CN105960070B - A kind of single feedback direct-push DC dimming LED lamp tube drive circuits - Google Patents
A kind of single feedback direct-push DC dimming LED lamp tube drive circuits Download PDFInfo
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- CN105960070B CN105960070B CN201610551279.1A CN201610551279A CN105960070B CN 105960070 B CN105960070 B CN 105960070B CN 201610551279 A CN201610551279 A CN 201610551279A CN 105960070 B CN105960070 B CN 105960070B
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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
Of the invention to disclose a kind of single feedback direct-push DC dimming LED lamp tube drive circuits, it includes AC DC change-over circuit, the power supply circuit of LED lamp tube driving, AC DC change-over circuit output voltage controlling circuit, AC DC change-over circuit inside Vcc " power down suppression circuit, PWM and turns DC adjusting control circuits, LED lamp tube current control circuit and single feedback LED lamp tube；The AC DC change-over circuit of the present invention exports design using single group, and output AC DC change-over circuit single group output voltage values size is that the voltage changed is supplied directly to single feedback LED lamp tube work, the EMI radiation noise of a large amount of high frequencies of no Boost circuit.Effectively reduction liquid crystal display product stand-by power consumption of the invention, more energy-conserving and environment-protective.Drive circuit cost of the invention is low, efficiency high, low standby power loss, with lower EMI radiation feature.
Description
Technical field
The present invention relates to a kind of single feedback direct-push DC dimming LED lamp tube drive circuits.
Background technology
Traditional lcd products LED lamp tube circuit theory is as shown in figure 1, AC mains 90V-264V is through handing over
Stream-DC converting circuit generates a low-voltage DC such as after carrying out voltage conversion：19V direct currents, the 19V direct currents pass through
Operating voltage after Boost circuit is boosted needed for one LED lamp tube of generation is such as：25V-70V direct currents supply electricity to LED lamp tube
Work, the Boost circuit is driven by booster circuit control chip, in the LED lamp tube each lamp string output feedback end with
Each feedback pin of booster circuit control chip is electrically connected, and each lamp string work in LED lamp tube is controlled by booster circuit control chip
Electric current when making, to control liquid crystal display picture mean flow rate, the booster driving circuit receives one from motherboard circuit（Diagram is not drawn
Go out）There is provided a switching signal, whether to control the LED lamp tube drive circuit works, the booster driving circuit receive one from
Motherboard circuit（Diagram is not drawn into）The DIM dim signals provided, to control electric current during each lamp string work in the LED lamp tube big
It is small, so as to control liquid crystal display picture mean flow rate.
But above-mentioned prior art there are problems that it is as follows：1st, LED lamp tube driving power supply plate part material cost price compared with
Height, is having begun to lack the market competitiveness in price.2nd, LED tube drive circuit (is free of AC-DC change-over circuit
Conversion efficiency) conversion efficiency is between 85%-90%, and conversion efficiency is not high, in the design new efficiency lcd products of EPA7.0
When, the power supply conversion efficiency for generally requiring further lifting AC-DC change-over circuit can be only achieved the new efficiency regulations of EPA7.0
Requirement, and LED lamp tube driving power supply plate part material can be caused when lifting the power supply conversion efficiency of AC-DC change-over circuit
Cost price is further lifted.3rd, the motherboard circuit inside lcd products needs 5V to power, it is necessary to from 19V by one group
DC-DC decompression converting circuits turn a 5V DC voltage, and 19V turns 5V DC-DC decompression converting circuits and turn under waiting condition
Change efficiency not high, only：30%-45% or so conversion efficiency.Therefore, the design cost of LED lamp tube driving power supply plate is reduced,
LED lamp tube driving conversion efficiency is lifted, reduction liquid crystal display product stand-by power consumption turns into the trend that technology develops.
The content of the invention
It is an object of the invention to overcome the deficiencies of the prior art and provide a kind of single feedback direct-push DC dimming LED (Light Emitting Diode) fluorescent tubes
Drive circuit.
The technical solution adopted by the present invention is：
A kind of single feedback direct-push DC dimming LED lamp tube drive circuits, it includes AC-DC change-over circuit, LED lamp tube
Power supply circuit, AC-DC change-over circuit output voltage controlling circuit, the AC-DC change-over circuit inside Vcc " of driving fall
Electric suppression circuit, PWM turn DC adjusting control circuits, 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 are entered
Row voltage conversion and the direct current that one group of variable values is exported by output end, AC-DC change-over circuit output end order
The input of the input of LED lamp tube and the power supply circuit of LED lamp tube driving is fed back, the power supply circuit of LED lamp tube driving is also set
There are switching signal receiving terminal, the first reference voltage output end, the second reference voltage output end and Vcc output ends, the exchange-straight
Circulation changes circuit output voltage control circuit and is provided with the first feedback input end, the second feedback input end and reference voltage receiving terminal,
The output end of single feedback LED lamp tube connects the input of LED lamp tube current control circuit and exchanges respectively-and it is straight
The first feedback input end that circuit output voltage controls circuit is changed in circulation；LED lamp tube current control circuit be additionally provided with feeder ear and
Control electric current signal receiving terminal, the Vcc of the power supply circuit of the feeder ear connection LED lamp tube driving of LED lamp tube current control circuit
Output end, the control electric current signal receiving terminal connection PWM of LED lamp tube current control circuit turns the output of DC adjusting control circuits
End；
PWM turns DC adjusting control circuits and is additionally provided with reference voltage input and dim signal receiving terminal, and PWM turns DC light modulation controls
First reference voltage output end of the power supply circuit of the reference voltage input connection LED lamp tube driving of circuit processed, PWM turns DC tune
The dim signal receiving terminal of light control circuit receives the DIM dim signals from mainboard, and just accounting for according to DIM dim signals
Sky is exported to LED lamp tube current control circuit to control single feedback LED lamp tube work than conversion one direct current dimmer voltage of generation
When size of current；The output end connection AC-DC conversion of Vcc " power down suppression circuits inside the AC-DC change-over circuit
Circuit output voltage controls Vcc " power down suppression circuits inside the second feedback input end of circuit, AC-DC change-over circuit
Switching signal receiving terminal receives Vcc " power down suppression circuits inside a switching signal from mainboard, AC-DC change-over circuit
When ensuring that LED lamp tube driving carries out standby not mode of operation by normal mode of operation, AC-DC change-over circuit internal control
Chip Vcc supply voltages are occurred without causes the control chip to produce under-voltage protection because of power down；Described AC-DC conversion electricity
The second reference voltage output of the power supply circuit of the reference voltage receiving terminal connection LED lamp tube driving of road output voltage controlling circuit
End, 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 exchange-straight by detecting single feedback LED lamp tube output end voltage
Circuit output terminal voltage is changed in circulation；The switching signal receiving terminal of the power supply circuit of described LED lamp tube driving, which is received, comes from mainboard
Switching signal, to control LED lamp tube drive power supply circuit whether work.
