 and a NAND gate (NANDgate) 212. In simple terms, chargingThe driving signal DRVP that pump circuit 102 can produce according to driving stage 206, helps output voltage V GHPu to want level running to above-mentioned similar, do not repeat them here.

Aspect the driving signal DRVP controlling in generation, divider resistance R1, R2 can be by output electricityPress VGH dividing potential drop to give comparator 208 to produce feedback voltage FBP. Comparator 208 can compare feedback voltageFBP and reference voltage VREF are to provide a comparison output signal COMP_OUT, and flip-flop 210 canTrigger and export the voltage standard of comparison output signal COMP_OUT at that time at the upper limb of frequency signal CLKPosition, so that a comparison sampled signal COMP_SAM to be provided, (relatively sampled signal COMP_SAM existsIn the cycle of frequency signal CLK, maintain identical level, be different from comparison output signal COMP_OUTMay be subject to outside noise or interference and have level to change), and NAND gate 212 can be according to sampled signal relativelyCOMP_SAM and frequency signal CLK produce a compare result signal COMP_SIG and give driving stage 206,Driving stage 206 can be produced according to this and drive signal DRVP, produce institute to control charge pump circuit 102The output voltage V GH wanting.

Specifically, please refer to Fig. 2 B, Fig. 2 B is the signal schematic representation of charge pump 20 shown in Fig. 2 A.As shown in Figure 2 B, after output voltage V GH is lower than a target voltage, (be that feedback voltage FBP is less than ginsengExamine voltage VREF), relatively sampled signal COMP_SAM starts at a upper limb of frequency signal CLKThe high levle of output one-period, relatively sampled signal COMP_SAM and frequency signal CLK are highWhen level (compare result signal COMP_SIG is low level), driving signal DRVP is high levleConstantly output voltage V GH is charged to control charge pump circuit 102. Then, at output voltage V GHAfter target voltage, relatively sampled signal COMP_SAM opens at another upper limb of frequency signal CLKThe begin low level of output one-period, makes to drive signal DRVP to maintain low level and not to output voltageVGH charging, now the output voltage V GH of output capacitance CS1 can be because of to external load supplying graduallyReduce, until lower than repeating again above-mentioned behavior after target voltage. In this case, due to charge pump 20Only compare feedback voltage FBP and reference voltage VREF, therefore there is no stability problem.

On the other hand, all will drive signal when the high levle of frequency signal CLK compared to charge pump 10DRVP is toggled to high levle, and charge pump 20 is only comparing sampled signal COMP_SAM and frequency signalCLK is that high levle is just toggled to driving signal DRVP high levle (while beating while driving signal DRVPDo not beat), the electric current at every turn discharging and recharging can be greater than average current (being load current), charge pump circuit when stable stateThe mean charging current of the output voltage V GH of 102 couples of output capacitance CS1 equals the electric discharge electricity of external loadStream, to maintain a target voltage by output voltage V GH.

Specifically the level height while, driving signal DRVP to be high levle and driving signal DRVP driveKinetic force is relevant. If comparator architecture, the transistor of driving stage 206 can be opened with all strength, therefore driveLevel when signal DRVP is high levle can be higher; If operational amplifier framework, operational amplifier104 output signal OP_OUT can adjust by adjustment transistor 106 fan-out capability of driving stage 108,Therefore the level while driving signal DRVP to be high levle can be lower. Charge pump circuit 102 provides load energySize be that number of times and the amplitude of high levle determines by driving signal DRVP to trigger, under different loads,Comparator architecture modulation be to trigger as the number of times of high levle, operational amplifier framework framework modulation be tactileSend out the amplitude for high levle.

