CN105592605A - LED load driving circuit - Google Patents

LED load driving circuit Download PDF

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Publication number
CN105592605A
CN105592605A CN201410568125.4A CN201410568125A CN105592605A CN 105592605 A CN105592605 A CN 105592605A CN 201410568125 A CN201410568125 A CN 201410568125A CN 105592605 A CN105592605 A CN 105592605A
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China
Prior art keywords
output
switch
input
circuit
electrically connected
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CN201410568125.4A
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CN105592605B (en
Inventor
孙建波
张旭光
章莉
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BCD Shanghai Micro Electronics Ltd
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BCD Semiconductor Manufacturing Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

Disclosed in the invention is an LED load driving circuit comprising a power supply circuit, a current control circuit, a feedback circuit, and an adjusting circuit. The adjusting circuit receives a feedback signal and a driving signal so as to control first state maintaining time of the current control circuit to be identical with width inputting time of the driving signal. Therefore, a problem that the conduction state maintaining time of the LED load is less than the width inputting time of the driving signal because rising of an output current value of the LED load driving circuit from zero to a stable current value needs certain response time can be solved; and linearity of the output current of the LED load driving circuit is improved. Especially for the LED load driving circuit with the low input duty ration, linearity of the output current can be improved obviously.

Description

A kind of LED load driving circuits
Technical field
The present invention relates to LED actuation techniques field, relate in particular to a kind of LED load driving circuits.
Background technology
Along with scientific and technical development, mobile phone, PAD, e-book, digital camera, MP3, GPS withAnd the application of the electronic product such as DPF makes rapid progress, also driven simultaneously associated electrical product fastDevelopment. And WLED (WhiteLightEmittingDiode, white light-emitting diode) and WLEDDriver(WhiteLightEmittingDiodeDriver, white light-emitting diode system drive) is owing to havingCertain dimming function, thus be widely used in LCD (LiquidCrystalDisplay, liquid crystal displayDevice) etc. in each electronic product backlight. But the LED driver linearity of the prior art is poor.
Summary of the invention
For solving the problems of the technologies described above, the embodiment of the present invention provides a kind of LED load driving circuits, withImprove the linearity of described LED load driving circuits.
For addressing the above problem, the embodiment of the present invention provides following technical scheme:
A kind of LED load driving circuits, comprising:
For LED load provides the power circuit of operating voltage;
Control the current control circuit that LED load current cut-offs, the duty of described current control circuitComprise: control the first state of LED load current conducting and control the second shape that LED load current endsState;
Detect the feedback circuit of LED load output feedback signal; And
Regulating circuit, by receiving described feedback signal and driving signal, controls described Current Control electricityIt is identical with the time of described driving signal input width that road maintains the time of the first state.
Preferably, described regulating circuit comprises: the first comparator, charge circuit, the first electric capacity, secondComparator, discharge loop and the 3rd switch;
The first comparator, receives described feedback signal, output the first control signal;
Charge circuit, by receiving described the first control signal and driving signal, controls described the first electricityThe charging interval of holding;
The second comparator, receives the first electric capacity and described charge circuit common port voltage, and output second is controlledSignal;
Discharge loop, by receiving the second control signal and driving signal, while controlling the electric discharge of the first electric capacityBetween identical with the charging interval of the first electric capacity;
The 3rd switch, by receiving the second control signal and driving signal, controls described current control circuitThe time that maintains the first state is identical with the time of described driving signal input width.
Preferably, described regulating circuit comprises:
The first comparator, the negative input of described the first comparator is provided with the first reference voltage, and describedThe electrode input end of one comparator is electrically connected with the output of feedback circuit, receives described feedback signal, defeatedGo out the first control signal;
Charge circuit, described charge circuit comprises charging current source and is electrically connected with described charging current sourceThe first switch, the input of described the first switch is electrically connected with charging current source, described the first switchThe first control end is electrically connected with the output of described the first comparator, the second control end of described the first switchBe electrically connected with driving signal input, by receiving described the first control signal and driving signal, controlThe charging interval of described the first electric capacity;
The first electric capacity, described first electric capacity one end is electrically connected with the output of described the first switch, the other endGround connection;
The second comparator, the ungrounded end of the negative input of described the second comparator and described the first electric capacityElectrical connection, the electrode input end ground connection of described the second comparator, by receive described the first electric capacity with described inCharge circuit common port voltage, output the second control signal;
Discharge loop, described discharge loop comprises discharge current source and is electrically connected with described discharge current sourceSecond switch, described discharge current source is identical with the size of current of described charging current source, described secondThe input of switch is electrically connected with the output of described the first switch, the first control end of described second switchBe electrically connected with driving signal input, the second control end of described second switch and described the second comparatorOutput electrical connection, by receiving the second control signal and driving signal, while controlling the electric discharge of the first electric capacityBetween identical with the charging interval of the first electric capacity;
The 3rd switch, the first input end of described the 3rd switch is electrically connected with driving signal input, described inThe second input of the 3rd switch is electrically connected with the output of described the second comparator, described the 3rd switchThe first output is electrically connected with described current control circuit, and the state of controlling described current control circuit switches,The second output of described the 3rd switch is electrically connected with described power circuit, controls opening of described power circuitClose, by receiving the second control signal and driving signal, control described current control circuit and maintain the first shapeThe time of state is identical with the time of described driving signal input width;
Wherein, when the first input end of described the first switch and the second input of described the first switch areWhen high level, described the first switch conduction, second switch disconnects, and described charging current source is described firstCapacitor charging; The second input of the first input end of described second switch and described second switch is lowWhen level, described second switch conducting, the first switch disconnects, and described the first electric capacity is by described electric discharge electricityThe electric discharge of stream source; When the second input of described the 3rd switch is high level, described the 3rd switch first defeatedGo out end for high level, control described current control circuit and switch to the second state, the of described the 3rd switchTwo outputs are low level, control described power circuit and close, and the second input of described the 3rd switch isWhen low level, the first output of described the 3rd switch is low level, controls described current control circuit and cutsChange to the first state, the second output of described the 3rd switch is high level, controls described power circuit and beatsOpen, for described LED load provides operating voltage.
Preferably, described in when described the first reference voltage is greater than described LED load conducting, feedback circuit is defeatedGo out voltage, and the output voltage of feedback circuit described in when being less than described LED load and closing.
Preferably, described the first switch comprises:
NAND gate, the first control end of described NAND gate is electrically connected with the output of described the first comparator,The second control end of described NAND gate is electrically connected with described driving signal input;
The one PMOS transistor, the transistorized source electrode of a described PMOS is electrically connected with charging current source,Drain electrode is electrically connected with described the first electric capacity, and grid is electrically connected with the output of described NAND gate.
Preferably, described second switch comprises:
The first nor gate, the first control end of described the first nor gate is electrically connected with driving signal input,The second control end of described the first nor gate is electrically connected with the output of described the second comparator;
The first nmos pass transistor, the source electrode of described the first nmos pass transistor and a described PMOSTransistorized drain electrode electrical connection, the source electrode of described the first nmos pass transistor and described discharge current source are electrically connectedConnect, the grid of described the first nmos pass transistor is electrically connected with the output of described the first nor gate.
