CN205912292U - Straight pushing -type DC of single feedback LED fluorescent tube drive circuit that adjusts luminance - Google Patents
Straight pushing -type DC of single feedback LED fluorescent tube drive circuit that adjusts luminance Download PDFInfo
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- CN205912292U CN205912292U CN201620737529.6U CN201620737529U CN205912292U CN 205912292 U CN205912292 U CN 205912292U CN 201620737529 U CN201620737529 U CN 201620737529U CN 205912292 U CN205912292 U CN 205912292U
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Abstract
The utility model discloses a straight pushing -type DC of single feedback LED fluorescent tube drive circuit that adjusts luminance, is it including exchanging direct current converting circuit, LED fluorescent tube driven supply circuit, interchange direct current converting circuit output voltage control circuit, interchange the inside vcc of direct current converting circuit " fall electric suppression circuit, PWM commentaries on classics DC light modulation control circuit, LED fluorescent tube current control circuit and singly feed back the LED fluorescent tube, the utility model discloses an exchange does direct current converting circuit adopt and singly organizes output design, output interflow it is that the voltage of change directly is supplied to and singly feeds back the work of LED fluorescent tube that direct current converting circuit singly organizes output voltage value size, and the EMI of a large amount of high frequencies of no boost boost circuit radiates the noise. The utility model discloses effectively reduce liquid crystal display product stand -by power consumption, it is more energy -concerving and environment -protective. The utility model discloses a drive circuit stand -by power consumption with low costs, efficient, low has lower EMI radiation characteristics.
Description
Technical field
This utility model is related to a kind of single direct-push dc that feeds back and dims LED lamp tube drive circuit.
Background technology
Traditional lcd products LED lamp pipe 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 unidirectional current, and this 19v unidirectional current passes through
Boost booster circuit boosted after generate a LED lamp pipe needed for running voltage such as: 25v-70v direct current supplies electricity to LED lamp pipe
Work, this boost booster circuit is driven by booster circuit control chip, in this LED lamp pipe each lamp string output feedback end with
Each feedback pin of booster circuit control chip is electrically connected, and controls each lamp string work in LED lamp pipe by booster circuit control chip
Electric current when making, to control liquid crystal display picture mean flow rate, this booster driving circuit receives one, and from motherboard circuit, (diagram is not drawn
Go out) switching signal that provides, in order to control this LED lamp tube drive circuit whether to work, this booster driving circuit receive one from
The dim dim signal that motherboard circuit (diagram is not drawn into) provides is big with electric current when controlling each lamp string work in this LED lamp pipe
Little, thus controlling liquid crystal display picture mean flow rate.
But above-mentioned prior art has a following problem: 1, LED lamp pipe driving power supply plate part material cost price is relatively
Height, is having begun to lack the market competitiveness in price.2nd, LED lamp tube drive circuit is (without AC-DC change-over circuit
Conversion efficiency), between 85%-90%, conversion efficiency is not high for conversion efficiency, in design epa7.0 new efficiency lcd products
When, the power supply conversion efficiency generally requiring to be lifted further AC-DC change-over circuit can be only achieved epa7.0 new efficiency regulation
Requirement, and lifted and LED lamp pipe driving power supply plate part material during the power supply conversion efficiency of AC-DC change-over circuit, can be caused
Cost price is lifted further.3rd, the motherboard circuit within lcd products needs 5v to power, and needs to pass through one group from 19v
Dc-dc decompression converting circuit is turning a 5v DC voltage, and 19v turns 5v dc-dc decompression converting circuit and turns under waiting condition
Change that efficiency is not high, only: 30%-45% about conversion efficiency.Therefore, reduce the design cost of LED lamp pipe driving power supply plate,
Lifting LED lamp pipe drives conversion efficiency, and reducing liquid crystal display product stand-by power consumption becomes the trend of technology development.
Content of the invention
The purpose of this utility model is to overcome the deficiencies in the prior art, provides a kind of single direct-push dc that feeds back to dim led
Lamp tube drive circuit.
The technical solution adopted in the utility model is:
A kind of single direct-push dc that feeds back dims LED lamp tube drive circuit, and it includes AC-DC change-over circuit, LED lamp pipe
The internal vcc of the power supply circuits of driving, AC-DC change-over circuit output voltage controlling circuit, AC-DC change-over circuit " falls
Electric suppression circuit, pwm turn dc adjusting control circuit, LED lamp tube current control circuit and single feedback LED lamp pipe；
The ac input end of described AC-DC change-over circuit receives AC mains, and AC mains are entered
Row voltage conversion the unidirectional current by outfan one group of variable values of output, AC-DC change-over circuit outfan order
The input of the power supply circuits of the input of feedback LED lamp pipe and the driving of LED lamp pipe, the power supply circuits that LED lamp pipe drives also set
There are switching signal receiving terminal, the first reference voltage output end, the second reference voltage output end and vcc outfan, described exchange-straight
Circulation is changed 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 outfan of described single feedback LED lamp pipe connects the input of LED lamp tube current control circuit and exchanging-directly respectively
The first feedback input end of circuit output voltage control 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 feeder ear of LED lamp tube current control circuit connects the vcc of the power supply circuits that LED lamp pipe drives
Outfan, the control electric current signal receiving terminal of LED lamp tube current control circuit connects the output that pwm turns dc adjusting control circuit
End；
Pwm turns dc adjusting control circuit and is additionally provided with reference voltage input and dim signal receiving terminal, and pwm turns dc light modulation control
The reference voltage input of circuit processed connects the first reference voltage output end of the power supply circuits that LED lamp pipe drives, and pwm turns dc and adjusts
The dim signal receiving terminal of light control circuit receives a dim dim signal being derived from mainboard, and just accounting for according to dim dim signal
The conversion of empty ratio generates a direct current dimmer voltage and exports to LED lamp tube current control circuit in order to control single feedback LED lamp pipe to work
When size of current；The outfan of the internal vcc of described AC-DC change-over circuit " power down suppression circuit connects AC-DC conversion
Second feedback input end of circuit output voltage control circuit, the internal vcc of AC-DC change-over circuit " power down suppression circuit
Switching signal receiving terminal receives a switching signal being derived from mainboard, the internal vcc of AC-DC change-over circuit " power down suppression circuit
When guaranteeing that the driving of this LED lamp pipe carries 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；Described AC-DC conversion electricity
The reference voltage receiving terminal of road output voltage controlling circuit connects the second reference voltage output of the power supply circuits that LED lamp pipe drives
End, the output of AC-DC change-over circuit output voltage controlling circuit terminates the feedback input end of AC-DC change-over circuit,
AC-DC change-over circuit output voltage controlling circuit controls exchange-directly by the single LED lamp pipe output end voltage that feeds back of detecting
Circuit output terminal voltage is changed in circulation；The switching signal receiving terminal of the power supply circuits that described LED lamp pipe drives receives and is derived from mainboard
Switching signal, in order to control LED lamp pipe drive power supply circuits whether work.