In the time that system is in stable state, charge pump circuit 102 must wait the charging current of output voltage V GHIn load current, output voltage V GH could stablize like this. Due to the driving signal of operational amplifier frameworkDRVP beats always, therefore charge pump circuit 102 just equals load electricity to the charging current of output voltage V GHStream; And the driving signal DRVP of comparator architecture once beats and do not beat, therefore charge pump circuit 102 is rightThe charged electrical of output voltage V GH fails to be convened for lack of a quorum and is greater than load current. Output ripple size is proportional to and discharges and recharges electricity againStream, therefore the larger comparator architecture of charging current causes output voltage V GH to have larger periodicity outputRipple, therefore comparator architecture can produce the audio-frequency noise that people's ear can be heard under some external load(20Hz-20KHz)。

For instance, please refer to Fig. 3, Fig. 3 is the driving signal DRVP shown in Fig. 2 under a certain loadsCause the schematic diagram of audio-frequency noise. As shown in Figure 3, when driving signal DRVP continuous trigger, (one is prominentRipple, burst) to high levle when output voltage V GH is raised to target voltage, although its continuous triggerFrequency (being that frequency signal CLK is higher than 20KHz), but between its twice continuous trigger every fallingIn 20Hz-20KHz (ripple frequency of output voltage V GH), and produce audio-frequency noise.

Therefore, although there is no stability problem with the charge pump 20 of comparator control, because it hasLarger output ripple therefore can produce audio-frequency noise under some external load.

Summary of the invention

Provide a kind of charge pump of avoiding audio-frequency noise and stability problem at this.

According to one side of the present disclosure, a kind of charge pump is provided, include a charge pump circuit, be used for rootAccording to a driving signal, produce an output voltage; One comparison circuit, is used for according to this output voltage and a ginsengExamine voltage, produce a comparative result; One circuit for detecting, is used for according to this comparative result to detect this outputThe frequency range of the ripple of voltage also produces a detecting result; And a driving stage, be used for according to this comparisonResult produces this driving signal, and adjusts the corresponding driving energy of this driving signal according to this detecting resultPower.

Coordinate detailed description and claims of following diagram, embodiment at this, by address the present inventionOther object and after advantage is specified in.

Brief description of the drawings

Figure 1A is the schematic diagram of a known charge pump.

Figure 1B is the signal schematic representation of the charge pump shown in Figure 1A.

Fig. 2 A is the schematic diagram of known another charge pump.

Fig. 2 B is the signal schematic representation of charge pump shown in Fig. 2 A.

Fig. 3 is that under a certain loads, one shown in Fig. 2 drives signal to cause the schematic diagram of audio-frequency noise.

Fig. 4 A is the schematic diagram of the embodiment of the present invention one charge pump.

Fig. 4 B is the schematic diagram of another charge pump of the embodiment of the present invention.

Fig. 5 is the circuit diagram of the circuit for detecting shown in Fig. 4 A.

Fig. 6 is the circuit diagram of the control circuit shown in Fig. 4 B.

Fig. 7 is the embodiment of the present invention in order to implement the schematic diagram of a charge pump of the charge pump shown in Fig. 4 A.

Fig. 8 A is the embodiment of the present invention in order to implement the signal of another charge pump of the charge pump shown in Fig. 4 BFigure.

Fig. 8 B is the signal schematic representation of charge pump shown in embodiment of the present invention Fig. 8 A.

Wherein, description of reference numerals is as follows:

