CN105960070A - Single-feedback direct-push type DC light-dimming LED tube driving circuit - Google Patents
Single-feedback direct-push type DC light-dimming LED tube driving circuit Download PDFInfo
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- CN105960070A CN105960070A CN201610551279.1A CN201610551279A CN105960070A CN 105960070 A CN105960070 A CN 105960070A CN 201610551279 A CN201610551279 A CN 201610551279A CN 105960070 A CN105960070 A CN 105960070A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/37—Converter circuits
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
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Abstract
The invention discloses a single-feedback direct-push type DC light-dimming LED tube driving circuit. The circuit comprises an AC-DC conversion circuit, an LED tube driving power supply circuit, an AC-DC conversion circuit output voltage control circuit, an AC-DC conversion circuit internal Vcc'' power-down suppression circuit, a PWM-to-DC light-dimming control circuit, an LED tube current control circuit and a single-feedback LED tube. The AC-DC conversion circuit utilizes a single-unit output design, the size of single-unit output voltage value of the AC-DC conversion circuit is variable, the output voltage is supplied directly to a single-feedback LED tube to work, and a large amount of high-frequency EMI radiation noises of a Boost circuit do not exist. According to the single-feedback direct-push type DC light-dimming LED tube driving circuit, standby power consumption of a liquid crystal display products is effectively reduced, and energy-saving and environment-friendly property is better. The single-feedback direct-push type DC light-dimming LED tube driving circuit has the characteristics of low costs, high efficiency, low standby power consumption and lower EMI radiation.
Description
Technical field
The present invention relates to a kind of single feedback direct-push DC dimming LED lamp tube drive circuit.
Background technology
nullTraditional lcd products LED lamp tube circuit theory is as shown in Figure 1,AC mains 90V-264V generates a low-voltage DC such as after AC-DC change-over circuit carries out voltage conversion: 19V unidirectional current,This 19V unidirectional current after Boost circuit is boosted, generate a LED lamp tube needed for running voltage such as: 25V-70V direct current supply electricity to LED lamp tube work,This Boost circuit is driven by booster circuit control chip,In this LED lamp tube, each lamp string output feedback end is electrically connected with each feedback pin of booster circuit control chip,By electric current when each lamp string works in booster circuit control chip control LED lamp tube,To control liquid crystal display picture mean flow rate,This booster driving circuit receives a switching signal provided from motherboard circuit (diagram is not drawn into),In order to whether to control this LED lamp tube drive circuit works,This booster driving circuit receives a DIM dim signal provided from motherboard circuit (diagram is not drawn into),Size of current during to control in this LED lamp tube the work of each lamp string,Thus control liquid crystal display picture mean flow rate.
But above-mentioned prior art also exists following problem: 1, LED lamp tube drives power panel part material cost price higher, lack the market competitiveness having begun in price.2, LED lamp tube drive circuit (without the conversion efficiency of AC-DC change-over circuit) conversion efficiency is between 85%-90%, conversion efficiency is the highest, when designing EPA7.0 new efficiency lcd products, the power supply conversion efficiency generally requiring lifting AC-DC change-over circuit further can be only achieved the requirement of EPA7.0 new efficiency regulation, and LED lamp tube can be caused when promoting the power supply conversion efficiency of AC-DC change-over circuit to drive power panel part material cost price to promote further.3, the motherboard circuit within lcd products needs 5V to power, need to turn a 5V DC voltage from 19V by one group of DC-DC decompression converting circuit, and 19V to turn 5V DC-DC decompression converting circuit conversion efficiency under waiting condition the highest, only have: the conversion efficiency of about 30%-45%.Therefore, reduce LED lamp tube and drive the design cost of power panel, promote LED lamp tube and drive conversion efficiency, reduce liquid crystal display product stand-by power consumption and become the trend of technology development.
Summary of the invention
It is an object of the invention to overcome the deficiencies in the prior art, it is provided that a kind of single feedback direct-push DC dimming LED lamp tube drive circuit.
The technical solution used in the present invention is:
A kind of single feedback direct-push DC dimming LED lamp tube drive circuit, it includes power supply circuits that AC-DC change-over circuit, LED lamp tube drive, AC-DC change-over circuit output voltage controlling circuit, the internal Vcc of AC-DC change-over circuit " power down suppression circuit, PWM turn DC adjusting control circuit, LED lamp tube current control circuit and single feed back LED lamp tube;
The ac input end of described AC-DC change-over circuit receives an AC mains, and AC mains is carried out voltage conversion and is exported the unidirectional current of one group of variable values by outfan, the input of the power supply circuits that the input of AC-DC change-over circuit outfan order feedback LED lamp tube and LED lamp tube drive, the power supply circuits that LED lamp tube drives are additionally provided with switching signal receiving terminal, first reference voltage output end, second reference voltage output end and Vcc outfan, described AC-DC change-over circuit output voltage controlling circuit is provided with the first feedback input end, second feedback input end and reference voltage receiving terminal,
The outfan of described single feedback LED lamp tube connects input and first feedback input end of AC-DC change-over circuit output voltage controlling circuit of LED lamp tube current control circuit respectively;LED lamp tube current control circuit is additionally provided with feeder ear and controls current signal receiving terminal, the feeder ear of LED lamp tube current control circuit connects the Vcc outfan of the power supply circuits that LED lamp tube drives, and the current signal receiving terminal connection PWM that controls of LED lamp tube current control circuit turns the outfan of DC adjusting control circuit;
PWM turns DC adjusting control circuit and is additionally provided with reference voltage input and dim signal receiving terminal, PWM turns the first reference voltage output end of the power supply circuits of the reference voltage input connection LED lamp tube driving of DC adjusting control circuit, PWM turns the dim signal receiving terminal of DC adjusting control circuit and receives one from the DIM dim signal of mainboard, and according to the positive duty cycle conversion of DIM dim signal generate a direct current dimmer voltage output to LED lamp tube current control circuit in order to control singly to feed back LED lamp tube work time size of current;The internal Vcc of described AC-DC change-over circuit " outfan of power down suppression circuit connects the second feedback input end of AC-DC change-over circuit output voltage controlling circuit, the internal Vcc of AC-DC change-over circuit " the switching signal receiving terminal of power down suppression circuit receives one from the switching signal of mainboard, the internal Vcc of AC-DC change-over circuit " power down suppression circuit guarantees that this LED lamp tube drives when being carried out standby not mode of operation by normal mode of operation, AC-DC change-over circuit internal control chip Vcc supply voltage occurs without and causes because of power down this control chip to produce under-voltage protection;The reference voltage receiving terminal of described AC-DC change-over circuit output voltage controlling circuit connects the second reference voltage output end of the power supply circuits that LED lamp tube drives, the feedback input end of the output termination AC-DC change-over circuit of AC-DC change-over circuit output voltage controlling circuit, AC-DC change-over circuit output voltage controlling circuit controls AC-DC change-over circuit output end voltage by detecting single feedback LED lamp tube output end voltage;The switching signal receiving terminal of the power supply circuits that described LED lamp tube drives receives the switching signal from mainboard, and whether the power supply circuits driven in order to control LED lamp tube work.