Further, described AC-DC change-over circuit includes bridge rectifier and filter circuit, transformator, feedback circuit
With AC-DC change-over circuit control chip,
The power supply circuits that described LED lamp pipe drives include reference voltage generating circuit and power supply conversion and control circuit；
Described LED lamp tube current control circuit includes the first N-shaped mos pipe q1, current sampling resistor r1, biasing resistor and
One amplifier op1；
Described 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 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；
AC-DC change-over circuit control chip has the first pin cs, second pin vdri, the 3rd pin vcc ", anti-
Feedback pin fb and grounding pin gnd, described transformator has the first winding positioned at primary side, the second winding and is located at secondary side
The tertiary winding, AC mains pass through one end that bridge rectifier and filter circuit access the first winding of transformator, first around
The other end of group is connected with the drain electrode of one the 5th N-shaped mos pipe q11, and the source electrode of the 5th N-shaped mos pipe q11 connects exchange-directly respectively
One end of the first pin cs and a resistance r18 of circuit control chip, the other end ground connection of resistance r18, the 5th N-shaped are changed in circulation
The grid of mos pipe q11 connects second pin vdri of AC-DC change-over circuit control chip, and one end of the second winding connects
The positive pole of one diode d12, the negative pole of diode d12 connects the 3rd pin of AC-DC change-over circuit control chip respectively
Vcc " and one end of electric capacity c12, the other end ground connection of electric capacity c12, the positive pole of one end connection diode d11 of the tertiary winding, two
The negative pole of pole pipe d11 connects one end of electric capacity c11 and one end of feedback circuit respectively, the other end of feedback circuit connect exchange-
Feedback pin fb of DC converting circuit control chip, the other end of electric capacity c11 connects the other end of the tertiary winding, the tertiary winding
Other end ground connection, the negative pole of diode d11 as the outfan of AC-DC change-over circuit, described first winding another
One end of end, one end of the second winding and the tertiary winding is Same Name of Ends；
The outfan of described AC-DC change-over circuit connects the input of single feedback LED lamp pipe and described power supply respectively
Conversion and the input of control circuit, the outfan of power supply conversion and control circuit connects the positive supply of the second amplifier op2 respectively
End and the input of reference voltage generating circuit, reference voltage generating circuit generates the first reference voltage and the second benchmark electricity respectively
Pressure；
The outfan of single feedback LED lamp pipe connects the drain electrode of the first N-shaped mos pipe q1 and the one of voltage sample resistance r2 respectively
End, the source electrode of the first N-shaped mos pipe q1 connects one end of current sampling resistor r1 and the negative input end of the first amplifier op1 respectively, electricity
The other end ground connection of stream sampling resistor r1, the grid of the first N-shaped mos pipe q1 connects the outfan of the first amplifier op1,
One end of biasing resistor connects the outfan of power supply conversion and control circuit, and the other end of biasing resistor connects first
The source electrode of N-shaped mos pipe q1；
Described pwm turns dc adjusting control circuit and receives a dim dim signal 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 signal and to the first amplifier op1 just exports
Hold into end,
The other end of voltage sample resistance r2 connects the negative input end of the second amplifier op2 and the one of frequency compensated circuit respectively
End, 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 second
Reference voltage,
The base stage of the outfan connection the first transistor q2 of the second amplifier op2, the grounded emitter of the first transistor q2, the
The colelctor electrode of one transistor q2 connects one end of feedback resistance r5 and one end of the first electric capacity c1 respectively, and feedback resistance r5's is another
End connects the reference edge of one end, one end of feedback resistance r4 and optocoupler and tl431 circuit of feedback resistance r3, feedback resistance respectively
The other end of r3 connects the outfan of AC-DC change-over circuit, the other end ground connection of feedback resistance r4, optocoupler and tl431 electricity
The other end on road connects AC-DC change-over circuit, and the other end of the first electric capacity c1 connects the emitter stage of transistor seconds q3, the
The base stage of two-transistor 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.
Further, described pwm turns dc adjusting control circuit and includes the second N-shaped mos pipe q4 and the 3rd N-shaped mos pipe q5, and
The grid of two N-shaped mos pipe q4 accesses dim dim signal, the source ground of the second N-shaped mos pipe q4, the leakage of the second N-shaped mos pipe q4
Pole connects the grid of the 3rd N-shaped mos pipe q5 and one end of the 4th resistance r6 respectively, the source ground of the 3rd N-shaped mos pipe q5, and
The drain electrode of three N-shaped mos pipe q5 connects one end of the 5th resistance r7 and one end of the 6th resistance r8 respectively, and the 4th resistance r6's is another
The other end of end and the 5th resistance r7 is respectively connected to the first reference voltage, and the other end of the 6th resistance r8 connects the second electric capacity respectively
One end of c2 and one end of the 7th resistance r9, the other end of the 7th resistance r9 connects one end and first of the 8th resistance r10 respectively
The positive input terminal of amplifier op1, the other end of the second electric capacity c2 and the other end of the 8th resistance r10 are grounded respectively.
Further, described power supply conversion and control circuit include the 4th N-shaped mos pipe q6, third transistor q7, the 4th crystalline substance
Body pipe q8 and Zener diode zd1, the emitter stage of third transistor q7 connect respectively AC-DC change-over circuit outfan and
One end of tenth resistance r12, the base stage of third transistor q7 connects one end of the 9th resistance r11 and the tenth resistance r12 respectively
The other end, the drain electrode of other end connection the 4th N-shaped mos pipe q6 of the 9th resistance r11, the source ground of the 4th N-shaped mos pipe q6,
The grid of the 4th N-shaped mos pipe q6 accesses the switching signal from mainboard, and the colelctor electrode of third transistor q7 connects the 11st resistance
One end of r13, the other end of the 11st resistance r13 connects the one of the 4th transistor q8 colelctor electrode and the 12nd resistance r14 respectively
End, the base stage of the 4th transistor q8 connects the negative pole of Zener diode zd1 and the other end of the 12nd resistance r14 respectively, and the 4th
The emitter stage of transistor q8 connects one end of the 3rd electric capacity c3, the other end ground connection of the 3rd electric capacity c3, Zener diode zd1 respectively
Plus earth, using the emitter stage of the 4th transistor q8 as power supply conversion and control circuit outfan.
