CN203301820U - Linear high-voltage LED (Light Emitting Diode) drive circuit - Google Patents
Linear high-voltage LED (Light Emitting Diode) drive circuit Download PDFInfo
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- CN203301820U CN203301820U CN2013203257244U CN201320325724U CN203301820U CN 203301820 U CN203301820 U CN 203301820U CN 2013203257244 U CN2013203257244 U CN 2013203257244U CN 201320325724 U CN201320325724 U CN 201320325724U CN 203301820 U CN203301820 U CN 203301820U
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Abstract
The utility model provides a linear high-voltage LED (Light Emitting Diode) drive circuit comprising a rectifier bridge; not less than two segments of LED strings; driving switches corresponding to the LED strings; a current sampling circuit used for detecting the current of the driving switches; and a constant current control circuit used for controlling the turn-on resistance of the driving switches. The linear high-voltage LED drive circuit provided by the utility model is used for controlling at least two segments of LED strings to partially or completely to shine with the change of direct current pulse voltage through the constant current control circuit and the driving switches, thereby both improving the light emission time of the LED strings and reducing the power consumption of the driving switches within one voltage pulse period and greatly improving the LED drive efficiency.
Description
Technical field
The utility model belong to light-emitting diode (Light Emitting Diode, hereinafter to be referred as: LED) lighting technical field is specifically related to a kind of linear low density LED drive circuit.
Background technology
At present, what the LED mains lighting supply mainly adopted is Switching Power Supply, and Switching Power Supply has advantages of that the high volume of efficiency is little.But Switching Power Supply also has the shortcoming that is difficult to overcome, be embodied in: due to the Switching Power Supply use is electrolytic capacitor and transformer or inductance, and the disadvantage of electrolytic capacitor is that the life-span is short, and reliability is not high, and at most also can only reach 5000-8000 hour its useful life; And the every raising of the working temperature of aluminium electrolytic capacitor generally can reduce 10% 10 ℃ of its useful lifes, and the working temperature of the Switching Power Supply of LED lamp is generally all 70 ℃ of left and right.Therefore, directly determined the useful life of Switching Power Supply the useful life of electrolytic capacitor, but, the life-span of LED lamp pearl generally but can reach 50000 hours, therefore, LED throws light on the life-span of the useful life of Switching Power Supply and LED lamp pearl and does not mate, thereby has affected the useful life of LED lamp pearl, causes the waste of resource.
Some companies use linear constant-current driving LED string luminous, accompanying drawing 1 is the linear constant current LED drive circuit structural representation of prior art, as Fig. 1, the positive pole of LED string 102 is connected on the output head anode of rectifier bridge stack 101, and the negative pole of LED string 102 is by the rear ground connection of a constant-current controller 103 (LED string 102 and constant-current controller 103 positions can exchange).This application only has when the output voltage of rectifier bridge stack during higher than the conducting voltage of LED string, and the LED string is just normally luminous; And when the output voltage of rectifier bridge stack during lower than the conducting voltage of LED string, most of power all consumes on constant-current controller, even the output voltage of rectifier bridge stack higher than the conducting voltage of LED string, also has a big chunk power consumption on constant-current controller.So this traditional linear constant-current LED type of drive not only luminous efficiency is low but also utilization rate of electrical is also low.
The utility model content
The purpose of this utility model is to solve the defect that above-mentioned prior art exists, a kind of control circuit of at least two sections LED string is provided, at least two sections LED strings are luminous with certain rule combination conducting when change in voltage, improved the luminous efficiency of LED and the utilization ratio of electric energy.
For realizing above-mentioned utility model purpose, the utility model adopts following technical scheme:
A kind of linear low density LED drive circuit comprises:
Rectifier bridge stack, described rectifier bridge stack are the all-wave with rectification function or the half-wave rectifying circuit that rectifier diode forms;
At least 2 sections LED of series connection go here and there mutually, described LED string comprises the LED string that is comprised of with the series connection form some LED or LED crystal grain or goes here and there with the LED that the form of series and parallel connections combination forms, and the conducting voltage that described LED goes here and there is higher than conducting voltage single led or LED crystal grain;
Corresponding with LED string number, for according to its conduction impedance, controlling at least 2 road driving switchs of every section LED string conducting state;
Current sampling circuit for monitoring stream Guo Mei road driving switch electric current;
For according to current sampling circuit, providing current value to control the constant-current control circuit of respective drive switch conduction impedance;
Be used to constant-current control circuit that the power supply of operating voltage is provided;
Reference voltage;
The output head anode of rectifier bridge stack is connected with the input of power supply and first section LED string; Described power supply is connected with reference voltage and constant-current control circuit; The input of every road driving switch is connected respectively the negative pole of every section LED string, the control end of every road driving switch is connected to respectively constant-current control circuit, the output of every road driving switch is connected to current sampling circuit jointly, and current sampling circuit is connected to respectively constant-current control circuit for monitoring driving switch electric current De Mei road, every road observation circuit; Reference voltage is connected with constant-current control circuit; The negative pole of output end of rectifier bridge stack is together with constant-current control circuit, current sampling circuit common ground.