Further, the AC-DC change-over circuit includes bridge rectifier and filter circuit, transformer, feedback circuit
With AC-DC change-over circuit control chip,
The power supply circuit of the LED lamp tube driving includes reference voltage generating circuit and power supply conversion and control circuit；
The LED lamp tube current control circuit includes the first N-type metal-oxide-semiconductor Q1, current sampling resistor R1, biasing resistor and the
One amplifier OP1；
The AC-DC change-over circuit output voltage controlling circuit include the second amplifier OP2, voltage sample resistance R2,
Frequency compensated circuit, the first transistor Q2, optocoupler and TL431 circuits, feedback resistance R3, feedback resistance R4 and feedback resistance R5；
Vcc " power down suppression circuit includes the first electric capacity C1 and second transistor inside the AC-DC change-over circuit
Q3；
AC-DC change-over circuit control chip has the first pin CS, second pin Vdri, the 3rd pin Vcc ", anti-
Pin FB and grounding pin GND is presented, the transformer has the first winding positioned at primary side, the second winding and positioned at secondary side
The tertiary winding, AC mains access one end of the first winding of transformer by bridge rectifier and filter circuit, first around
The other end of group is connected with one the 5th N-type metal-oxide-semiconductor Q11 drain electrode, and the 5th N-type metal-oxide-semiconductor Q11 source electrode connects exchange-directly respectively
The the first pin CS and a resistance R18 of circuit control chip one end, resistance R18 other end ground connection, the 5th N-type are changed in circulation
Metal-oxide-semiconductor Q11 grid connects the second pin Vdri of AC-DC change-over circuit control chip, one end connection of the second winding
One diode D12 positive pole, diode D12 negative pole connects the 3rd pin of AC-DC change-over circuit control chip respectively
Vcc " and electric capacity C12 one end, electric capacity C12 other end ground connection, one end connection diode D11 of tertiary winding positive pole, two
Pole pipe D11 negative pole connects electric capacity C11 one end and one end of feedback circuit respectively, and the other end connection exchange of feedback circuit-
The feedback pin FB of DC converting circuit control chip, electric capacity the C11 other end connect the other end of the tertiary winding, the tertiary winding
Other end ground connection, diode D11 negative pole as AC-DC change-over circuit output end, first winding it is another
The one end at end, one end of the second winding and the tertiary winding is Same Name of Ends；
The output end of the AC-DC change-over circuit connects the input of single feedback LED lamp tube and the power supply respectively
The output end of conversion and the input of control circuit, power supply conversion and control circuit connects the second amplifier OP2 positive supply respectively
End and the input of reference voltage generating circuit, reference voltage generating circuit generate the first reference voltage and the second benchmark electricity respectively
Pressure；
The output end of single feedback LED lamp tube connect respectively the first N-type metal-oxide-semiconductor Q1 drain electrode and voltage sample resistance R2 one
End, the first N-type metal-oxide-semiconductor Q1 source electrode connects current sampling resistor R1 one end and the first amplifier OP1 negative input end respectively, electricity
Sampling resistor R1 other end ground connection is flowed, the first N-type metal-oxide-semiconductor Q1 grid connects the first amplifier OP1 output end,
One end connection power supply conversion of biasing resistor and the output end of control circuit, the other end connection first of biasing resistor
N-type metal-oxide-semiconductor Q1 source electrode；
The PWM turns DC adjusting control circuits and receives a DIM dim signals and one first reference voltage respectively, and by first
Reference voltage generates a direct current dimmer voltage according to the positive duty cycle conversion of DIM dim signals and exported to the first amplifier OP1 just
Hold into end,
The voltage sample resistance R2 other end connect respectively the second amplifier OP2 negative input end and frequency compensated circuit one
End, the other end of frequency compensated circuit connects the second amplifier OP2 output end, the second amplifier OP2 positive input terminal access second
Reference voltage,
Second amplifier OP2 output end connection the first transistor Q2 base stage, the first transistor Q2 grounded emitter, the
One transistor Q2 colelctor electrode connects feedback resistance R5 one end and the first electric capacity C1 one end respectively, and feedback resistance R5's is another
End connects the reference edge of feedback resistance R3 one end, feedback resistance R4 one end and optocoupler and TL431 circuits, feedback resistance respectively
The R3 other end connects the output end of AC-DC change-over circuit, feedback resistance R4 other end ground connection, optocoupler and TL431 electricity
The other end connection AC-DC change-over circuit on road, the first electric capacity C1 other end connection second transistor Q3 emitter stage, the
Two-transistor Q3 switching signal of the base stage access from mainboard, second transistor Q3 grounded collector.
Further, the first transistor Q2 is NPN transistor, and the second transistor Q3 is PNP transistor.
Further, the PWM, which turns DC adjusting control circuits, includes the second N-type metal-oxide-semiconductor Q4 and the 3rd N-type metal-oxide-semiconductor Q5, the
Two N-type metal-oxide-semiconductor Q4 grid access DIM dim signals, the second N-type metal-oxide-semiconductor Q4 source ground, the second N-type metal-oxide-semiconductor Q4 leakage
Pole connects the 3rd N-type metal-oxide-semiconductor Q5 grid and the 4th resistance R6 one end, the 3rd N-type metal-oxide-semiconductor Q5 source ground, respectively
Three N-type metal-oxide-semiconductor Q5 drain electrode connects the 5th resistance R7 one end and the 6th resistance R8 one end respectively, and the 4th resistance R6's is another
End and the 5th resistance the R7 other end are respectively connected to the first reference voltage, and the 6th resistance R8 other end connects the second electric capacity respectively
C2 one end and the 7th resistance R9 one end, the 7th resistance R9 other end connect the 8th resistance R10 one end and first respectively
Amplifier OP1 positive input terminal, the second electric capacity C2 other end and the 8th resistance R10 other end are grounded respectively.
Further, the power supply conversion and control circuit include the 4th N-type metal-oxide-semiconductor Q6, third transistor Q7, the 4th crystalline substance
Body pipe Q8 and voltage-regulator diode ZD1, third transistor Q7 emitter stage connect respectively AC-DC change-over circuit output end and
Tenth resistance R12 one end, third transistor Q7 base stage connects the 9th resistance R11 one end and the tenth resistance R12 respectively
The other end, the 9th resistance R11 the 4th N-type metal-oxide-semiconductor Q6 of other end connection drain electrode, the 4th N-type metal-oxide-semiconductor Q6 source ground,
4th N-type metal-oxide-semiconductor Q6 switching signal of the grid access from mainboard, third transistor Q7 colelctor electrode connects the 11st resistance
R13 one end, the 11st resistance R13 other end connects the one of the 4th transistor Q8 colelctor electrodes and the 12nd resistance R14 respectively
End, the 4th transistor Q8 base stage connects voltage-regulator diode ZD1 negative pole and the 12nd resistance R14 other end, the 4th respectively
Transistor Q8 emitter stage connects the 3rd electric capacity C3 one end, the 3rd electric capacity C3 other end ground connection, voltage-regulator diode ZD1 respectively
Plus earth, using the 4th transistor Q8 emitter stage be used as power supply conversion and control circuit output end.
Further, the 3rd crystal Q7 is PNP transistor, and the 4th transistor Q8 is NPN transistor.
Further, the reference voltage generating circuit includes the 5th transistor Q9 and three-terminal shunt regulator U1, described
5th transistor Q9 colelctor electrode connects output end and the 17th resistance R19 one end of power supply conversion and control circuit respectively,
5th transistor Q9 base stage connects the 17th resistance R19 other end and three-terminal shunt regulator U1 cathode terminal respectively, the
Five transistor Q9 emitter stage connects the 15th resistance R17 one end, the 13rd resistance R15 one end and the 4th electric capacity C4 respectively
One end, the 13rd resistance R15 other end connects the 14th resistance R16 one end, three-terminal shunt regulator U1 reference edge
Respectively connection the 15th resistance R17 the other end and the 16th resistance R18 one end, three-terminal shunt regulator U1 anode tap,
The 16th resistance R18 other end, the 4th electric capacity C 4 other end and the 14th resistance R16 other end is grounded respectively, and the 5th
Transistor Q9 emitter stage exports the first reference voltage, and the 13rd resistance R15 other end exports the second reference voltage.
Further, the reference voltage of the reference edge of the three-terminal shunt regulator U1 is 2.5V, and three end is in parallel steady
Depressor U1 is TL431 voltage-stablizers.
Further, the 5th transistor Q9 is NPN transistor.
Further, the frequency compensated circuit is the RC frequency compensations that a compensation resistance and a compensating electric capacity are in series
Circuit.
