CN107046751B - A kind of linear constant current LED drive circuit, driving chip and driving device - Google Patents

Abstract

The present invention is suitable for field of LED drive technology, and providing a kind of linear constant current LED drive circuit, driving chip and driving device, the circuit includes: rectification module, constant-current driven module；And input voltage measurement module, it is detected for the output voltage to rectification module, generates voltage detecting value；It releases control module, stops release signal or signal of releasing for generating according to voltage detecting value；It releases module, for opening according to stopping releasing signal shutdown to cut off leakage current, or according to signal of releasing to export leakage current.Judge to access in no controllable silicon dimmer by control module of releasing, and when voltage detecting value is between the first reference voltage value and turn-on voltage, control module cutting leakage current of releasing to reduce circuit loss improves circuit efficiency.

Description

A kind of linear constant current LED drive circuit, driving chip and driving device

Technical field

The invention belongs to field of LED drive technology more particularly to a kind of linear constant current LED drive circuit, driving chip andDriving device.

Background technique

Light emitting diode (Light-Emitting Diode, LED) is used as a kind of new type light source, because it is high with brightness,Low energy consumption and service life long advantage and is widely used in every field, and linear constant current drive scheme is with its simple system structureIt is used widely in middle low power LED drive system.

Currently used controllable silicon light modulation linear constant current LED drive circuit is as shown in Figure 1, the circuit includes controllable silicon light modulationDevice 10, rectification module 20, module of releasing 30, constant-current driven module 40 and LED load 50, not accessing in the circuit shown in Fig. 1 canWhen controlling silicon light modulator 10, before the output voltage of rectification module 20 rises to the conducting voltage of LED load 50, LED load 50Middle no current, module of releasing 30 are connected, and have leakage current to flow through in module of releasing 30；Rise in the output voltage of rectification module 20To LED load 50 conducting voltage when, constant-current driven module 40 is connected, and has electric current to flow through in LED load 50, and module of releasing 30 is closedIt closes.According to the foregoing circuit course of work it is found that working as in controllable silicon light modulation linear constant current LED drive circuit without controllable silicon dimmer 10When access, during LED load 50 does not turn on, there is leakage current to flow through always in module of releasing 30, the presence of leakage current increasesBig circuit loss, reduces the efficiency of circuit.

Therefore, because when being accessed in existing controllable silicon light modulation linear constant current LED drive circuit without controllable silicon dimmer,LED load always exists leakage current during not turning on and flows through module of releasing, and it is big, low efficiency to there is loss so as to cause circuitProblem.

Summary of the invention

The purpose of the present invention is to provide a kind of linear constant current LED drive circuits, it is intended to solve existing controllable silicon light modulationAlways existing leakage current in linear constant current LED drive circuit during LED load does not turn on leads to that circuit loss is big, low efficiencyThe problem of.

The invention is realized in this way a kind of linear constant current LED drive circuit, connect with LED load, the linear constant currentLED drive circuit includes:

Rectification module, for rectifying to AC power source, two input terminals of the rectification module are connect with AC power source,First output end of the rectification module is connected with the input terminal of the LED load；

Constant-current driven module, for the LED load carry out constant current driving, the output end of the constant-current driven module withThe output end of LED load connects, and the ground terminal of the constant-current driven module is connect with the second output terminal of the rectification module；

Input voltage measurement module is detected for the output voltage to the rectification module and generates voltage detectingValue, the input terminal and output end of the input voltage measurement module are defeated with the first output end of the rectification module and second respectivelyOutlet connection；

It releases control module, for when judge whether there is controllable silicon dimmer access according to the voltage detecting value, in nothingWhen controllable silicon dimmer accesses, and the voltage detecting value is generated greater than the first reference voltage value and when being less than turn-on voltageStopping is released signal, and when there is controllable silicon dimmer access, and when the voltage detecting value is less than the turn-on voltage,Generation is released signal, and the input terminal of the control module of releasing is connect with the test side of the input voltage measurement module；

It releases module, for being released according to stopping signal shutdown of releasing to cut off leakage current, and according to describedLeakage current is opened and exported to signal, controlled end, input terminal and the output end of the module of releasing respectively with the control of releasingThe resistance connecting pin of the output end of module, the first output end of the rectification module and the constant-current driven module connects.