Further, described every road driving switch comprises control end, switch input terminal and output switching terminal, the control end of driving switch is connected with constant-current control circuit, its switch input terminal is connected with the negative pole of output end of every section LED string, its output switching terminal is connected with the input of current sampling circuit, by voltage or the electric current that changes control end, carrys out the conduction impedance of control switch input to output switching terminal.
Further, described current sampling circuit comprises that the output switching terminal that is no less than two sampling resistor ，Mei road driving switchs of mutually connecting connects the input of first sampling resistor jointly; The output head grounding of last sampling resistor; The input of each sampling resistor connects respectively constant-current control circuit.
The continuous current of ，Hou mono-road driving switch is greater than the continuous current of last road driving switch further, Dang Hou mono-road driving switch have electric current by the time constant-current control circuit can close before all driving switchs.
Further, described driving switch comprises NMOS pipe Q1, NMOS pipe Q2, NMOS pipe Q3; Described current sampling circuit comprises resistance R 1, resistance R 2, resistance R 3; Described constant-current control circuit comprises amplifier U1, amplifier U2, amplifier U3;
The negative pole of output end ground connection of rectifier bridge stack, its output head anode are connected with the input of power supply and first section LED string; The positive pole of described power supply and reference voltage and operational amplifier U1, operational amplifier U2, operational amplifier U3 is connected; The drain electrode of every road NMOS pipe is connected respectively the negative pole of every section LED string, the grid that the source electrode of every road NMOS pipe is connected to the input ，Mei road NMOS pipe of resistance R 1 jointly is connected respectively the output of operational amplifier U1, operational amplifier U2, operational amplifier U3; Resistance R 1, resistance R 2, resistance R 3 mutually after series connection by resistance R 3 ground connection; The in-phase input end of described operational amplifier U1, operational amplifier U2, operational amplifier U3 is connected with reference voltage respectively, and the inverting input of operational amplifier U1 is connected with the input of resistance R 1; The inverting input of operational amplifier U2 is connected with the tie point of resistance R 2 with resistance R 1; The inverting input of operational amplifier U3 is connected with the tie point of resistance R 3 with resistance R 2; The negative pole common ground of operational amplifier U1, operational amplifier U2, operational amplifier U3.
Further, described driving switch comprises NMOS pipe Q1, NMOS pipe Q2, NMOS pipe Q3; Described current sampling circuit comprises resistance R 8, resistance R 9, resistance R 10; Described constant-current control circuit comprises NPN triode Q4, NPN triode Q5, NPN triode Q6, resistance R 2, resistance R 3, resistance R 4, resistance R 5, resistance R 6, resistance R 7; Described power supply comprises resistance R 1, voltage-stabiliser tube D2; Described reference voltage is the conducting voltage between NPN triode Q4, NPN triode Q5, NPN triode Q6 base stage and emitter;
The negative pole of output end ground connection of rectifier bridge stack, its output head anode are connected with an end of resistance R 1 and the input of first section LED string, the other end of resistance R 1 is connected with an end of voltage-stabiliser tube D2 and resistance R 2, resistance R 3, resistance R 4 respectively, and the other end of resistance R 2, resistance R 3, resistance R 4 is corresponding respectively to be connected with the base stage of NPN triode Q4, NPN triode Q5, NPN triode Q6; The drain electrode of every road NMOS pipe is connected respectively the negative pole of every section LED string, the grid that the source electrode of every road NMOS pipe is connected to the input ，Mei road NMOS pipe of resistance R 8 jointly is connected respectively the collector electrode of NPN triode Q4, NPN triode Q5, NPN triode Q6; Resistance R 8, resistance R 9, resistance R 10 mutually after series connection by resistance R 10 ground connection; The emitter of described NPN triode Q4, NPN triode Q5, NPN triode Q6 is together with the other end common ground of voltage-stabiliser tube D2; The base stage of NPN triode Q4 is connected with the input of resistance R 8 after resistance R 5; The base stage of NPN triode Q5 is connected with the tie point of resistance R 9 with resistance R 8 after resistance R 6; The base stage of NPN triode Q6 is connected with the tie point of resistance R 10 with resistance R 9 after resistance R 7.
