CN103379697A - Drive circuit of light emitting diode - Google Patents
Drive circuit of light emitting diode Download PDFInfo
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- CN103379697A CN103379697A CN2012101202923A CN201210120292A CN103379697A CN 103379697 A CN103379697 A CN 103379697A CN 2012101202923 A CN2012101202923 A CN 2012101202923A CN 201210120292 A CN201210120292 A CN 201210120292A CN 103379697 A CN103379697 A CN 103379697A
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Abstract
The invention provides a drive circuit of a light emitting diode. The drive circuit of the light emitting diode comprises a conversion circuit, a current adjusting circuit, a conversion control circuit and a low light-adjusting protection lockout circuit. The conversion circuit performs power conversion to convert an input power supply into a drive voltage to drive a light emitting diode module to emit light. The current adjusting circuit is coupled with the light emitting diode module to adjust a light emitting diode current passing through the light emitting diode module, wherein the current adjusting circuit stops or conducts the light emitting diode current according to a light-adjusting signal, and carries out a protection program when the light emitting diode module is abnormal. The conversion control circuit controls the power conversion of the conversion circuit according to the electric level of at least one connection point of the light emitting diode module and the current adjusting circuit. The low light-adjusting protection lockout circuit is coupled with the current adjusting circuit and the conversion circuit, and stops the current adjusting circuit to carry out a protection program when the drive voltage is lower than a predetermined voltage value.
Description
Technical field
The invention relates to a kind of LED driving circuit, espespecially a kind of LED driving circuit with low light modulation protection blocking function.
Background technology
See also Fig. 1, Fig. 1 is the circuit diagram of traditional LED driving circuit.LED driving circuit comprises a change-over circuit 130, a current regulating circuit and a conversion control circuit 120.Change-over circuit couples an input power Vin, and carrying out an electric power conversion, to export a driving voltage Vout luminous to drive a light-emitting diode (LED) module LM.Current regulating circuit comprises current regulation control device 100, a transistor M and a current sense resistor R.Transistor M one first end couples the end of light-emitting diode (LED) module LM, and one second end couples current sense resistor R.The electric current of light-emitting diode (LED) module LM of flowing through is flowed through current sense resistor R simultaneously to produce a current detection signal Cs.Conversion control circuit 120 couples the tie point of transistor M and light-emitting diode (LED) module LM, controls the electric power conversion of change-over circuit 130 with the voltage feedback signal VFB according to tie point.
Current regulation control device 100 comprises a control circuit 102, open circuit comparator 104, a timing circuit 115 and one or door 110.Control circuit 102 to produce a current controling signal Ga, to adjust the conduction impedance of transistor M, makes the current stabilization of light-emitting diode (LED) module LM in a predetermined current value according to current detection signal Cs and a reference voltage signal Vr.When open circuit occurs light-emitting diode (LED) module LM, cause change-over circuit 130 no longer to provide electrical power to light-emitting diode (LED) module LM.At this moment, the level of current detection signal Cs can drop to and be lower than an open circuit near 0 volt and judge voltage Vop.When the level of comparator 104 at current detection signal Cs of opening a way is lower than open circuit judgement voltage Vop, will produce a high level signal.Timing circuit 115 couples a timing capacitor C t, carries out timing when receiving the high level signal that open circuit comparator 104 produces, with the erroneous judgement of avoiding causing because of dim signal or other noises.When the time that open circuit comparator 104 produces high level signal was longer than a predetermined period of time of timing circuit 115 settings, timing circuit 115 outputs one stopped Continuity signal Fa.Or door 110 couples timing circuit 115 and receives a dim signal Dim, adjusts current controling signal Ga according to dim signal Dim, to stop or the electric current of conducting light-emitting diode (LED) module LM.When timing circuit 115 outputs stopped Continuity signal Fa, then control circuit 102 continued to turn-off transistor M, makes no longer On current of light-emitting diode (LED) module LM.