Preferably, described the 3rd switch comprises: the second nor gate, the 3rd nor gate and not gate;
Wherein, the first input end of described the second nor gate is the first input end of described the 3rd switch, withDriving signal input electrical connection, the second input of described the second nor gate and described the 3rd nor gateOutput electrical connection; The output electricity of the first input end of described the 3rd nor gate and described the second nor gateConnect, the second input of described the 3rd nor gate is the second input of described the 3rd switch, with describedThe output electrical connection of the second comparator, the output of described the 3rd nor gate is the of described the 3rd switchTwo outputs, input, the power circuit of NAND gate are electrically connected simultaneously; The output of described not gate is instituteState the first output of the 3rd switch, be electrically connected with described current control circuit.
Preferably, the electrode input end of described the second comparator is by voltage source ground connection, described voltage sourceOutput voltage range is 20mV-100mV, comprises endpoint value.
Preferably, in the time that described LED load comprises multiple parallel connection LED load channel, described feedback circuitOutput voltage be the minimum voltage value in the output voltage of described multiple parallel connection LED load channels.
Preferably, described current control circuit comprises:
The first current source;
The first resistance, one end of described the first resistance is electrically connected with described the first current source output, anotherEnd ground connection;
The first operational amplifier, the electrode input end of described the first operational amplifier and described the first current source,The common port electrical connection of described the first resistance, the negative input of described the first operational amplifier is by secondResistance eutral grounding;
The second field-effect transistor, the output of the source electrode of described the second field-effect transistor and LED loadElectrical connection, the drain electrode of described the second field-effect transistor and described the first operational amplifier, the second resistanceCommon port electrical connection, the output electricity of the grid of described the second field-effect transistor and the first operational amplifierConnect;
The 3rd field-effect transistor, the source electrode of described the 3rd field-effect transistor and described the first operation amplifierThe output electrical connection of device, the grounded drain of described the 3rd field-effect transistor, described the 3rd field-effect crystalline substanceThe grid of body pipe is electrically connected with the first output of described regulating circuit.
Preferably, described power circuit is DCDC power circuit, or AC-DC power circuit, or LDOPower circuit.
Compared with prior art, technique scheme has the following advantages:
LED load driving circuits provided by the present invention, except comprising: power circuit, current control circuit,Outside feedback circuit, also comprise regulating circuit, described regulating circuit by receive described feedback signal andDrive signal, control the time that described current control circuit maintains the first state and input with described driving signalThe time of width is identical, thereby has solved output current value due to described LED load driving circuits by zeroRise in the process of stable electrical flow valuve and need certain response time, and the described LED load dimension causingThe time of holding the state of conducting is less than the problem of driving signal input width time, has improved described LED negativeCarry the linearity of drive circuit output current, especially for the LED load with lower input duty cycleDrive circuit, can significantly improve the linearity of its output current.
Brief description of the drawings
In order to be illustrated more clearly in the technical scheme in the embodiment of the present invention, in describing embodiment belowThe accompanying drawing of required use is briefly described, and apparently, the accompanying drawing in the following describes is the present inventionSome embodiment, for those of ordinary skill in the art, in the prerequisite of not paying creative workUnder, can also obtain according to these accompanying drawings other accompanying drawing.
The circuit that Fig. 1 is the LED load driving circuits that provides in one embodiment of the invention connects signalFigure;
Fig. 2 is in the LED load driving circuits providing in one embodiment of the invention, regulating circuitCircuit connection diagram;
Fig. 3 shows for the signal sequence in the LED load driving circuits providing in one embodiment of the inventionIntention;
Fig. 4 is in the LED load driving circuits providing in another embodiment of the present invention, regulating circuitCircuit connection diagram;
The circuit that Fig. 5 is the LED load driving circuits that provides in another embodiment of the present invention connects and showsIntention;
Fig. 6 is in the LED load driving circuits providing in another embodiment of the present invention, regulating circuitCircuit connection diagram.
Detailed description of the invention
Just as described in the background section, the LED driver linearity of the prior art is poor.
Inventor studies discovery, and this is because for PWM, (PulseWidthModulation, pulse is wideDegree modulation) light modulation, given pulse input, its frequency is fixed, but its pulse width is variable, thereby can realize by regulating impulse width the variation of LED driver output current mean value. ThisThe output current value of the LED driver of the mode of kind mainly presents two kinds of current output value, and zero-sum is stablized defeatedStable electrical flow valuve while going out. Because the output current value at described LED driver is by the stable electrical that rises to above freezingIn the process of flow valuve, the control circuit of LED driver needs certain response time, conventionally delicate 1In-3 delicate scopes. (be this driving of LED for the LED driver with higher input duty cycleThe pwm pulse input width time of device is greater than 3 delicate), this response time is to LED driverOutput current impact less, but (be LED for the LED driver with lower input duty cycleThe pwm pulse input width time of this driver is less than 3 delicate), this response time is to LEDThe output current impact of driver is comparatively remarkable, even may there is no electric current output when serious, causes LEDThe linearity of driver is poor, especially has the LED driver of lower input duty cycle.
In view of this, the embodiment of the present invention provides a kind of LED load driving circuits, comprising:
For LED load provides the power circuit of operating voltage;
Control the current control circuit that LED load current cut-offs, the duty of described current control circuitComprise: control the first state of LED load current conducting and control the second shape that LED load current endsState;
Detect the feedback circuit of the feedback signal of LED load output; And
Regulating circuit, by receiving described feedback signal and driving signal, controls described Current Control electricityIt is identical with the time of described driving signal input width that road maintains the time of the first state.
As can be seen here, the LED load driving circuits that the embodiment of the present invention provides, except comprising: power supply electricityOutside road, current control circuit, feedback circuit, also comprise regulating circuit, described regulating circuit is for logicalCross and receive described feedback signal and drive signal, control described current control circuit and maintain first stateTime is identical with the time of described driving signal input width, thereby has solved because described LED load is drivenMove the output current value of circuit by needing certain response time in the process that rises to stable electrical flow valuve above freezing,And the described LED load causing maintains the state time of conducting and is less than and drives asking of signal input width timeInscribe, improved the linearity of described LED load driving circuits output current, especially lower for havingThe LED load driving circuits of input duty cycle, can significantly improve the linearity of its output current.
For above-mentioned purpose of the present invention, feature and advantage can more be become apparent, below in conjunction with accompanying drawingThe specific embodiment of the present invention is described in detail.
Set forth detail in the following description so that fully understand the present invention. But the present invention canBe different from alternate manner described here and implement with multiple, those skilled in the art can be without prejudice to thisIn the situation of invention intension, do similar popularization. Therefore the present invention is not subject to the restriction of following public concrete enforcement.