the linear low density LED drive circuit that the utility model provides, by constant-current control circuit, control the conduction impedance of two-way driving switch at least and control conducting and the electric current that LED goes here and there, when the direct voltage after the rectifier bridge stack rectification is elevated to the conducting of first paragraph LED string electric current by first corresponding driving switch conducting constant current in a reduced-current value, constant-current control circuit turn-offs first driving switch and goes here and there by second front two sections LED of driving switch conducting when voltage continues to rise to first paragraph and the conducting simultaneously of second segment LED string, and make the constant current of front two sections LED string in a high current value, when voltage continues to rise to first paragraph again, when second segment and the 3rd section LED string conducting simultaneously, constant-current control circuit turn-offs second driving switch, and by the 3rd first three section of driving switch conducting LED string, and make the constant current of first three section LED string in a higher current value, if more LED string is arranged by that analogy, process is just in time opposite when voltage starts to descend.Like this along with the part or all of conducting of the variation LED of DC pulse moving voltage string, not only increase the ON time of LED string in the pulsation period but also reduced the loss of driving switch, greatly improved the efficiency that LED drives, and simple in structure, cost is low, is easy to realize.
The accompanying drawing explanation
Accompanying drawing 1 is the linear constant current LED drive circuit structural representation of prior art;
Accompanying drawing 2 is the linear high-voltage LED driving circuit structural representation of the utility model multistage;
Accompanying drawing 3 is the linear high-voltage LED driving circuit embodiment of the utility model multistage mono-electrical block diagram;
Accompanying drawing 4 is the linear high-voltage LED driving circuit embodiment of the utility model multistage bis-electrical block diagrams;
Accompanying drawing 5 is the linear high-voltage LED driving circuit voltage and current of the utility model multistage waveform schematic diagram.
Description of reference numerals: 101-rectifier bridge stack, 102-LED string, 103-constant-current controller, 203-driving switch, 204-power supply, 205-reference voltage, 206-constant-current control circuit, 207-current sampling circuit, 208-voltage waveform, 209-current waveform.
Embodiment
For making the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with the accompanying drawing in the utility model, technical scheme in the utility model is clearly and completely described, obviously, described embodiment is the utility model part embodiment, rather than whole embodiment.Based on the embodiment in the utility model, those of ordinary skills are not making under the creative work prerequisite the every other embodiment that obtains, and all belong to the scope of the utility model protection.
Accompanying drawing 2 is the linear high-voltage LED driving circuit structural representation of the utility model multistage; As shown in Figure 2, comprising: the driving switch 203 of rectifier bridge stack 101, LED string 102,102 conductings of driving LED string, power supply 204, reference voltage 205, the current sampling circuit 207 controlling the constant-current control circuit 206 of each driving switch conduction impedance, power for constant-current control circuit.The all-wave with rectification function or half-wave rectifying circuit that described rectifier bridge stack 101 forms for rectifier diode; Described LED string 102 comprises the LED string that is comprised of with the series connection form some LED or LED crystal grain or goes here and there with the LED that the form of series and parallel connections combination forms, and the conducting voltage that described LED goes here and there is higher than conducting voltage single led or LED crystal grain; Described driving switch 203 is for controlling every section LED string conducting state according to its conduction impedance, it comprises at least 2 road driving switchs; Described current sampling circuit 207 is for monitoring stream Guo Mei road driving switch electric current; Described constant-current control circuit 206 is for providing current value to control the conduction impedance of respective drive switch according to current sampling circuit 207; Described power supply 204 is used to constant-current control circuit that operating voltage is provided; Described reference voltage 205 is used to constant-current control circuit that reference voltage is provided.
Particularly, the output head anode of rectifier bridge stack is connected with the input of power supply and first section LED string; Described power supply is connected with reference voltage and constant-current control circuit; The input of every road driving switch is connected respectively the negative pole of every section LED string, the control end of every road driving switch is connected to respectively constant-current control circuit, the output of every road driving switch is connected to current sampling circuit jointly, and current sampling circuit is connected to respectively constant-current control circuit for monitoring driving switch electric current De Mei road, every road observation circuit; Reference voltage is connected with constant-current control circuit; The negative pole of output end of rectifier bridge stack is together with constant-current control circuit, current sampling circuit common ground.
Its operation principle is: rectifier bridge stack 101 becomes the civil power ac voltage rectifier of input at the DC pulse moving voltage that changes between 0 volt and peak-peak voltage, and is added on the LED string 102 of at least two sections series connection, and (in accompanying drawing 2, L1, L2 are one section LED string; L3, L4 are one section LED string; L5, L6 are one section LED string) when voltage rose to 102 conducting of first paragraph LED string, the driving switch conducting that constant-current control circuit control is connected with first paragraph LED string negative pole constant current were in a less current value, and this moment, first paragraph LED string was luminous; When voltage continues to rise to first paragraph and the conducting simultaneously of second segment LED string, constant-current control circuit is controlled and is turn-offed the driving switch that is connected with first LED string negative pole, make simultaneously the driving switch conducting that is connected with second segment LED string negative pole constant current in a larger current value, this moment, first paragraph and second segment LED string were luminous; When voltage continues to rise to first paragraph, second segment and the 3rd section LED string conducting simultaneously again, constant-current control circuit is controlled and is turn-offed the driving switch that is connected with second LED string negative pole, make simultaneously the driving switch conducting that is connected with the 3rd section LED string negative pole constant current in a larger current value, first paragraph, second segment and the 3rd section LED string are luminous at this moment; If more LED string control procedures are arranged by that analogy; Control procedure is just in time opposite when voltage drop.