When dim signal Dim is a low-key light time and change-over circuit 130 and conversion control circuit 120 operations when normal, the level of the tie point of transistor M and light-emitting diode (LED) module LM can maintain higher level.At this moment, conversion control circuit 120 can be judged that driving voltage Vout are too high and reduces driving voltage Vout.Even if this moment, transistor M was according to dim signal Dim and conducting, the level of current detection signal Cs still can be lower than open circuit and judge voltage Vop.Open circuit occured and carried out fastening lock protection in current regulation control device 100 meeting erroneous judgement light-emitting diode (LED) module LM this moment.Therefore, low light modulation or noise cause when judging into dim signal by accident, and traditional LED driving circuit has the problem that can't start, even and if dim signal transfer to one to a high-profile the light time LED driving circuit also can't recover because fastening lock protection.
Summary of the invention
Carrying out the low-key light time in view of traditional LED driving circuit of the prior art, having the problem that can't start.The present invention utilizes a low light modulation protection blocking circuit, crosses and forbids that the current regulation control device protects when low detecting low light modulation or driving voltage, LED driving circuit is unlikely enter to fasten the lock protection and can't ongoing operation.
For reaching above-mentioned purpose, the invention provides a kind of LED driving circuit, comprise a change-over circuit, a current regulating circuit, a conversion control circuit and a low light modulation protection blocking circuit.Change-over circuit is to carry out electric power conversion to convert an input power to a driving voltage luminous to drive a light-emitting diode (LED) module.Current regulating circuit is to couple light-emitting diode (LED) module with a flow through led current of light-emitting diode (LED) module of adjusting; wherein current regulating circuit stops or the conducting led current according to a dim signal, and carries out a defence program when the light-emitting diode (LED) module abnormal.Conversion control circuit is according to the electric power conversion of the level control change-over circuit of at least one tie point of light-emitting diode (LED) module and current regulating circuit.Low light modulation protection blocking circuit couples current regulating circuit and change-over circuit, and low light modulation protection blocking circuit stops current regulating circuit and carries out defence program when driving voltage is lower than a scheduled voltage.
The present invention also provides a kind of LED driving circuit, comprises a change-over circuit, a current regulating circuit, a conversion control circuit and a low light modulation protection blocking circuit.Change-over circuit is to carry out electric power conversion to convert an input power to a driving voltage luminous to drive a light-emitting diode (LED) module.Current regulating circuit is to couple light-emitting diode (LED) module with a flow through led current of light-emitting diode (LED) module of adjusting; wherein current regulating circuit stops or the conducting led current according to a dim signal, and carries out a defence program when the light-emitting diode (LED) module abnormal.Conversion control circuit is according to the electric power conversion of the level control change-over circuit of at least one tie point of light-emitting diode (LED) module and current regulating circuit.Low light modulation protection blocking circuit couples current regulating circuit, and low light modulation protection blocking circuit receives dim signal, and stops current regulating circuit in a conducting pulsewidth of dim signal during less than a predetermined pulse width value and carry out defence program.
The present invention also provides a kind of LED driving circuit, comprises a change-over circuit, a current regulating circuit, a conversion control circuit and a low light modulation protection blocking circuit.Change-over circuit is to carry out electric power conversion to convert an input power to a driving voltage luminous to drive a light-emitting diode (LED) module.Current regulating circuit is to couple light-emitting diode (LED) module with a flow through led current of light-emitting diode (LED) module of adjusting.Wherein current regulating circuit has at least one current regulation unit, and each current regulation unit comprises a transistor, a control circuit and a protective circuit.Transistor couples a drive end corresponding in the light-emitting diode (LED) module, to regulate the transistorized electric current of flowing through according to a current controling signal.Control circuit detects the transistorized electric current of flowing through, generation current control signal accordingly, and stop or On current according to a dim signal.Protective circuit detects transistorized state, to judge whether abnormal of light-emitting diode (LED) module, if then transistor is turned off.Conversion control circuit is according to the electric power conversion of the level control change-over circuit of at least one tie point of light-emitting diode (LED) module and current regulating circuit.Low light modulation protection blocking circuit couples current regulating circuit, and low light modulation protection blocking circuit receives at least one current controling signal, and during less than a predetermined pulse width value, stops the protective circuit of current regulating circuit at least one current controling signal arbitrary.