Further, described AC-DC change-over circuit includes bridge rectifier and filter circuit, transformator, feedback circuit and AC-DC change-over circuit control chip,
The power supply circuits that described LED lamp tube drives include reference voltage generating circuit and power supply conversion and control circuit;
Described LED lamp tube current control circuit includes the first N-type metal-oxide-semiconductor Q1, current sampling resistor R1, biasing resistor and the first amplifier OP1;
Described AC-DC change-over circuit output voltage controlling circuit includes the second amplifier OP2, voltage sample resistance R2, frequency compensated circuit, the first transistor Q2, optocoupler and TL431 circuit, feedback resistance R3, feedback resistance R4 and feedback resistance R5;
The internal Vcc of described AC-DC change-over circuit " power down suppression circuit includes the first electric capacity C1 and transistor seconds Q3;
nullAC-DC change-over circuit control chip has the first pin CS、Second pin Vdri、3rd pin Vcc "、Feedback pin FB and grounding pin GND,Described transformator has the first winding being positioned at primary side、Second winding and the tertiary winding being positioned at secondary side,AC mains accesses one end of the first winding of transformator by bridge rectifier and filter circuit,The other end of the first winding and the drain electrode of one the 5th N-type metal-oxide-semiconductor Q11 connect,The source electrode of the 5th N-type metal-oxide-semiconductor Q11 connects the first pin CS and one end of a resistance R18 of AC-DC change-over circuit control chip respectively,The other end ground connection of resistance R18,The grid of the 5th N-type metal-oxide-semiconductor Q11 connects the second pin Vdri of AC-DC change-over circuit control chip,One end of second winding connects the positive pole of a diode D12,The negative pole of diode D12 connects the 3rd pin Vcc of AC-DC change-over circuit control chip respectively " and one end of electric capacity C12,The other end ground connection of electric capacity C12,One end of the tertiary winding connects the positive pole of diode D11,The negative pole of diode D11 connects one end of electric capacity C11 and one end of feedback circuit respectively,The other end of feedback circuit connects feedback pin FB of AC-DC change-over circuit control chip,The other end of electric capacity C11 connects the other end of the tertiary winding,The other end ground connection of the tertiary winding,The negative pole of diode D11 is as the outfan of AC-DC change-over circuit,The other end of described first winding、One end of second winding and one end of the tertiary winding are Same Name of Ends;
The outfan of described AC-DC change-over circuit connects single input feeding back LED lamp tube and described power supply conversion and the input of control circuit respectively, the outfan of power supply conversion and control circuit connects the positive power source terminal of the second amplifier OP2 and the input of reference voltage generating circuit respectively, and reference voltage generating circuit generates the first reference voltage and the second reference voltage respectively;
The outfan of single feedback LED lamp tube connects drain electrode and one end of voltage sample resistance R2 of the first N-type metal-oxide-semiconductor Q1 respectively, the source electrode of the first N-type metal-oxide-semiconductor Q1 connects one end and the negative input end of the first amplifier OP1 of current sampling resistor R1 respectively, the other end ground connection of current sampling resistor R1, the grid of the first N-type metal-oxide-semiconductor Q1 connects the outfan of the first amplifier OP1
One end of biasing resistor connects power supply conversion and the outfan of control circuit, and the other end of biasing resistor connects the source electrode of the first N-type metal-oxide-semiconductor Q1;
Described PWM turns DC adjusting control circuit and receives a DIM dim signal and one first reference voltage respectively, and the anode that the first reference voltage generates a direct current dimmer voltage output to the first amplifier OP1 according to the positive duty cycle conversion of DIM dim signal is entered end,
The other end of voltage sample resistance R2 connects the negative input end of the second amplifier OP2 and one end of frequency compensated circuit respectively, and the other end of frequency compensated circuit connects the outfan of the second amplifier OP2, and the positive input terminal of the second amplifier OP2 accesses the second reference voltage,
The outfan of the second amplifier OP2 connects the base stage of the first transistor Q2, the grounded emitter of the first transistor Q2, the colelctor electrode of the first transistor Q2 connects one end and one end of the first electric capacity C1 of feedback resistance R5 respectively, the other end of feedback resistance R5 connects one end of feedback resistance R3 respectively, one end of feedback resistance R4 and optocoupler and the reference edge of TL431 circuit, the other end of feedback resistance R3 connects the outfan of AC-DC change-over circuit, the other end ground connection of feedback resistance R4, the other end of optocoupler and TL431 circuit connects AC-DC change-over circuit, the other end of the first electric capacity C1 connects the emitter stage of transistor seconds Q3, the base stage of transistor seconds Q3 accesses the switching signal from mainboard, the grounded collector of transistor seconds Q3.
Further, described the first transistor Q2 is NPN transistor, and described transistor seconds Q3 is PNP transistor.
nullFurther,Described PWM turns DC adjusting control circuit and includes the second N-type metal-oxide-semiconductor Q4 and the 3rd N-type metal-oxide-semiconductor Q5,The grid of the second N-type metal-oxide-semiconductor Q4 accesses DIM dim signal,The source ground of the second N-type metal-oxide-semiconductor Q4,The drain electrode of the second N-type metal-oxide-semiconductor Q4 connects grid and one end of the 4th resistance R6 of the 3rd N-type metal-oxide-semiconductor Q5 respectively,The source ground of the 3rd N-type metal-oxide-semiconductor Q5,The drain electrode of the 3rd N-type metal-oxide-semiconductor Q5 connects one end and one end of the 6th resistance R8 of the 5th resistance R7 respectively,The other end of the 4th resistance R6 and the other end of the 5th resistance R7 are respectively connected to the first reference voltage,The other end of the 6th resistance R8 connects one end and one end of the 7th resistance R9 of the second electric capacity C2 respectively,The other end of the 7th resistance R9 connects one end and the positive input terminal of the first amplifier OP1 of the 8th resistance R10 respectively,The other end of the second electric capacity C2 and the other end of the 8th resistance R10 ground connection respectively.
nullFurther,Described power supply conversion and control circuit include the 4th N-type metal-oxide-semiconductor Q6、Third transistor Q7、4th transistor Q8 and Zener diode ZD1,The emitter stage of third transistor Q7 connects outfan and one end of the tenth resistance R12 of AC-DC change-over circuit respectively,The base stage of third transistor Q7 connects one end and the other end of the tenth resistance R12 of the 9th resistance R11 respectively,The other end of the 9th resistance R11 connects the drain electrode of the 4th N-type metal-oxide-semiconductor Q6,The source ground of the 4th N-type metal-oxide-semiconductor Q6,The grid of the 4th N-type metal-oxide-semiconductor Q6 accesses the switching signal from mainboard,The colelctor electrode of third transistor Q7 connects one end of the 11st resistance R13,The other end of the 11st resistance R13 connects the 4th transistor Q8 colelctor electrode and one end of the 12nd resistance R14 respectively,The base stage of the 4th transistor Q8 connects negative pole and the other end of the 12nd resistance R14 of Zener diode ZD1 respectively,The emitter stage of the 4th transistor Q8 connects one end of the 3rd electric capacity C3 respectively,The other end ground connection of the 3rd electric capacity C3,The plus earth of Zener diode ZD1,Change and the outfan of control circuit using the emitter stage of the 4th transistor Q8 as power supply.
Further, described 3rd crystal Q7 is PNP transistor, and described 4th transistor Q8 is NPN transistor.
nullFurther,Described reference voltage generating circuit includes the 5th transistor Q9 and three-terminal shunt regulator U1,The colelctor electrode of described 5th transistor Q9 connects power supply conversion and the outfan of control circuit and one end of the 17th resistance R19 respectively,The base stage of the 5th transistor Q9 connects the other end and the cathode terminal of three-terminal shunt regulator U1 of the 17th resistance R19 respectively,The emitter stage of the 5th transistor Q9 connects one end of the 15th resistance R17 respectively、One end of 13rd resistance R15 and one end of the 4th electric capacity C4,The other end of the 13rd resistance R15 connects one end of the 14th resistance R16,The reference edge of three-terminal shunt regulator U1 connects the other end and one end of the 16th resistance R18 of the 15th resistance R17 respectively,The anode tap of three-terminal shunt regulator U1、The other end of the 16th resistance R18、The other end of the 4th electric capacity C 4 and the other end of the 14th resistance R16 ground connection respectively,The emitter stage of the 5th transistor Q9 exports the first reference voltage,The other end of the 13rd resistance R15 exports the second reference voltage.
Further, the reference voltage of the reference edge of described three-terminal shunt regulator U1 is 2.5V, and described three-terminal shunt regulator U1 is TL431 manostat.
Further, described 5th transistor Q9 is NPN transistor.
Further, described frequency compensated circuit is the RC frequency compensated circuit that a compensation resistance and one compensates capacitances in series.