As shown in Figure 1, the embodiment of the present invention provides a kind of LED load driving circuits, comprising:
For LED load provides the power circuit 1 of operating voltage;
Control the current control circuit 2 that LED load current cut-offs, the work of described current control circuit 2State comprises: control the first state of LED load current conducting and control the of LED load current cut-offTwo-state;
Detect the feedback circuit 4 of LED load output feedback signal; And
Regulating circuit 3, by receiving described feedback signal and driving signal, controls described Current Control electricityIt is identical with the time of described driving signal input width that road 2 maintains the time of the first state.
In a preferred embodiment of the invention, described driving signal is provided by pwm signal source, belowProvided by pwm signal source with described driving signal, the LED load that the embodiment of the present invention is provided is drivenMoving circuit describes in detail, but the present invention do not limit this, in other embodiments of the invention,Described driving signal can also be provided by other signal sources.
As described in Figure 1, in a specific embodiment of the present invention, described power circuit 1 is negative with LEDCarry input electrical connection, for LED load provides operating voltage; Described current control circuit 2 is negative with LEDCarry output electrical connection, control cut-offfing of LED load current, the work shape of described current control circuit 2State comprises: control the first state of LED load current conducting and control second of LED load current cut-offState; The first output of described regulating circuit 3 is electrically connected with described current control circuit 2, controls instituteState current control circuit 2 states and switch, the second output of described regulating circuit 3 and power circuit 1 electricityConnect, control the switching of power circuit 1; The input of described feedback circuit 4 and LED load outputElectrical connection, the first output of described feedback circuit 4 is connected with the input of regulating circuit 3, described anti-The second output of current feed circuit 4 is connected with the input of power circuit 1, by the electricity of LED load outputPressure feeds back to described regulating circuit 3 and power circuit 1; Described pwm signal source 5 and described regulating circuit3 electrical connections, for described regulating circuit 3 provides driving signal;
Wherein, described regulating circuit 3 control time that described current control circuit 2 maintains the first state withThe time of described pwm pulse input width is identical.
In a preferred embodiment of the invention, described regulating circuit 3 comprises: the first comparator, fillElectricity loop, the first electric capacity, the second comparator, discharge loop and the 3rd switch, wherein, described the first ratioBe used for receiving described feedback signal compared with device, output the first control signal; Described charge circuit is used for by connecingReceive described the first control signal and drive signal, controlling the charging interval of described the first electric capacity; DescribedTwo comparators are used for receiving the first electric capacity and described charge circuit common port voltage, output the second control signal;Described discharge loop, for by receiving the second control signal and driving signal, is controlled the electric discharge of the first electric capacityTime is identical with the charging interval of the first electric capacity; Described the 3rd switch is for passing through to receive the second control signalWith drive signal, controlling described current control circuit, to maintain time and the described driving signal of the first state defeatedThe time that enters width is identical.
Concrete, as shown in Figure 2, the negative input of described the first comparator D1 is provided with first with reference to electricityPress Vref1, the output FB of the electrode input end of described the first comparator D1 and feedback circuit 4 is electrically connectedConnect, receive described feedback signal, output the first control signal;
Described charge circuit comprise charging current source Ic and be electrically connected with described charging current source Ic firstSwitch 31, the input of described the first switch 31 is electrically connected with charging current source Ic, described the first switchThe first control end of 31 is electrically connected with the output of described the first comparator D1, described the first switch 31The second control end is electrically connected with the input that drives signal, by receiving described the first control signal and drivingMove signal, control the charging interval of described the first capacitor C 1;
The first capacitor C 1, described first capacitor C 1 one end is electrically connected with the output of described the first switch 31,Other end ground connection;
The second comparator D2, the negative input of described the second comparator D2 and described the first capacitor C 1The electrical connection of ungrounded end, the electrode input end ground connection of described the second comparator D2, by receiving described theOne capacitor C 1 and described charge circuit common port voltage, output the second control signal;
Discharge loop, described discharge loop comprise discharge current source Idis and with described discharge current source IdisThe second switch 32 of electrical connection, the size of current of described discharge current source Idis and described charging current source IcIdentical, the input of described second switch 32 is electrically connected with the output of described the first switch 31, described inThe first control end of second switch 32 is electrically connected with driving signal input, of described second switch 32Two control ends are electrically connected with the output of described the second comparator D2, by receiving the second control signal and drivingMoving signal, the discharge time of controlling the first capacitor C 1 is identical with the charging interval of the first capacitor C 1;
The 3rd switch 33, the first input end of described the 3rd switch 33 is electrically connected with driving signal input,The second input of described the 3rd switch 33 is electrically connected with the output of described the second comparator D2, described inThe first output DIMB of the 3rd switch 33 is electrically connected with described current control circuit 2, controls described electricityThe state of flow control circuit 2 switches, the second output DIM and the described power supply of described the 3rd switch 33Circuit 1 is electrically connected, and controls the switching of described power circuit 1, by receiving the second control signal and drivingSignal, controls described current control circuit and maintains time of the first state and described driving signal input widthTime identical;
Wherein, when the second input of the first input end of described the first switch 31 and described the first switch 31When end is high level, described the first switch 31 conductings, second switch 32 disconnects, described charging currentSource Ic is that described the first capacitor C 1 is charged; The first input end of described second switch 32 and described second is openedWhen the second input of pass 32 is low level, described second switch 32 conductings, the first switch 31 disconnects,Described the first capacitor C 1 is by described discharge current source Idis electric discharge; Described the 3rd switch 33 second defeatedWhile entering end for high level, the first output of described the 3rd switch 33 is high level, controls described electric current controlCircuit 2 processed switches to the second state, and the second output of described the 3rd switch 33 is low level, controls instituteState power circuit 1 and close, when the second input of described the 3rd switch 33 is low level, the described the 3rd opensThe first output of pass 33 is low level, controls described current control circuit 2 and switches to the first state, instituteThe second output of stating the 3rd switch 33 is high level, controls described power circuit 1 and opens, and be described LEDLoad provides operating voltage.
It should be noted that, in embodiments of the present invention, described in described the first reference voltage Vref 1 is greater thanThe output voltage of feedback circuit 4 described in when LED load conducting, and be less than described LED load and close time instituteState the output voltage of feedback circuit 4.
Also it should be noted that, in the time that described LED load comprises multiple parallel connection LED load channel, described inThe output voltage FB of feedback circuit 4 be in the output voltage of described multiple parallel connection LED load channelsSmall voltage value, to ensure that each LED load channel all has the stable output of full scale in the time working.
Concrete, as shown in Figure 3, in the time that the output signal in pwm signal source 5 rises beginning, now,The output signal in described pwm signal source 5 is high level, and driving signal is high level, described LEDLoad not yet enters conducting state, and the current i LED of described LED load is zero, described feedback circuit 4The voltage of output FB is the voltage of LED load while closing, i.e. described feedback circuit 4 output FBVoltage be greater than described the first reference voltage Vref 1, so the output voltage of the first comparator D1 is high electricityFlat.