Above general introduction and ensuing detailed description are all exemplary in nature, are in order to further specify claim of the present invention.And relevant other objects and advantages of the present invention will be set forth in follow-up explanation and accompanying drawing.
Description of drawings
Fig. 1 is the circuit diagram of traditional LED driving circuit;
Fig. 2 is the circuit diagram according to the LED driving circuit of one first preferred embodiment of the present invention;
Fig. 3 is the circuit diagram according to the LED driving circuit of one second preferred embodiment of the present invention;
Fig. 4 is the circuit diagram according to the low light modulation protection blocking circuit of another preferred embodiment of the present invention;
Fig. 5 is the circuit diagram according to the low light modulation protection blocking circuit of an again preferred embodiment of the present invention.
Description of reference numerals:
Prior art:
100: the current regulation control device;
102: control circuit;
104: the open circuit comparator;
110: or door;
115: timing circuit 115;
120: conversion control circuit 120;
130: change-over circuit 130;
Vin: input power;
Vout: driving voltage;
LM: light-emitting diode (LED) module;
M: transistor;
R: current sense resistor;
Cs: current detection signal;
VFB: voltage feedback signal;
Vr: reference voltage signal;
Ga: current controling signal;
Vop: open circuit is judged voltage;
Ct: timing electric capacity;
Dim: dim signal;
Fa: stop Continuity signal.
The present invention:
120: conversion control circuit;
130: change-over circuit;
150: the current regulation control device;
152: control circuit;
154: the open circuit comparator;
156: the short circuit comparator;
160,160 ': or door;
165: timing circuit;
200,300,400,500: low light modulation protection blocking circuit;
210,310,510: dimming detection circuit;
220,320,420: output voltage detecting circuit;
230,330: the protection halt circuit;
Vin: input power;
Vout: driving voltage;
LM: light-emitting diode (LED) module;
I, I1, I2: led current;
Dim: dim signal;
M: transistor;
R: current sense resistor;
Cs, Cs1, Cs2: current detection signal;
VFB: voltage feedback signal;
Vr: reference voltage signal;
G1, G2: current controling signal;
Vop: open circuit is judged voltage;
VS: voltage detection signal;
Vsh: voltage is judged in short circuit;
Ct: timing electric capacity;
F1, F2: stop Continuity signal;
Sps: protection stop signal;
SW1, SW2, SW3, SW4, SW5: switch;
Rd1, Rd2: resistance;
LM1, LM2: light-emitting diode string;
150 ': current regulating circuit;
150a, 150b: current regulation unit;
D1, D2: terminal voltage;
Fault: error notification signal;
Dd, Dd1, Dd2, Dd3, Dd4; Diode;
Rov, Rd1, Rd2, Rd3, Rd4, Rd5, Rd6: resistance;
C1, C2, C3, C4: electric capacity;
Z1, Z2: Zener diode;
360: overvoltage crowbar;
ERR: overvoltage notification signal;
425: comparator;
Vps: judge voltage;
Vdd: positive supply;
105: the light-emitting diode abnormal detection circuit;
145: the minimum voltage testing circuit.
Embodiment
See also Fig. 2, Fig. 2 is the circuit diagram according to the LED driving circuit of one first preferred embodiment of the present invention.LED driving circuit comprises a conversion control circuit 120, a change-over circuit 130, a current regulating circuit and a low light modulation protection blocking circuit 200.Change-over circuit 130 is to carry out electric power conversion to convert an input power Vin to a driving voltage Vout luminous to drive a light-emitting diode (LED) module LM.Current regulating circuit couples light-emitting diode (LED) module LM with the flow through led current I of light-emitting diode (LED) module LM of adjusting.Current regulating circuit also stops or conducting led current I according to a dim signal Dim, and carry out a defence program when light-emitting diode (LED) module LM abnormal.