The present invention uses above technical scheme, 1, AC-DC change-over circuit design is exported using single group, output voltage is straight
Connect and be supplied to LED lamp tube to work.2nd, LED lamp tube is using single Feedback Design mode, i.e., each lamp string (String) in LED lamp tube is defeated
Go out termination together.3rd, LED tube current is accurately controlled by first amplifier OP1 or error amplifier.4th, pass through
Second amplifier OP2 or error amplifier accurately control LED lamp tube output end voltage, so as to control AC-DC to turn
Circuit single group output voltage is changed, i.e.,:AC-DC change-over circuit single group output voltage values size is to change, and on-fixed
, it is ensured that LED lamp tube driving has higher conversion efficiency >=93%.5th, the switching signal provided by motherboard circuit, switching signal
During for High high level, it is straight that the output of AC-DC change-over circuit in power panel supplies electricity to LED lamp tube just like 18V-21V direct current
Connect work, and when lcd products carry out holding state, switching signal is exchange in Low low levels, power panel-straight
Stream change-over circuit is only exported just like 15V or lower direct current, and generation 5V direct currents are supplied electricity to after being changed through DC-DC decompression converting circuits
Motherboard circuit works, and for DC-DC decompression converting circuits, input voltage is lower, and its conversion efficiency can be of a relatively high, such as the present invention
LED drivings power panel when standby, the conversion efficiency of DC-DC decompression converting circuits (15V turns 5V) is 55%-60%, and is passed
LED drive power plate unite when standby, the conversion efficiency of DC-DC decompression converting circuits (19V turns 5V) is 30%-45%, therefore this hair
Bright LED tube drive circuit has lower stand-by power consumption.6th, LED tube drive circuit of the invention use exchange-
DC converting circuit single group output direct current is supplied directly to LED lamp tube work, and the driving of traditional LED lamp pipe uses friendship
LED lamp tube work is also just supplied after Boost circuit is boosted after stream-DC converting circuit single group output direct current,
The EMI radiation noise of a large amount of high frequencies can be produced during the Boost circuit N-type metal-oxide-semiconductor switch, therefore New LED driving is electric
Source plate reduces EMI and solves difficulty.7th, the C1 electric capacity in parallel and one between the first transistor Q2 colelctor electrode and emitter stage
Q3PNP electric crystals so that the LED lamp tube driving of lcd products is entered under the conditions of standby mode by normal work, i.e.,：It is main
When the switching signal that plate circuit is provided is changed into low level Low from high level High, the exchange of AC-DC change-over circuit primary side-
Vcc " the energization pins of DC converting circuit control chip will not be dropped to because of power down less than institute inside the control chip energization pins
The under-voltage protection value (UVLO) of setting, to ensure that the lcd products, can be by normal when pushing button the on ＆ off switch of plate
Mode of operation smoothly enters standy operation mode.8th, Q1N raceway grooves N-type metal-oxide-semiconductor source electrode and power supply conversion and control circuit output
One Roffset biasing resistors are set between end, in lcd products normal work, when the positive dutycycle of DIM dim signals
It can ensure that liquid crystal display picture is at completely dark picture when being transferred to minimum 0%.The LED of the present invention is driven compared with traditional LED lamp pipe
Driving has：Price is low, efficiency high, low standby power loss, with lower EMI radiation feature.
Brief description of the drawings
The present invention is described in further details below in conjunction with the drawings and specific embodiments；
The circuit theory schematic diagram that Fig. 1 drives for traditional LED lamp tube；
Fig. 2 is a kind of schematic block circuit diagram of single feedback direct-push DC dimming LED lamp tube drive circuits of the present invention；
Fig. 3 is a kind of circuit diagram of single feedback direct-push DC dimming LED lamp tube drive circuits of the present invention；
Fig. 4 turns DC adjusting control circuits for a kind of PWM of single feedback direct-push DC dimming LED lamp tube drive circuits of the present invention
Schematic diagram；
Power supply conversions and control circuit of the Fig. 5 for a kind of single feedback direct-push DC dimming LED lamp tube drive circuits of the present invention
Schematic diagram；
Fig. 6 shows for a kind of reference voltage generating circuit of single feedback direct-push DC dimming LED lamp tube drive circuits of the present invention
It is intended to；
Fig. 7 shows for a kind of AC-DC change-over circuit of single feedback direct-push DC dimming LED lamp tube drive circuits of the present invention
It is intended to；
If AC-DC change-over circuit when Fig. 8 is without AC-DC change-over circuit inside Vcc " power down suppression circuits
Waveform diagram during supply voltage Vcc " power down；
Fig. 9 be the present invention increase exchanges-DC converting circuit inside AC-DC conversion electricity after Vcc " power down suppression circuits
The supply voltage Vcc " on road waveform diagram；
Figure 10 is a kind of chip alternative structure signal of single feedback direct-push DC dimming LED lamp tube drive circuits of the present invention
Figure.
Embodiment
As shown in one of Fig. 2-10, the present invention it include AC-DC change-over circuit, LED lamp tube drive power supply circuit,
Vcc " power down suppression circuit, PWM turn inside AC-DC change-over circuit output voltage controlling circuit, AC-DC change-over circuit
DC adjusting control circuits, 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 are entered
Row voltage conversion and the direct current that one group of variable values is exported by output end, AC-DC change-over circuit output end order
The input of the input of LED lamp tube and the power supply circuit of LED lamp tube driving is fed back, the power supply circuit of LED lamp tube driving is also set
There are switching signal receiving terminal, the first reference voltage output end, the second reference voltage output end and Vcc output ends, the exchange-straight
Circulation changes circuit output voltage control circuit and is provided with the first feedback input end, the second feedback input end and reference voltage receiving terminal,
The output end of single feedback LED lamp tube connects the input of LED lamp tube current control circuit and exchanges respectively-and it is straight
The first feedback input end that circuit output voltage controls circuit is changed in circulation；LED lamp tube current control circuit be additionally provided with feeder ear and
Control electric current signal receiving terminal, the Vcc of the power supply circuit of the feeder ear connection LED lamp tube driving of LED lamp tube current control circuit
Output end, the control electric current signal receiving terminal connection PWM of LED lamp tube current control circuit turns the output of DC adjusting control circuits
End；
PWM turns DC adjusting control circuits and is additionally provided with reference voltage input and dim signal receiving terminal, and PWM turns DC light modulation controls
First reference voltage output end of the power supply circuit of the reference voltage input connection LED lamp tube driving of circuit processed, PWM turns DC tune
The dim signal receiving terminal of light control circuit receives the DIM dim signals from mainboard, and just accounting for according to DIM dim signals
Sky is exported to LED lamp tube current control circuit to control single feedback LED lamp tube work than conversion one direct current dimmer voltage of generation
When size of current；The output end connection AC-DC conversion of Vcc " power down suppression circuits inside the AC-DC change-over circuit
Circuit output voltage controls Vcc " power down suppression circuits inside the second feedback input end of circuit, AC-DC change-over circuit
Switching signal receiving terminal receives Vcc " power down suppression circuits inside a switching signal from mainboard, AC-DC change-over circuit
When ensuring that LED lamp tube driving carries out standby not mode of operation by normal mode of operation, AC-DC change-over circuit internal control
Chip Vcc supply voltages are occurred without causes the control chip to produce under-voltage protection because of power down；Described AC-DC conversion electricity
The second reference voltage output of the power supply circuit of the reference voltage receiving terminal connection LED lamp tube driving of road output voltage controlling circuit
End, 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 exchange-straight by detecting single feedback LED lamp tube output end voltage
Circuit output terminal voltage is changed in circulation；The switching signal receiving terminal of the power supply circuit of described LED lamp tube driving, which is received, comes from mainboard
Switching signal, to control LED lamp tube drive power supply circuit whether work.