Again because the output signal in described pwm signal source 5 is in propradation, described pwm signal source5 output signal is also high level, and described driving signal is high level, therefore, and described the first switchThe second input of 31 first input end and described the first switch 31 is high level, and now described firstSwitch 31 conductings; Again due to after described the first switch 31 conductings, described the first capacitor C 1 is by described theOne switch 31 is electrically connected with described charging current source Ic, therefore described the first capacitor C 1 and described the first switch31 common port Vcap is high potential, and the negative input of described the second comparator D2 is high potential,The electrode input end ground connection of described the second comparator D2, therefore described the second comparator D2 negative inputVoltage is greater than the voltage of its electrode input end, and the output of described the second comparator D2 is low level, i.e. instituteThe first input end of stating second switch 32 is high level, and the second input of described second switch 32 is lowLevel, described second switch 32 ends, and described charging current source Ic is that described the first capacitor C 1 is charged;Because the first input end of described the 3rd switch 33 is electrically connected with pwm signal source 5, the described the 3rd opens againThe second input of pass 33 is electrically connected with the output of the second comparator D2, therefore described the 3rd switch 33First input end is high level, and the second input of described the 3rd switch 33 is low level, and the described the 3rd opensThe first output DIMB output low level of pass 33, described current control circuit 2 switches to described LEDThe first state of load conducting, the second output DIM output high level of described the 3rd switch 33, controlMake described power circuit 1 and open, for described LED load provides operating voltage.
In the time of described LED load conducting, the voltage drop of described LED load output, now, described inThe voltage of feedback circuit 4 output FB is less than described the first reference voltage Vref 1, described the first comparatorThe output of D1 is low level, and the first control end of described the first switch 31 is low level, described firstThe second control end of switch 31 still maintains high level, thus described the first switch 31 end, described charged electricalStream source Ic stops charging for described the first capacitor C 1, the public affairs of described the first capacitor C 1 and described charge circuitHold altogether Vcap to maintain this voltage.
It should be noted that, in embodiments of the present invention, described in the described LED load conducting moment is preferablyWhen the current i LED of LED load is its conducting 1/2 of maximum current, but the present invention do not limit this,Specifically depend on the circumstances.
In the time that 5 outputs of described pwm signal source decline beginning, now, export in described pwm signal source 5Signal vanishing, described driving signal is low level, the first control end of described the first switch 31 is still tieed upHold low level, described the second control end also switches to low level, and described the first switch 31 maintains cut-off state;The first control end of described second switch 32 switches to low level, and the second control end still maintains low level, this32 conductings of Shi Suoshu second switch, described the first capacitor C 1 is discharged through described discharge loop, now, instituteThe voltage of stating the ungrounded end Vcap of the first capacitor C 1 is still greater than zero, i.e. described the second comparator D2 negative poleThe voltage of input is greater than the voltage of its electrode input end, therefore the output of described the second comparator D2 is still defeatedGo out low level. Because the first input end of described the 3rd switch 33 switches to low level, the described the 3rd opens againThe second input of pass 33 maintains low level, the first output DIMB output of described the 3rd switch 33Be still low level, described current control circuit 2 maintains the first state of described LED load current conducting,The second output DIM output of described the 3rd switch 33 is still high level, and described power circuit 1 continuesFor described LED load provides operating voltage.
In the time of described the first capacitor C 1 discharge off, described the first capacitor C 1 is public with described charge circuitThe lower voltage zero of end Vcap, the voltage of the first input end of described the second comparator D2 reduces to zero,The output of described the second comparator D2 switches to high level, on the first not impact of switch 31, described inThe first switch 31 continues to maintain cut-off state, and the first control end of described second switch 32 maintains low level,The second control end of described second switch 32 switches to high level, and now, described second switch 32 ends,Described the first capacitor C 1 stops electric discharge; The first input end of described the 3rd switch 33 is still low level, instituteThe second input of stating the 3rd switch 33 switches to high level, the first output of described the 3rd switch 33DIMB exports high level, and described current control circuit 2 switches to the second shape of LED load current cut-offState, the second output DIM output low level of described the 3rd switch 33, described power circuit 1 cuts out,Stop as described LED load provides operating voltage, described LED load driving circuits quits work. Now,The operating voltage when voltage of described feedback circuit 4 output FB rises to described LED load cut-off,The outputting cutting of described the first comparator D1 gains high level, until next pwm pulse signal rise time,Described LED load driving circuits starts next circulation, restarts work.
It should be noted that, because the charging interval of described the first capacitor C 1 is very short, therefore, the present invention coupleThe capacitance of described the first capacitor C 1 is not done concrete regulation, charges in described the first capacitor C 1 as long as ensureBefore time finishes, described the first capacitor C 1 can be unsaturated.
Because described charging current source Ic is identical with the size of current of described discharge current source Idis, therefore,Ideally, the charging interval of described the first capacitor C 1 is identical with discharge time, again because described firstThe output current value of the charging interval of capacitor C 1 and described LED load driving circuits by above freezing rise to stableThe response time of current value is identical, therefore, switched to after low level by high level at described pwm signal,It is identical with the described response time that described LED load maintains the time (being the time of late release) of conducting,Thereby ensure that described regulating circuit 3 controls described current control circuit 2 and maintain time and the institute of the first stateState and drive the time of signal input width identical, solved the output due to described LED load driving circuitsCurrent value is by needing certain response time in the process that rises to stable electrical flow valuve above freezing, and cause described inThe state time that LED load maintains conducting is less than and drives the signal problem of input width time, has improved instituteState the linearity of LED load driving circuits output current.
On the basis of above-mentioned arbitrary embodiment, in one embodiment of the invention, as shown in Figure 4,Described the first switch 31 comprises:
NAND gate G1, the first control end of described NAND gate G1 and the output of described the first comparator D1End electrical connection, the second control end of described NAND gate G1 is electrically connected with driving signal input;
The one PMOS transistor P1, source electrode and the charging current source of a described PMOS transistor P1Ic electrical connection, the drain electrode of a described PMOS transistor P1 is electrically connected with described the first capacitor C 1, instituteThe grid of stating a PMOS transistor P1 is electrically connected with the output of described NAND gate G1.
Concrete, when described LED load not yet enters conducting state, described LED load current is less than1/2 o'clock of its complete conducting state institute corresponding current, between described charge circuit and described the first capacitor C 1Path be off-state, the voltage of described feedback circuit 4 outputs is the voltage of LED load while closing,The voltage that is described feedback circuit 4 outputs is greater than described the first reference voltage Vref 1, so first comparesThe output voltage of device D1 is high level.
Now, if the output signal in described pwm signal source 5 is low level, described driving signal is lowLevel, described NAND gate G1 output output high level, a described PMOS transistor P1 maintains and cutsOnly state, the loop between described charging current source Ic and described the first capacitor C 1 still maintains off-state.If the output signal in described pwm signal source 5 is also high level, described driving signal is high level, instituteState the output output low level of NAND gate G1, a described PMOS transistor P1 conducting, described in fillPath conducting between electricity current source Ic and described the first capacitor C 1, described in described charging current source Ic warpThe one PMOS transistor P1 is that described the first capacitor C 1 is charged.