Current regulating circuit comprises a current regulation control device 150, a transistor M and a current sense resistor R.Transistor M one first end couples the end of light-emitting diode (LED) module LM, and one second end couples current sense resistor R.Led current I flows through current sense resistor R to produce a current detection signal Cs.Conversion control circuit 120 couples the tie point of transistor M and light-emitting diode (LED) module LM, controls the electric power conversion of change-over circuit 130 with the voltage feedback signal VFB according to tie point.Current regulation control device 150 comprises a control circuit 152, protective circuit and one or door 160, and wherein protective circuit comprises an open circuit comparator 154, a short circuit comparator 156, a timing circuit 165.Control circuit 152 to produce a current controling signal G1, to adjust the conduction impedance of transistor M, makes led current I be stable at a predetermined current value according to current detection signal Cs and a reference voltage signal Vr.When open circuit occurs light-emitting diode (LED) module LM, cause change-over circuit 130 no longer to provide electrical power to light-emitting diode (LED) module LM.At this moment, the level of current detection signal Cs can drop to and be lower than an open circuit near 0 volt and judge voltage Vop.When the level of comparator 154 at current detection signal Cs of opening a way is lower than open circuit judgement voltage Vop, will produce a high level signal.One light-emitting diode abnormal detection circuit 105 couples the tie point of transistor M and light-emitting diode (LED) module LM, has a resistance of series connection and an electric capacity to carry out filtering and to detect to produce a voltage detection signal VS.When light-emitting diode (LED) module LM was short-circuited, the tie point of transistor M and light-emitting diode (LED) module LM can rise to an abnormal high level and keep, and this moment, the level of voltage detection signal VS can be higher than short circuit judgement voltage Vsh.When short circuit comparator 156 when the level of voltage detection signal VS is higher than short circuit and judges voltage Vsh, will produce a high level signal.
Low light modulation protection blocking circuit 200 comprises a dimming detection circuit 210, an output voltage detecting circuit 220 and a protection halt circuit 230.Dimming detection circuit 210 has a diode Dd and a RC filter circuit, and wherein the RC filter circuit comprises a resistance R d1 and a capacitor C 1 in parallel, and the anode of diode Dd is in order to receive dim signal Dim, and negative terminal couples the RC filter circuit.When dim signal Dim inputs, no matter how little its pulse duration is, all can charge to produce a protection stop signal Sps to the capacitor C 1 in the RC filter circuit.Output voltage detecting circuit 220 comprises a bleeder circuit and an interrupteur SW 2, and bleeder circuit one end couples change-over circuit 130 to determine whether actuating switch SW2 according to driving voltage Vout.One end of interrupteur SW 2 couples dimming detection circuit 210, and the level of drop-down protection stop signal Sps when conducting is to stop to protect the generation of stop signal Sps.That is to say that when driving voltage Vout was lower than a scheduled voltage, interrupteur SW 2 was for turn-offing, dimming detection circuit 210 can normally produce protection stop signal Sps.And when driving voltage Vout was greater than or equal to scheduled voltage, interrupteur SW 2 was conducting, and protection stop signal Sps will stop to produce.Protection halt circuit 230 comprises a resistance R d2 and an interrupteur SW 1, couples the protective circuit in dimming detection circuit 210 and the current regulation control device 150, when receiving protection stop signal Sps, forbids that current regulating circuit carries out defence program.
See also Fig. 3, Fig. 3 is the circuit diagram according to the LED driving circuit of one second preferred embodiment of the present invention.Compared to embodiment shown in Figure 2, the Main Differences point is that the light-emitting diode (LED) module in the present embodiment is many string light-emitting diode strings, and low light modulation protection blocking circuit is judged according to the current controling signal that current regulating circuit produces.Be described in detail as follows.