Further, the power supply circuit of the LED lamp tube driving includes reference voltage generating circuit and power supply conversion and controlled
Circuit processed；
The LED lamp tube current control circuit includes the first N-type metal-oxide-semiconductor Q1, current sampling resistor R1, biasing resistor and the
One amplifier OP1；
The AC-DC change-over circuit output voltage controlling circuit include the second amplifier OP2, voltage sample resistance R2,
Frequency compensated circuit, the first transistor Q2, optocoupler and TL431 circuits, feedback resistance R3, feedback resistance R4 and feedback resistance R5；
Vcc " power down suppression circuit includes the first electric capacity C1 and second transistor inside the AC-DC change-over circuit
Q3；
The output end of the AC-DC change-over circuit connects the input of single feedback LED lamp tube and the power supply respectively
The output end of conversion and the input of control circuit, power supply conversion and control circuit is connecting amplifier OP1, amplifier OP2 just respectively
The input of power end and reference voltage generating circuit, reference voltage generating circuit generates the first reference voltage V ref1 pressures respectively
With the second reference voltage V ref2；
The output end of single feedback LED lamp tube connect respectively the first N-type metal-oxide-semiconductor Q1 drain electrode and voltage sample resistance R2 one
End, the first N-type metal-oxide-semiconductor Q1 source electrode connects current sampling resistor R1 one end and the first amplifier OP1 negative input end respectively, electricity
Sampling resistor R1 other end ground connection is flowed, the first N-type metal-oxide-semiconductor Q1 grid connects the first amplifier OP1 output end,
Biasing resistor Roffset one end connection power supply conversion and the output end of control circuit, biasing resistor Roffset's
The other end connects the first N-type metal-oxide-semiconductor Q1 source electrode；
The PWM turns DC adjusting control circuits and receives a DIM dim signals and one first reference voltage V ref1 respectively, and
The first reference voltage V ref1 is generated into a direct current dimmer voltage according to the positive duty cycle conversion of DIM dim signals to export to first
Amplifier OP1 anode enters end,
The voltage sample resistance R2 other end connect respectively the second amplifier OP2 negative input end and frequency compensated circuit one
End, the other end of frequency compensated circuit connects the second amplifier OP2 output end, the second amplifier OP2 positive input terminal access second
Reference voltage V ref2,
Second amplifier OP2 output end connection the first transistor Q2 base stage, the first transistor Q2 grounded emitter, the
One transistor Q2 colelctor electrode connects feedback resistance R5 one end and the first electric capacity C1 one end respectively, and feedback resistance R5's is another
End connects the reference edge of feedback resistance R3 one end, feedback resistance R4 one end and optocoupler and TL431 circuits, feedback resistance respectively
The R3 other end connects the output end of AC-DC change-over circuit, feedback resistance R4 other end ground connection, optocoupler and TL431 electricity
The other end connection AC-DC change-over circuit on road, the first electric capacity C1 other end connection second transistor Q3 emitter stage, the
Two-transistor Q3 switching signal of the base stage access from mainboard, second transistor Q3 grounded collector.
The first transistor Q2 is NPN transistor, and the second transistor Q3 is PNP transistor.
Specifically, the first amplifier OP1, current sampling resistor R1, first N-type metal-oxide-semiconductor Q1, PWM turn DC tune in the present invention
Light control circuit constitutes a LED lamp tube current control circuit, and the LED lamp tube current control circuit is negative-feedback circuit, OP1 amplifiers
With empty short feature, i.e.,：V1+=V1-, LED tube 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 circuits constitute an AC-DC change-over circuit
Output end voltage Vout controls circuit (being also single feedback LED lamp tube input terminal voltage control circuit)；Pass through voltage sample resistance
Voltage V2- after noise signal (Noise) decay in the voltage sampled is supplied to the second amplifier OP2 negative input by R2
End, the second amplifier OP2 positive input terminals receive the second reference voltage V ref2 exported from reference voltage generating circuit, the second amplifier
OP2 output ends electrically connect frequency compensated circuit and the first transistor Q2 base stage (Base), the second amplifier OP2 and frequency compensation electricity
Road constitutes an integrating circuit, is negative-feedback circuit, therefore the second amplifier OP2 has empty short feature, i.e.,：V2-=V2+=Vref2, i.e.,：
During normal work, single output end voltage size for feeding back LED lamp tube is controlled as basically identical with Vref2 voltages so that this hair
When bright LED lamp tube drives normal work, AC-DC change-over circuit output end voltage Vout=Vled+Vref2, wherein
Vled------ is the voltage at LED lamp tube two ends when LED lamp tube works；And now the first transistor Q2 can be operated in amplification region,
A motional impedance Rce would generally be produced between the first transistor Q2 colelctor electrode and emitter stage, therefore in optocoupler and TL431 circuits
Pull down resistor total impedance R=R4//(R5+Rce) of reference edge (R ends), due to the electricity at reference edge R ends in optocoupler and TL431 circuits
Press as 2.5V, therefore AC-DC change-over circuit output end voltage Vout1 during the LED tube drive circuit normal work of the present invention=
Vled+Vref2=2.5V*（R3+R）/R.
Further, biasing resistor mentioned above is the resistance Roffset in Fig. 3, and the effect of biasing resistor is in liquid
During crystal display product normal work, when the positive dutycycle of DIM dim signals is transferred to minimum 0% (Duty=0%), it is ensured that liquid crystal
Show that picture is at completely dark picture, in lcd products normal work, when the positive dutycycle of DIM dim signals is transferred to
During minimum 0% (Duty=0%), positive input terminal voltage V1+=0V of the first amplifier OP1 amplifiers is short according to the first amplifier OP1 amplifier void
Feature:V1+=V1-=0V, now LED tube current Ilamp should be 0mA, but be inputted because the first amplifier OP1 inputs are present
Offset voltage（Input offset voltage）So that the first amplifier OP1 amplifier output ends still suffer from the output electricity of certain value
Pressure so that the first N-type metal-oxide-semiconductor Q1 is in lightly conducting state so that LED lamp tube still has a faint electric current to flow through, produces one micro-
Weak light so that liquid crystal display picture can not be in complete dark picture, and works as and set a biasing resistor Roffset, and then sets one
During bias current Ioffset (Ioffset ≈ Vcc/Roffset), the Ioffset electric currents flow through current sampling resistor R1,
The negative input end of one amplifier OP1 amplifiers produces a bias voltage Voffset=Ioffset*R1, as long as the voltage is more than OP1 amplifiers
During maximum input offset voltage Vio in specifications, OP1 amplifiers output end voltage is 0V so that the first N-type metal-oxide-semiconductor Q1 is in
Completely switched off state, now LED tube current Ilamp=0mA, liquid crystal display picture handles dark picture completely.
Further, the power supply conversion and control circuit receive an AC-DC change-over circuit output end voltage Vout
With a switching signal provided from motherboard circuit, when the switching signal that motherboard circuit is provided is high level (High), supply
AC-DC change-over circuit output end voltage Vout is converted into supply voltage Vcc supplies first by electricity conversion and control circuit
Amplifier OP1 and the second amplifier OP2 work, while supplying reference voltage generating circuit work, and is produced by reference voltage generating circuit
Bear two groups of reference voltage the first reference voltage V ref1 and the second reference voltage V ref2, therefore switching signal is when being high level, this
The LED lamp tube driving normal work of invention, now, second transistor Q3 cut-offs；
When lcd products need to enter standy operation mode, the motherboard circuit meeting inside lcd products
A switching signal is provided for low level (Low) signal, power supply conversion and control circuit stopping provide Vcc and supply voltage to the first fortune
OP1, the second amplifier OP2 and reference voltage generating circuit are put, LED drivings of the invention are stopped, the cut-off of Q2 electric crystals,
AC-DC change-over circuit output voltage Vout2=2.5V* of standy operation mode（R3+R4）/ R4, because of R4>
R4//(R5+Rce), therefore lcd products AC-DC change-over circuit output voltage Vout2 ratios under waiting condition are normal
Vout1 voltages are much smaller during work, such as：During liquid crystal display product product normal work, AC-DC change-over circuit output voltage
Vout1=19V, and settable output voltage Vout2=15V is even lower in the standby state, this can reduce liquid crystal display product
Standby power, traditional LED lamp pipe driving power supply plate is either in the standby state or in normal work, AC-DC
Change-over circuit single group exports 19V fixation DC voltage, the DC-DC conversions that the 19V DC voltages pass through in motherboard circuit
The circuits such as the Scaler IC in 5V output direct current supply motherboard circuits are generated after device to work；And the LED drivings of the present invention
Direct current of the AC-DC change-over circuit single group output voltage between 19V ~ 21V during the power panel normal work of circuit, and
Under holding state, AC-DC change-over circuit single group exports such as≤15V fixation DC voltage.With PHILIPS
Exemplified by 223V5 machines, according to traditional LED Boost boosting driving power supply plates, when input ac voltage is under holding state
The input power that 240V is measured is in 280mW or so；According to the LED drive circuit of the present invention, then when input is handed under holding state
Stream voltage is that the input power that 240V is measured is only in 230mW or so.