The present invention uses above technical scheme, 1, AC-DC change-over circuit use single group output design, output voltage is supplied directly to LED lamp tube work.2, each lamp string (String) outfan during LED lamp tube uses single Feedback Design mode, i.e. LED lamp tube is connected together.3, LED lamp tube electric current is controlled accurately by first amplifier OP1 or error amplifier.4, LED lamp tube output end voltage is controlled accurately by second amplifier OP2 or error amplifier, thus control AC-DC change-over circuit list group output voltage, that is: AC-DC change-over circuit list group output voltage values size is variation, and revocable, it is ensured that LED lamp tube drives higher conversion efficiency >=93%.null5、The switching signal provided by motherboard circuit,When switching signal is High high level,AC-DC change-over circuit output in power panel supplies electricity to LED lamp tube on-line operation just like the direct current of 18V-21V,And when lcd products carries out holding state,Switching signal is Low low level,AC-DC change-over circuit in power panel only exports the unidirectional current just like 15V or lower,After DC-DC decompression converting circuit is changed, generate 5V direct current supply electricity to motherboard circuit work,For DC-DC decompression converting circuit,Input voltage is the lowest,Its conversion efficiency can be of a relatively high,As the present invention LED drive power panel when standby,The conversion efficiency of DC-DC decompression converting circuit (15V turns 5V) is 55%-60%,And tradition LED drive power plate is when standby,The conversion efficiency of DC-DC decompression converting circuit (19V turns 5V) is 30%-45%,Therefore the LED lamp tube drive circuit of the present invention has lower stand-by power consumption.6, the LED lamp tube drive circuit of the present invention uses AC-DC change-over circuit list group output unidirectional current and is supplied directly to LED lamp tube work, and traditional LED lamp pipe drives and also just to supply LED lamp tube work after using AC-DC change-over circuit list group output unidirectional current after Boost circuit is boosted, the EMI radiation noise of a large amount of high frequency can be produced during this Boost circuit N-type metal-oxide-semiconductor switch, therefore New LED drives power panel to reduce EMI solution difficulty.7, a C1 electric capacity in parallel and a Q3PNP electric crystal between the colelctor electrode and emitter stage of the first transistor Q2, the LED lamp tube making lcd products drives under the conditions of being entered standby mode by normal work, that is: motherboard circuit provide switching signal from high level High become low level Low time, the Vcc of AC-DC change-over circuit primary side AC-DC change-over circuit control chip " energization pins will not drop to less than the under-voltage protection value (UVLO) set by this control chip energization pins inside because of power down, to guarantee that this lcd products is when the on & off switch of the plate that pushes button, standy operation mode can be smoothly entered by normal mode of operation.8, between Q1N raceway groove N-type metal-oxide-semiconductor source electrode and power supply conversion and control circuit outfan, a Roffset biasing resistor is set, when lcd products normally works, can ensure that when the positive dutycycle of DIM dim signal is transferred to minimum 0% liquid crystal display picture is at the darkest picture.The LED of the present invention drives to drive compared with traditional LED lamp pipe to be had: price is low, the high and low stand-by power consumption of efficiency, has lower EMI radiation feature.
Accompanying drawing explanation
Below in conjunction with the drawings and specific embodiments, the present invention is described in further details;
Fig. 1 is the circuit theory schematic diagram that traditional LED lamp tube drives;
Fig. 2 is a kind of single schematic block circuit diagram feeding back direct-push DC dimming LED lamp tube drive circuit of the present invention;
Fig. 3 is a kind of single circuit diagram feeding back direct-push DC dimming LED lamp tube drive circuit of the present invention;
Fig. 4 is that the PWM of a kind of single feedback direct-push DC dimming LED lamp tube drive circuit of the present invention turns DC adjusting control circuit schematic diagram;
Fig. 5 is power supply conversion and the control circuit schematic diagram of a kind of single feedback direct-push DC dimming LED lamp tube drive circuit of the present invention;
Fig. 6 is a kind of single reference voltage generating circuit schematic diagram feeding back direct-push DC dimming LED lamp tube drive circuit of the present invention;
Fig. 7 is a kind of single AC-DC change-over circuit schematic diagram feeding back direct-push DC dimming LED lamp tube drive circuit of the present invention;
If Fig. 8 is not have the internal Vcc of AC-DC change-over circuit " power down suppression circuit time AC-DC change-over circuit supply voltage Vcc " power down time waveform diagram;
Fig. 9 is that the present invention increases exchanges the-internal Vcc of DC converting circuit " the supply voltage Vcc of AC-DC change-over circuit after power down suppression circuit " waveform diagram;
Figure 10 is a kind of single chip alternative structure schematic diagram feeding back direct-push DC dimming LED lamp tube drive circuit of the present invention.
Detailed description of the invention
As shown in one of Fig. 2-10, the present invention it include power supply circuits that AC-DC change-over circuit, LED lamp tube drive, AC-DC change-over circuit output voltage controlling circuit, the internal Vcc of AC-DC change-over circuit " power down suppression circuit, PWM turn DC adjusting control circuit, LED lamp tube current control circuit and single feedback LED lamp tube;
The ac input end of described AC-DC change-over circuit receives an AC mains, and AC mains is carried out voltage conversion and is exported the unidirectional current of one group of variable values by outfan, the input of the power supply circuits that the input of AC-DC change-over circuit outfan order feedback LED lamp tube and LED lamp tube drive, the power supply circuits that LED lamp tube drives are additionally provided with switching signal receiving terminal, first reference voltage output end, second reference voltage output end and Vcc outfan, described AC-DC change-over circuit output voltage controlling circuit is provided with the first feedback input end, second feedback input end and reference voltage receiving terminal,
The outfan of described single feedback LED lamp tube connects input and first feedback input end of AC-DC change-over circuit output voltage controlling circuit of LED lamp tube current control circuit respectively;LED lamp tube current control circuit is additionally provided with feeder ear and controls current signal receiving terminal, the feeder ear of LED lamp tube current control circuit connects the Vcc outfan of the power supply circuits that LED lamp tube drives, and the current signal receiving terminal connection PWM that controls of LED lamp tube current control circuit turns the outfan of DC adjusting control circuit;
PWM turns DC adjusting control circuit and is additionally provided with reference voltage input and dim signal receiving terminal, PWM turns the first reference voltage output end of the power supply circuits of the reference voltage input connection LED lamp tube driving of DC adjusting control circuit, PWM turns the dim signal receiving terminal of DC adjusting control circuit and receives one from the DIM dim signal of mainboard, and according to the positive duty cycle conversion of DIM dim signal generate a direct current dimmer voltage output to LED lamp tube current control circuit in order to control singly to feed back LED lamp tube work time size of current;The internal Vcc of described AC-DC change-over circuit " outfan of power down suppression circuit connects the second feedback input end of AC-DC change-over circuit output voltage controlling circuit, the internal Vcc of AC-DC change-over circuit " the switching signal receiving terminal of power down suppression circuit receives one from the switching signal of mainboard, the internal Vcc of AC-DC change-over circuit " power down suppression circuit guarantees that this LED lamp tube drives when being carried out standby not mode of operation by normal mode of operation, AC-DC change-over circuit internal control chip Vcc supply voltage occurs without and causes because of power down this control chip to produce under-voltage protection;The reference voltage receiving terminal of described AC-DC change-over circuit output voltage controlling circuit connects the second reference voltage output end of the power supply circuits that LED lamp tube drives, the feedback input end of the output termination AC-DC change-over circuit of AC-DC change-over circuit output voltage controlling circuit, AC-DC change-over circuit output voltage controlling circuit controls AC-DC change-over circuit output end voltage by detecting single feedback LED lamp tube output end voltage;The switching signal receiving terminal of the power supply circuits that described LED lamp tube drives receives the switching signal from mainboard, and whether the power supply circuits driven in order to control LED lamp tube work.