Light-emitting diode (LED) module comprises at least two light-emitting diode string LM1, LM2, is coupled to respectively corresponding current regulation unit 150a, 150b in the current regulating circuit 150 '.The circuit structure of current regulation unit 150a, 150b can be with reference to current regulation control device 150 shown in Figure 2.Led current I1, the I2 of light-emitting diode string LM1, LM2 flows through a current sense resistor R with generation current detection signal Cs1, Cs2. Current regulation unit 150a, 150b are respectively according to current detection signal Cs1, Cs2 and generation current control signal G1, G2 make led current I1, I2 be stable at a predetermined current value.One minimum voltage testing circuit 145 couples the negative terminal of at least two light-emitting diode string LM1, LM2, to produce a voltage feedback signal VFB according to the lowest among terminal voltage D1, the D2.120 of one conversion control circuits are controlled the electric power conversion of a change-over circuit 130 according to voltage feedback signal VFB, to regulate a driving voltage Vout.
One low light modulation protection blocking circuit 300 comprises a dimming detection circuit 310, an output voltage detecting circuit 320 and a protection halt circuit 330.Dimming detection circuit 310 has at least two diode Dd1, Dd2 and a RC filter circuit.The anode of diode Dd1, Dd2 is coupled to current regulation unit 150a, 150b corresponding in the current regulating circuit 150 ', in order to received current control signal G1, G2, negative terminal couples the RC filter circuit, and wherein the RC filter circuit comprises a resistance R d2 and a capacitor C 2 in parallel.During one dim signal Dim input current regulating circuit 150 ', current regulating circuit 150 ' is with generation current control signal G1, G2.When dimming detection circuit 310 detects current controling signal G1, G2 arbitrary, no matter how little its pulse duration is, all can charge to produce a protection stop signal Sps to capacitor C 2.Output voltage detecting circuit 320 comprises a Zener diode Z1, a bleeder circuit and an interrupteur SW 4.The negative terminal of Zener diode Z1 couples change-over circuit 130, and anode couples bleeder circuit, actuating switch SW4 when driving voltage Vout is greater than or equal to a scheduled voltage.Effect at this increase Zener diode Z1 is driving voltage Vout corresponding when control switch SW4 is switched on more accurately.One end of interrupteur SW 4 couples dimming detection circuit 310, and the level of drop-down protection stop signal Sps when conducting is to stop to protect the generation of stop signal Sps.Protection halt circuit 330 comprises a diode Dd3, a resistance R d3 and an interrupteur SW 3; couple the timing capacitor C t in dimming detection circuit 310 and the current regulating circuit; when receiving protection stop signal Sps; to timing capacitor C t discharge, current regulation unit 150a, 150b can't be reached according to timing capacitor C t timing forbid that current regulating circuit carries out the effect of defence program.
In addition, also additionally increase by an overvoltage crowbar 360 in the present embodiment.Overvoltage crowbar 360 comprises a resistance R ov and a Zener diode Z2.The negative terminal of Zener diode Z2 couples a dividing point of bleeder circuit in the output voltage detecting circuit 320, and anode couples the end of resistance R ov to produce an overvoltage notification signal ERR, the other end ground connection of resistance R ov.As driving voltage Vout when normal (being higher than scheduled voltage); because of the action of output voltage detecting circuit 320, low light modulation protection blocking circuit 300 will be not can not discharge and makes the current regulating circuit 150 ' can unusually protecting for light-emitting diode (LED) module timing capacitor C t.When the level that so continues abnormally to rise to the dividing point of bleeder circuit in the output voltage detecting circuit 320 as driving voltage Vout also is higher than the breakdown voltage of Zener diode Z2; overvoltage crowbar 360 can produce overvoltage notification signal ERR to conversion control circuit 120, makes conversion control circuit 120 carry out one and crosses high voltage protective.
If whether the low light modulation protection blocking main circuit among above-mentioned two embodiment is lower than the defence program whether scheduled voltage stops current regulating circuit with driving voltage Vout, and dim signal or current controling signal are auxiliary judgment, are to be omitted.See also Fig. 4, Fig. 4 is the circuit diagram according to the low light modulation protection blocking circuit of another preferred embodiment of the present invention.Compared to low light modulation protection blocking circuit 200 shown in Figure 2, a low light modulation protection blocking circuit 400 of present embodiment replaces dimming detection circuit 210 and output voltage detecting circuit 220 with an output voltage detecting circuit 420.Output voltage detecting circuit 420 comprises a bleeder circuit and a comparator 425.Bleeder circuit couples change-over circuit to produce a dividing potential drop according to driving voltage Vout, and comparator 425 relatively this dividing potential drop and is judged voltage Vps.When driving voltage Vout is lower than a scheduled voltage, dividing potential drop can be lower than to be judged voltage Vps and makes comparator 425 produce a protection stop signal Sps to protecting halt circuit 230.The explanation of protection halt circuit 230 sees also corresponding explanation among Fig. 2.