When switching signal provided in motherboard circuit is changed into low level from high level, second transistor Q3 conductings, the
One transistor Q2 ends, and feedback resistance R5 charges to the first electric capacity C1.When after 5 t=R5*C1 times, the first electric capacity
C1 both end voltages can be risen to about 2.5V or so by 0V.Now series impedance R " can be by between feedback resistance R5 and the first electric capacity C1
R5+Rce (Q2) rises to infinity, pull down resistor total impedance R=R4//R ".AC-DC change-over circuit output end voltage is met
Vout=2.5V* (R3+R)/R=2.5V* (R3/R+1), i.e., after 5 t=R5*C1 times, the output of AC-DC change-over circuit
The voltage at end can by such as normal work when 19V drop at leisure within 15V, now AC-DC change-over circuit output electricity
It is set during standy operation mode that voltage-controlled circuit processed can correctly control AC-DC change-over circuit output end voltage slowly to drop to
The magnitude of voltage of meter, it is ensured that AC-DC change-over circuit switching signal during high level (High) to low level (Low) it is defeated
Going out voltage can normally decline, and occur without that output voltage is extremely too low to cause AC-DC change-over circuit primary side control chip
There is under-voltage protection (UVLO) problem in Vcc " energization pins.To ensure the lcd products when the on ＆ off switch for pushing button plate
When, remain to smoothly enter standy operation mode by normal mode of operation.
As shown in figure 4, the PWM, which turns DC adjusting control circuits, includes the second N-type metal-oxide-semiconductor Q4 and the 3rd N-type metal-oxide-semiconductor Q5,
Second N-type metal-oxide-semiconductor Q4 grid access DIM dim signals, the second N-type metal-oxide-semiconductor Q4 source ground, the second N-type metal-oxide-semiconductor Q4's
Drain electrode respectively connection the 3rd N-type metal-oxide-semiconductor Q5 grid and the 4th resistance R6 one end, the 3rd N-type metal-oxide-semiconductor Q5 source ground,
3rd N-type metal-oxide-semiconductor Q5 drain electrode connects the 5th resistance R7 one end and the 6th resistance R8 one end respectively, and the 4th resistance R6's is another
One end and the 5th resistance the R7 other end are respectively connected to the first reference voltage V ref1, and the 6th resistance R8 other end is connected respectively
Second electric capacity C2 one end and the 7th resistance R9 one end, the 7th resistance R9 other end connect the one of the 8th resistance R10 respectively
End and the first amplifier OP1 positive input terminal, the second electric capacity C2 other end and the 8th resistance R10 other end are grounded respectively.
Specifically, the second N-type metal-oxide-semiconductor Q4 grid receives what a motherboard circuit inside lcd products was provided
One DIM dim signals, the DIM dim signals are by the N-type metal-oxide-semiconductor Q5 of the second N-type metal-oxide-semiconductor Q4/ the 3rd by the first reference voltage
Vref1 reference voltages generate a V1 direct currents after carrying out voltage conversion by the 5th resistance R7, the 6th resistance R8 and the second electric capacity C2
Voltage, the V1 DC voltages size and the positive dutycycle of DIM dim signals（Duty）Size is relevant, and DIM dim signals are just accounted for
It is empty than bigger, then V1 voltages are higher, and the positive dutycycle of DIM dim signals is smaller, then V1 voltages are lower, such as：Work as liquid crystal display
During the positive dutycycle Duty of DIM dim signals=100% of the motherboard circuit output of interiors of products, V1=Vref1* (R9+R10)/(R7+
R8+R9+R10)；During the positive dutycycle Duty of DIM dim signals=0% of the motherboard circuit output inside lcd products,
V1=0V；V1 DC voltages generate a direct current dimmer voltage signal V1+ after the 7th resistance R9 and the 8th resistance R10 partial pressures and carried
The operating current size of amplifier or the positive input terminal control LED lamp tube of error amplifier is supplied, so as to control liquid crystal display to draw
Face mean flow rate.
As shown in figure 5, the power supply conversion and control circuit include the 4th N-type metal-oxide-semiconductor Q6, third transistor Q7, the 4th
Transistor Q8 and voltage-regulator diode ZD1, third transistor Q7 emitter stage connects the output end of AC-DC change-over circuit respectively
With the tenth resistance R12 one end, third transistor Q7 base stage connects the 9th resistance R11 one end and the tenth resistance R12 respectively
The other end, the 9th resistance R11 other end connects the 4th N-type metal-oxide-semiconductor Q6 drain electrode, and the 4th N-type metal-oxide-semiconductor Q6 source electrode connects
Ground, the 4th N-type metal-oxide-semiconductor Q6 switching signal of the grid access from mainboard, third transistor Q7 colelctor electrode connection the 11st
Resistance R13 one end, the 11st resistance R13 other end connects the 4th transistor Q8 colelctor electrodes and the 12nd resistance R14 respectively
One end, the 4th transistor Q8 base stage connects voltage-regulator diode ZD1 negative pole and the 12nd resistance R14 other end respectively,
4th transistor Q8 emitter stage connects the 3rd electric capacity C3 one end, the 3rd electric capacity C3 other end ground connection, the pole of voltage stabilizing two respectively
Pipe ZD1 plus earth, power supply conversion and the output end of control circuit are used as using the 4th transistor Q8 emitter stage.
The third transistor Q7, the 4th N-type metal-oxide-semiconductor Q6, the 9th resistance R11, the tenth resistance R12 constitute a switch control
Circuit processed, for whether controlling LED lamp tube drive circuit works；12nd resistance R14, the 4th transistor Q8, voltage-regulator diode
ZD1, the 3rd electric capacity C3 constitute a voltage stabilizing Vcc power supply circuits, such as：Voltage-regulator diode ZD1 is 9.1V, when the 4th transistor Q8 is turned on
Vbe voltages are 0.7V, then supply voltage Vcc=9.1V-0.7V=8.4V；When the 4th N-type metal-oxide-semiconductor Q6 grid receives mainboard electricity
The switching signal that road is provided is high level signal（High）When, the 4th N-type metal-oxide-semiconductor Q6, third transistor Q7 conducting, power supply conversion
And the Vcc of control circuit output one supplies voltage to the first amplifier of amplifier OP1, the second amplifier OP2 and reference voltage generating circuit,
LED lamp tube driving starts normal work.Under the conditions of standby mode is carried out in lcd products, the 4th N-type metal-oxide-semiconductor Q6's
The switching signal that grid receives motherboard circuit offer is low level signal（Low）When, the 4th N-type metal-oxide-semiconductor Q6, third transistor
Q7 ends, and power supply conversion and control circuit stop output Vcc and supply voltage to the first amplifier of amplifier OP1, the second amplifier OP2 and base
Quasi- voltage generation circuit, LED lamp tube driving is stopped, and now liquid crystal display, which is produced, enters under standby mode because of LED lamp tube
Drive circuit does not work and very energy saving.