Further, described 3rd crystal q7 is pnp transistor, and described 4th transistor q8 is npn transistor.
Further, described reference voltage generating circuit includes the 5th transistor q9 and three-terminal shunt regulator u1, described
The colelctor electrode of the 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 of the 17th resistance r19 and the cathode terminal of three-terminal shunt regulator u1 respectively, the
The emitter stage of five transistor q9 connects one end, one end of the 13rd resistance r15 and the 4th electric capacity c4 of the 15th resistance r17 respectively
One end, 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
The connection other end of the 15th resistance r17 and one end of the 16th resistance r18 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 are grounded respectively, and the 5th
The emitter stage of transistor q9 exports the first reference voltage, and 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 ends are in parallel steady
Depressor u1 is tl431 manostat.
Further, described 5th transistor q9 is npn transistor.
Further, described frequency compensated circuit is the rc frequency compensation that a compensation resistance and a compensating electric capacity are in series
Circuit.
This utility model adopt above technical scheme, 1, AC-DC change-over circuit adopt single group output design, output electricity
Pressure is supplied directly to the work of LED lamp pipe.2nd, LED lamp pipe is using single Feedback Design mode, i.e. each lamp string in LED lamp pipe
(string) outfan is connected together.3rd, LED lamp pipe electricity is accurately controlled by first amplifier op1 or error amplifier
Stream.4th, LED lamp pipe output end voltage is accurately controlled by second amplifier op2 or error amplifier, thus controlling friendship
Stream-DC converting circuit single group output voltage it may be assumed that AC-DC change-over circuit single group output voltage values size be change,
And revocable it is ensured that LED lamp pipe drive have higher conversion efficiency >=93%.5th, the switching signal being provided by motherboard circuit,
When switching signal is high high level, the AC-DC change-over circuit output in power panel supplies electricity to just like the direct current of 18v-21v
LED lamp pipe on-line operation, and when lcd products carry out holding state, switching signal is low low level, in power panel
AC-DC change-over circuit only export unidirectional current just like 15v or lower, generate after the conversion of dc-dc decompression converting circuit
5v direct current supplies electricity to motherboard circuit work, and for dc-dc decompression converting circuit, input voltage is lower, and its conversion efficiency can be relatively
Height, if the power panel of led driving of the present utility model is when standby, the conversion efficiency of dc-dc decompression converting circuit (15v turns 5v)
For 55%-60%, and traditional led driving power supply plate is when standby, and the conversion efficiency of dc-dc decompression converting circuit (19v turns 5v) is
30%-45%, therefore LED lamp tube drive circuit of the present utility model has lower stand-by power consumption.6th, LED lamp pipe of the present utility model
Drive circuit uses AC-DC change-over circuit single group output unidirectional current and is supplied directly to the work of LED lamp pipe, and traditional
LED lamp pipe drives after using AC-DC change-over circuit single group output unidirectional current and also will boost through boost booster circuit
Just supply LED lamp pipe work afterwards, can produce the emi radiation of a large amount of high frequencies during this boost booster circuit N-shaped mos pipe switch
Noise, therefore new led driving power supply plate reduces emi and solves difficulty.7th, the colelctor electrode of the first transistor q2 and emitter stage it
Between a c1 electric capacity in parallel and a q3pnp electric crystal so that the LED lamp pipe of lcd products drives to be entered by normal work treats
Under machine mode condition it may be assumed that motherboard circuit provide switching signal from high level high be changed into low level low when, AC-DC turns
Change the vcc of primary circuit top-cross stream-DC converting circuit control chip " energization pins will not drop to less than this control core because of power down
Under-voltage protection value (uvlo) set by piece energization pins inside, to guarantee this lcd products opening when the plate that pushes button
When crucial, standy operation mode can be smoothly entered by normal mode of operation.8th, q1n raceway groove N-shaped mos pipe source electrode and power supply conversion
And a roffset biasing resistor is set between control circuit output end, in lcd products normal work, when dim adjusts
The positive dutycycle of optical signal is transferred to when minimum 0% and be can ensure that liquid crystal display picture is at completely dark picture.Of the present utility model
Led drives more traditional LED lamp pipe driving to have: price is low, efficiency high, low standby power loss, has lower emi radiation feature.
Brief description
Below in conjunction with the drawings and specific embodiments, this utility model is described in further details；
Fig. 1 is the circuit theory schematic diagram that traditional LED lamp pipe drives；
Fig. 2 is the schematic block circuit diagram that a kind of single feedback direct-push dc of this utility model dims LED lamp tube drive circuit；
Fig. 3 is the circuit diagram that a kind of single feedback direct-push dc of this utility model dims LED lamp tube drive circuit；
Fig. 4 is that the pwm that a kind of single feedback direct-push dc of this utility model dims LED lamp tube drive circuit turns dc brightness adjustment control
Circuit diagram；
Fig. 5 is that a kind of single feedback direct-push dc of this utility model dims the power supply conversion of LED lamp tube drive circuit and controls
Circuit diagram；
Fig. 6 is that the reference voltage that a kind of single feedback direct-push dc of this utility model dims LED lamp tube drive circuit produces electricity
Road schematic diagram；
Fig. 7 is the AC-DC conversion electricity that a kind of single feedback direct-push dc of this utility model dims LED lamp tube drive circuit
Road schematic diagram；
If Fig. 8 is not have the internal vcc of AC-DC change-over circuit " power down suppression circuit when AC-DC change-over circuit
Waveform diagram during supply voltage vcc " power down；
Fig. 9 increases exchanges for this utility model-internal the vcc of DC converting circuit " AC-DC turns after power down suppression circuit
Change the supply voltage vcc of circuit " waveform diagram；
Figure 10 is that the chip alternative structure that a kind of single feedback direct-push dc of this utility model dims LED lamp tube drive circuit is shown
It is intended to.