See also Fig. 5, Fig. 5 is the circuit diagram according to the low light modulation protection blocking circuit of an again preferred embodiment of the present invention.One low light modulation protection blocking circuit 500 of present embodiment is that from the difference of low light modulation protection blocking circuit 300 shown in Figure 3 the circuit framework of dimming detection circuit is different, and remaining circuit is all identical.One dimming detection circuit 510 comprises a diode Dd4, a RC filter circuit and a decision circuitry, and wherein the RC filter circuit comprises a capacitor C 4 and resistance R d5, Rd6, and decision circuitry comprises a resistance R d4, an interrupteur SW 5 and a capacitor C 3.The anode of diode Dd4 is in order to receive dim signal Dim, and negative terminal is coupled to the RC filter circuit that is made of resistance R d6 and capacitor C 4 by resistance R d5.The effect of resistance R d5 is to adjust dim signal Dim also reaches protection simultaneously to the charging rate of capacitor C 4 effect.The RC filter circuit couples a controlled end of interrupteur SW 5.The end of resistance R d4 couples a positive supply Vdd, and the other end couples interrupteur SW 5, and capacitor C 3 couples a tie point of resistance R d4 and interrupteur SW 5.Dim signal Dim charges to capacitor C 4 by resistance R d5, and resistance R d6 is to capacitor C 4 discharges.Therefore when the pulsewidth of dim signal Dim representative conducting (ON) during less than a predetermined pulse width, the voltage of capacitor C 4 can't rise to a level that is enough to actuating switch SW5.This moment, interrupteur SW 5 was shutoff, and 3 chargings produce a protection stop signal Sps to positive supply Vdd to capacitor C by resistance R d4.When the conducting pulsewidth of dim signal Dim was equal to or greater than predetermined pulse width, the voltage of capacitor C 4 can arrive the level that is enough to actuating switch SW5, and capacitor C 3 is discharged.This moment, the voltage waveform of capacitor C 3 was that level that triangular wave and peak value deficiency reach switch in the conducting protection halt circuit 330 is equal to and stops to produce protection stop signal Sps.Therefore, the low light modulation protection blocking circuit of present embodiment can judge further that also the conducting pulsewidth of dim signal Dim determines whether the advantage that protection halt circuit 330 is started.Certainly, present embodiment also can change to detect current controling signal and replaces the judgement whether dim signal stops to protect.In addition, at present embodiment, represent light modulation ON with high level, but on some practical application example, may represent light modulation ON with low level, the conducting pulsewidth of this moment refers to low level pulsewidth.And output voltage detecting circuit 320 is auxiliary circuit at present embodiment, can be omitted and does not affect advantage of the present invention.
During actual enforcement low light modulation protection blocking circuit of the present invention, can jointly form one chip with current regulating circuit.And the resistance in the RC filter circuit or electric capacity make dimming detection circuit can adjust according to practical application request the susceptibility of dim signal or current controling signal or the setting of predetermined pulse width with external form design in the dimming detection circuit.
It should be noted that at last: above each embodiment is not intended to limit only in order to technical scheme of the present invention to be described; Although with reference to aforementioned each embodiment the present invention is had been described in detail, those of ordinary skill in the art is to be understood that: it still can be made amendment to the technical scheme that aforementioned each embodiment puts down in writing, and perhaps some or all of technical characterictic wherein is equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution break away from the scope of various embodiments of the present invention technical scheme.