10,20,40,70,80 charge pumps

102,402 charge pump circuits

104 operational amplifiers

106 adjust transistor

108,206,408 driving stages

204,404 comparison circuits

208,702 comparators

210, DFF1, DFF2,704 flip-flops

212,706 NAND gates

406 circuit for detecting

410,60,802 control circuits

502 timers

504 edge detection unit

506 pulse wave conversion equipments

508,614 nor gates

602 transmission control units

604 transmission units

606 counters

608 edge detection unit

610 reset signal generation units

612 phase inverters

DRVP, DRVP ＇ drive signal

VGH, VGH ＇ output voltage

AVDD input voltage

CF1, CF2, CS1 electric capacity

R1, R2 resistance

FBP feedback voltage

VREF, VREF ＇ reference voltage

OP_OUT output signal

CLK frequency signal

COMP_OUT, COMP_OUT ＇ comparison output signal

COMP_SAM, COMP_SAM ＇ be sampled signal relatively

COMP_SIG, COMP_SIG ＇ compare result signal

COMP comparative result

DET detects result

TS frequency signal

D data input pin

CK frequency end

Q, QB output

The RSTB end of resetting

COMP_PUL is pulse wave signal relatively

DRVP_LIM transmission of control signals

DCON drive control signal

CNT count signal

Detailed description of the invention

Please refer to Fig. 4 A, Fig. 4 A is the schematic diagram of the embodiment of the present invention one charge pump 40. Charge pump 40Similar to charge pump 20 parts, therefore the similar person of the effect of assembly and signal represents with same-sign. AsShown in Fig. 4 A, charge pump 40 includes a charge pump circuit 402, a comparison circuit 404, a detectingCircuit 406 and a driving stage 408. In simple terms, charge pump circuit 402 can be according to a driving signalDRVP ＇, produces an output voltage V GH ＇. Comparison circuit 404 can be according to output voltage V GH ＇ and oneReference voltage VREF ＇, produces a comparative result COMP. Circuit for detecting 406 can be according to comparative resultCOMP is with the frequency range of the ripple (ripple) of detecting output voltage V GH ＇ and produce a detecting knotFruit DET. Driving stage 408 can produce and drive signal DRVP ＇ according to comparative result COMP, and foundationDetecting result DET adjusts and drives the corresponding driving force of signal DRVP ＇. Thus, chargingPump 40 can, by the driving force of adjusting driving stage 408, be controlled the ripple size of output voltage V GH ＇,To avoid audio-frequency noise.

Specifically, whether detecting result DET can indicate the ripples wave frequency of output voltage V GH ＇ to existIn one audiorange. Wherein, circuit for detecting 406 for example can be by an arteries and veins of detecting comparative result COMPThe wave spacing time is (high according to output voltage V GH ＇ to judge the ripple frequency of output voltage V GH ＇Time in target voltage judges). In an enforcement example, in detecting result DET instruction outputThe ripples wave frequency of voltage VGH ＇ is outside an audiorange time, and driving stage 408 maintains current driving signalThe corresponding driving force of DRVP ＇; At the ripple frequency of detecting result DET instruction output voltage V GH ＇Rate in audiorange time, drives signal DRVP ＇ to reduce its driving force, and then makes output voltageThe ripple frequency of VGH ＇ higher than this audiorange (drive the driving force of signal DRVP ＇ lower,More need frequently to drive to maintain output voltage V GH ＇ in target level).

It should be noted that according to the embodiment shown in Fig. 4 B, in charge pump 40, circuit for detecting 406Be coupled to comparison circuit 404 to receive comparative result COMP, and be coupled to driving stage 408 with outputDET is to driving stage 408 for detecting result, makes driving stage 408 directly adjust and drive according to detecting result DETThe moving corresponding driving force of signal DRVP ＇. But, as shown in Figure 4 B, in other embodiments,Charge pump 40 can also comprise a control circuit 410, is coupled between comparison circuit 404 and driving stage 408,And be coupled to circuit for detecting 406, be used for adjusting according to comparative result COMP and detecting result DETDrive the corresponding driving force of signal DRVP ＇. Similarly, in this case, this control circuit canAccording to detecting result DET, to determine whether comparative result COMP is sent to driving stage 408. BetterGround, in the time that the ripple frequency of detecting result DET instruction output voltage V GH ＇ is in an audiorange,The pulse wave that this control circuit can limit at least a portion number of comparative result COMP is sent to driving stage408, will drive signal DRVP ＇ to be toggled to the number of high levle to reduce driving stage 408, and then reduceIts driving force, makes the ripple frequency of output voltage V GH ＇ higher than this audiorange.

Particularly, please refer to Fig. 5, Fig. 5 is the electricity of the circuit for detecting 406 shown in Fig. 4 A or Fig. 4 BOne embodiment of road schematic diagram. As shown in Figure 5, circuit for detecting 406 include a timer 502 andOne edge detecting unit 504. Timer 502 is coupled to comparison circuit 404, for compared result COMPThe pulse wave of a corresponding signal carries out timing interval time, indicates this pulse wave to produce a frequency signal TSWhether arrive a given time interval time. Edge detection unit 504 is coupled to timer 502, forThe edge of detecting frequency signal TS is to produce a detection signal as this detecting result DET. Edge detectionUnit 504 can comprise a flip-flop (flip-flop) DFF1, and it has a frequency end CK and is coupled to frequencySignal TS, and an output Q provides detection signal DET. Circuit for detecting 406 can also comprise an arteries and veinsRipple conversion equipment 506 and a nor gate 508. Pulse wave conversion equipment 506 be coupled to comparison circuit 404 withBetween timer 502, for comparing pulse wave signal according to comparative result COMP to produce oneCOMP_PUL via nor gate 508 to timer 502, so that result COMP is corresponding as a comparisonOne signal.