The 3rd crystal Q7 is PNP transistor, and the 4th transistor Q8 is NPN transistor.
As shown in fig. 6, the reference voltage generating circuit includes the 5th transistor Q9 and three-terminal shunt regulator U1, it is described
5th transistor Q9 colelctor electrode connects output end and the 17th resistance R19 one end of power supply conversion and control circuit respectively,
5th transistor Q9 base stage connects the 17th resistance R19 other end and three-terminal shunt regulator U1 cathode terminal respectively, the
Five transistor Q9 emitter stage connects the 15th resistance R17 one end, the 13rd resistance R15 one end and the 4th electric capacity C4 respectively
One end, the 13rd resistance R15 other end connects the 14th resistance R16 one end, three-terminal shunt regulator U1 reference edge
Respectively connection the 15th resistance R17 the other end and the 16th resistance R18 one end, three-terminal shunt regulator U1 anode tap,
The 16th resistance R18 other end, the 4th electric capacity C 4 other end and the 14th resistance R16 other end is grounded respectively, and the 5th
The other end that transistor Q9 emitter stage exports the first reference voltage V ref1, the 13rd resistance R15 exports the second reference voltage
Vref2。
The reference voltage of the reference edge of the three-terminal shunt regulator U1 is 2.5V, and the three-terminal shunt regulator U1 is
TL431 voltage-stablizers.Therefore first reference voltage V ref1=2.5V* (R17+R18) produced by the reference voltage generating circuit/
R18, such as：R17=R18=10K Ω, then Vref1=5V, by obtaining second reference voltage after R15 resistance, R16 electric resistance partial pressures
Vref2=Vref1*R16/ (R15+R16), such as：R15=22K Ω, R16=3.9K Ω, then Vref2=0.752V.
The 5th transistor Q9 is NPN transistor.
The frequency compensated circuit is the RC frequency compensated circuits that a compensation resistance and a compensating electric capacity are in series.The frequency
The effect of rate compensation circuit is to allow AC-DC change-over circuit to export Vout voltage more to stablize.
As shown in fig. 7, the AC-DC change-over circuit includes bridge rectifier and filter circuit, transformer, feedback circuit
With AC-DC change-over circuit control chip, AC-DC change-over circuit control chip has the first pin CS, second pin
Vdri, the 3rd pin Vcc ", feedback pin FB and grounding pin GND, the transformer have positioned at primary side the first winding,
Second winding and the tertiary winding positioned at secondary side, AC mains access the of transformer by bridge rectifier and filter circuit
One end of one winding, the other end of the first winding is connected with one the 5th N-type metal-oxide-semiconductor Q11 drain electrode, the 5th N-type metal-oxide-semiconductor Q11's
Source electrode connects the first pin CS and a resistance R18 of AC-DC change-over circuit control chip one end respectively, resistance R18's
The other end is grounded, and the 5th N-type metal-oxide-semiconductor Q11 grid 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, and diode D12 negative pole connects AC-DC change-over circuit respectively
The 3rd pin Vcc " and electric capacity C12 of control chip one end, electric capacity C12 other end ground connection, one end connection of the tertiary winding
Diode D11 positive pole, diode D11 negative pole connects electric capacity C11 one end and one end of feedback circuit, feedback circuit respectively
The other end connect AC-DC change-over circuit control chip feedback pin FB, electric capacity C11 the other end connection tertiary winding
The other end, the other end ground connection of the tertiary winding, diode D11 negative pole is used as the output end of AC-DC change-over circuit, institute
The one end for stating the other end, one end of the second winding and the tertiary winding of the first winding is Same Name of Ends.
If as shown in figure 8, do not increase exchanges-DC converting circuit inside Vcc " power down suppression circuits when, in switching signal
Low level is changed into from high level, power-off problems occur in the Vcc " supply voltages of AC-DC change-over circuit control chip.Power down
Reason：When lcd products enter standby mode by normal work, the switching signal of the motherboard circuit inside machine can be by
High level is changed into low level, and now the first transistor Q2 can be cut off conducting, and sampling feedback pull down resistor resistance moment can be by
R4//(R5+Rce (Q2)) is changed into R4, i.e. pull down resistor moment change is big, and AC-DC change-over circuit control chip output Vdri draws
Pin stops output PWM square waves and carrys out driving transformer progress energy conversion.Due to the feedback circuit inside AC-DC change-over circuit
There is time t2 operating lag problem, therefore need the AC-DC change-over circuit control chip after the t1+t2 times to export Vdri
Pin can just export PWM square waves and carry out driving transformer progress energy conversion.Correspondence t2 times, the control of AC-DC change-over circuit
Vcc " the supply voltages of chip occur as soon as power-off problems, if minimum voltage is less than AC-DC change-over circuit control during Vcc " power down
The under-voltage protection value (UVLO) of chip internal processed, the AC-DC change-over circuit control chip will start under-voltage protection function,
Make Switching Power Supply can not normal work
As shown in figure 9, increase exchanges-DC converting circuit inside after Vcc " power down suppression circuits, AC-DC conversion electricity
Road builtin voltage Vcc " voltages occur without power-off problems, to ensure the lcd products when the on ＆ off switch for pushing button plate
When, remain to smoothly enter standy operation mode by normal mode of operation.
As shown in Figure 10, the invention also discloses a LED lamp tube drive control chip, the LED lamp tube drive control core
Piece be integrated with the PWM turn DC adjusting control circuits, power supply conversion and control circuit, reference voltage generating circuit, it is described including
Following pin, be respectively：1st, Vcc energization pins, supply voltage is provided for the control chip；2nd, COMP feedback pins, pass through
The detecting of Pin8 pins is single to feed back LED lamp tube output end voltage to adjust AC-DC change-over circuit output voltage Vout sizes；3、
On_Off switch control pins, for whether controlling the New LED driving work；4th, DIM dims pin, for controlling this new
LED lamp tube size of current when LED drives work；5th, GND grounding pins；6th, Iset LEDs tube current sets pin, passes through R21
Resistance is come maximum current when setting the LED lamp tube to work；7th, GM frequency compensations pin, by external R22 resistance and C21 electric capacity, makes
The work that whole LED drive system can be stablized；8th, LED pins, for detecting LED lamp tube output end voltage and electric current.