Claims (12)
1. a LED driving circuit is characterized in that, comprises:
One change-over circuit, to convert an input power to a driving voltage luminous to drive a light-emitting diode (LED) module in order to carry out electric power conversion;
One current regulating circuit, in order to couple this light-emitting diode (LED) module with a flow through led current of this light-emitting diode (LED) module of adjusting, wherein this current regulating circuit stops according to a dim signal or this led current of conducting, and carries out a defence program when this light-emitting diode (LED) module abnormal;
One conversion control circuit is controlled the electric power conversion of this change-over circuit according to the level of at least one tie point of this light-emitting diode (LED) module and this current regulating circuit; And
One low light modulation protection blocking circuit couples this current regulating circuit and this change-over circuit, and this low light modulation protection blocking circuit stops this current regulating circuit and carries out this defence program when this driving voltage is lower than a scheduled voltage.
2. LED driving circuit according to claim 1, wherein this current regulating circuit has at least one current regulation unit, and each this current regulation unit comprises:
One transistor couples a drive end corresponding in this light-emitting diode (LED) module, to regulate this transistorized electric current of flowing through according to a current controling signal;
One control circuit detects this transistorized this electric current of flowing through, and produces accordingly this current controling signal; And
One protective circuit detects this transistorized state, to judge whether abnormal of this light-emitting diode (LED) module, if then this transistor is turned off.
3. LED driving circuit according to claim 2; wherein this protective circuit comprises a timing circuit; state in order to this light-emitting diode (LED) module of timing is a unusual duration; when this protective circuit surpasses a predetermined period of time in this duration; produce one and stop Continuity signal, this transistor is turned off.
4. LED driving circuit according to claim 1 wherein should comprise by low light modulation protection blocking circuit:
One output voltage detecting circuit couples this change-over circuit and is lower than this scheduled voltage generation one protection stop signal at this driving voltage; And
One protection halt circuit couples this output voltage detecting circuit and this protective circuit, when receiving this protection stop signal, forbids that this current regulating circuit carries out this defence program.
5. a LED driving circuit is characterized in that, comprises:
One change-over circuit, to convert an input power to a driving voltage luminous to drive a light-emitting diode (LED) module in order to carry out electric power conversion;
One current regulating circuit, in order to couple this light-emitting diode (LED) module with a flow through led current of this light-emitting diode (LED) module of adjusting, wherein this current regulating circuit stops according to a dim signal or this led current of conducting, and carries out a defence program when this light-emitting diode (LED) module abnormal;
One conversion control circuit is controlled the electric power conversion of this change-over circuit according to the level of at least one tie point of this light-emitting diode (LED) module and this current regulating circuit; And
One low light modulation protection blocking circuit couples this current regulating circuit, and this low light modulation protection blocking circuit receives this dim signal, and stops this current regulating circuit in a conducting pulsewidth of this dim signal during less than a predetermined pulse width value and carry out this defence program.
6. LED driving circuit according to claim 5, wherein
This protective circuit comprises a timing circuit, is a unusual duration in order to the state of this light-emitting diode (LED) module of timing, when this protective circuit surpasses a predetermined period of time in this duration, produces one and stops Continuity signal, and this transistor is turned off.
7. LED driving circuit according to claim 5 wherein should comprise by low light modulation protection blocking circuit:
One dimming detection circuit receives this dim signal, during less than a predetermined value, produces a protection stop signal in an ON time of this dim signal representative or a conducting duty ratio; And
One protection halt circuit couples this dimming detection circuit and this protective circuit, when receiving this protection stop signal, stops this protective circuit.
8. the described LED driving circuit of arbitrary claim in 7 according to claim 6, wherein this dimming detection circuit comprises:
One RC filter circuit is in order to receive this dim signal;
One decision circuitry couples this RC filter circuit, determines whether to produce this protection stop signal according to a level of this RC filter circuit.