Another object of the present invention, which also resides in, provides a kind of LED driving core including above-mentioned linear constant current LED drive circuitPiece.

Another object of the present invention, which also resides in, provides a kind of LED driving dress including above-mentioned linear constant current LED drive circuitIt sets.

In the present invention, linear constant current LED drive circuit includes: rectification module, constant-current driven module；And input voltage inspectionModule is surveyed, is detected for the output voltage to rectification module, voltage detecting value is generated；It releases control module, is used for basisVoltage detecting value, which generates, stops release signal or signal of releasing；Release module, for according to the signal shutdown that stops releasing to cut offLeakage current, or opened according to signal of releasing to export leakage current.Judged by control module of releasing in no controllable silicon light modulationDevice access, and voltage detecting value be between the first reference voltage value and turn-on voltage when, control release module cutting releaseElectric current improves circuit efficiency to reduce circuit loss.

Detailed description of the invention

Fig. 1 is the structure chart for the controllable silicon light modulation linear constant current LED drive circuit that the prior art provides；

Fig. 2 is the structure chart of linear constant current LED drive circuit provided in an embodiment of the present invention；

Fig. 3 is the exemplary circuit figure of linear constant current LED drive circuit provided in an embodiment of the present invention；

Fig. 4 is the exemplary circuit figure of logic unit in linear constant current LED drive circuit provided in an embodiment of the present invention；

Fig. 5 be another embodiment of the present invention provides linear constant current LED drive circuit exemplary circuit figure；

Fig. 6 is the output voltage of rectification module and output in linear constant current LED drive circuit provided in an embodiment of the present inventionThe waveform diagram of electric current；

Fig. 7 is the output voltage of rectification module in the controllable silicon light modulation linear constant current LED drive circuit of prior art offerWith the waveform diagram of output electric current.

Specific embodiment

In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawings and embodiments, rightThe present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, andIt is not used in the restriction present invention.

Fig. 2 shows the structures of linear constant current LED drive circuit provided in an embodiment of the present invention, for ease of description, onlyPart related to the present invention is shown, details are as follows:

As a preferred embodiment of the present invention, the linear constant current LED drive circuit is connect with LED load 300, and including wholeFlow module 100, constant-current driven module 200, input voltage measurement module 400, control module of releasing 500 and module 600 of releasing.

Rectification module 100 rectifies AC power source, and two input terminals of rectification module 100 are connect with AC power source, wholeFirst output end of flow module 100 is connected with the input terminal of LED load 300.Specifically, rectification module is rectifier bridge.

Constant-current driven module 200 carries out constant current driving, the output end and LED of constant-current driven module 200 to LED load 300The output end connection of load 300, the ground terminal of constant-current driven module 200 are connect with the second output terminal of rectification module 100.

Input voltage measurement module 400 detects the output voltage of rectification module 100, generates voltage detecting value, defeatedThe input terminal and output end for entering voltage detection module 400 connect with the first output end and second output terminal of rectification module 100 respectivelyIt connects.

Control module of releasing 500 judges whether there is controllable silicon dimmer access according to voltage detecting value, in no thyristor regulatingWhen light device accesses, and voltage detecting value generates greater than the first reference voltage value and when being less than turn-on voltage and stops signal of releasing,When there is controllable silicon dimmer access, and when voltage detecting value is less than turn-on voltage, generation is released signal, control module of releasing500 input terminal is connect with the test side of input voltage measurement module 400；

Wherein, when accessing controllable silicon dimmer in linear constant current LED drive circuit, when controllable silicon dimmer does not turn on,The first reference voltage value V1 is set by the output voltage values of rectification module 100 at this time；When the output voltage etc. of rectification module 100When the turn-on voltage of LED load 300, the voltage value that the test side of input voltage measurement module 400 is exported is above-mentioned leadsLogical voltage value.

Specifically, releasing control module 500 when voltage detecting value is equal to the first reference voltage value V1, and it is delayed first in advanceIf after the time, judge voltage detecting value whether in the second preset time less than the second reference voltage value V2；

If so, judging no controllable silicon dimmer access；

If it is not, then judgement has controllable silicon dimmer access.