Specific embodiment
As shown in one of Fig. 2-10, this utility model it include AC-DC change-over circuit, LED lamp pipe drive power supply
The internal vcc of circuit, AC-DC change-over circuit output voltage controlling circuit, AC-DC change-over circuit " power down suppression circuit,
Pwm turns dc adjusting control circuit, LED lamp tube current control circuit and single feedback LED lamp pipe；
The ac input end of described AC-DC change-over circuit receives AC mains, and AC mains are entered
Row voltage conversion the unidirectional current by outfan one group of variable values of output, AC-DC change-over circuit outfan order
The input of the power supply circuits of the input of feedback LED lamp pipe and the driving of LED lamp pipe, the power supply circuits that LED lamp pipe drives also set
There are switching signal receiving terminal, the first reference voltage output end, the second reference voltage output end and vcc outfan, described exchange-straight
Circulation is changed 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 outfan of described single feedback LED lamp pipe connects the input of LED lamp tube current control circuit and exchanging-directly respectively
The first feedback input end of circuit output voltage control 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 feeder ear of LED lamp tube current control circuit connects the vcc of the power supply circuits that LED lamp pipe drives
Outfan, the control electric current signal receiving terminal of LED lamp tube current control circuit connects the output that pwm turns dc adjusting control circuit
End；
Pwm turns dc adjusting control circuit and is additionally provided with reference voltage input and dim signal receiving terminal, and pwm turns dc light modulation control
The reference voltage input of circuit processed connects the first reference voltage output end of the power supply circuits that LED lamp pipe drives, and pwm turns dc and adjusts
The dim signal receiving terminal of light control circuit receives a dim dim signal being derived from mainboard, and just accounting for according to dim dim signal
The conversion of empty ratio generates a direct current dimmer voltage and exports to LED lamp tube current control circuit in order to control single feedback LED lamp pipe to work
When size of current；The outfan of the internal vcc of described AC-DC change-over circuit " power down suppression circuit connects AC-DC conversion
Second feedback input end of circuit output voltage control circuit, the internal vcc of AC-DC change-over circuit " power down suppression circuit
Switching signal receiving terminal receives a switching signal being derived from mainboard, the internal vcc of AC-DC change-over circuit " power down suppression circuit
When guaranteeing that the driving of this LED lamp pipe carries 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；Described AC-DC conversion electricity
The reference voltage receiving terminal of road output voltage controlling circuit connects the second reference voltage output of the power supply circuits that LED lamp pipe drives
End, the output of AC-DC change-over circuit output voltage controlling circuit terminates the feedback input end of AC-DC change-over circuit,
AC-DC change-over circuit output voltage controlling circuit controls exchange-directly by the single LED lamp pipe output end voltage that feeds back of detecting
Circuit output terminal voltage is changed in circulation；The switching signal receiving terminal of the power supply circuits that described LED lamp pipe drives receives and is derived from mainboard
Switching signal, in order to control LED lamp pipe drive power supply circuits whether work.
Further, the power supply circuits that described LED lamp pipe drives include reference voltage generating circuit and power supply conversion and control
Circuit processed；
Described LED lamp tube current control circuit includes the first N-shaped mos pipe q1, current sampling resistor r1, biasing resistor and
One amplifier op1；
Described 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 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 the input of single feedback LED lamp pipe and described power supply respectively
Conversion and the input of control circuit, the outfan of power supply conversion and control circuit is just connecting amplifier op1, amplifier op2 respectively
Power end and the input of reference voltage generating circuit, reference voltage generating circuit generates the first reference voltage vref1 pressure respectively
With the second reference voltage vref2；
The outfan of single feedback LED lamp pipe connects the drain electrode of the first N-shaped mos pipe q1 and the one of voltage sample resistance r2 respectively
End, the source electrode of the first N-shaped mos pipe q1 connects one end of current sampling resistor r1 and the negative input end of the first amplifier op1 respectively, electricity
The other end ground connection of stream sampling resistor r1, the grid of the first N-shaped mos pipe q1 connects the outfan of the first amplifier op1,
One end of biasing resistor roffset connects the outfan of power supply conversion and control circuit, biasing resistor roffset's
The other end connects the source electrode of the first N-shaped mos pipe q1；
Described pwm turns dc adjusting control circuit and receives a dim dim signal and one first reference voltage vref1 respectively, and
First reference voltage vref1 is generated a direct current dimmer voltage according to the positive duty cycle conversion of dim dim signal export to first
The anode of amplifier op1 enters end,
The other end of voltage sample resistance r2 connects the negative input end of the second amplifier op2 and the one of frequency compensated circuit respectively
End, 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 second
Reference voltage vref2,
The base stage of the outfan connection the first transistor q2 of the second amplifier op2, the grounded emitter of the first transistor q2, the
The colelctor electrode of one transistor q2 connects one end of feedback resistance r5 and one end of the first electric capacity c1 respectively, and feedback resistance r5's is another
End connects the reference edge of one end, one end of feedback resistance r4 and optocoupler and tl431 circuit of feedback resistance r3, feedback resistance respectively
The other end of r3 connects the outfan of AC-DC change-over circuit, the other end ground connection of feedback resistance r4, optocoupler and tl431 electricity
The other end on road connects AC-DC change-over circuit, and the other end of the first electric capacity c1 connects the emitter stage of transistor seconds q3, the
The base stage of two-transistor 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, in this utility model, the first amplifier op1, current sampling resistor r1, first N-shaped mos pipe q1, pwm turn
Dc adjusting control circuit forms a LED lamp tube current control circuit, and this LED lamp tube current control circuit is negative-feedback circuit, op1
Amplifier has empty short feature, that is: v1+=v1-, LED lamp 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 circuit constitute an AC-DC change-over circuit
Output end voltage vout control circuit (being also single feedback LED lamp pipe input pressure control circuit)；By voltage sample resistance r2
Voltage v2- after noise signal (noise) decay in the voltage being sampled is supplied to the negative input of the second amplifier op2
End, the second amplifier op2 positive input terminal receives the second reference voltage vref2 from reference voltage generating circuit output, the second amplifier
Op2 outfan electrically connects the base stage (base) of frequency compensated circuit and the first transistor q2, the second amplifier op2 and frequency compensation electricity
Road form an integrating circuit, be negative-feedback circuit, thus the second amplifier op2 there is empty short feature it may be assumed that v2-=v2+=vref2 it may be assumed that
During normal work, the output end voltage size of single feedback LED lamp pipe be controlled as basically identical with vref2 voltage so that this reality
When driving normal work with new LED lamp pipe, AC-DC change-over circuit output end voltage vout=vled+vref2, wherein
The voltage at LED lamp pipe two ends when vled------ works for LED lamp pipe；And now the first transistor q2 can be operated in amplification region,
A motional impedance rce would generally be produced between the colelctor electrode of the first transistor q2 and emitter stage, therefore in optocoupler and tl431 circuit
Pull down resistor total impedance r=r4//(r5+rce) of reference edge (r end), due to the electricity at reference edge r end in optocoupler and tl431 circuit
Press as 2.5v, therefore AC-DC change-over circuit output end voltage during LED lamp tube drive circuit normal work of the present utility model
Vout1=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 signal is transferred to minimum 0%, (duty=0%) is 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 signal is transferred to
When minimum 0% (duty=0%), the positive input terminal voltage v1+=0v of the first amplifier op1 amplifier is short according to the first amplifier op1 amplifier void
Feature: v1+=v1-=0v, now LED lamp tube current ilamp should be 0ma, but because the first amplifier op1 input has input
Offset voltage (input offset voltage) is so that the first amplifier op1 amplifier outfan still suffers from the output electricity of certain value
Pressure, so that the first N-shaped mos pipe q1 is in lightly conducting state so that LED lamp pipe still has a faint electric current to flow through, produces one micro-
Weak light is so that liquid crystal display picture cannot be in dark picture entirely, and works as setting one biasing resistor roffset, and then arranges one
During bias current ioffset (ioffset ≈ vcc/roffset), this ioffset electric current flows through current sampling resistor r1,
The negative input end of one amplifier op1 amplifier produces a bias voltage voffset=ioffset*r1, as long as this voltage is more than op1 amplifier
During maximum input offset voltage vio in specifications, op1 amplifier output end voltage is 0v so that the first N-shaped mos pipe q1 is in
Completely switched off state, now LED lamp tube current ilamp=0ma, liquid crystal display picture processes dark picture completely.