Further, the power supply circuits that described LED lamp tube drives include reference voltage generating circuit and power supply conversion and control circuit;
Described LED lamp tube current control circuit includes the first N-type metal-oxide-semiconductor Q1, current sampling resistor R1, biasing resistor and the first amplifier OP1;
Described AC-DC change-over circuit output voltage controlling circuit includes the second amplifier OP2, voltage sample resistance R2, frequency compensated circuit, the first transistor Q2, optocoupler and TL431 circuit, feedback resistance R3, feedback resistance R4 and feedback resistance R5;
The internal Vcc of described AC-DC change-over circuit " power down suppression circuit includes the first electric capacity C1 and transistor seconds Q3;
The outfan of described AC-DC change-over circuit connects single input feeding back LED lamp tube and described power supply conversion and the input of control circuit respectively, the outfan of power supply conversion and control circuit connects amplifier OP1, the positive power source terminal of amplifier OP2 and the input of reference voltage generating circuit respectively, and reference voltage generating circuit generates the first reference voltage V ref1 pressure and the second reference voltage V ref2 respectively;
The outfan of single feedback LED lamp tube connects drain electrode and one end of voltage sample resistance R2 of the first N-type metal-oxide-semiconductor Q1 respectively, the source electrode of the first N-type metal-oxide-semiconductor Q1 connects one end and the negative input end of the first amplifier OP1 of current sampling resistor R1 respectively, the other end ground connection of current sampling resistor R1, the grid of the first N-type metal-oxide-semiconductor Q1 connects the outfan of the first amplifier OP1
One end of biasing resistor Roffset connects power supply conversion and the outfan of control circuit, and the other end of biasing resistor Roffset connects the source electrode of the first N-type metal-oxide-semiconductor Q1;
Described PWM turns DC adjusting control circuit and receives a DIM dim signal and one first reference voltage V ref1 respectively, and the anode that the first reference voltage V ref1 generates a direct current dimmer voltage output to the first amplifier OP1 according to the positive duty cycle conversion of DIM dim signal is entered end
The other end of voltage sample resistance R2 connects the negative input end of the second amplifier OP2 and one end of frequency compensated circuit respectively, and the other end of frequency compensated circuit connects the outfan of the second amplifier OP2, and the positive input terminal of the second amplifier OP2 accesses the second reference voltage V ref2,
The outfan of the second amplifier OP2 connects the base stage of the first transistor Q2, the grounded emitter of the first transistor Q2, the colelctor electrode of the first transistor Q2 connects one end and one end of the first electric capacity C1 of feedback resistance R5 respectively, the other end of feedback resistance R5 connects one end of feedback resistance R3 respectively, one end of feedback resistance R4 and optocoupler and the reference edge of TL431 circuit, the other end of feedback resistance R3 connects the outfan of AC-DC change-over circuit, the other end ground connection of feedback resistance R4, the other end of optocoupler and TL431 circuit connects AC-DC change-over circuit, the other end of the first electric capacity C1 connects the emitter stage of transistor seconds Q3, the base stage of transistor seconds Q3 accesses the switching signal from mainboard, the grounded collector of transistor seconds Q3.
Described the first transistor Q2 is NPN transistor, and described transistor seconds Q3 is PNP transistor.
Specifically, first amplifier OP1, current sampling resistor R1, first N-type metal-oxide-semiconductor Q1, PWM turn DC adjusting control circuit and form a LED lamp tube current control circuit in the present invention, this LED lamp tube current control circuit is negative-feedback circuit, OP1 amplifier has empty short feature, that is: V1+=V1-, LED lamp tube electric current Ilamp=(V1-)/R1=(V1+)/R1.
Voltage sample resistance R2, frequency compensated circuit, the second amplifier OP2 (or error amplifier), the first transistor Q2, feedback resistance R3, feedback resistance R4, feedback resistance R5 and optocoupler and TL431 circuit constitute an AC-DC change-over circuit output end voltage Vout control circuit (being also single feedback LED lamp tube input pressure control circuit);nullAfter being decayed by the noise signal (Noise) in the voltage that voltage sample resistance R2 will be sampled, voltage V2-is supplied to the negative input end of the second amplifier OP2,Second amplifier OP2 positive input terminal receives the second reference voltage V ref2 from reference voltage generating circuit output,Second amplifier OP2 outfan electrical connection frequency compensated circuit and the base stage (Base) of the first transistor Q2,Second amplifier OP2 and frequency compensated circuit form an integrating circuit,For negative-feedback circuit,Therefore the second amplifier OP2 has empty short feature,That is: V2-=V2+=Vref2,When i.e.: normally working,The output end voltage size of single feedback LED lamp tube is controlled as basically identical with Vref2 voltage,The LED lamp tube making the present invention drives when normally working,AC-DC change-over circuit output end voltage Vout=Vled+Vref2,The voltage at LED lamp tube two ends when wherein Vled------is LED lamp tube work;And now the first transistor Q2 can be operated in amplification region; a motional impedance Rce would generally be produced between colelctor electrode and the emitter stage of the first transistor Q2; therefore pull down resistor total impedance R=R4//(R5+Rce) of the reference edge (R end) in optocoupler and TL431 circuit; owing in optocoupler and TL431 circuit, the voltage of reference edge R end is 2.5V, therefore AC-DC change-over circuit output end voltage Vout1=Vled+Vref2=2.5V*(R3+R when the LED lamp tube drive circuit of the present invention normally works)/R.
nullFurther,Resistance Roffset in biasing resistor mentioned above i.e. Fig. 3,The effect of biasing resistor is when lcd products normally works,When the positive dutycycle of DIM dim signal is transferred to minimum 0% (Duty=0%),Guarantee that liquid crystal display picture is at the darkest picture,When lcd products normally works,When the positive dutycycle of DIM dim signal is transferred to minimum 0% (Duty=0%),The positive input terminal voltage V1+=0V of the first amplifier OP1 amplifier,According to empty short feature: the V1+=V1-=0V of the first amplifier OP1 amplifier,Now LED lamp tube electric current Ilamp should be 0mA,But owing to the first amplifier OP1 input exists input offset voltage (Input offset voltage),The first amplifier OP1 amplifier outfan is made to still suffer from the output voltage of certain value,The first N-type metal-oxide-semiconductor Q1 is made to be in lightly conducting state,LED lamp tube is made still to have a faint electric current to flow through,Produce a faint light,Make liquid crystal display picture cannot be in complete dark picture,And when arranging a biasing resistor Roffset,And then when a bias current Ioffset (Ioffset ≈ Vcc/Roffset) is set,This Ioffset electric current flows through current sampling resistor R1,Negative input end in the first amplifier OP1 amplifier produces a bias voltage Voffset=Ioffset*R1,As long as this voltage is more than the maximum input offset voltage Vio in OP1 amplifier specifications,OP1 amplifier output end voltage is 0V,The first N-type metal-oxide-semiconductor Q1 is made to be in completely switched off state,Now LED lamp tube electric current Ilamp=0mA,Liquid crystal display picture processes dark picture completely.
Further, described power supply conversion and control circuit receive the switching signal that an AC-DC change-over circuit output end voltage Vout and provides from motherboard circuit, when the switching signal that motherboard circuit is provided is high level (High), AC-DC change-over circuit output end voltage Vout is converted into a supply voltage Vcc and supplies the first amplifier OP1 and the work of the second amplifier OP2 by power supply conversion and control circuit, it is supplied simultaneously to reference voltage generating circuit work, and produced two groups of reference voltage first reference voltage V ref1 and the second reference voltage V ref2 by reference voltage generating circuit, therefore switching signal is when being high level, the LED lamp tube of the present invention drives normal work, now, transistor seconds Q3 ends;
When lcd products needs to enter standy operation mode, motherboard circuit within lcd products can provide a switching signal to be low level (Low) signal, power supply conversion and control circuit stop providing Vcc to supply voltage to the first amplifier OP1, the second amplifier OP2 and reference voltage generating circuit, the LED of the present invention drives and quits work, Q2 electric crystal ends
nullThe AC-DC change-over circuit output voltage Vout2=2.5V*(R3+R4 of standy operation mode)/R4,Because of R4 > R4//(R5+Rce),Therefore lcd products AC-DC change-over circuit output voltage Vout2 under waiting condition is more much smaller than Vout1 voltage during normal work,As: when liquid crystal display product product normally works,AC-DC change-over circuit output voltage Vout1=19V,And it is even lower to arrange output voltage Vout2=15V in the standby state,This can reduce the standby power of liquid crystal display product,Traditional LED lamp pipe drives power panel to be no matter in the standby state or when normally working,The fixing DC voltage of AC-DC change-over circuit list group one 19V of output,Generate the circuit such as the Scaler IC in a 5V output unidirectional current supply motherboard circuit after this 19V DC voltage dc-dc in motherboard circuit to work;And the power panel of the LED drive circuit of present invention AC-DC change-over circuit list group output voltage unidirectional current between 19V ~ 21V when normally working, and in the standby state, AC-DC change-over circuit list group exports the fixing DC voltage of such as≤15V.As a example by PHILIPS 223V5 machine, according to tradition LED
Boost boosting drives power panel, is that the input power that records of 240V is at about 280mW when input ac voltage under holding state;According to the LED drive circuit of the present invention, then it is that the input power that 240V records is only at about 230mW when input ac voltage under holding state.