Further specifically, the first preset time and the second preset time are two adjacent periods, the first preset timeEnd point be the second preset time starting point, the first preset time may be configured as N microsecond, N > 0.As linear constant current LEDWhen accessing controllable silicon dimmer in driving circuit, when controllable silicon dimmer is maximum cut phase angle, by the defeated of rectification module 100 at this timeVoltage value is set as above-mentioned second reference voltage value V2 out；Second reference voltage value V2 is greater than the first reference voltage value V1.

Module of releasing 600 is according to signal shutdown of releasing is stopped, and to cut off leakage current, and is opened simultaneously according to signal of releasingExport leakage current, controlled end, input terminal and the output end of module of releasing 600 respectively with the output end for control module 500 of releasing,The resistance connecting pin connection of the first output end and constant-current driven module 200 of rectification module 100.

In the present embodiment, the AC rectification of input is direct current, input voltage measurement module 400 by rectification module 100The DC voltage exported to rectification module 100 detects, and the voltage detecting value that will test is exported to control module of releasing500.When control module 500 of releasing judges that voltage detecting value is equal to the first reference voltage value V1, by the first preset timeAfter delay, control module of releasing 500 judge the voltage detecting value in the second preset time whether less than the second reference voltage value V2,If so, showing to access in linear constant current LED drive circuit without controllable silicon dimmer, in the premise that no controllable silicon dimmer accessesUnder, when control module 500 of releasing judges that voltage detecting value is greater than the first reference voltage value V1 and is less than turn-on voltage, releaseThe output of control module 500 stops releasing signal so that the closing of module 600 of releasing.I.e. when no controllable silicon dimmer accesses, in electricityPressure detected value is greater than the first reference voltage value V1 and LED load 300 does not turn on period, and module of releasing 600 is closed.

In the embodiment of the present invention, when being accessed in linear constant current LED drive circuit without controllable silicon dimmer, in LED load300 do not turn in the part-time of period, and module of releasing 600 is to close, and reduce circuit loss, improve circuit efficiency.

Fig. 3 shows the exemplary circuit of linear constant current LED drive circuit provided in an embodiment of the present invention, for the ease of sayingBright, only the parts related to the present invention are shown.

As an embodiment of the present invention, input voltage measurement module 400 includes:

First resistor R1 and second resistance R2；

The first end of first resistor R1 be input voltage measurement module 400 input terminal, the second end of first resistor R1 withThe first end of second resistance R2 connects the test side to form input voltage measurement module 400 altogether, and the second end of second resistance R2 is defeatedEnter the output end of voltage detection module 400.

As an embodiment of the present invention, control module of releasing 500 includes:

First comparator A1, the second comparator A2 and logic unit 501；

The inverting input terminal of first comparator A1 and the non-inverting input terminal of the second comparator A2 connect to be formed to release altogether and control mouldThe output end of the input terminal of block 500, the output end of first comparator A1 and the second comparator A2 respectively with logic unit 501One input terminal and the second input terminal are connected, and the non-inverting input terminal of first comparator A1 is connected with the first power supply, and second comparesThe inverting input terminal of device A2 is connected with second source, and the output end of logic unit 501 is the output of control module 500 of releasingEnd.

When logic unit 501 judges that voltage detecting value is equal to the first reference voltage according to the output signal of first comparator A1When value V1, after the first preset time, if logic unit 501 according to the output signal of the second comparator A2 judge second it is default whenInterior voltage detecting value is then believed in logic unit 501 according to the output of first comparator A1 less than the second reference voltage value V2During number judging that voltage detecting value is greater than the first reference voltage value V1 and is less than turn-on voltage, the output of logic unit 501 stopsSignal release to module 600 of releasing, so that the closing of module 600 of releasing.

Specifically, the output voltage values of the first power supply are the first reference voltage value V1, the output voltage values of second source areSecond reference voltage value V2.