Under this configuration, when pulse wave conversion equipment 506 detect comparative result COMP conversion position accurate (for example byLow level transfers high levle to) time (that is output voltage V GH ＇ is lower than target voltage), relatively pulse waveSignal COMP_PUL triggers as high levle, makes timer 502 reset to start timing (timer 502One reset end RSTB in the time of low level, reset), if timer 502 timing given time (as 50s,Drop in audiorange 20KHz) to be reset not yet (be that comparative result COMP is not again by low againLevel transfers high levle to), frequency signal TS is triggered as high levle, detection signal DET is also switchedFor high levle. Thus, circuit for detecting 406 can be by the pulse wave interval of detecting comparative result COMPTime produces detection signal DET, whether drops on audio frequency model with the ripple frequency of indicating output voltage V GH ＇Enclose.

On the other hand, please refer to Fig. 6, Fig. 6 is the circuit diagram of the control circuit 60 in Fig. 4 BAn embodiment. As shown in Figure 6, control circuit 60 includes a transmission control unit 602 and a biographyDefeated unit 604. Transmission control unit 602 is coupled between comparison circuit 404 and circuit for detecting 406,In order to according to detecting result DET and comparative result COMP, produce a transmission of control signalsDRVP_LIM, and transmission unit 604 is coupled between comparison circuit 404 and driving stage 408, and moreBe coupled to transmission control unit 602, in order to according to transmission of control signals DRVP_LIM, whether to determineExport comparative result COMP to driving stage 408 as a drive control signal DCON.

In the case, when the ripples wave frequency of detecting result DET instruction output voltage V GH ＇ higher thanWhen audiorange, transmission of control signals DRVP_LIM controls transmission unit 604 by comparative result COMPExport driving stage 408 to, driving stage 408 still will be driven according to the whole pulse waves of comparative result COMPSignal DRVP ＇ is toggled to high levle to drive. Otherwise, when detecting result DET instruction output electricityThe ripples wave frequency position of pressing VGH ＇ is in audiorange time, transmission control unit 602 compared resultThe pulse wave of corresponding each train of pulse of COMP is counted, and has both fixed a number when this pulse wave number arrives oneAfter order, produce transmission of control signals DRVP_LIM and stop comparative result to control transmission unit 604COMP exports driving stage 408 to, makes driving stage 408 only according to comparative result COMP part pulse waveDriving signal DRVP ＇ is toggled to high levle to drive, and then reduces its driving force, makeThe ripple frequency of output voltage V GH ＇ is higher than this audiorange.

Concrete enforcement in example, transmission control unit 602 includes a counter 606 and one sideEdge detecting unit 608. Counter 606 is coupled to comparison circuit 404, can compared result COMP institutePulse number in each corresponding train of pulse is counted (as to a compare result signal COMP_SIG ＇Counting), to produce a count signal CNT. Edge detection unit 608 is coupled to counter 404 and detectsSlowdown monitoring circuit 406, with according to detecting result DET, detects a particular edge of count signal CNT to produceTransmission of control signals DRVP_LIM. Detailed speech, as detecting result DET instruction output voltage V GH ＇Ripples wave frequency position in audiorange time, if counter 606 compared result COMP are correspondingPulse number in each train of pulse counts up to this prearranged number, can produce this certain edges thereof of count signal CNTEdge, makes edge detection unit 608 produce transmission of control signals DRVP_LIM to control transmission unit 604Stop exporting comparative result COMP (as compare result signal COMP_SIG ＇ counting) to driving stage408。