When the switching signal provided in motherboard circuit is become low level from high level, transistor seconds Q3 turns on, and the first transistor Q2 ends, and the first electric capacity C1 is charged by feedback resistance R5.When, after 5 t=R5*C1 time, the first electric capacity C1 both end voltage can be risen to about about 2.5V by 0V.Now series impedance R between feedback resistance R5 and the first electric capacity C1 " infinity, pull down resistor total impedance R=R4//R can be risen to by R5+Rce (Q2) ".nullAC-DC change-over circuit output end voltage meets Vout=2.5V* (R3+R)/R=2.5V* (R3/R+1),I.e. after 5 t=R5*C1 time,Within the voltage of AC-DC change-over circuit outfan can be dropped to 15V at leisure by 19V during such as normal work,The control AC-DC change-over circuit output end voltage that now AC-DC change-over circuit output voltage controlling circuit can be correct slowly drops to magnitude of voltage designed during standy operation mode,Guarantee AC-DC change-over circuit output voltage energy normal decline during switching signal is by high level (High) to low level (Low),Occurring without that output voltage is abnormal the most too low causes AC-DC change-over circuit primary side control chip Vcc " there is under-voltage protection (UVLO) problem in energization pins.To guarantee that this lcd products when the on & off switch of the plate that pushes button, remains to be smoothly entered standy operation mode by normal mode of operation.
nullAs shown in Figure 4,Described PWM turns DC adjusting control circuit and includes the second N-type metal-oxide-semiconductor Q4 and the 3rd N-type metal-oxide-semiconductor Q5,The grid of the second N-type metal-oxide-semiconductor Q4 accesses DIM dim signal,The source ground of the second N-type metal-oxide-semiconductor Q4,The drain electrode of the second N-type metal-oxide-semiconductor Q4 connects grid and one end of the 4th resistance R6 of the 3rd N-type metal-oxide-semiconductor Q5 respectively,The source ground of the 3rd N-type metal-oxide-semiconductor Q5,The drain electrode of the 3rd N-type metal-oxide-semiconductor Q5 connects one end and one end of the 6th resistance R8 of the 5th resistance R7 respectively,The other end of the 4th resistance R6 and the other end of the 5th resistance R7 are respectively connected to the first reference voltage V ref1,The other end of the 6th resistance R8 connects one end and one end of the 7th resistance R9 of the second electric capacity C2 respectively,The other end of the 7th resistance R9 connects one end and the positive input terminal of the first amplifier OP1 of the 8th resistance R10 respectively,The other end of the second electric capacity C2 and the other end of the 8th resistance R10 ground connection respectively.
nullSpecifically,The grid of the second N-type metal-oxide-semiconductor Q4 receives a DIM dim signal provided from the motherboard circuit within lcd products,First reference voltage V ref1 reference voltage is passed through the 5th resistance R7 by the second N-type metal-oxide-semiconductor Q4/ the 3rd N-type metal-oxide-semiconductor Q5 by this DIM dim signal、6th resistance R8 and the second electric capacity C2 generates a V1 DC voltage after carrying out voltage conversion,This V1 DC voltage size is relevant with positive dutycycle (Duty) size of DIM dim signal,The positive dutycycle of DIM dim signal is the biggest,Then V1 voltage is the highest,The positive dutycycle of DIM dim signal is the least,Then V1 voltage is the lowest,As: during when DIM dim signal positive dutycycle Duty=100% that the motherboard circuit within lcd products exports,V1=Vref1*(R9+R10)/(R7+R8+R9+R10);When positive dutycycle Duty=0% of DIM dim signal that the motherboard circuit within lcd products exports, V1=0V;V1 DC voltage generates the operating current size that a direct current dimmer voltage signal V1+ is supplied to the positive input terminal control LED lamp tube of amplifier or error amplifier after the 7th resistance R9 and the 8th resistance R10 dividing potential drop, thus controls liquid crystal display picture mean flow rate.
nullAs shown in Figure 5,Described power supply conversion and control circuit include the 4th N-type metal-oxide-semiconductor Q6、Third transistor Q7、4th transistor Q8 and Zener diode ZD1,The emitter stage of third transistor Q7 connects outfan and one end of the tenth resistance R12 of AC-DC change-over circuit respectively,The base stage of third transistor Q7 connects one end and the other end of the tenth resistance R12 of the 9th resistance R11 respectively,The other end of the 9th resistance R11 connects the drain electrode of the 4th N-type metal-oxide-semiconductor Q6,The source ground of the 4th N-type metal-oxide-semiconductor Q6,The grid of the 4th N-type metal-oxide-semiconductor Q6 accesses the switching signal from mainboard,The colelctor electrode of third transistor Q7 connects one end of the 11st resistance R13,The other end of the 11st resistance R13 connects the 4th transistor Q8 colelctor electrode and one end of the 12nd resistance R14 respectively,The base stage of the 4th transistor Q8 connects negative pole and the other end of the 12nd resistance R14 of Zener diode ZD1 respectively,The emitter stage of the 4th transistor Q8 connects one end of the 3rd electric capacity C3 respectively,The other end ground connection of the 3rd electric capacity C3,The plus earth of Zener diode ZD1,Change and the outfan of control circuit using the emitter stage of the 4th transistor Q8 as power supply.
Described third transistor Q7, the 4th N-type metal-oxide-semiconductor Q6, the 9th resistance R11, the tenth resistance R12 constitute an ON-OFF control circuit, are used for whether controlling LED lamp tube drive circuit works;12nd resistance R14, the 4th transistor Q8, Zener diode ZD1, the 3rd electric capacity C3 form voltage stabilizing Vcc power supply circuits, as: Zener diode ZD1 is 9.1V, during the 4th transistor Q8 conducting, Vbe voltage is 0.7V, then supply voltage Vcc=9.1V-0.7V=8.4V;When the switching signal that the grid of the 4th N-type metal-oxide-semiconductor Q6 receives a motherboard circuit offer is high level signal (High), 4th N-type metal-oxide-semiconductor Q6, third transistor Q7 turn on, power supply conversion and control circuit export a Vcc and supply voltage to amplifier the first amplifier OP1, the second amplifier OP2 and reference voltage generating circuit, and LED lamp tube drives and starts normal work.Under the conditions of carrying out standby mode in lcd products, the grid of the 4th N-type metal-oxide-semiconductor Q6 receives switching signal that a motherboard circuit provides when being low level signal (Low), 4th N-type metal-oxide-semiconductor Q6, third transistor Q7 are ended, power supply conversion and control circuit stop output Vcc and supply voltage to amplifier the first amplifier OP1, the second amplifier OP2 and reference voltage generating circuit, LED lamp tube drives and quits work, and now liquid crystal display produces and enters under standby mode because LED lamp tube drive circuit does not works and very energy saving.
Described 3rd crystal Q7 is PNP transistor, and described 4th transistor Q8 is NPN transistor.
nullAs shown in Figure 6,Described reference voltage generating circuit includes the 5th transistor Q9 and three-terminal shunt regulator U1,The colelctor electrode of described 5th transistor Q9 connects power supply conversion and the outfan of control circuit and one end of the 17th resistance R19 respectively,The base stage of the 5th transistor Q9 connects the other end and the cathode terminal of three-terminal shunt regulator U1 of the 17th resistance R19 respectively,The emitter stage of the 5th transistor Q9 connects one end of the 15th resistance R17 respectively、One end of 13rd resistance R15 and one end of the 4th electric capacity C4,The other end of the 13rd resistance R15 connects one end of the 14th resistance R16,The reference edge of three-terminal shunt regulator U1 connects the other end and one end of the 16th resistance R18 of the 15th resistance R17 respectively,The anode tap of three-terminal shunt regulator U1、The other end of the 16th resistance R18、The other end of the 4th electric capacity C 4 and the other end of the 14th resistance R16 ground connection respectively,The emitter stage of the 5th transistor Q9 exports the first reference voltage V ref1,The other end of the 13rd resistance R15 exports the second reference voltage V ref2.