Further, described power supply conversion and control circuit receive an AC-DC change-over circuit output end voltage vout
The switching signal providing from motherboard circuit with one, when the switching signal that motherboard circuit is provided is high level (high), supplies
AC-DC change-over circuit output end voltage vout is converted into a supply voltage vcc supply first by electricity conversion and control circuit
Amplifier op1 and the work of the second amplifier op2, are supplied simultaneously to reference voltage generating circuit work, and are produced by reference voltage generating circuit
Bear two groups of reference voltage the first reference voltage vref1 and the second reference voltage vref2, therefore when switching signal is high level, this
The LED lamp pipe of utility model drives normal work, and now, transistor seconds q3 ends；
When lcd products need to enter standy operation mode, the motherboard circuit meeting within lcd products
A switching signal is provided to be low level (low) signal, power supply conversion and control circuit stop providing vcc to supply voltage to the first fortune
Put op1, the second amplifier op2 and reference voltage generating circuit, led of the present utility model drives and quits work, and q2 electric crystal ends,
The 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 ratio under waiting condition is normal
During work, vout1 voltage is much smaller, such as: during liquid crystal display product product normal work, AC-DC change-over circuit output voltage
Vout1=19v, and can arrange that output voltage vout2=15v is even lower in the standby state, this can reduce liquid crystal display product
Standby power, no matter traditional LED lamp pipe driving power supply plate is AC-DC in the standby state or in normal work
Change-over circuit single group exports the fixing DC voltage of a 19v, dc-dc conversion in motherboard circuit for this 19v DC voltage
Generate a 5v after device and export the circuit work such as the scaler ic in unidirectional current supply motherboard circuit；And led of the present utility model
Unidirectional current between 19v ~ 21v for the AC-DC change-over circuit single group output voltage during power panel normal work of drive circuit,
And in the standby state, AC-DC change-over circuit single group exports the fixing DC voltage of a such as≤15v.With philips
As a example 223v5 machine, according to traditional led boost boosting driving power supply plate, when input ac voltage is under holding state
The input power that 240v records is in 280mw；According to led drive circuit of the present utility model, then when defeated under holding state
Enter input power that alternating voltage records for 240v and be only in 230mw.
Switching signal provided in motherboard circuit from high level be changed into low level when, transistor seconds q3 turns on, the
One transistor q2 cut-off, feedback resistance r5 is charged to the first electric capacity c1.When after 5 t=r5*c1 time, the first electric capacity
C1 both end voltage can rise to about 2.5v by 0v.Now series impedance r between feedback resistance r5 and the first electric capacity c1 " can be by
R5+rce (q2) rises to infinity, pull down resistor total impedance r=r4//r ".AC-DC change-over circuit output end voltage meets
Vout=2.5v* (r3+r)/r=2.5v* (r3/r+1), that is, after 5 t=r5*c1 time, AC-DC change-over circuit exports
Within the voltage at end can drop to 15v at leisure by 19v during such as normal work, now AC-DC change-over circuit output electricity
It is set during standy operation mode that pressure control circuit can correctly control AC-DC change-over circuit output end voltage slowly to drop to
The magnitude of voltage of meter is it is ensured that AC-DC change-over circuit is defeated during switching signal is by high level (high) to low level (low)
Go out voltage can normally decline, occur without that output voltage is extremely too low to cause AC-DC change-over circuit primary side control chip
Under-voltage protection (uvlo) problem in vcc " energization pins.To guarantee this lcd products when the on ＆ off switch of the plate that pushes button
When, remain to smoothly enter standy operation mode by normal mode of operation.
As shown in figure 4, described pwm turns dc adjusting control circuit includes the second N-shaped mos pipe q4 and the 3rd N-shaped mos pipe q5,
The grid access dim dim signal of the second N-shaped mos pipe q4, the source ground of the second N-shaped mos pipe q4, the second N-shaped mos pipe q4's
The drain electrode connection grid of the 3rd N-shaped mos pipe q5 and one end of the 4th resistance r6 respectively, the source ground of the 3rd N-shaped mos pipe q5,
The drain electrode of the 3rd N-shaped mos pipe q5 connects one end of the 5th resistance r7 and one end of the 6th resistance r8 respectively, and the 4th resistance r6's is another
The other end of one end and the 5th resistance r7 is respectively connected to the first reference voltage vref1, and the other end of the 6th resistance r8 connects respectively
One end of second electric capacity c2 and one end of the 7th resistance r9, the other end of the 7th resistance r9 connects the one of the 8th resistance r10 respectively
End and the positive input terminal of the first amplifier op1, the other end of the second electric capacity c2 and the other end of the 8th resistance r10 are grounded respectively.