In a particular example, edge detection unit 608 can comprise a flip-flop DFF2 and a replacementSignal generation unit 610. Flip-flop DFF2 has a frequency end CK and is coupled to count signal CNT,And one output QB transmission of control signals DRVP_LIM is provided, and one reset end RSTB coupleTo circuit for detecting 406. Reset signal generation unit 610 is coupled to the replacement end RSTB of flip-flop DFF2And between circuit for detecting 406, for corresponding according to detecting result DET and comparative result COMPThe relatively pulse wave signal COMP_PUL flip-flop DFF2 that determines whether resetting. Wherein, reset signal producesRaw unit 610 for example can include a phase inverter 612 and a nor gate 614, and phase inverter 612 hasOne input is coupled to circuit for detecting 406, is respectively coupled to anti-phase and nor gate 614 has two inputsOne output of device 612 and be coupled to comparison pulse wave signal COMP_PUL, and an output couplesTo the replacement end RSTB of flip-flop DFF2.

In the case, when detection signal DET instruction switches to high levle with instruction output voltage V GH ＇Ripple frequency while dropping on audiorange, if relatively pulse wave signal COMP_PUL trigger for high levle withWhen instruction comparative result COMP transfers high levle to by low level, (output voltage V GH ＇ is lower than target electricityPress), the replacement end RSTB of flip-flop DFF2 receives a low level signal and resets, to export Gao ZhunThe transmission of control signals DRVP_LIM of position, makes transmission unit 604 export comparative result COMP institute rightThe pulse wave of the train of pulse of answering. Then, because a replacement end RSTB of counter 606 can be at comparative resultWhen transferring low level to, COMP resets (as output signal COMP_OUT ＇ or comparison sampled signalCOMP_SAM ＇ transfers low level to, and output voltage V GH ＇ reaches target voltage), therefore counter606 pulse number countings in can corresponding each train of pulse of compared result COMP, with arrive shouldWhen prearranged number, triggered the frequency end of flip-flop DFF2 by count signal CNT, control letter transmittingNumber DRVP_LIM switches to low level, makes transmission unit 604 not export comparative result COMP instituteCorresponding train of pulse, with subsequent pulses, to reduce driving force, makes the ripple of output voltage V GH ＇ frequentlyRate is higher than this audiorange.

Main spirits that it should be noted that above-described embodiment is that charge pump 40 can detect comparative resultCOMP with the ripples wave frequency that judges output voltage V GH ＇ whether in an audiorange, then determine beThe driving force of no adjustment driving stage 408, to avoid output voltage V GH ＇ frequency in an audiorangeAnd absence of audio noise. Those of ordinary skill in the art work as and can change according to this, and are not limited to this.

Please refer to Fig. 7, Fig. 7 is that the embodiment of the present invention is in order to implement one of the charge pump 40 shown in Fig. 4 AThe schematic diagram of charge pump 70. Charge pump circuit 402 shown in Fig. 7 and the charge pump circuit shown in Fig. 2 A102 is similar, and therefore the similar person of the effect of assembly and signal represents with same-sign. As shown in Figure 7, thanInclude a comparator 702, a flip-flop 704 and a NAND gate 706 compared with circuit 404. Comparator702 have two inputs is coupled to respectively output voltage V GH ＇ and reference voltage VREF ＇, and one is defeatedGo out end, for a comparison output signal COMP_OUT ＇ is provided. It is defeated that flip-flop 704 includes dataThe output, the frequency end CK that enter to hold D to be coupled to comparator 702 are used for receiving a frequency signal CLK,And a data output end Q, for provide one relatively sampled signal COMP_SAM ＇ (be flip-flop 704Can trigger and export the electricity of comparison output signal COMP_OUT ＇ at that time at the upper limb of frequency signal CLKPress level, therefore relatively sampled signal COMP_SAM ＇ maintains within a cycle of frequency signal CLKIdentical level, is different from comparison output signal COMP_OUT ＇ and may be subject to outside noise or interference and hasLevel changes). NAND gate 706 has two inputs and is coupled to respectively the data output end Q of flip-flop 704And frequency signal CLK, and an output, for a compare result signal COMP_SIG ＇ is provided.