The utility model controls at least two sections LED strings along with the changing unit of DC pulse moving voltage by constant-current control circuit and driving switch or all conducting is luminous, the conducting fluorescent lifetime that had both improved the LED string in cycle at a mains ripple has also reduced the power consumption of driving switch, has greatly improved the efficiency that LED drives.
Further, described every road driving switch comprises control end, switch input terminal and output switching terminal, the control end of driving switch is connected with constant-current control circuit, its switch input terminal is connected with the negative pole of output end of every section LED string, its output switching terminal is connected with the input of current sampling circuit, by voltage or the electric current that changes control end, carrys out the conduction impedance of control switch input to output switching terminal.
Further, described current sampling circuit comprises that the output switching terminal that is no less than two sampling resistor ，Mei road driving switchs of mutually connecting connects the input of first sampling resistor jointly; The output head grounding of last sampling resistor; The input of each sampling resistor connects respectively constant-current control circuit.
The continuous current of ，Hou mono-road driving switch is greater than the continuous current of last road driving switch further, Dang Hou mono-road driving switch have electric current by the time constant-current control circuit can close before all driving switchs.
Below by following 2 specific embodiments, the utility model is further elaborated:
Accompanying drawing 3 is the linear high-voltage LED driving circuit embodiment of the utility model multistage mono-electrical block diagram, and as shown in Figure 3, driving switch 203 comprises NMOS pipe Q1, NMOS pipe Q2, NMOS pipe Q3; Described current sampling circuit 207 comprises resistance R 1, resistance R 2, resistance R 3; Described constant-current control circuit 206 comprises operational amplifier U1, operational amplifier U2, operational amplifier U3.
Particularly, the negative pole of output end ground connection of rectifier bridge stack 101, its output head anode are connected with the input of power supply 204 and first section LED string; The positive pole of described power supply 204 and reference voltage 205 and amplifier U1, amplifier U2, amplifier U3 is connected; The drain electrode of every road NMOS pipe is connected respectively the negative pole of every section LED string, the grid that the source electrode of every road NMOS pipe is connected to the input ，Mei road NMOS pipe of resistance R 1 jointly is connected respectively the output of operational amplifier U1, operational amplifier U2, operational amplifier U3; Resistance R 1, resistance R 2, resistance R 3 mutually after series connection by resistance R 3 ground connection; The in-phase input end of described operational amplifier U1, operational amplifier U2, operational amplifier U3 is connected with reference voltage respectively, and the inverting input of operational amplifier U1 is connected with the input of resistance R 1; The inverting input of operational amplifier U2 is connected with the tie point of resistance R 2 with resistance R 1; The inverting input of operational amplifier U3 is connected with the tie point of resistance R 3 with resistance R 2; The negative pole common ground of operational amplifier U1, operational amplifier U2, operational amplifier U3.