The reference voltage of the reference edge of described three-terminal shunt regulator U1 is 2.5V, and described three-terminal shunt regulator U1 is TL431 manostat.Therefore first reference voltage V ref1=2.5V* (R17+R18)/R18 produced by this reference voltage generating circuit, as: R17=R18=10K Ω, then Vref1=5V, by obtaining second reference voltage V ref2=Vref1*R16/ (R15+R16) after R15 resistance, R16 electric resistance partial pressure, as: R15=22K Ω, R16=3.9K Ω, then Vref2=0.752V.
Described 5th transistor Q9 is NPN transistor.
Described frequency compensated circuit is the RC frequency compensated circuit that a compensation resistance and one compensates capacitances in series.This frequency compensated circuit effect is to make AC-DC change-over circuit output Vout voltage more stable.
nullAs shown in Figure 7,Described AC-DC change-over circuit includes bridge rectifier and filter circuit、Transformator、Feedback circuit and AC-DC change-over circuit control chip,AC-DC change-over circuit control chip has the first pin CS、Second pin Vdri、3rd pin Vcc "、Feedback pin FB and grounding pin GND,Described transformator has the first winding being positioned at primary side、Second winding and the tertiary winding being positioned at secondary side,AC mains accesses one end of the first winding of transformator by bridge rectifier and filter circuit,The other end of the first winding and the drain electrode of one the 5th N-type metal-oxide-semiconductor Q11 connect,The source electrode of the 5th N-type metal-oxide-semiconductor Q11 connects the first pin CS and one end of a resistance R18 of AC-DC change-over circuit control chip respectively,The other end ground connection of resistance R18,The grid of the 5th N-type metal-oxide-semiconductor Q11 connects the second pin Vdri of AC-DC change-over circuit control chip,One end of second winding connects the positive pole of a diode D12,The negative pole of diode D12 connects the 3rd pin Vcc of AC-DC change-over circuit control chip respectively " and one end of electric capacity C12,The other end ground connection of electric capacity C12,One end of the tertiary winding connects the positive pole of diode D11,The negative pole of diode D11 connects one end of electric capacity C11 and one end of feedback circuit respectively,The other end of feedback circuit connects feedback pin FB of AC-DC change-over circuit control chip,The other end of electric capacity C11 connects the other end of the tertiary winding,The other end ground connection of the tertiary winding,The negative pole of diode D11 is as the outfan of AC-DC change-over circuit,The other end of described first winding、One end of second winding and one end of the tertiary winding are Same Name of Ends.
As shown in Figure 8, if not increasing exchanges-internal the Vcc of DC converting circuit " power down suppression circuit time, become low level, the Vcc of AC-DC change-over circuit control chip in switching signal from high level " supply voltage there will be power-off problems.Power down reason: when lcd products is entered standby mode by normal work, the switching signal of the motherboard circuit within machine can be become low level from high level, now the first transistor Q2 can be cut off conducting, R4 can be become from R4//(R5+Rce (Q2)) between sampling feedback pull down resistor resistance Shun, i.e. becoming big between pull down resistor Shun, AC-DC change-over circuit control chip output Vdri pin stopping output PWM square wave carrys out driving transformer and carries out energy conversion.Feedback circuit within AC-DC change-over circuit has a time t2 operating lag problem, therefore needs AC-DC change-over circuit control chip output Vdri pin after the t1+t2 time just can export PWM square wave and carry out driving transformer and carry out energy conversion.The corresponding t2 time; the Vcc of AC-DC change-over circuit control chip " supply voltage occurs as soon as power-off problems; if Vcc " power down time minimum voltage less than the under-voltage protection value (UVLO) within AC-DC change-over circuit control chip; this AC-DC change-over circuit control chip will start under-voltage protection function, makes Switching Power Supply normally to work.
As shown in Figure 9, increase exchanges-internal the Vcc of DC converting circuit " after power down suppression circuit; AC-DC change-over circuit builtin voltage Vcc " voltage occurs without power-off problems, to guarantee that this lcd products when the on & off switch of the plate that pushes button, remains to be smoothly entered standy operation mode by normal mode of operation.
As shown in Figure 10, the invention also discloses a LED lamp tube and drive control chip, described LED lamp tube drives control chip to be integrated with, and described PWM turns DC adjusting control circuit, power supply is changed and control circuit, reference voltage generating circuit, described include following pin, be respectively as follows: 1, Vcc energization pins, provide supply voltage for this control chip;2, COMP feedback pin, is detectd by Pin8 pin, and single feedback LED lamp tube output end voltage regulates AC-DC change-over circuit output voltage Vout size;3, On_Off switch control pin, is used for whether controlling this New LED driving work;4, DIM dims pin, is used for controlling LED lamp tube size of current during this New LED driving work;5, GND grounding pin;6, Iset LED lamp tube electric current arranges pin, maximum current when arranging LED lamp tube work by R1 resistance;7, GM frequency compensation pin, by external R2 resistance and C1 electric capacity, makes the work that whole LED drive system energy is stable;8, LED pin, is used for detecting LED lamp tube output end voltage and electric current.
The present invention uses above technical scheme, 1, AC-DC change-over circuit use single group output design, output voltage is supplied directly to LED lamp tube work.2, each lamp string (String) outfan during LED lamp tube uses single Feedback Design mode, i.e. LED lamp tube is connected together.3, LED lamp tube electric current is controlled accurately by first amplifier OP1 or error amplifier.4, LED lamp tube output end voltage is controlled accurately by second amplifier OP2 or error amplifier, thus control AC-DC change-over circuit list group output voltage, that is: AC-DC change-over circuit list group output voltage values size is variation, and revocable, it is ensured that LED lamp tube drives higher conversion efficiency >=93%.null5、The switching signal provided by motherboard circuit,When switching signal is High high level,AC-DC change-over circuit output in power panel supplies electricity to LED lamp tube on-line operation just like the direct current of 18V-21V,And when lcd products carries out holding state,Switching signal is Low low level,AC-DC change-over circuit in power panel only exports the unidirectional current just like 15V or lower,After DC-DC decompression converting circuit is changed, generate 5V direct current supply electricity to motherboard circuit work,For DC-DC decompression converting circuit,Input voltage is the lowest,Its conversion efficiency can be of a relatively high,As the present invention LED drive power panel when standby,The conversion efficiency of DC-DC decompression converting circuit (15V turns 5V) is 55%-60%,And tradition LED drive power plate is when standby,The conversion efficiency of DC-DC decompression converting circuit (19V turns 5V) is 30%-45%,Therefore the LED lamp tube drive circuit of the present invention has lower stand-by power consumption.6, the LED lamp tube drive circuit of the present invention uses AC-DC change-over circuit list group output unidirectional current and is supplied directly to LED lamp tube work, and traditional LED lamp pipe drives and also just to supply LED lamp tube work after using AC-DC change-over circuit list group output unidirectional current after Boost circuit is boosted, the EMI radiation noise of a large amount of high frequency can be produced during this Boost circuit N-type metal-oxide-semiconductor switch, therefore New LED drives power panel to reduce EMI solution difficulty.7, a C1 electric capacity in parallel and a Q3PNP electric crystal between the colelctor electrode and emitter stage of the first transistor Q2, the LED lamp tube making lcd products drives under the conditions of being entered standby mode by normal work, that is: motherboard circuit provide switching signal from high level High become low level Low time, the Vcc of AC-DC change-over circuit primary side AC-DC change-over circuit control chip " energization pins will not drop to less than the under-voltage protection value (UVLO) set by this control chip energization pins inside because of power down, to guarantee that this lcd products is when the on & off switch of the plate that pushes button, standy operation mode can be smoothly entered by normal mode of operation.8, between Q1 N-channel N-type metal-oxide-semiconductor source electrode and power supply conversion and control circuit outfan, a Roffset biasing resistor is set, when lcd products normally works, can ensure that when the positive dutycycle of DIM dim signal is transferred to minimum 0% liquid crystal display picture is at the darkest picture.The LED of the present invention drives to drive compared with traditional LED lamp pipe to be had: price is low, the high and low stand-by power consumption of efficiency, has lower EMI radiation feature.
In sum, only presently preferred embodiments of the present invention, when not limiting, with this, the scope that the present invention implements, the most generally the most still belong in the range of patent lid of the present invention with modifying according to the simple equivalence change that scope of the present invention patent and invention description content are made.