It should be noted that aforementioned comparative result COMP comprise comparison output signal COMP_OUT ＇,Relatively one at least in the middle of sampled signal COMP_SAM ＇ and compare result signal COMP_SIG ＇.In other words, although illustrating circuit for detecting 406, Fig. 7 receives comparison output signal COMP_OUT ＇, and realOn border, circuit for detecting 406 can receive comparison output signal COMP_OUT ＇ or comparison sampled signalCOMP_SAM ＇ (stability is better), and a detection signal of output representative detecting result DET is to drivingMoving level 408 is controlled.

In addition, also it is noted that the compare result signal that in Fig. 7, driving stage 408 receivesThe comparative result COMP that COMP_SIG ＇ receives corresponding to driving stage 408 in Fig. 4 A. AnotherAspect, the comparative result COMP that Fig. 6 Counter 606 is counted can comprise compare result signalCOMP_SIG ＇, and the comparative result COMP that its end RSTB that resets receives also can be relatively outputSignal COMP_OUT ＇ or comparison sampled signal COMP_SAM ＇, and transmission unit 604 receivesComparative result COMP be compare result signal COMP_SIG ＇.

Moreover in Fig. 7, driving stage 408 drives signal by the transistor for generating that uses different sizeDRVP ＇, with drive according to the detection signal adjustment of representative detecting result DET signal DRVP ＇ correspondenceDriving force. In other embodiments, can otherwise adjust driving force. For example, driveMoving level 408 also can drive signal DRVP ＇ by producing with the parallel transistor of different numbers, with rootDetection signal adjustment according to representative detecting result DET drives the corresponding driving force of signal DRVP ＇,Or driving stage 408 can comprise multiple buffers, central one is at least led according to detecting result DETLead to or close, driving the corresponding driving force of signal DRVP ＇ to adjust.

On the other hand, please refer to Fig. 8 A, Fig. 8 A is that the embodiment of the present invention is in order to implement shown in Fig. 4 BThe schematic diagram of another charge pump 80 of charge pump 40. Charge pump 80 is similar to charge pump 70 parts, because ofThe similar person of effect of this assembly and signal represents with same-sign. Charge pump 80 is main with charge pump 70Difference is, charge pump 80 more comprises a control circuit 802, is used for receiving compare result signalCOMP_SIG ＇ and detection signal, to come according to compare result signal COMP_SIG ＇ and detection signalDCON is to driving stage 408 for output drive control signal, and circuit for detecting 406 receives relatively sampled signalCOMP_SAM ＇ (but also can receive comparison output signal COMP_OUT ＇). In this case, driveLevel 408 is by changing the number of times that charge pump circuit 402 is charged continuously, to adjust driving signalCorresponding this driving force of DRVP ＇.

For instance, please refer to Fig. 8 B, Fig. 8 B is charge pump 80 shown in embodiment of the present invention Fig. 8 ASignal schematic representation. Shown in Fig. 8 B, as relatively sampled signal COMP_SAM ＇ of circuit for detecting 406 detectingsA pulse wave be greater than given time (as 50s, dropping in audiorange 20KHz) interval time,Detecting result DET is toggled to high levle, makes control circuit 802 only by compare result signalThe part pulse wave of COMP_SIG ＇ exports driving stage 408 to, and related minimizing drives the arteries and veins of signal DRVP ＇Wave number and driving force thereof, so that the ripple frequency of output voltage V GH ＇ is higher than this audiorange.

In known technology, have a limit with the framework of operational amplifier control in output, in differenceWhen external load and output capacitance CS1, can change this limit, thereby have the consideration of stability. Although and withThe charge pump of comparator control does not have stability problem, but because it has larger output ripple, therefore existsUnder some external load, can produce audio-frequency noise. In comparison, above-described embodiment is by detecting comparative resultCOMP with the ripples wave frequency that judges output voltage V GH ＇ whether in an audiorange, then determine beThe driving force of no adjustment driving stage 408, to avoid output voltage V GH ＇ frequency in an audiorangeAnd absence of audio noise, and control and therefore can promote stability with comparator.

The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for thisThe technical staff in field, the present invention can have various modifications and variations. All in spirit of the present invention andWithin principle, any amendment of doing, be equal to replacement, improvement etc., all should be included in protection of the present inventionWithin scope.