When after the conducting of described LED load current, described in the output end voltage of described feedback circuit 4 drops toVoltage when LED load conducting, described the first comparator D1 output low level, now, if described PWMThe output signal of signal source 5 is still high level, and described driving signal is still high level, described and non-The output output high level of door G1, a described PMOS transistor P1 cut-off, described charging currentPath between source Ic and described the first capacitor C 1 disconnects. When the output signal in described pwm signal source 5Switch to low level, described driving signal switches to low level, and the output of described NAND gate G1 stillOutput high level, a described PMOS transistor P1 maintains cut-off state, described charging current source IcAnd the path between described the first capacitor C 1 still maintains off-state.
On the basis of above-mentioned arbitrary embodiment, in another embodiment of the present invention, continue as Fig. 4Shown in, described second switch 32 comprises:
The first nor gate G2, the first control end of described the first nor gate G2 and driving signal input electricityConnect, the second control end of described the first nor gate G2 and the output of described the second comparator D2 are electrically connectedConnect;
The first nmos pass transistor N1, the source electrode of described the first nmos pass transistor N1 and described firstThe drain electrode electrical connection of PMOS transistor P1, the source electrode of described the first nmos pass transistor N1 with described in putElectricity current source Idis electrical connection, the grid of described the first nmos pass transistor N1 and described the first nor gateThe output electrical connection of G2.
Concrete, when described the first comparator D1 is output as high level, and described pwm signal source 5 is defeatedWhile going out high level, the path conducting between described charge circuit and the first capacitor C 1, described the second comparatorD2 output low level, described the first nor gate G2 output low level, described the first nmos pass transistorN1 cut-off, the loop between described discharge current source Idis and described the first capacitor C 1 disconnects. When describedWhen pwm signal source 5 output signals switch to low level, described the second comparator D2 output maintains low electricityFlat, the output switching of the first nor gate G2 is high level, described the first nmos pass transistor N1 conducting,Loop conducting between described discharge current source Idis and described the first capacitor C 1, described the first capacitor C 1Discharge through described the first nmos pass transistor N1 and discharge current source Idis.
Until after described the first capacitor C 1 discharge off, the output of described the second comparator D2 switches toHigh level, now, no matter the output signal in described pwm signal source 5 is high level or low level, instituteState the equal output low level of the first nor gate G2, the first nmos pass transistor N1 cut-off, described discharge currentLoop between source Idis and described the first capacitor C 1 disconnects.
On the basis of above-mentioned arbitrary embodiment, in yet another embodiment of the present invention, as shown in Figure 4,Described the 3rd switch 33 comprises: the second nor gate G3, the 3rd nor gate G4 and not gate G5; Wherein,The first input end of described the second nor gate G3 is the first input end of described the 3rd switch 33, with describedDriving signal input electrical connection, the second input of described the second nor gate G3 and described the 3rd nor gateThe output electrical connection of G4; The first input end of described the 3rd nor gate G4 and described the second nor gate G3Output electrical connection, the second input of described the 3rd nor gate G4 is the of described the 3rd switch 33Two inputs, are electrically connected with the output of described the second comparator D2, and described the 3rd nor gate G4's is defeatedGo out the second output that end is described the 3rd switch 33, input, the power circuit 1 of NAND gate G1 are sameIn time, is electrically connected; The output of described not gate G5 is the first output of described the 3rd switch 33, with describedCurrent control circuit 2 is electrically connected.
Concrete, before the work of described LED load driving circuits, described power circuit 1 is in cutting out shapeState, described current control circuit 2 is for controlling the second state of LED load current cut-off, so time described inThe first output of the 3rd switch 33 is high level, and the second output of described the 3rd switch 33 is low electricityFlat, the output of described the 3rd nor gate G4 is low level.
When the output signal (driving signal) in described pwm signal source 5 is during in propradation, described inThe output of the second comparator D2 is low level, the first input end of described the second nor gate G3 and PWMSignal source 5 is electrically connected, and is high level, the second input of described the second nor gate G3 and the described the 3rd orThe second output electrical connection (initial output letter of described the 3rd nor gate G4 the second output of not gate G4Number be low level), be low level, therefore the output of described the second nor gate G3 is low level; DescribedThe first input end of three nor gate G4 is electrically connected with the output of described the second nor gate G3, is low level,The second input of described the 3rd nor gate G4 is electrically connected with the output of described the second comparator D2, alsoFor low level, therefore the output of described the 3rd nor gate G4 switches to high level, control described power circuit1 opens, for described LED load provides operating voltage; The input of described not gate G5 and the described the 3rdThe output of nor gate G4 electrically connects as high level, therefore the output of described not gate G5 is low level, and controlMake the first state that described current control circuit 2 switches to the conducting of described LED load current.
In the time of described LED load conducting, the voltage drop of described LED load output, now, described inThe voltage of feedback circuit 4 outputs is less than described the first reference voltage Vref 1, described the first comparator D1Output be low level, the first control end of described the first switch 31 is low level, described the first switchThe second control end of 31 still maintains high level, thus described the first switch 31 end, described charging current source IcStop charging for described the first capacitor C 1, described the first capacitor C 1 maintains this voltage, and described second relativelyThe output of device D2 maintains low level, and described pwm signal source 5 maintains high level, described the 3rd switch33 maintain the first output low level, control described current control circuit 2 and keep described LED load currentThe first state of conducting, described the 3rd switch 33 second outputs are high level, control described power circuit1 stays open state, for described LED load provides operating voltage.
In the time that described pwm signal source 5 output signals (driving signal) decline beginning, now, described inPwm signal source 5 output signal vanishing (driving signal to become low level), described the second comparatorThe output of D2 still maintains low level, and the first input end of described the second nor gate G3 is defeated with driving signalEntering end electrical connection, is low level, the second input of described the second nor gate G3 and described the 3rd nor gateThe second output electrical connection of G4, is high level, and the output of described the second nor gate G3 is exported low electricityFlat; The first input end of described the 3rd nor gate G4 is electrically connected with the output of described the second nor gate G3For low level, the second input of described the 3rd nor gate G4 and the output of described the second comparator D2Electrically connect as low level, the output of described the 3rd nor gate G4 is still high level, controls described power supply electricityRoad 1 stays open state, for described LED load provides operating voltage, described the 3rd nor gate G4'sThe first output (being the output of not gate G5) is still low level, controls described current control circuit 2 and protectsHold the first state of described LED load current conducting.
In the time of described the first capacitor C 1 discharge off, the electricity of the first input end of described the second comparator D2Pressure drop is zero, and the output of described the second comparator D2 switches to high level, described pwm signal source 5Output signal (being described driving signal) still for low level, now, described the second nor gate G3 firstInput and described pwm signal source 5 electrically connect as low level, and described the second nor gate G3 second inputsEnd electrically connects as high level with the 3rd nor gate G4, and output is low level; Described the 3rd nor gate G4First input end be electrically connected with the output of described the second nor gate G3, be low level, the described the 3rd orThe second input of not gate G4 is electrically connected with the output of described the second comparator D2, is high level, instituteThe output of stating the 3rd nor gate G4 switches to low level, and control power circuit 1 and close, be no longer LEDLoad provides operating voltage, and the output of not gate G5 switches to high level, controls described current control circuit2 switch to the second state of LED load current cut-off.