The operation principle of the present embodiment is: as shown in Figure 3, ac commercial power voltage is after full-wave rectification bridge D1 rectification, its cathode output end connects power supply, LED and goes here and there L1-L6, after DC pulse moving voltage is increased to power initiation since 0 volt, operational amplifier U1, U2 and U3 start working, so the negative input voltage of three operational amplifiers is that high voltage output is near supply voltage much smaller than the reference voltage operational amplifier output terminal of electrode input end at this moment, the grid of NMOS pipe Q1, Q2 and Q3 is high voltage, and three NMOS pipes all are in the low-resistance conducting state; The drain-to-source that electric current manage Q1 by NMOS when voltage is elevated to first paragraph LED string L1, L2 conducting is flowed through sampling resistor R1, R2 and R3 to ground, when the voltage on R1 equals reference voltage, the output voltage of operational amplifier U1 is reduced to rapidly an appropriate value and Q1 is drained to the conduction impedance of source electrode, increase electric current reduce and be maintained at a constant current value, and voltage continues rising operational amplifier U1 can remain unchanged the electric current of Q1 according to the magnitude of voltage regulation output voltage of sampling resistor R1.The drain-to-source that the electric current that flows through second segment LED string L3 and L4 when voltage is elevated to first paragraph and second segment LED string L1, L2, L3 and L4 conducting simultaneously manage Q2 by NMOS is flowed through sampling resistor R1, R2 and R3 to ground, flow through like this sampling resistor R1, R2 and the R3 electric current increase to ground, the voltage of resistance R 1 also increases simultaneously simultaneously, the output voltage of operational amplifier U1 further descends, and the electric current of Q1 reduces; The output voltage of operational amplifier U2 is reduced to rapidly an appropriate value and Q2 is drained to the conduction impedance of source electrode, increase electric current reduce and be maintained at a Constant Electric Current flow valuve when the electric current of voltage rising second segment LED string continues to increase the voltage that makes sampling resistor R2 and equals reference voltage; The voltage of sampling resistor R1 reduced thereby the Q1 grid voltage was ended near 0 volt of Q1 rapidly considerably beyond the output voltage of reference voltage operational amplifier U1 this moment, and voltage continues rising operational amplifier U2 remains unchanged the electric current of Q2 according to the magnitude of voltage regulation output voltage of sampling resistor R2.The drain-to-source that the electric current that flows through the 3rd section LED string L5 and L6 when voltage is elevated to first paragraph, second segment and the 3rd section LED string L1, L2, L3, L4, L5 and L6 conducting simultaneously manage Q3 by NMOS is flowed through sampling resistor R1, R2 and R3 to ground, flow through like this sampling resistor R1, R2 and the R3 electric current continuation increase to ground, the voltage of resistance R 2 also increases simultaneously simultaneously, the output voltage of operational amplifier U2 synchronously reduces, and the electric current of Q2 reduces; When the raise output voltage of the electric current of the 3rd section LED string operational amplifier U3 when continuing to increase the voltage that makes sampling resistor R3 and equaling reference voltage of voltage is reduced to rapidly an appropriate value and Q3 is drained to the conduction impedance of source electrode, increase electric current reduce and be maintained at a Constant Electric Current flow valuve; So this moment sampling resistor R2 voltage considerably beyond reference voltage the output voltage of operational amplifier U2 further reduce thereby the Q2 grid voltage ended near 0 volt of Q2.If more LED string courses of work are arranged by that analogy, while after voltage reaches peak value, starting to descend, the course of work is just in time opposite.
The present embodiment at least two sections LED strings when change in voltage are luminous with certain rule combination conducting, improved the luminous efficiency of LED and the utilization ratio of electric energy, and its Drive and Control Circuit is simple in structure, and cost is low, is suitable for the large-scale popularization application.
Accompanying drawing 4 is the linear high-voltage LED driving circuit embodiment of the utility model multistage bis-electrical block diagrams, and as shown in Figure 4, driving switch 203 comprises NMOS pipe Q1, NMOS pipe Q2, NMOS pipe Q3; Current sampling circuit 207 comprises resistance R 8, resistance R 9, resistance R 10; Constant-current control circuit 206 comprises NPN triode Q4, NPN triode Q5, NPN triode Q6, resistance R 2, resistance R 3, resistance R 4, resistance R 5, resistance R 6, resistance R 7; Power supply 204 comprises resistance R 1, voltage-stabiliser tube D2; Described reference voltage is the conducting voltage between NPN triode Q4, NPN triode Q5, NPN triode Q6 base stage and emitter, and this conducting voltage is generally 0.4 volt to 0.7 volt.
Particularly, the negative pole of output end ground connection of rectifier bridge stack 101, its output head anode are connected with an end of resistance R 1 and the input of first section LED string, the other end of resistance R 1 is connected with an end of voltage-stabiliser tube D2 and resistance R 2, resistance R 3, resistance R 4 respectively, and the other end of resistance R 2, resistance R 3, resistance R 4 is corresponding respectively to be connected with the collector electrode of NPN triode Q4, NPN triode Q5, NPN triode Q6; The drain electrode of every road NMOS pipe is connected respectively the negative pole of every section LED string, the grid that the source electrode of every road NMOS pipe is connected to the input ，Mei road NMOS pipe of resistance R 8 jointly is connected respectively the collector electrode of NPN triode Q4, NPN triode Q5, NPN triode Q6; Resistance R 8, resistance R 9, resistance R 10 mutually after series connection by resistance R 10 ground connection; The emitter of described NPN triode Q4, NPN triode Q5, NPN triode Q6 is together with the other end common ground of voltage-stabiliser tube D2; The base stage of NPN triode Q4 is connected with the input of resistance R 8 after resistance R 5; The base stage of NPN triode Q5 is connected with the tie point of resistance R 9 with resistance R 8 after resistance R 6; The base stage of NPN triode Q6 is connected with the tie point of resistance R 10 with resistance R 9 after resistance R 7.