The preferred implementation of logic unit 501 in the embodiment of the present invention, as shown in figure 4, logic unit 501 includes:

5th resistance R5, the 6th resistance R6, first capacitor C1, the second capacitor C2, the first phase inverter G1, the second phase inverterG2, third phase inverter G3, the 4th phase inverter G4, the 5th phase inverter G5, the first nor gate G6, the second nor gate G7, NAND gate G8,Latch U1 and d type flip flop U2；

The input terminal of first phase inverter G1 and the clear terminal CLR1 of latch U1 are respectively the first input of logic unit 501End and the second input terminal, the output end of the first phase inverter G1 is connected with the first end of the 5th resistance R5, and the of the 5th resistance R5The first end at two ends, the first end of first capacitor C1 and the 6th resistance R6 is connected to the input terminal of the second phase inverter G2 altogether, and second is anti-The output end of phase device G2, the input terminal of third phase inverter G3, the first input end of NAND gate G8 and the second nor gate G7 firstInput terminal is connected to the input terminal of third phase inverter G3, the first end and the 5th of the second end of the 6th resistance R6, the second capacitor C2 altogetherThe input terminal of phase inverter G5 is connected to the second input terminal of the second nor gate G7, the output end and NAND gate G8 of the 5th phase inverter G5 altogetherThe second input terminal be connected, the output end of NAND gate G8 is connected with the set end SET2 of d type flip flop U2, third phase inverter G3Output end be connected with the input terminal of the 4th phase inverter G4, the first of the output end of the 4th phase inverter G4 and the first nor gate G6Input terminal is connected, and the output end of the second nor gate G7 and the set end SET1 of latch U1 are connected to the of the first nor gate G6 altogetherTwo input terminals, the third input terminal of the first nor gate G6 are connected with the output end Q2 of d type flip flop U2, the output end of latch U1Q1 is connected with the clear terminal CLR2 of d type flip flop U2, and the output end of the first nor gate G6 is the output end of logic unit 501, theThe second end of one capacitor C1 and the second end of the second capacitor C2 are connected to power ground, the input terminal D1 and d type flip flop of latch U1 altogetherThe input terminal D2 of U2 is connected to power supply altogether.

Specifically, the product of the resistance value of the 5th resistance R5 and the capacitance of first capacitor C1 is the first preset time；6thThe product of the resistance value of resistance R6 and the capacitance of the second capacitor C2 is the second preset time.

As an embodiment of the present invention, module of releasing 600 includes:

Third comparator A3,3rd resistor R3, the 4th resistance R4 and switching tube S1；

The first end of the controlled end of third comparator A3, the first end of 3rd resistor R3 and the 4th resistance R4 is respectively to releaseControlled end, input terminal and the output end of module 600, the non-inverting input terminal and output end of third comparator A3 respectively with third power supplyIt is connected with the controlled end of switching tube S1, the inverting input terminal of third comparator A3 and the output end of switching tube S1 are connected to the 4th altogetherThe second end of the second end of resistance R4,3rd resistor R3 is connected with the input terminal of switching tube S1.

The output stopping of control module of releasing 500 releases signal to the controlled end of third comparator A3, so that third comparatorA3 stops output drive signal to switching tube S1, and then turns off switching tube S1, to make the closing of module 600 of releasing；It releases controlMolding block 500 export release signal to third comparator A3 controlled end so that third comparator A3 output drive signal is to openingPipe S1 is closed, and then switching tube S1 is connected, to make the conducting of module 600 of releasing.

Specifically, the output voltage values of third power supply are third reference voltage value V3, when the reverse phase of third comparator A3 is defeatedWhen entering the input voltage value at end greater than third reference voltage value V3, third comparator A3 exports low level, so that switching tube S1 is closedDisconnected, module of releasing 600 is closed.When the input voltage value of the inverting input terminal of third comparator A3 is greater than third reference voltage value V3When, show that the conducting of LED load 300, constant-current driven module 200 work, at this point, the closing of module 600 of releasing.

Specifically, switching tube S1 is NMOS tube, drain electrode, source electrode and the grid of NMOS tube are respectively the input of switching tube S1End, output end and controlled end.

As an embodiment of the present invention, constant-current driven module 200 includes:

Current constant control chip U3 and the 7th resistance R7；

The output and ground of current constant control chip U3 is respectively the output and ground of constant-current driven module 200,The resistance connecting pin of current constant control chip U3 and the first end of the 7th resistance R7 meet the resistance company to form constant-current driven module 200 altogetherEnd is connect, the second end of the 7th resistance R7 is connected with the ground terminal of current constant control chip U3.

Specifically, the chip of model SM2082 can be selected in current constant control chip U3.