Specifically, the grid of the second N-shaped mos pipe q4 receives what a motherboard circuit within from lcd products provided
One dim dim signal, this dim dim signal passes through the second N-shaped mos pipe q4/ the 3rd N-shaped mos pipe q5 by the first reference voltage
Vref1 reference voltage generates a v1 direct current after the 5th resistance r7, the 6th resistance r8 and the second electric capacity c2 carry out voltage conversion
Voltage, this v1 DC voltage size is relevant with positive dutycycle (duty) size of dim dim signal, just the accounting for of dim dim signal
Empty ratio is bigger, then v1 voltage is higher, and the positive dutycycle of dim dim signal is less, then v1 voltage is lower, such as: works as liquid crystal display
During positive dutycycle duty=100% of dim dim signal of motherboard circuit output of interiors of products, v1=vref1* (r9+r10)/(r7+
r8+r9+r10)；During positive dutycycle duty=0% of dim dim signal that the motherboard circuit within when lcd products exports,
v1=0v；V1 DC voltage carries through generating a direct current dimmer voltage signal v1+ after the 7th resistance r9 and the 8th resistance r10 partial pressure
The operating current size of the positive input terminal control LED lamp pipe of supply amplifier or error amplifier, thus control liquid crystal display to draw
Face mean flow rate.
As shown in figure 5, described power supply conversion and control circuit include the 4th N-shaped mos pipe q6, third transistor q7, the 4th
Transistor q8 and Zener diode zd1, the emitter stage of third transistor q7 connects the outfan of AC-DC change-over circuit respectively
With one end of the tenth resistance r12, the base stage of third transistor q7 connects one end and the tenth resistance r12 of the 9th resistance r11 respectively
The other end, the other end of the 9th resistance r11 connects the drain electrode of the 4th N-shaped mos pipe q6, and the source electrode of the 4th N-shaped mos pipe q6 connects
Ground, the grid of the 4th N-shaped mos pipe q6 accesses the switching signal from mainboard, and the colelctor electrode of third transistor q7 connects the 11st
One end of resistance r13, the other end of the 11st resistance r13 connects the 4th transistor q8 colelctor electrode and the 12nd resistance r14 respectively
One end, the base stage of the 4th transistor q8 connects the negative pole of Zener diode zd1 and the other end of the 12nd resistance r14 respectively,
The emitter stage of the 4th transistor q8 connects one end of the 3rd electric capacity c3, the other end ground connection of the 3rd electric capacity c3, voltage stabilizing two pole respectively
The plus earth of pipe zd1, using the emitter stage of the 4th transistor q8 as the outfan of power supply conversion and control circuit.
Described third transistor q7, the 4th N-shaped mos pipe q6, the 9th resistance r11, the tenth resistance r12 constitute a switch control
Circuit processed, for controlling LED lamp tube drive circuit whether to work；12nd resistance r14, the 4th transistor q8, Zener diode
Zd1, the 3rd electric capacity c3 form voltage stabilizing vcc power supply circuits, such 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 grid of the 4th N-shaped mos pipe q6 receives a mainboard electricity
When the switching signal that road provides is high level signal (high), the 4th N-shaped mos pipe q6, the conducting of third transistor q7, power supply conversion
And control circuit output one vcc supplies voltage to amplifier first amplifier op1, the second amplifier op2 and reference voltage generating circuit,
LED lamp pipe drives and starts normal work.Under the conditions of carrying out standby mode in lcd products, the 4th N-shaped mos pipe q6's
When the switching signal that grid receives a motherboard circuit offer is low level signal (low), the 4th N-shaped mos pipe q6, third transistor
Q7 ends, and power supply conversion and control circuit stop output vcc and supply voltage to amplifier first amplifier op1, the second amplifier op2 and base
Quasi- voltage generation circuit, LED lamp pipe drives and quits work, and now liquid crystal display produces and enters under standby mode because of LED lamp pipe
Drive circuit does not work and very energy saving.
Described 3rd crystal q7 is pnp transistor, and described 4th transistor q8 is npn transistor.
As shown in fig. 6, described reference voltage generating circuit includes the 5th transistor q9 and three-terminal shunt regulator u1, described
The colelctor electrode of the 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 of the 17th resistance r19 and the cathode terminal of three-terminal shunt regulator u1 respectively, the
The emitter stage of five transistor q9 connects one end, one end of the 13rd resistance r15 and the 4th electric capacity c4 of the 15th resistance r17 respectively
One end, 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
The connection other end of the 15th resistance r17 and one end of the 16th resistance r18 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 are grounded respectively, and the 5th
The emitter stage of transistor q9 exports the first reference voltage vref1, and the other end of the 13rd resistance r15 exports the second reference voltage
vref2.
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 vref1=2.5v* (r17+r18) produced by this reference voltage generating circuit/
R18, such as: r17=r18=10k ω, then vref1=5v, obtain second reference voltage after r15 resistance, r16 electric resistance partial pressure
Vref2=vref1*r16/ (r15+r16), such 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 a compensating electric capacity are in series.This frequency
The effect of rate compensation circuit is to make AC-DC change-over circuit output vout voltage more stable.
As shown in fig. 7, described AC-DC change-over circuit includes bridge rectifier and filter circuit, transformator, 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, described transformator have the first winding positioned at primary side,
Second winding and the tertiary winding being located at secondary side, AC mains pass through that bridge rectifier and filter circuit access transformator
One end of one winding, the other end of the first winding is connected with the drain electrode of one the 5th N-shaped mos pipe q11, the 5th N-shaped mos pipe q11's
Source electrode connects one end of the first pin cs and a resistance r18 of AC-DC change-over circuit control chip respectively, resistance r18's
The other end is grounded, and the grid of the 5th N-shaped mos pipe q11 connects 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 the negative pole of diode d12 connects AC-DC change-over circuit respectively
One end of 3rd pin vcc of control chip " and 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, feedback circuit respectively
The other end connect feedback pin fb of AC-DC change-over circuit control chip, the other end of electric capacity c11 connects the tertiary winding
The other end, 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, institute
The one end stating the other end, one end of the second winding and the tertiary winding of the first winding is Same Name of Ends.
If during the as shown in figure 8 ,-internal vcc of DC converting circuit that do not increase exchanges " power down suppression circuit, in switching signal
Low level, the vcc of AC-DC change-over circuit control chip are changed into from high level " supply voltage occurs power-off problems.Power down
Reason: when lcd products enter standby mode by normal work, the switching signal of the motherboard circuit within machine can be by
High level is changed into low level, and now the first transistor q2 can be cut off conducting, can be by between sampling feedback pull down resistor resistance Shun
R4//(r5+rce (q2)) is changed into r4, and that is, pull down resistor Shun anaplasia is big, and AC-DC change-over circuit control chip output vdri draws
Foot stopping output pwm square wave carrys out driving transformer and carries out energy conversion.Due to the feedback circuit within AC-DC change-over circuit
There is time t2 operating lag problem, therefore need AC-DC change-over circuit control chip output vdri after the t1+t2 time
Pin just can export pwm square wave to be carried out driving transformer and carries out energy conversion.The corresponding t2 time, AC-DC change-over circuit controls
The vcc of chip " supply voltage occurs as soon as power-off problems, if vcc " power down when minimum voltage be less than AC-DC change-over circuit control
The under-voltage protection value (uvlo) of chip internal processed, this AC-DC change-over circuit control chip will start under-voltage protection function,
Make the Switching Power Supply cannot normal work.