the operation principle of the present embodiment particularly, as shown in Figure 4, ac commercial power voltage is after full-wave rectification bridge 101 rectifications, its output contact resistance R1, LED go here and there L1-L6, when voltage during higher than the voltage stabilizing value of voltage-stabiliser tube D2, the voltage of voltage-stabiliser tube positive pole is the voltage stabilizing value of voltage-stabiliser tube, and the grid of NMOS pipe Q1, Q2 and Q3 was three NMOS pipes of high voltage (the voltage stabilizing value of voltage-stabiliser tube) and all was in the low-resistance conducting state this moment, when voltage is elevated to first paragraph LED string L1, during LED string L2 conducting, the drain-to-source that electric current is managed Q1 by the NMOS sampling resistor R8 that finally flows through, resistance R 9 and resistance R 10 are to ground, when the voltage on resistance R 8 equals NPN triode Q4 base stage to the conducting voltage of emitter, the collector electrode of Q4 is to the emitter conducting, because the dividing potential drop of resistance R 2 makes the Q4 collector electrode, the Q1 grid voltage is reduced to rapidly an appropriate value and Q1 is drained to the conduction impedance of source electrode, increase electric current reduce and be maintained at a constant current value, voltage continues rising NPN triode Q4 can remain unchanged the electric current of Q1 according to the magnitude of voltage adjusting collector voltage of sampling resistor R8.The drain-to-source that the electric current that flows through second segment LED string L3 and LED string L4 when voltage is elevated to first paragraph and second segment LED string L1, LED string L2, LED string L3 and LED string L4 conducting simultaneously manage Q2 by NMOS is flowed through sampling resistor R8, R9 and R10 to ground, flow through like this electric current increase to ground of sampling resistor R8, resistance R 9 and resistance R 10, the voltage of resistance R 8 also increases simultaneously simultaneously, the voltage of Q4 base stage synchronously increases, the Q4 collector electrode reduces the R2 dividing potential drop to the conduction impedance of emitter to be increased collector voltage and further descends, and the electric current of Q1 reduces; When the electric current of voltage rising second segment LED string continues to increase the voltage that makes sampling resistor R9 and equals NPN triode Q5 base stage to the conducting voltage of emitter, the collector electrode of Q5 is to the emitter conducting, because the dividing potential drop of resistance R 3 makes Q5 collector electrode, Q2 grid voltage be reduced to rapidly an appropriate value, Q2 drained to the conduction impedance of source electrode, increase electric current reduce and be maintained at a Constant Electric Current flow valuve; So this moment sampling resistor R8 voltage the conducting voltage considerably beyond the Q4 base stage to emitter the Q4 saturation conduction, thereby the R2 dividing potential drop makes the Q1 grid voltage end near 0 volt of Q1, and voltage continues rising NPN triode Q5 can remain unchanged the electric current of Q2 according to the magnitude of voltage adjusting collector voltage of sampling resistor R9.when voltage is elevated to first paragraph, second segment and the 3rd section LED string L1, LED goes here and there L2, LED goes here and there L3, LED goes here and there L4, the drain-to-source that the electric current that flows through the 3rd section LED string L5 and LED string L6 when LED string L5 and LED string L6 conducting is simultaneously managed Q3 by the NMOS sampling resistor R8 that flows through, R9 and R10 are to ground, flow through like this sampling resistor R8, resistance R 9 and resistance R 10 continue to increase to the electric current on ground, the voltage of resistance R 9 also increases simultaneously simultaneously, the voltage of Q5 base stage synchronously increases, the Q5 collector electrode reduces the R3 dividing potential drop to the conduction impedance of emitter to be increased collector voltage and further descends, the electric current of Q2 reduces, when voltage raises the collector electrode of the electric current of the 3rd section LED string Q6 when continuing to increase the voltage that makes sampling resistor R10 and equaling NPN triode Q6 base stage to the conducting voltage of emitter to the emitter conducting, because making Q6 collector electrode, Q3 grid voltage be reduced to rapidly an appropriate value, the dividing potential drop of resistance R 4 Q3 is drained to the conduction impedance increase electric current of source electrode reduce and be maintained at a Constant Electric Current flow valuve, so this moment sampling resistor R9 voltage the conducting voltage considerably beyond the Q5 base stage to emitter the Q5 saturation conduction, thereby the R3 dividing potential drop makes the Q2 grid voltage end near 0 volt of Q2.If more LED string courses of work are arranged by that analogy, while after voltage reaches peak value, starting to descend, the course of work is just in time opposite.
The utility model constant-current control circuit can also be triode, the circuit with identical function that metal-oxide-semiconductor or logical control device forms.The utility model driving switch device can also be managed for PMOS, NPN triode, PNP triode.