Claims

1. a charge pump, is characterized in that, includes:

One charge pump circuit, is used for according to a driving signal, produces an output voltage;

One comparison circuit, is used for according to this output voltage and a reference voltage, produces a comparative result;

One circuit for detecting, is used for by pulse wave interval time of this comparative result of detecting, according to this relativelyResult with detect this output voltage ripple a frequency range and produce a detecting result; And

One driving stage, is used for producing this driving signal according to this comparative result, and adjusts according to this detecting resultThe corresponding driving force of whole this driving signal.

2. charge pump as claimed in claim 1, is characterized in that, this detecting result relates to shows this output electricityWhether one ripple frequency of pressing is in an audiorange.

3. charge pump as claimed in claim 2, is characterized in that, indicates this output electricity in this detecting resultThis ripple frequency of pressing is in this audiorange time, and this driving signal reduces its driving force, and thenMake this ripple frequency of this output voltage higher than this audiorange.

4. charge pump as claimed in claim 1, is characterized in that, this circuit for detecting is coupled to that this is more electricRoad to be to receive this comparative result, and is coupled to this driving stage to export this detecting result to this drivingLevel.

5. charge pump as claimed in claim 1, is characterized in that, more comprises a control circuit, is coupled toBetween this comparison circuit and this driving stage, and be coupled to this circuit for detecting, be used for according to this comparisonResult and this detecting result are adjusted the corresponding driving force of this driving signal.

6. charge pump as claimed in claim 5, is characterized in that, this control circuit is according to this detecting result,To determine whether this comparative result is sent to this driving stage.

7. charge pump as claimed in claim 5, is characterized in that, shows this output when this detecting result relates toOne ripple frequency of voltage is in an audiorange time, and this control circuit limits this comparative result extremelyThe pulse wave of few a part of number is sent to this driving stage.

8. charge pump as claimed in claim 1, is characterized in that, this circuit for detecting includes:

One timer, is coupled to this comparison circuit, for the arteries and veins to the corresponding signal of this comparative resultWhether the wave spacing time is carried out timing, indicate this pulse wave to arrive interval time to produce a frequency signalReach a given time; And

One edge detecting unit, it is coupled to this timer, for the edge of detecting this frequency signal to produceA raw detection signal is as this detecting result.

9. charge pump as claimed in claim 8, is characterized in that, this edge detection unit comprises one firstFlip-flop, it has a frequency end and is coupled to this frequency signal, and an output provides this detectingSignal.

10. charge pump as claimed in claim 8, is characterized in that, more comprises a pulse wave conversion equipment, couplingBe connected between this comparison circuit and this timer, for comparing arteries and veins according to this comparative result to produce oneRipple signal is to this timer.

11. charge pumps as claimed in claim 5, is characterized in that, this control circuit comprises:

One transmission control unit, is coupled between this comparison circuit and this circuit for detecting, in order to detect according to thisSurvey result and this comparative result, produce a transmission of control signals; And

One transmission unit, is coupled between this comparison circuit and this driving stage, and is more coupled to this transmission controlUnit processed, in order to according to this transmission of control signals, to determine whether this comparative result is exported toThis driving stage.

12. charge pumps as claimed in claim 11, is characterized in that, when this detecting result is indicated this output electricityThis ripple frequency of pressing is during higher than an audiorange, and this transmission unit of this transmission of control signals control willThis comparative result exports this driving stage to.

13. charge pumps as claimed in claim 11, is characterized in that, this transmission control unit is when this detecting knotThis ripple frequency position that fruit is indicated this output voltage is in an audiorange time, to this comparative result instituteThe pulse wave of each corresponding train of pulse is counted, and arrives after a prearranged number when this pulse wave number,Producing this transmission of control signals stops exporting this comparative result to this driving to control this transmission unitLevel.

14. charge pumps as claimed in claim 11, is characterized in that, this transmission control unit comprises:

One counter, is coupled to this comparison circuit, in corresponding each train of pulse of this comparative resultPulse number is counted, to produce a count signal; And

One edge detecting unit, is coupled to this counter and this circuit for detecting, with according to this detecting result,Detect a rising edge of this count signal or falling edge to produce this transmission of control signals.