On the basis of above-mentioned arbitrary embodiment, in one embodiment of the invention, as shown in Figure 5,Described current control circuit 2 comprises:
The first current source I1;
The first resistance R 1, one end of described the first resistance R 1 and described the first current source I1 output are electrically connectedConnect other end ground connection;
The first operational amplifier A 1, the electrode input end of described the first operational amplifier A 1 and described firstThe common port electrical connection of current source I1, described the first resistance R 1, described the first operational amplifier A 1 negativeUtmost point input is by the second resistance R 2 ground connection;
The second field-effect transistor N2, the source electrode of described the second field-effect transistor N2 and LED loadOutput electrical connection, the drain electrode of described the second field-effect transistor N2 and described the first operational amplifier A 1,The common port electrical connection of the second resistance R 2, the grid of described the second field-effect transistor N2 and the first computingThe output Vg electrical connection of amplifier A1;
The 3rd field-effect transistor N3, the source electrode of described the 3rd field-effect transistor N3 and described the first fortuneCalculate the output Vg electrical connection of amplifier A1, the grounded drain of described the 3rd field-effect transistor N3,The grid of described the 3rd field-effect transistor N3 is electrically connected with the first output of described regulating circuit 3.
Concrete, as shown in Figure 3, when the first output DIMB of described regulating circuit 3 exports low electricityAt ordinary times, the 3rd field-effect transistor N3 cut-off, the electricity of described the first operational amplifier A 1 electrode input endPressure is greater than the voltage of its negative input, and its output Vg rises to high level, described the second field-effect crystalline substanceBody pipe N2 conducting, path conducting between described LED load and the second resistance R 2, described Current Control electricityRoad 2 is in controlling the first state of LED load current conducting. When described regulating circuit 3 first outputsWhen defeated DIMB goes out high level, described the 3rd field-effect transistor N3 conducting, described the second field effect transistorThe grid of pipe N2, through described the 3rd field-effect transistor N3 ground connection, drops to low level, described firstThe voltage Vg of operational amplifier A 1 electrode input end drops to low level, described the second field-effect transistorN2 cut-off, described current control circuit 2 is in controlling the second state of LED load current cut-off.
On the basis of above-mentioned arbitrary embodiment, in one embodiment of the invention, as shown in Figure 5,Described power circuit 1 can be DCDC power circuit, or AC-DC power circuit, or LDO power supplyCircuit, the present invention does not limit this. Preferably, in a specific embodiment of the present invention, instituteState power circuit 1 for DCDC power circuit, more preferably DCDC booster power supply circuit. Wherein, instituteStating DCDC booster power supply circuit comprises: boost pressure controller, inductance L 1, the 4th field-effect transistor N4,Sustained diode 0 and the second capacitor C 2, wherein, the first input end of described boost pressure controller and feedbackThe output electrical connection of circuit 4, second of the second input of described boost pressure controller and regulating circuit 3Output electrical connection, the grid of the output of described boost pressure controller and the 4th field-effect transistor N4 is electrically connectedConnect, the source electrode of described the 4th field-effect transistor N4 is electrically connected with extraneous power supply by inductance L 1, described inThe direct ground connection of drain electrode of the 4th field-effect transistor N4. The input of described sustained diode 0 with described inThe common port electrical connection of inductance L 1, the 4th field-effect transistor N4, the output of described sustained diode 0End is electrically connected with the input of LED load. Described second capacitor C 2 one end and sustained diode 0, LEDThe common port electrical connection of load, other end ground connection. Because the work of described DCDC booster power supply circuit is formerReason has been conventionally known to one of skill in the art, and the present invention is no longer described in detail this.
The linearity of the LED the load driving circuits below embodiment of the present invention being provided is carried out theory and is saidBright.
Note tDIM_on: for the time width that pwm signal source output signal is high level, can be low to moderate 1us;tdelay: while starting as high level for pwm signal, to described LED load driving circuits stable output electric currentThe time of value, the output current value of described LED load driving circuits is by the stable electrical flow valuve of rising to above freezingResponse time; tdelay2: while starting as low level for pwm signal, the time of closing to described LED load;Voltage after described the first capacitor charging completes is vcap, and capacitance is C1, and charging current is Ic, electric dischargeElectric current is Idis.
, the charging interval t of described the first electric capacity is:
Tdis discharge time of described the first electric capacity is:
Again because charging current Ic is identical with discharge current Idis size, so the charging of described the first electric capacityTime is identical with discharge time, therefore ideally, the time of described LED load steady operation (described inCurrent control circuit maintains the time of the first state) and time of described pwm pulse input width betweenError is:
Error = t DIM _ on + Δt t DIM _ on - 1 = t DIM _ on - t delay + t delay 2 t DIM _ on - 1 = t DIM _ on - t + tdis t DIM _ on - 1 = 0 ;
As can be seen here, the error of the LED load driving circuits that the embodiment of the present invention provides is zero, improvesThe linearity of described LED load driving circuits output current, especially for thering is lower input dutyThe LED load driving circuits of ratio, can significantly improve the linearity of its output current.
Because the comparator in reality is mostly imperfect comparator, and imperfect comparator has a ginsengNumber tcomp time delay, mainly, in tens nano-seconds, this parameter time delay can be to described LEDError between the time of the time of load steady operation and described pwm pulse input width causes necessarilyImpact.
In addition, the input of imperfect comparator also has an offset voltage vos, mainly at 1mV-10mVScope in, also can be to the time of described LED load steady operation and described pwm pulse input widthTime between error affect.
Therefore under non-ideality, the charging interval t of described the first electric capacity is:
Tdis discharge time of described the first electric capacity is:
The time (described current control circuit maintains the time of the first state) of described LED load steady operationAnd the error between the time of described pwm pulse input width is:
Error = Δt t DIM _ on = t DIM _ on - t delay + t delay 2 t DIM _ on + tcomp - 1 = ( vcap + vos - 0 ) * C 1 Idis * t DIM _ on - ( vcap - 0 ) * C 1 Ic * t DIM _ on + tcomp t DIM _ on = vos * C 1 Idis * t DIM _ on + tcomp t DIM _ on ;
In a specific embodiment of the present invention, establish the parameter of described the second comparator and get time delayLarge value 50ns, and for the LED load driving circuits compared with low duty ratio, its pwm signal source output arteries and veinsThe time of rushing width is generally 1 delicate-3 delicate, in the present embodiment, and the output of described pwm signal sourceIt is 1 delicate that pulse width time is got, the mistake that exists parameter to introduce time delay due to described the second comparatorDifference is:
Error 1 = tcomp t DIM _ on = 50 1 * 1000 * 100 % = 5 % .
In addition, the offset voltage vos of described the second comparator negative pole mainly in the scope of 1mV-10mV,Get in the present embodiment maximum 10mV, and the voltage of the first capacitor charging after completing is that vcap can establishMeter to relatively high current potential, in the present embodiment, is made as 1.5V, due to described the second comparator theThe offset voltage of one input causes the charging interval to increaseTherefore, due to described secondThe error that the offset voltage of comparator is introduced is negligible.