Accompanying drawing 5 is the linear high-voltage LED driving circuit voltage and current of the utility model multistage waveform schematic diagram, as shown in Figure 5, the 208th, the current waveform, the 209th the during normal operation of linear low density LED driver, the voltage waveform the during normal operation of linear low density LED driver.
Driving switch of the present utility model is high withstand voltage device can be not breakdown, has good thermal diffusivity and the performance that can bear larger power consumption.
Finally it should be noted that: above embodiment only, in order to the technical solution of the utility model to be described, is not intended to limit; Although with reference to previous embodiment, the utility model is had been described in detail, those of ordinary skill in the art is to be understood that: it still can be modified to the technical scheme that aforementioned each embodiment puts down in writing, or part 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 spirit and scope of each embodiment technical scheme of the utility model.
Claims (6)
1. a linear low density LED drive circuit, is characterized in that, comprising:
Rectifier bridge stack, described rectifier bridge stack are the all-wave with rectification function or the half-wave rectifying circuit that rectifier diode forms;
At least 2 sections LED of series connection go here and there mutually, described LED string comprises the LED string that is comprised of with the series connection form some LED or LED crystal grain or goes here and there with the LED that the form of series and parallel connections combination forms, and the conducting voltage that described LED goes here and there is higher than conducting voltage single led or LED crystal grain;
Corresponding with LED string number, for according to its conduction impedance, controlling at least 2 road driving switchs of every section LED string conducting state;
Current sampling circuit for monitoring stream Guo Mei road driving switch electric current;
For according to current sampling circuit, providing current value to control the constant-current control circuit of respective drive switch conduction impedance;
Be used to constant-current control circuit that the power supply of operating voltage is provided;
Reference voltage;
The output head anode of rectifier bridge stack is connected with the input of power supply and first section LED string; Described power supply is connected with reference voltage and constant-current control circuit; The input of every road driving switch is connected respectively the negative pole of every section LED string, the control end of every road driving switch is connected to respectively constant-current control circuit, the output of every road driving switch is connected to current sampling circuit jointly, and current sampling circuit is connected to respectively constant-current control circuit for monitoring driving switch electric current De Mei road, every road observation circuit; Reference voltage is connected with constant-current control circuit; The negative pole of output end of rectifier bridge stack is together with constant-current control circuit, current sampling circuit common ground.
2. linear low density LED drive circuit according to claim 1, it is characterized in that, described every road driving switch comprises control end, switch input terminal and output switching terminal, the control end of driving switch is connected with constant-current control circuit, its switch input terminal is connected with the negative pole of output end of every section LED string, its output switching terminal is connected with the input of current sampling circuit, by voltage or the electric current that changes control end, carrys out the conduction impedance of control switch input to output switching terminal.
3. linear low density LED drive circuit according to claim 1, is characterized in that, described current sampling circuit comprises that the output switching terminal that is no less than two sampling resistor ，Mei road driving switchs of mutually connecting connects the input of first sampling resistor jointly; The output head grounding of last sampling resistor; The input of each sampling resistor connects respectively constant-current control circuit.
4. linear low density LED drive circuit according to claim 1, it is characterized in that, the continuous current of a rear road driving switch is greater than the continuous current of last road driving switch, Dang Hou mono-road driving switch have electric current by the time constant-current control circuit can close before all driving switchs.
5. the described linear low density LED drive circuit of according to claim 1-4 any one, is characterized in that, described driving switch comprises NMOS pipe Q1, NMOS pipe Q2, NMOS pipe Q3; Described current sampling circuit comprises resistance R 1, resistance R 2, resistance R 3; Described constant-current control circuit comprises amplifier U1, amplifier U2, amplifier U3;
The negative pole of output end ground connection of rectifier bridge stack, its output head anode are connected with the input of power supply and first section LED string; The positive pole of described power supply and reference voltage and operational amplifier U1, operational amplifier U2, operational amplifier U3 is connected; The drain electrode of every road NMOS pipe is connected respectively the negative pole of every section LED string, the grid that the source electrode of every road NMOS pipe is connected to the input ，Mei road NMOS pipe of resistance R 1 jointly is connected respectively the output of operational amplifier U1, operational amplifier U2, operational amplifier U3; Resistance R 1, resistance R 2, resistance R 3 mutually after series connection by resistance R 3 ground connection; The in-phase input end of described operational amplifier U1, operational amplifier U2, operational amplifier U3 is connected with reference voltage respectively, and the inverting input of operational amplifier U1 is connected with the input of resistance R 1; The inverting input of operational amplifier U2 is connected with the tie point of resistance R 2 with resistance R 1; The inverting input of operational amplifier U3 is connected with the tie point of resistance R 3 with resistance R 2; The negative pole common ground of operational amplifier U1, operational amplifier U2, operational amplifier U3.