In embodiments of the present invention, as shown in figure 5, LED load 300 includes N number of light emitting diode and third capacitor C3, perseveranceThe output end of stream drive module 200 includes i+1 sub- output end (O₁~O_i+1), wherein N is integer more than or equal to 1,0≤I < N, and i is integer；

N number of light emitting diode is sequentially connected in series, the first Light-emitting diode LED in N number of light emitting diode₁Anode withThe first end of third capacitor C3 connects the input terminal to form LED load 300, the N light emitting diode in N number of light emitting diode altogetherLED_NCathode be connected with the second end of third capacitor C3, the cathode of i light emitting diode in N number of light emitting diode andN Light-emitting diode LED_NCathode be LED load 300 output end, the cathode and N luminous two of i light emitting diodePole pipe LED_NCathode respectively with the i+1 of constant-current driven module 200 sub- output end (O₁~O_i+1) be connected.

It is illustrated below in conjunction with working principle of the Fig. 3 to linear constant current LED drive circuit, details are as follows:

The alternating current of input is converted to direct current by rectification module 100, and input voltage measurement module 400 is to rectification module100 output voltage is detected, and voltage detecting value is exported to control module 500 of releasing.When logic unit 501 is according toWhen the output signal of one comparator A1 judges that voltage detecting value is equal to the first reference voltage value V1, when first risen at the moment is defaultBetween after, whether logic unit 501 judges the voltage detecting value in the second preset time according to the output signal of the second comparator A2Less than the second reference voltage value V2, if so, judging that voltage is examined according to the output signal of first comparator A1 in logic unit 501During measured value is greater than the first reference voltage value V1 and is less than turn-on voltage, the output of logic unit 501 stops releasing signal to letting outAmplification module 600, so that the closing of module 600 of releasing.It is greater than the first reference voltage value V1 in voltage detecting value and is less than conducting voltageDuring value, module of releasing 600 is closed, and LED load 300 is not turned on, and constant-current driven module 200 does not work.It is worth in voltage detecting smallWhen the first reference voltage value V1, the output of logic unit 501 releases signal to module 600 of releasing, so that module 600 of releasing is ledLogical, leakage current flows through 3rd resistor R3, switching tube S1, the 4th resistance R4 and the 7th resistance R7, at this point, LED load 300 is not ledLogical, constant-current driven module 200 does not work.It is greater than the turn-on voltage of LED load 300 in the output voltage values of rectification module 100When, LED load 300 is connected, and constant-current driven module 200 works, and the input voltage value of the inverting input terminal of third comparator A3 is bigLow level is exported so that switching tube S1 is turned off in third reference voltage value V3, third comparator A3, that is, module of releasing 600 is closed.

The wave of the output electric current Iin of the output voltage Vin and rectification module 100 of the rectification module 100 of circuit shown in Fig. 3Shape figure is as shown in Figure 6；The output voltage Vin of the rectification module 20 of circuit shown in the Fig. 1 being previously mentioned in background of inventionIt is as shown in Figure 7 with the waveform diagram of the output electric current Iin of rectification module 20.Wherein, V11 is the electricity of input voltage measurement module 400The output voltage values of pressure detected value rectification module 100 corresponding when being the first reference voltage value V1, VLED are LED load 300Turn-on voltage, as Vin < VLED, LED load 300 is not turned on, and Iin is generated by module 600 of releasing, as Vin >=VLEDWhen, LED load 300 is connected, and Iin is the operating current of LED load 300.By Fig. 6 and Fig. 7 comparison it is found that in the Vin < VLED phaseBetween, circuit shown in Fig. 3 is in V11 < Vin < VLED, no leakage current, and module of releasing 600 is closing, and circuit shown in Fig. 1In V11 < Vin < VLED, there are leakage current, module of releasing 600 is conducting.

In the embodiment of the present invention, during not turning in LED load 300, module 600 of releasing in circuit shown in Fig. 3 relative toThe turn-on time of module of releasing in circuit shown in Fig. 1 30 shortens, and therefore, circuit shown in Fig. 3 reduces circuit loss, improves electricityRoad efficiency.

Application advantage based on above-mentioned linear constant current LED drive circuit in LED drive device, the present invention also provides oneKind includes the LED drive chip of above-mentioned linear constant current LED drive circuit.