It should be noted that, for actual comparators, the voltage of its input cannot drop to zero orLower, the voltage of the second comparator negative input cannot drop to zero or lower, therefore, and for justVoltage in described the second comparator negative input and its electrode input end compares, of the present inventionIn an embodiment, be provided with fixing offset voltage in the electrode input end inside of described the second comparator,Described offset voltage is preferably 20mV-100mV, comprises endpoint value, and more preferably 50mV, with 50mVFor example, lack the discharge time of described the first electric capacityIn another reality of the present inventionExecute in example, as shown in Figure 6, can also connect by voltage source V c at described the second comparator electrode input endGround, the output voltage of described voltage source V c is preferably 20mV-100mV, comprises endpoint value, more preferablyFor 50mV, continue taking 50mV as example, be equivalent to described the second comparator electrode input end and introduce 50mVOffset voltage, in like manner, lacked the discharge time of described the first electric capacity
If the capacitance of the first electric capacity is 5pF, discharge current is 5 μ A, the electric discharge of described the first electric capacityTime shorten 5pF*50mV/5 μ A=50ns, and the reaction time of described the second comparator is also 50ns, byThis is visible, and described the first electric capacity shortens suitable with the reaction time of described the second comparator, thereby makes instituteThe actual error of stating the second comparator is very little, in the described LED load driving circuits course of work, described inThe time (described current control circuit maintains the time of the first state) of LED load steady operation with described inError between the time of pwm pulse input width is very little, and then makes described LED load drive electricityThe linearity on road (especially having the LED load driving circuits of lower input duty cycle) is very high.
In sum, the LED load driving circuits that the embodiment of the present invention provides, except comprising: power supply electricityOutside road, current control circuit, feedback circuit, also comprise regulating circuit, described regulating circuit is by connecingReceive described feedback signal and drive signal, controlling described current control circuit and maintain the time of the first stateIdentical with the time of described driving signal input width, thus solve because described LED load drives electricityThe output current value on road is by needing certain response time in the process that rises to stable electrical flow valuve above freezing, and leadsThe state that the described LED load causing maintains conducting is less than the problem of driving signal input width time, improvesThe linearity of described LED load driving circuits output current, especially for thering is lower input dutyThe LED load driving circuits of ratio, can significantly improve the linearity of its output current.
In this description, various piece adopts the mode of going forward one by one to describe, what each part stressed is withThe difference of other parts, between various piece identical similar part mutually referring to.
To the above-mentioned explanation of the disclosed embodiments, professional and technical personnel in the field can be realized or useThe present invention. To be aobvious and easy for those skilled in the art to the multiple amendment of these embodimentSee, General Principle as defined herein can be in the situation that not departing from the spirit or scope of the present invention,Realize in other embodiments. Therefore, the present invention will can not be restricted to embodiment illustrated herein, andTo meet the widest scope consistent with principle disclosed herein and features of novelty.

Claims (11)

1. a LED load driving circuits, is characterized in that, comprising:
For LED load provides the power circuit of operating voltage;
Control the current control circuit that LED load current cut-offs, the duty of described current control circuitComprise: control the first state of LED load current conducting and control the second shape that LED load current endsState;
Detect the feedback circuit of LED load output feedback signal; And
Regulating circuit, by receiving described feedback signal and driving signal, controls described Current Control electricityIt is identical with the time of described driving signal input width that road maintains the time of the first state.
2. drive circuit according to claim 1, is characterized in that, described regulating circuit comprises:The first comparator, charge circuit, the first electric capacity, the second comparator, discharge loop and the 3rd switch;
The first comparator, receives described feedback signal, output the first control signal;
Charge circuit, by receiving described the first control signal and driving signal, controls described the first electricityThe charging interval of holding;
The second comparator, receives the first electric capacity and described charge circuit common port voltage, and output second is controlledSignal;
Discharge loop, by receiving the second control signal and driving signal, while controlling the electric discharge of the first electric capacityBetween identical with the charging interval of the first electric capacity;
The 3rd switch, by receiving the second control signal and driving signal, controls described current control circuitThe time that maintains the first state is identical with the time of described driving signal input width.
3. drive circuit according to claim 2, is characterized in that, described regulating circuit comprises:
The first comparator, the negative input of described the first comparator is provided with the first reference voltage, and describedThe electrode input end of one comparator is electrically connected with the output of feedback circuit, receives described feedback signal, defeatedGo out the first control signal;
Charge circuit, described charge circuit comprises charging current source and is electrically connected with described charging current sourceThe first switch, the input of described the first switch is electrically connected with charging current source, described the first switchThe first control end is electrically connected with the output of described the first comparator, the second control end of described the first switchBe electrically connected with driving signal input, by receiving described the first control signal and driving signal, controlThe charging interval of described the first electric capacity;
The first electric capacity, described first electric capacity one end is electrically connected with the output of described the first switch, the other endGround connection;
The second comparator, the ungrounded end of the negative input of described the second comparator and described the first electric capacityElectrical connection, the electrode input end ground connection of described the second comparator, by receive described the first electric capacity with described inCharge circuit common port voltage, output the second control signal;
Discharge loop, described discharge loop comprises discharge current source and is electrically connected with described discharge current sourceSecond switch, described discharge current source is identical with the size of current of described charging current source, described secondThe input of switch is electrically connected with the output of described the first switch, the first control end of described second switchBe electrically connected with driving signal input, the second control end of described second switch and described the second comparatorOutput electrical connection, by receiving the second control signal and driving signal, while controlling the electric discharge of the first electric capacityBetween identical with the charging interval of the first electric capacity;
The 3rd switch, the first input end of described the 3rd switch is electrically connected with driving signal input, described inThe second input of the 3rd switch is electrically connected with the output of described the second comparator, described the 3rd switchThe first output is electrically connected with described current control circuit, and the state of controlling described current control circuit switches,The second output of described the 3rd switch is electrically connected with described power circuit, controls opening of described power circuitClose, by receiving the second control signal and driving signal, control described current control circuit and maintain the first shapeThe time of state is identical with the time of described driving signal input width;
Wherein, when the first input end of described the first switch and the second input of described the first switch areWhen high level, described the first switch conduction, second switch disconnects, and described charging current source is described firstCapacitor charging; The second input of the first input end of described second switch and described second switch is lowWhen level, described second switch conducting, the first switch disconnects, and described the first electric capacity is by described electric discharge electricityThe electric discharge of stream source; When the second input of described the 3rd switch is high level, described the 3rd switch first defeatedGo out end for high level, control described current control circuit and switch to the second state, the of described the 3rd switchTwo outputs are low level, control described power circuit and close, and the second input of described the 3rd switch isWhen low level, the first output of described the 3rd switch is low level, controls described current control circuit and cutsChange to the first state, the second output of described the 3rd switch is high level, controls described power circuit and beatsOpen, for described LED load provides operating voltage.
4. drive circuit according to claim 3, is characterized in that, described the first reference voltage is largeThe output voltage of feedback circuit described in the time of described LED load conducting, and be less than described LED load and closeThe output voltage of Shi Suoshu feedback circuit.