Claims (10)
1. a single feedback direct-push DC dimming LED lamp tube drive circuit, it is characterised in that: it includes power supply circuits that AC-DC change-over circuit, LED lamp tube drive, AC-DC change-over circuit output voltage controlling circuit, the internal Vcc of AC-DC change-over circuit " power down suppression circuit, PWM turn DC adjusting control circuit, LED lamp tube current control circuit and single feed back LED lamp tube;
The ac input end of described AC-DC change-over circuit receives an AC mains, and AC mains is carried out voltage conversion and is exported the unidirectional current of one group of variable values by outfan, the input of the power supply circuits that the input of AC-DC change-over circuit outfan order feedback LED lamp tube and LED lamp tube drive, the power supply circuits that LED lamp tube drives are additionally provided with switching signal receiving terminal, first reference voltage output end, second reference voltage output end and Vcc outfan, described AC-DC change-over circuit output voltage controlling circuit is provided with the first feedback input end, second feedback input end and reference voltage receiving terminal,
The outfan of described single feedback LED lamp tube connects input and first feedback input end of AC-DC change-over circuit output voltage controlling circuit of LED lamp tube current control circuit respectively;LED lamp tube current control circuit is additionally provided with feeder ear and controls current signal receiving terminal, the feeder ear of LED lamp tube current control circuit connects the Vcc outfan of the power supply circuits that LED lamp tube drives, and the current signal receiving terminal connection PWM that controls of LED lamp tube current control circuit turns the outfan of DC adjusting control circuit;
Described PWM turns DC adjusting control circuit and is additionally provided with reference voltage input and dim signal receiving terminal, PWM turns the first reference voltage output end of the power supply circuits of the reference voltage input connection LED lamp tube driving of DC adjusting control circuit, PWM turns the dim signal receiving terminal reception one DIM dim signal from mainboard of DC adjusting control circuit, and generates a direct current dimmer voltage output to LED lamp tube current control circuit according to the positive duty cycle conversion of DIM dim signal;The internal Vcc of described AC-DC change-over circuit " outfan of power down suppression circuit connects the second feedback input end of AC-DC change-over circuit output voltage controlling circuit; the internal Vcc of AC-DC change-over circuit " the switching signal receiving terminal of power down suppression circuit receives one from the switching signal of mainboard; the internal Vcc of AC-DC change-over circuit " power down suppression circuit guarantees that this LED lamp tube drives when being carried out standby not mode of operation by normal mode of operation, AC-DC change-over circuit occurs without and causes under-voltage protection because of internal power down;The reference voltage receiving terminal of described AC-DC change-over circuit output voltage controlling circuit connects the second reference voltage output end of the power supply circuits that LED lamp tube drives, the feedback input end of the output termination AC-DC change-over circuit of AC-DC change-over circuit output voltage controlling circuit, AC-DC change-over circuit output voltage controlling circuit controls AC-DC change-over circuit output end voltage by detecting single feedback LED lamp tube output end voltage;The switching signal receiving terminal of the power supply circuits that described LED lamp tube drives receives the switching signal from mainboard, and whether the power supply circuits driven in order to control LED lamp tube work.
A kind of single feedback direct-push DC dimming LED lamp tube drive circuit, it is characterised in that: described AC-DC change-over circuit includes bridge rectifier and filter circuit, transformator, feedback circuit and AC-DC change-over circuit control chip,
The power supply circuits that described LED lamp tube drives include reference voltage generating circuit and power supply conversion and control circuit;
Described LED lamp tube current control circuit includes the first N-type metal-oxide-semiconductor Q1, current sampling resistor R1, biasing resistor and the first amplifier OP1;
Described AC-DC change-over circuit output voltage controlling circuit includes the second amplifier OP2, voltage sample resistance R2, frequency compensated circuit, the first transistor Q2, optocoupler and TL431 circuit, feedback resistance R3, feedback resistance R4 and feedback resistance R5;
The internal Vcc of described AC-DC change-over circuit " power down suppression circuit includes the first electric capacity C1 and transistor seconds Q3;
nullAC-DC change-over circuit control chip has the first pin CS、Second pin Vdri、3rd pin Vcc "、Feedback pin FB and grounding pin GND,Described transformator has the first winding being positioned at primary side、Second winding and the tertiary winding being positioned at secondary side,AC mains accesses one end of the first winding of transformator by bridge rectifier and filter circuit,The other end of the first winding and the drain electrode of one the 5th N-type metal-oxide-semiconductor Q11 connect,The source electrode of the 5th N-type metal-oxide-semiconductor Q11 connects the first pin CS and one end of a resistance R18 of AC-DC change-over circuit control chip respectively,The other end ground connection of resistance R18,The grid of the 5th N-type metal-oxide-semiconductor Q11 connects the second pin Vdri of AC-DC change-over circuit control chip,One end of second winding connects the positive pole of a diode D12,The negative pole of diode D12 connects the 3rd pin Vcc of AC-DC change-over circuit control chip respectively " and one end of electric capacity C12,The other end ground connection of electric capacity C12,One end of the tertiary winding connects the positive pole of diode D11,The negative pole of diode D11 connects one end of electric capacity C11 and one end of feedback circuit respectively,The other end of feedback circuit connects feedback pin FB of AC-DC change-over circuit control chip,The other end of electric capacity C11 connects the other end of the tertiary winding,The other end ground connection of the tertiary winding,The negative pole of diode D11 is as the outfan of AC-DC change-over circuit,The other end of described first winding、One end of second winding and one end of the tertiary winding are Same Name of Ends;
The outfan of described AC-DC change-over circuit connects single input feeding back LED lamp tube and described power supply conversion and the input of control circuit respectively, the outfan of power supply conversion and control circuit connects the positive power source terminal of the second amplifier OP2 and the input of reference voltage generating circuit respectively, and reference voltage generating circuit generates the first reference voltage and the second reference voltage respectively;
The outfan of single feedback LED lamp tube connects drain electrode and one end of voltage sample resistance R2 of the first N-type metal-oxide-semiconductor Q1 respectively, the source electrode of the first N-type metal-oxide-semiconductor Q1 connects one end and the negative input end of the first amplifier OP1 of current sampling resistor R1 respectively, the other end ground connection of current sampling resistor R1, the grid of the first N-type metal-oxide-semiconductor Q1 connects the outfan of the first amplifier OP1
One end of biasing resistor connects power supply conversion and the outfan of control circuit, and the other end of biasing resistor connects the source electrode of the first N-type metal-oxide-semiconductor Q1;
Described PWM turns DC adjusting control circuit and receives a DIM dim signal and one first reference voltage respectively, and the anode that the first reference voltage generates a direct current dimmer voltage output to the first amplifier OP1 according to the positive duty cycle conversion of DIM dim signal is entered end,
The other end of voltage sample resistance R2 connects the negative input end of the second amplifier OP2 and one end of frequency compensated circuit respectively, and the other end of frequency compensated circuit connects the outfan of the second amplifier OP2, and the positive input terminal of the second amplifier OP2 accesses the second reference voltage,
The outfan of the second amplifier OP2 connects the base stage of the first transistor Q2, the grounded emitter of the first transistor Q2, the colelctor electrode of the first transistor Q2 connects one end and one end of the first electric capacity C1 of feedback resistance R5 respectively, the other end of feedback resistance R5 connects one end of feedback resistance R3 respectively, one end of feedback resistance R4 and optocoupler and the reference edge of TL431 circuit, the other end of feedback resistance R3 connects the outfan of AC-DC change-over circuit, the other end ground connection of feedback resistance R4, the other end of optocoupler and TL431 circuit connects AC-DC change-over circuit, the other end of the first electric capacity C1 connects the emitter stage of transistor seconds Q3, the base stage of transistor seconds Q3 accesses the switching signal from mainboard, the grounded collector of transistor seconds Q3.