6. the described linear low density LED drive circuit of according to claim 1-4 any one, is characterized in that, described driving switch comprises NMOS pipe Q1, NMOS pipe Q2, NMOS pipe Q3; Described current sampling circuit comprises resistance R 8, resistance R 9, resistance R 10; Described constant-current control circuit comprises NPN triode Q4, NPN triode Q5, NPN triode Q6, resistance R 2, resistance R 3, resistance R 4, resistance R 5, resistance R 6, resistance R 7; Described power supply comprises resistance R 1, voltage-stabiliser tube D2; Described reference voltage is the conducting voltage between NPN triode Q4, NPN triode Q5, NPN triode Q6 base stage and emitter;
The negative pole of output end ground connection of rectifier bridge stack, its output head anode are connected with an end of resistance R 1 and the input of first section LED string, the other end of resistance R 1 is connected with an end of voltage-stabiliser tube D2 and resistance R 2, resistance R 3, resistance R 4 respectively, and the other end of resistance R 2, resistance R 3, resistance R 4 is corresponding respectively to be connected with the base stage of NPN triode Q4, NPN triode Q5, NPN triode Q6; The drain electrode of every road NMOS pipe is connected respectively the negative pole of every section LED string, the grid that the source electrode of every road NMOS pipe is connected to the input ，Mei road NMOS pipe of resistance R 8 jointly is connected respectively the collector electrode of NPN triode Q4, NPN triode Q5, NPN triode Q6; Resistance R 8, resistance R 9, resistance R 10 mutually after series connection by resistance R 10 ground connection; The emitter of described NPN triode Q4, NPN triode Q5, NPN triode Q6 is together with the other end common ground of voltage-stabiliser tube D2; The base stage of NPN triode Q4 is connected with the input of resistance R 8 after resistance R 5; The base stage of NPN triode Q5 is connected with the tie point of resistance R 9 with resistance R 8 after resistance R 6; The base stage of NPN triode Q6 is connected with the tie point of resistance R 10 with resistance R 9 after resistance R 7.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2013203257244U CN203301820U (en) | 2013-06-07 | 2013-06-07 | Linear high-voltage LED (Light Emitting Diode) drive circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2013203257244U CN203301820U (en) | 2013-06-07 | 2013-06-07 | Linear high-voltage LED (Light Emitting Diode) drive circuit |
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| CN203301820U true CN203301820U (en) | 2013-11-20 |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016107395A1 (en) * | 2014-12-31 | 2016-07-07 | 四川新力光源股份有限公司 | Led constant-current driving device |
| CN104244493B (en) * | 2013-06-07 | 2017-03-29 | 陕西亚成微电子股份有限公司 | A kind of linear low density LED drive circuit |
| CN107959991A (en) * | 2017-10-23 | 2018-04-24 | 东莞达文西光电有限公司 | A kind of dimming driving circuit |
| CN108024417A (en) * | 2017-12-22 | 2018-05-11 | 泉芯电子技术(深圳)有限公司 | high-voltage linear segmented LED drive circuit |
| CN108601158A (en) * | 2018-06-22 | 2018-09-28 | 广州怡泰照明电子科技有限公司 | A kind of linear constant current LED lamp circuit |
| CN112969264A (en) * | 2021-02-07 | 2021-06-15 | 深圳市美矽微半导体有限公司 | RGB (Red, Green and blue) three-color lamp control circuit and control method thereof |
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2013
- 2013-06-07 CN CN2013203257244U patent/CN203301820U/en not_active Withdrawn - After Issue
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104244493B (en) * | 2013-06-07 | 2017-03-29 | 陕西亚成微电子股份有限公司 | A kind of linear low density LED drive circuit |
| WO2016107395A1 (en) * | 2014-12-31 | 2016-07-07 | 四川新力光源股份有限公司 | Led constant-current driving device |
| CN107959991A (en) * | 2017-10-23 | 2018-04-24 | 东莞达文西光电有限公司 | A kind of dimming driving circuit |
| CN108024417A (en) * | 2017-12-22 | 2018-05-11 | 泉芯电子技术(深圳)有限公司 | high-voltage linear segmented LED drive circuit |
| CN108024417B (en) * | 2017-12-22 | 2024-01-16 | 泉芯电子技术(深圳)有限公司 | High-voltage linear sectional type LED driving circuit |
| CN108601158A (en) * | 2018-06-22 | 2018-09-28 | 广州怡泰照明电子科技有限公司 | A kind of linear constant current LED lamp circuit |
| CN112969264A (en) * | 2021-02-07 | 2021-06-15 | 深圳市美矽微半导体有限公司 | RGB (Red, Green and blue) three-color lamp control circuit and control method thereof |
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Granted publication date: 20131120 Effective date of abandoning: 20170329 |