The present invention uses above technical scheme, 1, AC-DC change-over circuit design is exported using single group, output voltage is straight
Connect and be supplied to LED lamp tube to work.2nd, LED lamp tube is using single Feedback Design mode, i.e., each lamp string (String) in LED lamp tube is defeated
Go out termination together.3rd, LED tube current is accurately controlled by first amplifier OP1 or error amplifier.4th, pass through
Second amplifier OP2 or error amplifier accurately control LED lamp tube output end voltage, so as to control AC-DC to turn
Circuit single group output voltage is changed, i.e.,:AC-DC change-over circuit single group output voltage values size is to change, and on-fixed
, it is ensured that LED lamp tube driving has higher conversion efficiency >=93%.5th, the switching signal provided by motherboard circuit, switching signal
During for High high level, it is straight that the output of AC-DC change-over circuit in power panel supplies electricity to LED lamp tube just like 18V-21V direct current
Connect work, and when lcd products carry out holding state, switching signal is exchange in Low low levels, power panel-straight
Stream change-over circuit is only exported just like 15V or lower direct current, and generation 5V direct currents are supplied electricity to after being changed through DC-DC decompression converting circuits
Motherboard circuit works, and for DC-DC decompression converting circuits, input voltage is lower, and its conversion efficiency can be of a relatively high, such as the present invention
LED drivings power panel when standby, the conversion efficiency of DC-DC decompression converting circuits (15V turns 5V) is 55%-60%, and is passed
LED drive power plate unite when standby, the conversion efficiency of DC-DC decompression converting circuits (19V turns 5V) is 30%-45%, therefore this hair
Bright LED tube drive circuit has lower stand-by power consumption.6th, LED tube drive circuit of the invention use exchange-
DC converting circuit single group output direct current is supplied directly to LED lamp tube work, and the driving of traditional LED lamp pipe uses friendship
LED lamp tube work is also just supplied after Boost circuit is boosted after stream-DC converting circuit single group output direct current,
The EMI radiation noise of a large amount of high frequencies can be produced during the Boost circuit N-type metal-oxide-semiconductor switch, therefore New LED driving is electric
Source plate reduces EMI and solves difficulty.7th, the C1 electric capacity in parallel and one between the first transistor Q2 colelctor electrode and emitter stage
Q3PNP electric crystals so that the LED lamp tube driving of lcd products is entered under the conditions of standby mode by normal work, i.e.,：It is main
When the switching signal that plate circuit is provided is changed into low level Low from high level High, the exchange of AC-DC change-over circuit primary side-
Vcc " the energization pins of DC converting circuit control chip will not be dropped to because of power down less than institute inside the control chip energization pins
The under-voltage protection value (UVLO) of setting, to ensure that the lcd products, can be by normal when pushing button the on ＆ off switch of plate
Mode of operation smoothly enters standy operation mode.8th, Q1 N-channels N-type metal-oxide-semiconductor source electrode and power supply conversion and control circuit output
One Roffset biasing resistors are set between end, in lcd products normal work, when the positive dutycycle of DIM dim signals
It can ensure that liquid crystal display picture is at completely dark picture when being transferred to minimum 0%.The LED of the present invention is driven compared with traditional LED lamp pipe
Driving has：Price is low, efficiency high, low standby power loss, with lower EMI radiation feature.
In summary, only presently preferred embodiments of the present invention, when the scope that the present invention is implemented can not be limited with this, i.e.,
Generally the simple equivalent changes and modifications made according to scope of the present invention patent and invention description content all still belongs to the present invention
In the range of patent lid.
Claims (10)
1. a kind of single feedback direct-push DC dimming LED lamp tube drive circuits, it is characterised in that：It includes AC-DC conversion electricity
Road, power supply circuit, AC-DC change-over circuit output voltage controlling circuit, the AC-DC change-over circuit of LED lamp tube driving
Internal Vcc " power down suppression circuit, PWM turn DC adjusting control circuits, 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 are carried out into electricity
Pressure conversion and the direct current that one group of variable values is exported by output end, AC-DC change-over circuit output end order feedback
The input of the power supply circuit of input and the LED lamp tube driving of LED lamp tube, the power supply circuit of LED lamp tube driving is additionally provided with out
OFF signal receiving terminal, the first reference voltage output end, the second reference voltage output end and Vcc output ends, the AC-DC turn
Change circuit output voltage control circuit and be provided with the first feedback input end, the second feedback input end and reference voltage receiving terminal,
The input and AC-DC that the output end of single feedback LED lamp tube connects LED lamp tube current control circuit respectively turn
Change the first feedback input end that circuit output voltage controls circuit；LED lamp tube current control circuit is additionally provided with feeder ear and control
Current signal receiving terminal, the Vcc outputs of the power supply circuit of the feeder ear connection LED lamp tube driving of LED lamp tube current control circuit
End, the control electric current signal receiving terminal connection PWM of LED lamp tube current control circuit turns the output end of DC adjusting control circuits；
Described PWM turns DC adjusting control circuits and is additionally provided with reference voltage input and dim signal receiving terminal, and PWM turns DC light modulations
The first reference voltage output end of the power supply circuit of the reference voltage input connection LED lamp tube driving of circuit is controlled, PWM turns DC
The dim signal receiving terminal of adjusting control circuit receives the DIM dim signals from mainboard, and according to DIM dim signals just
Duty cycle conversion generates a direct current dimmer voltage and exported to LED lamp tube current control circuit；In the AC-DC change-over circuit
The output end of portion Vcc " power down suppression circuits connects the second feed back input of AC-DC change-over circuit output voltage controlling circuit
The switching signal receiving terminal of Vcc " power down suppression circuits receives a switch from mainboard inside end, AC-DC change-over circuit
Vcc " power down suppression circuits ensure that LED lamp tube driving is carried out by normal mode of operation inside signal, AC-DC change-over circuit
During standby not mode of operation, AC-DC change-over circuit is occurred without causes under-voltage protection because of internal power down；Described exchange-
Second base of the power supply circuit of the reference voltage receiving terminal connection LED lamp tube driving of DC converting circuit output voltage controlling circuit
Quasi- voltage output end, the output of AC-DC change-over circuit output voltage controlling circuit terminates the anti-of AC-DC change-over circuit
Input is presented, AC-DC change-over circuit output voltage controlling circuit is controlled by detecting single feedback LED lamp tube output end voltage
AC-DC change-over circuit output end voltage processed；The switching signal receiving terminal of the power supply circuit of described LED lamp tube driving is received
Whether switching signal from mainboard, the power supply circuit to control LED lamp tube to drive works.
2. a kind of list feeds back direct-push DC dimming LED lamp tube drive circuits according to claim 1, it is characterised in that：It is described
AC-DC change-over circuit includes bridge rectifier and filter circuit, transformer, feedback circuit and AC-DC change-over circuit control
Coremaking piece,
The power supply circuit of the LED lamp tube driving includes reference voltage generating circuit and power supply conversion and control circuit；
The LED lamp tube current control circuit includes the first N-type metal-oxide-semiconductor Q1, current sampling resistor R1, biasing resistor and the first fortune
Put OP1；
The AC-DC change-over circuit output voltage controlling circuit includes the second amplifier OP2, voltage sample resistance R2, frequency
Compensation circuit, the first transistor Q2, optocoupler and TL431 circuits, feedback resistance R3, feedback resistance R4 and feedback resistance R5；
Vcc " power down suppression circuit includes the first electric capacity C1 and second transistor Q3 inside the AC-DC change-over circuit；
There is AC-DC change-over circuit control chip the first pin CS, second pin Vdri, the 3rd pin Vcc ", feedback to draw
Pin FB and grounding pin GND, the transformer has the positioned at the first winding of primary side, the second winding and positioned at secondary side
Three winding, AC mains access one end of the first winding of transformer by bridge rectifier and filter circuit, the first winding
The other end is connected with one the 5th N-type metal-oxide-semiconductor Q11 drain electrode, and the 5th N-type metal-oxide-semiconductor Q11 source electrode connects AC-DC and turned respectively
Change the first pin CS and a resistance R18 of circuit control chip one end, resistance R18 other end ground connection, the 5th N-type metal-oxide-semiconductor
Q11 grid connects the second pin Vdri of AC-DC change-over circuit control chip, and one end of the second winding connects one or two poles
Pipe D12 positive pole, diode D12 negative pole connect respectively AC-DC change-over circuit control chip the 3rd pin Vcc " and
Electric capacity C12 one end, electric capacity C12 other end ground connection, one end connection diode D11 of tertiary winding positive pole, diode D11
Negative pole connect electric capacity C11 one end and one end of feedback circuit respectively, the other end connection AC-DC conversion of feedback circuit
The feedback pin FB of circuit control chip, electric capacity the C11 other end connect the other end of the tertiary winding, the other end of the tertiary winding
Ground connection, diode D11 negative pole as AC-DC change-over circuit output end, the other end of first winding, second around
One end of group and one end of the tertiary winding are Same Name of Ends；
The output end of the AC-DC change-over circuit connects input and the power supply conversion of single feedback LED lamp tube respectively
And control circuit input, power supply conversion and control circuit output end connect respectively the second amplifier OP2 positive power source terminal and
The input of reference voltage generating circuit, reference voltage generating circuit generates the first reference voltage and the second reference voltage respectively；
The output end of single feedback LED lamp tube connects the first N-type metal-oxide-semiconductor Q1 drain electrode and voltage sample resistance R2 one end respectively,
First N-type metal-oxide-semiconductor Q1 source electrode connects current sampling resistor R1 one end and the first amplifier OP1 negative input end, electric current respectively
Sampling resistor R1 other end ground connection, the first N-type metal-oxide-semiconductor Q1 grid connects the first amplifier OP1 output end,
One end connection power supply conversion of biasing resistor and the output end of control circuit, the other end of biasing resistor connect the first N-type
Metal-oxide-semiconductor Q1 source electrode；
The PWM turns DC adjusting control circuits and receives a DIM dim signals and one first reference voltage respectively, and by the first benchmark
Voltage generates a direct current dimmer voltage according to the positive duty cycle conversion of DIM dim signals and exports to the first amplifier OP1 anode
End,
The voltage sample resistance R2 other end connects the second amplifier OP2 negative input end and one end of frequency compensated circuit respectively,
The other end of frequency compensated circuit connects the second amplifier OP2 output end, and the second amplifier OP2 positive input terminal accesses the second benchmark
Voltage,
Second amplifier OP2 output end connection the first transistor Q2 base stage, the first transistor Q2 grounded emitter, first is brilliant
Body pipe Q2 colelctor electrode connects feedback resistance R5 one end and the first electric capacity C1 one end, the feedback resistance R5 other end point respectively
Not Lian Jie feedback resistance R3 one end, feedback resistance R4 one end and optocoupler and TL431 circuits reference edge, feedback resistance R3's
The output end of other end connection AC-DC change-over circuit, feedback resistance R4 other end ground connection, optocoupler and TL431 circuits
The other end connects AC-DC change-over circuit, the first electric capacity C1 other end connection second transistor Q3 emitter stage, the second crystalline substance
Body pipe Q3 switching signal of the base stage access from mainboard, second transistor Q3 grounded collector.