A kind of single feedback direct-push DC dimming LED lamp tube drive circuit, it is characterised in that: described the first transistor Q2 is NPN transistor, and described transistor seconds Q3 is PNP transistor.
nullA kind of single feedback direct-push DC dimming LED lamp tube drive circuit,It is characterized in that: described PWM turns DC adjusting control circuit and includes the second N-type metal-oxide-semiconductor Q4 and the 3rd N-type metal-oxide-semiconductor Q5,The grid of the second N-type metal-oxide-semiconductor Q4 accesses DIM dim signal,The source ground of the second N-type metal-oxide-semiconductor Q4,The drain electrode of the second N-type metal-oxide-semiconductor Q4 connects grid and one end of the 4th resistance R6 of the 3rd N-type metal-oxide-semiconductor Q5 respectively,The source ground of the 3rd N-type metal-oxide-semiconductor Q5,The drain electrode of the 3rd N-type metal-oxide-semiconductor Q5 connects one end and one end of the 6th resistance R8 of the 5th resistance R7 respectively,The other end of the 4th resistance R6 and the other end of the 5th resistance R7 are respectively connected to the first reference voltage,The other end of the 6th resistance R8 connects one end and one end of the 7th resistance R9 of the second electric capacity C2 respectively,The other end of the 7th resistance R9 connects one end and the positive input terminal of the first amplifier OP1 of the 8th resistance R10 respectively,The other end of the second electric capacity C2 and the other end of the 8th resistance R10 ground connection respectively.
nullA kind of single feedback direct-push DC dimming LED lamp tube drive circuit,It is characterized in that: described power supply conversion and control circuit include the 4th N-type metal-oxide-semiconductor Q6、Third transistor Q7、4th transistor Q8 and Zener diode ZD1,The emitter stage of third transistor Q7 connects outfan and one end of the tenth resistance R12 of AC-DC change-over circuit respectively,The base stage of third transistor Q7 connects one end and the other end of the tenth resistance R12 of the 9th resistance R11 respectively,The other end of the 9th resistance R11 connects the drain electrode of the 4th N-type metal-oxide-semiconductor Q6,The source ground of the 4th N-type metal-oxide-semiconductor Q6,The grid of the 4th N-type metal-oxide-semiconductor Q6 accesses the switching signal from mainboard,The colelctor electrode of third transistor Q7 connects one end of the 11st resistance R13,The other end of the 11st resistance R13 connects the 4th transistor Q8 colelctor electrode and one end of the 12nd resistance R14 respectively,The base stage of the 4th transistor Q8 connects negative pole and the other end of the 12nd resistance R14 of Zener diode ZD1 respectively,The emitter stage of the 4th transistor Q8 connects one end of the 3rd electric capacity C3 respectively,The other end ground connection of the 3rd electric capacity C3,The plus earth of Zener diode ZD1,Change and the outfan of control circuit using the emitter stage of the 4th transistor Q8 as power supply.
A kind of single feedback direct-push DC dimming LED lamp tube drive circuit, it is characterised in that: described 3rd crystal Q7 is PNP transistor, and described 4th transistor Q8 is NPN transistor.
nullA kind of single feedback direct-push DC dimming LED lamp tube drive circuit,It is characterized in that: described reference voltage generating circuit includes the 5th transistor Q9 and three-terminal shunt regulator U1,The colelctor electrode of described 5th transistor Q9 connects power supply conversion and the outfan of control circuit and one end of the 17th resistance R19 respectively,The base stage of the 5th transistor Q9 connects the other end and the cathode terminal of three-terminal shunt regulator U1 of the 17th resistance R19 respectively,The emitter stage of the 5th transistor Q9 connects one end of the 15th resistance R17 respectively、One end of 13rd resistance R15 and one end of the 4th electric capacity C4,The other end of the 13rd resistance R15 connects one end of the 14th resistance R16,The reference edge of three-terminal shunt regulator U1 connects the other end and one end of the 16th resistance R18 of the 15th resistance R17 respectively,The anode tap of three-terminal shunt regulator U1、The other end of the 16th resistance R18、The other end of the 4th electric capacity C 4 and the other end of the 14th resistance R16 ground connection respectively,The emitter stage of the 5th transistor Q9 exports the first reference voltage,The other end of the 13rd resistance R15 exports the second reference voltage.
A kind of single feedback direct-push DC dimming LED lamp tube drive circuit, it is characterised in that: the reference voltage of the reference edge of described three-terminal shunt regulator U1 is 2.5V, and described three-terminal shunt regulator U1 is TL431 manostat.
A kind of single feedback direct-push DC dimming LED lamp tube drive circuit, it is characterised in that: described 5th transistor Q9 is NPN transistor.
A kind of single feedback direct-push DC dimming LED lamp tube drive circuit, it is characterised in that: described frequency compensated circuit is the RC frequency compensated circuit that a compensation resistance and one compensates capacitances in series.
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Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
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Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102752918A (en) * | 2012-06-15 | 2012-10-24 | 福建捷联电子有限公司 | Half-bridge-structure LED (light-emitting diode) drive circuit controlled by secondary side |
US20130285553A1 (en) * | 2009-11-06 | 2013-10-31 | Neofocal Systems, Inc. | System And Method For Single Conductor Power, Control, And Feedback System |
CN203368838U (en) * | 2013-06-28 | 2013-12-25 | 上海信耀电子有限公司 | LED driver |
CN105554954A (en) * | 2016-01-26 | 2016-05-04 | 佛山市南海区联合广东新光源产业创新中心 | Control chip for LED (Light-Emitting Diode) driving |
CN205912292U (en) * | 2016-07-13 | 2017-01-25 | 福建捷联电子有限公司 | Straight pushing -type DC of single feedback LED fluorescent tube drive circuit that adjusts luminance |
-
2016
- 2016-07-13 CN CN201610551279.1A patent/CN105960070B/en active Active
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20130285553A1 (en) * | 2009-11-06 | 2013-10-31 | Neofocal Systems, Inc. | System And Method For Single Conductor Power, Control, And Feedback System |
CN102752918A (en) * | 2012-06-15 | 2012-10-24 | 福建捷联电子有限公司 | Half-bridge-structure LED (light-emitting diode) drive circuit controlled by secondary side |
CN203368838U (en) * | 2013-06-28 | 2013-12-25 | 上海信耀电子有限公司 | LED driver |
CN105554954A (en) * | 2016-01-26 | 2016-05-04 | 佛山市南海区联合广东新光源产业创新中心 | Control chip for LED (Light-Emitting Diode) driving |
CN205912292U (en) * | 2016-07-13 | 2017-01-25 | 福建捷联电子有限公司 | Straight pushing -type DC of single feedback LED fluorescent tube drive circuit that adjusts luminance |
Cited By (16)
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---|---|---|---|---|
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CN107770914B (en) * | 2017-11-03 | 2023-10-10 | 赛尔富电子有限公司 | LED lamp power supply |
CN107770914A (en) * | 2017-11-03 | 2018-03-06 | 赛尔富电子有限公司 | A kind of LED lamp power supply |
CN109560805A (en) * | 2018-12-29 | 2019-04-02 | 惠州华科电器有限公司 | Single-button electronic switching circuit |
CN110149747A (en) * | 2019-05-15 | 2019-08-20 | 福建捷联电子有限公司 | The driving circuit and design method of LED lamp tube are directly supplied electricity to power supply adaptor |
CN110149747B (en) * | 2019-05-15 | 2021-12-31 | 冠捷电子科技(福建)有限公司 | Driving circuit for directly supplying power to LED lamp tube by power adapter and design method |
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CN113316289A (en) * | 2020-02-26 | 2021-08-27 | 苏州佳世达电通有限公司 | LED power supply circuit |
CN113316289B (en) * | 2020-02-26 | 2024-07-16 | 苏州佳世达电通有限公司 | LED power supply circuit |
CN112311223A (en) * | 2020-10-22 | 2021-02-02 | 福建捷联电子有限公司 | DC-DC converter with peak delay start notification |
CN115066066A (en) * | 2021-04-16 | 2022-09-16 | 深圳市紫光新能源技术有限公司 | Lamp control method |
US11297775B1 (en) | 2021-07-22 | 2022-04-12 | Boulder Lamp, Inc. | LED grow light system with time varying light intensity |
CN114825939A (en) * | 2022-03-09 | 2022-07-29 | 冠捷电子科技(福建)有限公司 | High-precision switching power supply circuit based on double-group output of single transformer |
CN114825939B (en) * | 2022-03-09 | 2024-10-22 | 冠捷电子科技(福建)有限公司 | High-precision switching power supply circuit based on double-group output of single transformer |
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