As shown in figure 9, increase exchanges-the internal vcc of DC converting circuit " after power down suppression circuit, AC-DC conversion electricity
Road builtin voltage vcc " voltage occurs without power-off problems, to guarantee this lcd products when the on ＆ off switch of the plate that pushes button
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 pipe drive control chip, described LED lamp pipe drives to be controlled
Coremaking piece is integrated with described pwm and turns dc adjusting control circuit, power supply conversion and control circuit, reference voltage generating circuit, described
Including following pin, it is respectively as follows: 1, vcc energization pins, provide supply voltage for this control chip；2nd, comp feedback pin, leads to
Cross pin8 pin to detect, list feeds back LED lamp pipe output end voltage to adjust AC-DC change-over circuit output voltage vout size；
3rd, on_off switch control pin, for controlling whether this new led drives work；4th, dim light modulation pin, for controlling this new
LED lamp tube current size when type led drives work；5th, gnd grounding pin；6th, iset LED lamp tube current setting pin, passes through
R1 resistance is come maximum current when arranging the work of LED lamp pipe；7th, gm frequency compensation pin, by external r2 resistance and c1 electric capacity, makes
The stable work of whole led drive system energy；8th, led pin, for detecting LED lamp pipe output end voltage and electric current.
This utility model adopt above technical scheme, 1, AC-DC change-over circuit adopt single group output design, output electricity
Pressure is supplied directly to the work of LED lamp pipe.2nd, LED lamp pipe is using single Feedback Design mode, i.e. each lamp string in LED lamp pipe
(string) outfan is connected together.3rd, LED lamp pipe electricity is accurately controlled by first amplifier op1 or error amplifier
Stream.4th, LED lamp pipe output end voltage is accurately controlled by second amplifier op2 or error amplifier, thus controlling friendship
Stream-DC converting circuit single group output voltage it may be assumed that AC-DC change-over circuit single group output voltage values size be change,
And revocable it is ensured that LED lamp pipe drive have higher conversion efficiency >=93%.5th, the switching signal being provided by motherboard circuit,
When switching signal is high high level, the AC-DC change-over circuit output in power panel supplies electricity to just like the direct current of 18v-21v
LED lamp pipe on-line operation, and when lcd products carry out holding state, switching signal is low low level, in power panel
AC-DC change-over circuit only export unidirectional current just like 15v or lower, generate after the conversion of dc-dc decompression converting circuit
5v direct current supplies electricity to motherboard circuit work, and for dc-dc decompression converting circuit, input voltage is lower, and its conversion efficiency can be relatively
Height, if the power panel of led driving of the present utility model is when standby, the conversion efficiency of dc-dc decompression converting circuit (15v turns 5v)
For 55%-60%, and traditional led driving power supply plate is when standby, and the conversion efficiency of dc-dc decompression converting circuit (19v turns 5v) is
30%-45%, therefore LED lamp tube drive circuit of the present utility model has lower stand-by power consumption.6th, LED lamp pipe of the present utility model
Drive circuit uses AC-DC change-over circuit single group output unidirectional current and is supplied directly to the work of LED lamp pipe, and traditional
LED lamp pipe drives after using AC-DC change-over circuit single group output unidirectional current and also will boost through boost booster circuit
Just supply LED lamp pipe work afterwards, can produce the emi radiation of a large amount of high frequencies during this boost booster circuit N-shaped mos pipe switch
Noise, therefore new led driving power supply plate reduces emi and solves difficulty.7th, the colelctor electrode of the first transistor q2 and emitter stage it
Between a c1 electric capacity in parallel and a q3pnp electric crystal so that the LED lamp pipe of lcd products drives to be entered by normal work treats
Under machine mode condition it may be assumed that motherboard circuit provide switching signal from high level high be changed into low level low when, AC-DC turns
Change the vcc of primary circuit top-cross stream-DC converting circuit control chip " energization pins will not drop to less than this control core because of power down
Under-voltage protection value (uvlo) set by piece energization pins inside, to guarantee this lcd products opening when the plate that pushes button
When crucial, standy operation mode can be smoothly entered by normal mode of operation.8th, q1 n-channel N-shaped mos pipe source electrode and power supply turn
Change and control circuit output end between a roffset biasing resistor is set, in lcd products normal work, work as dim
The positive dutycycle of dim signal is transferred to when minimum 0% and be can ensure that liquid crystal display picture is at completely dark picture.Of the present utility model
Led drives more traditional LED lamp pipe driving to have: price is low, efficiency high, low standby power loss, has lower emi radiation feature.
In sum, preferred embodiment only of the present utility model, implements when limiting this utility model with this
Scope, the simple equivalence changes generally made according to this utility model claim and invention description content and modification
All still belong in the range of this utility model patent lid.
Claims (10)
1. a kind of single feed back direct-push dc light modulation LED lamp tube drive circuit it is characterised in that: it includes AC-DC conversion electricity
Road, the power supply circuits of LED lamp pipe driving, AC-DC change-over circuit output voltage controlling circuit, AC-DC change-over circuit
Internal vcc " power down suppression circuit, pwm turn dc adjusting control circuit, LED lamp tube current control circuit and single feedback LED lamp pipe；
The ac input end of described AC-DC change-over circuit receives AC mains, and AC mains are carried out electricity
Pressure is changed and is exported the unidirectional current of one group of variable values by outfan, and AC-DC change-over circuit outfan order is fed back
The input of the power supply circuits of the input of LED lamp pipe and the driving of LED lamp pipe, the power supply circuits that LED lamp pipe drives are additionally provided with out
OFF signal receiving terminal, the first reference voltage output end, the second reference voltage output end and vcc outfan, described AC-DC turns
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 outfan of described single feedback LED lamp pipe connects the input of LED lamp tube current control circuit respectively and AC-DC turns
Change the first feedback input end of circuit output voltage control circuit；LED lamp tube current control circuit is additionally provided with feeder ear and control
Current signal receiving terminal, the feeder ear of LED lamp tube current control circuit connects the vcc output of the power supply circuits that LED lamp pipe drives
End, the control electric current signal receiving terminal of LED lamp tube current control circuit connects the outfan that pwm turns dc adjusting control circuit；
Described pwm turns dc adjusting control circuit and is additionally provided with reference voltage input and dim signal receiving terminal, and pwm turns dc light modulation
The reference voltage input of control circuit connects the first reference voltage output end of the power supply circuits that LED lamp pipe drives, and pwm turns dc
The dim signal receiving terminal of adjusting control circuit receives a dim dim signal being derived from mainboard, and according to dim dim signal just
Duty cycle conversion generates a direct current dimmer voltage and exports to LED lamp tube current control circuit；In described AC-DC change-over circuit
The outfan of portion vcc " power down suppression circuit connects the second feed back input of AC-DC change-over circuit output voltage controlling circuit
The switching signal receiving terminal of end, the internal vcc of AC-DC change-over circuit " power down suppression circuit receives a switch being derived from mainboard
Signal, the internal vcc of AC-DC change-over circuit " power down suppression circuit guarantees that this LED lamp pipe drives and is carried out by normal mode of operation
During standby not mode of operation, AC-DC change-over circuit occurs without and causes under-voltage protection because of internal power down；Described exchange-
The reference voltage receiving terminal of DC converting circuit output voltage controlling circuit connects the second base of the power supply circuits that LED lamp pipe drives
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
Feedback input, AC-DC change-over circuit output voltage controlling circuit is controlled by the single LED lamp pipe output end voltage that feeds back of detecting
AC-DC change-over circuit output end voltage processed；The switching signal receiving terminal of the power supply circuits that described LED lamp pipe drives receives
From the switching signal of mainboard, whether the power supply circuits in order to control LED lamp pipe to drive work.