Application advantage based on above-mentioned linear constant current LED drive circuit in LED drive device, the present invention also provides oneKind includes the LED drive device of above-mentioned linear constant current LED drive circuit.

In the embodiment of the present invention, linear constant current LED drive circuit includes: rectification module, constant-current driven module；And inputVoltage detection module is detected for the output voltage to rectification module, generates voltage detecting value；It releases control module, usesStop release signal or signal of releasing in generating according to voltage detecting value；It releases module, for according to stopping signal shutdown of releasingTo cut off leakage current, or according to signal unlatching of releasing to export leakage current.Judged by control module of releasing without controllableThe access of silicon light modulator, and when voltage detecting value is between the first reference voltage value and turn-on voltage, control module of releasing is cutDisconnected leakage current improves circuit efficiency to reduce circuit loss.

The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all in essence of the inventionMade any modifications, equivalent replacements, and improvements etc., should all be included in the protection scope of the present invention within mind and principle.

Claims (10)

1. a kind of linear constant current LED drive circuit, connect with LED load, which is characterized in that the linear constant current LED driving electricityRoad includes:

Rectification module, for rectifying to AC power source, two input terminals of the rectification module are connect with AC power source, describedFirst output end of rectification module is connected with the input terminal of the LED load；

Constant-current driven module, for carrying out constant current driving, the output end and LED of the constant-current driven module to the LED loadThe output end of load connects, and the ground terminal of the constant-current driven module is connect with the second output terminal of the rectification module；

Input voltage measurement module is detected for the output voltage to the rectification module and is generated voltage detecting value, instituteState input voltage measurement module input terminal and output end respectively with the first output end and second output terminal of the rectification moduleConnection；

It releases control module, for when judge whether there is controllable silicon dimmer access according to the voltage detecting value, without controllableWhen silicon light modulator accesses, and the voltage detecting value generates and stops greater than the first reference voltage value and when being less than turn-on voltageIt releases signal, and when there is controllable silicon dimmer access, and when the voltage detecting value is less than the turn-on voltage, generatesIt releases signal, the input terminal of the control module of releasing is connect with the test side of the input voltage measurement module；

It releases module, for releasing signal shutdown to cut off leakage current, and according to the signal of releasing according to the stoppingOpen and export leakage current, controlled end, input terminal and the output end of the module of releasing respectively with the control module of releasingOutput end, the rectification module the first output end and the constant-current driven module resistance connecting pin connection.

2. linear constant current LED drive circuit as described in claim 1, which is characterized in that the control module of releasing is describedVoltage detecting value be equal to the first reference voltage value when, and be delayed the first preset time after, judge the voltage detecting value whetherLess than the second reference voltage value in second preset time；

If so, judging no controllable silicon dimmer access；

If it is not, then judgement has controllable silicon dimmer access.

3. linear constant current LED drive circuit as described in claim 1, which is characterized in that the input voltage measurement module packetInclude first resistor and second resistance；

The first end of the first resistor be the input voltage measurement module input terminal, the second end of the first resistor withThe first end of the second resistance connects the test side to form the input voltage measurement module, the second end of the second resistance altogetherFor the output end of the input voltage measurement module.

4. linear constant current LED drive circuit as claimed in claim 2, which is characterized in that the control module of releasing includes theOne comparator, the second comparator and logic unit；

The inverting input terminal of the first comparator and the non-inverting input terminal of second comparator connect to form the control of releasing altogetherThe output end of the input terminal of molding block, the output end of the first comparator and second comparator respectively with the logic listThe first input end and the second input terminal of member are connected, and the non-inverting input terminal of the first comparator is connected with the first power supply,The inverting input terminal of second comparator is connected with second source, and the output end of the logic unit is the control of releasingThe output end of module；

When the logic unit judges that the voltage detecting value is equal to described first according to the output signal of the first comparatorWhen reference voltage value, after the first preset time, if the logic unit judges according to the output signal of second comparatorVoltage detecting value in second preset time is greater than first reference voltage value and is less than second reference voltage value,Then judge that the voltage detecting value is greater than first ginseng according to the output signal of the first comparator in the logic unitDuring examining voltage value and being less than turn-on voltage, logic unit output stops releasing signal to the module of releasing, so thatThe module closing of releasing.