15. charge pumps as claimed in claim 14, is characterized in that, this edge detection unit comprises one secondFlip-flop, it has a frequency end and is coupled to this count signal, and an output provides this transmissionControl signal, and a replacement end is coupled to this circuit for detecting.

16. charge pumps as claimed in claim 15, is characterized in that, this edge detection unit more comprises:

One reset signal generation unit, is coupled between this replacement end and this circuit for detecting, should for foundationDetecting result and this comparative result corresponding one relatively pulse wave signal determines whether that replacement shouldThe second flip-flop.

17. charge pumps as claimed in claim 16, is characterized in that, this reset signal generation unit comprises:

One phase inverter, it has an input and is coupled to this circuit for detecting, and an output;

One nor gate, has two inputs and is respectively coupled to this output of this phase inverter and is coupled to thisRelatively pulse wave signal, and an output is coupled to this replacement end of this second flip-flop.

18. charge pumps as claimed in claim 1, is characterized in that, this comparison circuit comprises:

One comparator, it has two inputs and is coupled to respectively this output voltage and this reference voltage, andOne output, for providing a comparison output signal;

One the 3rd flip-flop, includes this output, a frequency that a data input pin is coupled to this comparatorRate end is used for receiving a frequency signal, and a data output end, for a relatively sampling is providedSignal; And

One NAND gate, have two inputs be coupled to respectively the 3rd flip-flop this data output end andThis frequency signal, and an output, for a compare result signal is provided, wherein this comparesResult comprises in the middle of this comparison output signal, this comparison sampled signal and this compare result signal extremelyFew one.

19. charge pumps as claimed in claim 18, is characterized in that, this circuit for detecting receives that this is more defeatedGo out maybe this comparison sampled signal of signal, and output represents that a detection signal of this detecting result drives to thisMoving level.

20. charge pumps as claimed in claim 18, is characterized in that,

This circuit for detecting receives maybe this comparison sampled signal of this comparison output signal, and output represents this detectingOne detection signal of result, and

This charge pump more comprises a control circuit, receives this compare result signal and this detection signal, to comply withExport a drive control signal to this driving stage according to this compare result signal and this detection signal.

21. charge pumps as claimed in claim 1, is characterized in that, this driving stage is by changing this chargingThe number of times that pump circuit charges continuously, to adjust corresponding this driving force of this driving signal.

22. charge pumps as claimed in claim 1, is characterized in that, this driving stage is by using different sizeThis driving signal of transistor for generating, to adjust corresponding this driving force of this driving signal.

23. charge pumps as claimed in claim 1, is characterized in that, this driving stage is by using different numbersParallel transistor to produce this driving signal, to adjust corresponding this driving energy of this driving signalPower.

24. charge pumps as claimed in claim 1, is characterized in that, this driving stage comprises multiple buffers,In the middle of one at least carry out conducting or close according to this detecting result.

25. 1 kinds of charge pumps, is characterized in that, include:

One circuit for detecting, is used for according to this comparative result to detect the frequency model of ripple of this output voltageEnclose and produce a detecting result;

One driving stage, is used for producing this driving signal according to this comparative result, and adjusts according to this detecting resultThe corresponding driving force of whole this driving signal; And

One control circuit, is coupled between this comparison circuit and this driving stage, and is coupled to this detecting electricityRoad, is used for adjusting this driving signal corresponding one according to this comparative result and this detecting resultDriving force;

Wherein, this control circuit is according to this detecting result, to determine whether this comparative result is sent to thisDriving stage.

26. charge pumps as claimed in claim 25, is characterized in that, this detecting result relates to shows this outputWhether one ripple frequency of voltage is in an audiorange.

27. 1 kinds of charge pumps, is characterized in that, include:

One circuit for detecting, is used for according to this comparative result to detect the frequency model of ripple of this output voltageEnclose and produce a detecting result; And

One driving stage, is used for producing this driving signal according to this comparative result, and adjusts according to this detecting resultThe corresponding driving force of whole this driving signal;

Wherein, this detecting result relates to a ripple frequency of showing this output voltage whether in an audiorange.