5. drive circuit according to claim 3, is characterized in that, described the first switch comprises:
NAND gate, the first control end of described NAND gate is electrically connected with the output of described the first comparator,The second control end of described NAND gate is electrically connected with described driving signal input;
The one PMOS transistor, the transistorized source electrode of a described PMOS is electrically connected with charging current source,Drain electrode is electrically connected with described the first electric capacity, and grid is electrically connected with the output of described NAND gate.
6. drive circuit according to claim 5, is characterized in that, described second switch comprises:
The first nor gate, the first control end of described the first nor gate is electrically connected with driving signal input,The second control end of described the first nor gate is electrically connected with the output of described the second comparator;
The first nmos pass transistor, the source electrode of described the first nmos pass transistor and a described PMOSTransistorized drain electrode electrical connection, the source electrode of described the first nmos pass transistor and described discharge current source are electrically connectedConnect, the grid of described the first nmos pass transistor is electrically connected with the output of described the first nor gate.
7. drive circuit according to claim 2, is characterized in that, described the 3rd switch comprises:The second nor gate, the 3rd nor gate and not gate;
Wherein, the first input end of described the second nor gate is the first input end of described the 3rd switch, withDriving signal input electrical connection, the second input of described the second nor gate and described the 3rd nor gateOutput electrical connection; The output electricity of the first input end of described the 3rd nor gate and described the second nor gateConnect, the second input of described the 3rd nor gate is the second input of described the 3rd switch, with describedThe output electrical connection of the second comparator, the output of described the 3rd nor gate is the of described the 3rd switchTwo outputs, input, the power circuit of NAND gate are electrically connected simultaneously; The output of described not gate is instituteState the first output of the 3rd switch, be electrically connected with described current control circuit.
8. drive circuit according to claim 2, is characterized in that, described the second comparator justUtmost point input is by voltage source ground connection, and the output voltage range of described voltage source is 20mV-100mV, bagDraw together endpoint value.
9. drive circuit according to claim 1, is characterized in that, when described LED load bagWhile drawing together multiple parallel connection LED load channel, the output voltage of described feedback circuit is described multiple parallel connection LEDMinimum voltage value in the output voltage of load channel.
10. drive circuit according to claim 1, is characterized in that, described current control circuitComprise:
The first current source;
The first resistance, one end of described the first resistance is electrically connected with described the first current source output, anotherEnd ground connection;
The first operational amplifier, the electrode input end of described the first operational amplifier and described the first current source,The common port electrical connection of described the first resistance, the negative input of described the first operational amplifier is by secondResistance eutral grounding;
The second field-effect transistor, the output of the source electrode of described the second field-effect transistor and LED loadElectrical connection, the drain electrode of described the second field-effect transistor and described the first operational amplifier, the second resistanceCommon port electrical connection, the output electricity of the grid of described the second field-effect transistor and the first operational amplifierConnect;
The 3rd field-effect transistor, the source electrode of described the 3rd field-effect transistor and described the first operation amplifierThe output electrical connection of device, the grounded drain of described the 3rd field-effect transistor, described the 3rd field-effect crystalline substanceThe grid of body pipe is electrically connected with the first output of described regulating circuit.
11. drive circuits according to claim 1, is characterized in that, described power circuit is DCDCPower circuit, or AC-DC power circuit, or LDO power circuit.
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018119819A1 (en) * 2016-12-29 2018-07-05 Texas Instruments Incorporated Adaptive turn-off delay time compensation for led controller
CN110174853A (en) * 2019-06-13 2019-08-27 苏州科达科技股份有限公司 The stabilising arrangement and method of loaded work piece electric current
CN112394672A (en) * 2020-11-30 2021-02-23 中船动力研究院有限公司 Single-set interface multifunctional electromagnetic valve driving circuit
CN114967809A (en) * 2022-05-24 2022-08-30 芯海科技（深圳）股份有限公司 Current stabilizing circuit and current stabilizing method thereof, integrated circuit and electronic equipment

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090039853A1 (en) * 2007-08-06 2009-02-12 Rohm Co., Ltd. Power supply device and electronic appliance provided therewith
CN101621877A (en) * 2008-07-03 2010-01-06 台达电子工业股份有限公司 Current feed circuit and current control circuit of light emitting diode
CN102740564A (en) * 2012-06-28 2012-10-17 上海新进半导体制造有限公司 Light emitting diode (LED) driving circuit and control method of LED
CN102957318A (en) * 2011-08-25 2013-03-06 恒耀电子股份有限公司 Light emitting module with light emitting diodes and voltage conversion device of light emitting module
JP5584827B2 (en) * 2011-04-26 2014-09-03 ルネサスエレクトロニクス株式会社 PFC signal generation circuit, PFC control system using the same, and PFC control method
US20140297144A1 (en) * 2013-03-27 2014-10-02 Jtekt Corporation Electrical load control device, abnormality determination method, and abnormality determination program

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090039853A1 (en) * 2007-08-06 2009-02-12 Rohm Co., Ltd. Power supply device and electronic appliance provided therewith
CN101621877A (en) * 2008-07-03 2010-01-06 台达电子工业股份有限公司 Current feed circuit and current control circuit of light emitting diode
JP5584827B2 (en) * 2011-04-26 2014-09-03 ルネサスエレクトロニクス株式会社 PFC signal generation circuit, PFC control system using the same, and PFC control method
CN102957318A (en) * 2011-08-25 2013-03-06 恒耀电子股份有限公司 Light emitting module with light emitting diodes and voltage conversion device of light emitting module
CN102740564A (en) * 2012-06-28 2012-10-17 上海新进半导体制造有限公司 Light emitting diode (LED) driving circuit and control method of LED
US20140297144A1 (en) * 2013-03-27 2014-10-02 Jtekt Corporation Electrical load control device, abnormality determination method, and abnormality determination program

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018119819A1 (en) * 2016-12-29 2018-07-05 Texas Instruments Incorporated Adaptive turn-off delay time compensation for led controller
US10111285B2 (en) 2016-12-29 2018-10-23 Texas Instruments Incorporated Adaptive turn-off delay time compensation for LED controller
CN110174853A (en) * 2019-06-13 2019-08-27 苏州科达科技股份有限公司 The stabilising arrangement and method of loaded work piece electric current
CN110174853B (en) * 2019-06-13 2020-09-25 苏州科达科技股份有限公司 Load working current stabilizing device and method
CN112394672A (en) * 2020-11-30 2021-02-23 中船动力研究院有限公司 Single-set interface multifunctional electromagnetic valve driving circuit
CN112394672B (en) * 2020-11-30 2022-01-28 中船动力研究院有限公司 Single-set interface multifunctional electromagnetic valve driving circuit
CN114967809A (en) * 2022-05-24 2022-08-30 芯海科技（深圳）股份有限公司 Current stabilizing circuit and current stabilizing method thereof, integrated circuit and electronic equipment
CN114967809B (en) * 2022-05-24 2023-10-27 芯海科技（深圳）股份有限公司 Current stabilizing circuit, current stabilizing method thereof, integrated circuit and electronic equipment

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