9. LED driving circuit is characterized in that comprising:
One change-over circuit, to convert an input power to a driving voltage luminous to drive a light-emitting diode (LED) module in order to carry out electric power conversion;
One current regulating circuit, in order to couple this light-emitting diode (LED) module with a flow through led current of this light-emitting diode (LED) module of adjusting, wherein this current regulating circuit has at least one current regulation unit, and each this current regulation unit comprises:
One transistor couples a drive end corresponding in this light-emitting diode (LED) module, to regulate this transistorized electric current of flowing through according to a current controling signal;
One control circuit detects this transistorized this electric current of flowing through, and produces accordingly this current controling signal, and stops or this electric current of conducting according to a dim signal; And
One protective circuit detects this transistorized state, to judge whether abnormal of this light-emitting diode (LED) module, if then this transistor is turned off;
One conversion control circuit is controlled the electric power conversion of this change-over circuit according to the level of at least one tie point of this light-emitting diode (LED) module and this current regulating circuit; And
One low light modulation protection blocking circuit; couple this current regulating circuit; should receive this at least one current controling signal by low light modulation protection blocking circuit, and during less than a predetermined pulse width value, stop the protective circuit of this current regulating circuit this at least one current controling signal arbitrary.
10. LED driving circuit according to claim 9, wherein
This protective circuit comprises a timing circuit, is a unusual duration in order to the state of this light-emitting diode (LED) module of timing, when this protective circuit surpasses a predetermined period of time in this duration, produces one and stops Continuity signal, and this transistor is turned off.
11. LED driving circuit according to claim 9 wherein should comprise by low light modulation protection blocking circuit:
One dimming detection circuit receives this dim signal, during less than a predetermined value, produces a protection stop signal in an ON time of this dim signal representative or a conducting duty ratio; And
One protection halt circuit couples this dimming detection circuit and this protective circuit, when receiving this protection stop signal, stops this protective circuit.
12. the described LED driving circuit of arbitrary claim in 11 according to claim 10, wherein this dimming detection circuit comprises:
One RC filter circuit is in order to receive this dim signal;
One decision circuitry couples this RC filter circuit, determines whether to produce this protection stop signal according to a level of this RC filter circuit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210120292.3A CN103379697B (en) | 2012-04-23 | 2012-04-23 | LED driving circuit |
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|---|---|---|---|
| CN201210120292.3A CN103379697B (en) | 2012-04-23 | 2012-04-23 | LED driving circuit |
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| CN103379697B CN103379697B (en) | 2015-08-19 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103533721A (en) * | 2013-10-31 | 2014-01-22 | 矽力杰半导体技术(杭州)有限公司 | Pulse type current LED drive circuit |
| CN112188669A (en) * | 2019-07-04 | 2021-01-05 | 力林科技股份有限公司 | LED backlight system and LED control circuit |
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| US20040004446A1 (en) * | 2002-07-05 | 2004-01-08 | Hun-Huang Liu | Drive circuit for an led lighting apparatus |
| TW200844706A (en) * | 2007-02-17 | 2008-11-16 | Seiko Instr Inc | Voltage regulator |
| CN101400200A (en) * | 2007-09-25 | 2009-04-01 | 新巨企业股份有限公司 | AC electricity driving method for LED and working voltage thereof |
| US20110291591A1 (en) * | 2010-05-25 | 2011-12-01 | Green Solution Technology Co., Ltd. | Driving circuit and control circuit |
-
2012
- 2012-04-23 CN CN201210120292.3A patent/CN103379697B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040004446A1 (en) * | 2002-07-05 | 2004-01-08 | Hun-Huang Liu | Drive circuit for an led lighting apparatus |
| TW200844706A (en) * | 2007-02-17 | 2008-11-16 | Seiko Instr Inc | Voltage regulator |
| CN101400200A (en) * | 2007-09-25 | 2009-04-01 | 新巨企业股份有限公司 | AC electricity driving method for LED and working voltage thereof |
| US20110291591A1 (en) * | 2010-05-25 | 2011-12-01 | Green Solution Technology Co., Ltd. | Driving circuit and control circuit |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103533721A (en) * | 2013-10-31 | 2014-01-22 | 矽力杰半导体技术(杭州)有限公司 | Pulse type current LED drive circuit |
| CN112188669A (en) * | 2019-07-04 | 2021-01-05 | 力林科技股份有限公司 | LED backlight system and LED control circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103379697B (en) | 2015-08-19 |
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