3. a kind of list feeds back direct-push DC dimming LED lamp tube drive circuits according to claim 2, it is characterised in that：It is described
The first transistor Q2 is NPN transistor, and the second transistor Q3 is PNP transistor.
4. a kind of list feeds back direct-push DC dimming LED lamp tube drive circuits according to claim 1, it is characterised in that：It is described
PWM, which turns DC adjusting control circuits, includes the second N-type metal-oxide-semiconductor Q4 and the 3rd N-type metal-oxide-semiconductor Q5, and the second N-type metal-oxide-semiconductor Q4 grid connects
Enter DIM dim signals, the second N-type metal-oxide-semiconductor Q4 source ground, the second N-type metal-oxide-semiconductor Q4 drain electrode connects the 3rd N-type MOS respectively
One end of pipe Q5 grid and the 4th resistance R6, the 3rd N-type metal-oxide-semiconductor Q5 source ground, the 3rd N-type metal-oxide-semiconductor Q5 drain electrode point
Not Lian Jie the 5th resistance R7 one end and the 6th resistance R8 one end, the 4th resistance R6 other end and the 5th resistance R7's is another
End is respectively connected to the first reference voltage, and the 6th resistance R8 other end connects the second electric capacity C2 one end and the 7th resistance R9 respectively
One end, the 7th resistance R9 other end connects the 8th resistance R10 one end and the first amplifier OP1 positive input terminal respectively,
The two electric capacity C2 other end and the 8th resistance R10 other end are grounded respectively.
5. a kind of list feeds back direct-push DC dimming LED lamp tube drive circuits according to claim 2, it is characterised in that：It is described
Power supply conversion and control circuit include the 4th N-type metal-oxide-semiconductor Q6, third transistor Q7, the 4th transistor Q8 and voltage-regulator diode
ZD1, third transistor Q7 emitter stage connect the output end of AC-DC change-over circuit and the tenth resistance R12 one end respectively,
Third transistor Q7 base stage connects the 9th resistance R11 one end and the tenth resistance R12 other end, the 9th resistance R11 respectively
The other end connect the 4th N-type metal-oxide-semiconductor Q6 drain electrode, the 4th N-type metal-oxide-semiconductor Q6 source ground, the 4th N-type metal-oxide-semiconductor Q6 grid
The switching signal from mainboard is accessed in pole, and third transistor Q7 colelctor electrode connects the 11st resistance R13 one end, the 11st electricity
The resistance R13 other end connects the 4th transistor Q8 colelctor electrodes and the 12nd resistance R14 one end, the 4th transistor Q8 base respectively
Pole connects voltage-regulator diode ZD1 negative pole and the 12nd resistance R14 other end, the 4th transistor Q8 emitter stage difference respectively
The 3rd electric capacity C3 one end is connected, the 3rd electric capacity C3 other end ground connection, voltage-regulator diode ZD1 plus earth is brilliant with the 4th
The output end of circuit is changed and controlled to body pipe Q8 emitter stage as power supply.
6. a kind of list feeds back direct-push DC dimming LED lamp tube drive circuits according to claim 5, it is characterised in that：It is described
3rd crystal Q7 is PNP transistor, and the 4th transistor Q8 is NPN transistor.
7. a kind of list feeds back direct-push DC dimming LED lamp tube drive circuits according to claim 2, it is characterised in that：It is described
Reference voltage generating circuit includes the 5th transistor Q9 and three-terminal shunt regulator U1, the colelctor electrode point of the 5th transistor Q9
It Lian Jie not power and change and control output end and the 17th resistance R19 one end of circuit, the 5th transistor Q9 base stage difference
Connect the 17th resistance R19 other end and three-terminal shunt regulator U1 cathode terminal, the 5th transistor Q9 emitter stage difference
Connect one end of the 15th resistance R17 one end, the 13rd resistance R15 one end and the 4th electric capacity C4, the 13rd resistance R15
The other end connect the 14th resistance R16 one end, three-terminal shunt regulator U1 reference edge connects the 15th resistance R17 respectively
The other end and the 16th resistance R18 one end, three-terminal shunt regulator U1 anode tap, the 16th resistance R18 other end,
4th electric capacity C 4 other end and the 14th resistance R16 other end are grounded respectively, the 5th transistor Q9 emitter stage output the
One reference voltage, the 13rd resistance R15 other end exports the second reference voltage.
8. a kind of list feeds back direct-push DC dimming LED lamp tube drive circuits according to claim 7, it is characterised in that：It is described
The reference voltage of three-terminal shunt regulator U1 reference edge is 2.5V, and the three-terminal shunt regulator U1 is TL431 voltage-stablizers.
9. a kind of list feeds back direct-push DC dimming LED lamp tube drive circuits according to claim 7, it is characterised in that：It is described
5th transistor Q9 is NPN transistor.
10. a kind of list feeds back direct-push DC dimming LED lamp tube drive circuits according to claim 2, it is characterised in that：It is described
Frequency compensated circuit is the RC frequency compensated circuits that a compensation resistance and a compensating electric capacity are in series.
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| CN106594688A (en) * | 2016-12-21 | 2017-04-26 | 陈代辉 | Novel driving module |
| CN107770914B (en) * | 2017-11-03 | 2023-10-10 | 赛尔富电子有限公司 | 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 |
| 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 |
| CN110418465A (en) * | 2019-07-31 | 2019-11-05 | 福建捷联电子有限公司 | A kind of power supply adaptor directly driving LED lamp tube inside liquid crystal display product |
| CN113316289A (en) * | 2020-02-26 | 2021-08-27 | 苏州佳世达电通有限公司 | LED power supply circuit |
| CN112311223B (en) * | 2020-10-22 | 2022-05-17 | 冠捷电子科技(福建)有限公司 | DC-DC converter with peak delay start notification |
| US11297775B1 (en) | 2021-07-22 | 2022-04-12 | Boulder Lamp, Inc. | LED grow light system with time varying light intensity |
| CN117440555B (en) * | 2023-12-20 | 2024-03-05 | 杭州方千科技有限公司 | Circuit for controlling LED stroboscopic explosion and light supplementing device |
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