5. linear constant current LED drive circuit as described in claim 1, which is characterized in that the module of releasing includes third ratioCompared with device, 3rd resistor, the 4th resistance and switching tube；

The first end of the controlled end of the third comparator, the first end of the 3rd resistor and the 4th resistance is respectively instituteState the controlled end, input terminal and output end of module of releasing, the non-inverting input terminal and output end of the third comparator are respectively withThree power supplys are connected with the controlled end of the switching tube, the inverting input terminal of the third comparator and the output of the switching tubeEnd is connected to the second end of the 4th resistance altogether, and the second end of the 3rd resistor is connected with the input terminal of the switching tube；

The control module output stopping of releasing releases signal to the controlled end of the third comparator, so that the third comparesDevice stops output drive signal to the switching tube, and then turns off the switching tube, to make the module closing of releasing.

6. linear constant current LED drive circuit as claimed in claim 4, which is characterized in that the logic unit includes the 5th electricityResistance, the 6th resistance, first capacitor, the second capacitor, the first phase inverter, the second phase inverter, third phase inverter, the 4th phase inverter,Five phase inverters, the first nor gate, the second nor gate, NAND gate, latch and d type flip flop；

The input terminal of first phase inverter and the clear terminal of the latch are respectively the first input end of the logic unitWith the second input terminal, the output end of first phase inverter is connected with the first end of the 5th resistance, the 5th resistanceSecond end, the first end of the first end of the first capacitor and the 6th resistance be connected to the input of second phase inverter altogetherEnd, the output end of second phase inverter, the input terminal of the third phase inverter, the first input end of the NAND gate and describedThe first input end of second nor gate is connected to the input terminal of the third phase inverter altogether, the second end of the 6th resistance, describedThe input terminal of the first end of second capacitor and the 5th phase inverter is connected to the second input terminal of second nor gate altogether, describedThe output end of 5th phase inverter is connected with the second input terminal of the NAND gate, and the output end of the NAND gate and the D are touchedThe set end of hair device is connected, and the output end of the third phase inverter is connected with the input terminal of the 4th phase inverter, describedThe output end of 4th phase inverter is connected with the first input end of first nor gate, the output end of second nor gate withThe set end of the latch is connected to the second input terminal of first nor gate, the third input terminal of first nor gate altogetherIt is connected with the output end of the d type flip flop, the output end of the latch is connected with the clear terminal of the d type flip flop, instituteThe output end for stating the first nor gate is the output end of the logic unit, the second end of the first capacitor and second capacitorSecond end be connected to power ground altogether, the input terminal of the input terminal of the latch and the d type flip flop is connected to power supply altogether.

7. linear constant current LED drive circuit as described in claim 1, which is characterized in that the constant-current driven module includes perseveranceFlow control chip and the 7th resistance；

The output and ground of the current constant control chip is respectively the output and ground of the constant-current driven module, instituteThe first end of the resistance connecting pin and the 7th resistance of stating current constant control chip connects the electricity to form the constant-current driven module altogetherConnecting pin is hindered, the second end of the 7th resistance is connected with the ground terminal of the current constant control chip.

8. linear constant current LED drive circuit as described in claim 1, which is characterized in that the LED load includes N number of shinesDiode and third capacitor, the output end of the constant-current driven module include i+1 sub- output ends, wherein N be more than or equal to1 integer, 0≤i < N, and i are integer；

N number of light emitting diode is connected in series, the anode of the first light emitting diode in N number of light emitting diode with it is describedThe first end of third capacitor connects the input terminal to form the LED load, the N light-emitting diodes in N number of light emitting diode altogetherThe cathode of pipe is connected with the second end of the third capacitor, the cathode of i light emitting diode in N number of light emitting diodeAnd the cathode of N light emitting diode is the output end of the LED load, the cathode and N luminous two of i light emitting diodeThe cathode of pole pipe is connected with the i+1 of the constant-current driven module sub- output ends respectively.

9. a kind of LED drive chip, which is characterized in that the LED drive chip includes that claim 1 to 8 is described in any itemLinear constant current LED drive circuit.

10. a kind of LED drive device, which is characterized in that the LED drive device includes that claim 1 to 8 is described in any itemLinear constant current LED drive circuit.