2. according to claim 1 a kind of single feed back direct-push dc light modulation 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
Coremaking piece,
The power supply circuits that described LED lamp pipe drives include reference voltage generating circuit and power supply conversion and control circuit；
Described LED lamp tube current control circuit includes the first N-shaped mos pipe q1, current sampling resistor r1, biasing resistor and the first fortune
Put op1；
Described 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 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；
AC-DC change-over circuit control chip has the first pin cs, second pin vdri, the 3rd pin vcc ", feedback draw
Foot fb and grounding pin gnd, described transformator has the first winding positioned at primary side, the second winding and be located at secondary side the
Three winding, AC mains pass through one end of the first winding of bridge rectifier and filter circuit access transformator, the first winding
The other end is connected with the drain electrode of one the 5th N-shaped mos pipe q11, and the source electrode of the 5th N-shaped mos pipe q11 connects AC-DC respectively and turns
Change one end of the first pin cs and a resistance r18 of circuit control chip, the other end ground connection of resistance r18, the 5th N-shaped mos pipe
The grid of q11 connects second pin vdri of AC-DC change-over circuit control chip, and one end of the second winding connects one or two poles
The positive pole of pipe 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, diode d11
Negative pole connect one end of electric capacity c11 and one end of feedback circuit respectively, the other end of feedback circuit connects AC-DC conversion
Feedback pin fb of circuit control chip, the other end of electric capacity c11 connects the other end of the tertiary winding, the other end of the tertiary winding
Ground connection, the negative pole of diode d11 as the outfan of AC-DC change-over circuit, the other end of described first winding, second around
One end of one end of group and the tertiary winding is Same Name of Ends；
The outfan of described AC-DC change-over circuit connects input and the described power supply conversion of single feedback LED lamp pipe respectively
And the input of control circuit, power supply conversion and control circuit outfan 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 outfan of single feedback LED lamp pipe connects the drain electrode of the first N-shaped mos pipe q1 and one end of voltage sample resistance r2 respectively,
The source electrode of the first N-shaped mos pipe q1 connects one end of current sampling resistor r1 and the negative input end of the first amplifier op1, electric current respectively
The other end ground connection of sampling resistor r1, the grid of the first N-shaped mos pipe q1 connects the outfan of the first amplifier op1,
One end of biasing resistor connects the outfan of power supply conversion and control circuit, and the other end of biasing resistor connects the first N-shaped
The source electrode of mos pipe q1；
Described pwm turns dc adjusting control circuit and receives a dim dim signal 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 signal and exports to enter to the anode of the first amplifier op1
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,
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 benchmark
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, and first is brilliant
The colelctor electrode of body pipe q2 connects one end of feedback resistance r5 and one end of the first electric capacity c1 respectively, and the other end of feedback resistance r5 divides
Not Lian Jie feedback resistance r3 one end, one end of feedback resistance r4 and optocoupler and tl431 circuit reference edge, feedback resistance r3's
The outfan of other end connection AC-DC change-over circuit, the other end ground connection of feedback resistance r4, optocoupler and tl431 circuit
The other end connects AC-DC change-over circuit, and the other end of the first electric capacity c1 connects the emitter stage of transistor seconds q3, and second is brilliant
The base stage of body pipe q3 accesses the switching signal from mainboard, the grounded collector of transistor seconds q3.
3. according to claim 1 a kind of single feed back direct-push dc light modulation 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.
4. according to claim 1 a kind of single feed back direct-push dc light modulation LED lamp tube drive circuit it is characterised in that: described
Pwm turns dc adjusting control circuit and includes the second N-shaped mos pipe q4 and the 3rd N-shaped mos pipe q5, and the grid of the second N-shaped mos pipe q4 connects
Enter dim dim signal, the source ground of the second N-shaped mos pipe q4, the drain electrode of the second N-shaped mos pipe q4 connects the 3rd N-shaped mos respectively
The grid of pipe q5 and one end of the 4th resistance r6, the source ground of the 3rd N-shaped mos pipe q5, the drain electrode of the 3rd N-shaped mos pipe q5 divides
Not Lian Jie one end of the 5th resistance r7 and one end of the 6th resistance r8, the other end of the 4th resistance r6 and the 5th resistance r7's is another
End is respectively connected to the first reference voltage, and the other end of the 6th resistance r8 connects one end and the 7th resistance r9 of the second electric capacity c2 respectively
One end, the other end of the 7th resistance r9 connects one end of the 8th resistance r10 and the positive input terminal of the first amplifier op1 respectively,
The other end of the other end of two electric capacity c2 and the 8th resistance r10 is grounded respectively.
5. according to claim 1 a kind of single feed back direct-push dc light modulation LED lamp tube drive circuit it is characterised in that: described
Power supply conversion and control circuit include the 4th N-shaped mos pipe q6, third transistor q7, the 4th transistor q8 and Zener diode
Zd1, the emitter stage of third transistor q7 connects the outfan of AC-DC change-over circuit and one end of the tenth resistance r12 respectively,
The base stage of third transistor q7 connects one end of the 9th resistance r11 and the other end of the tenth resistance r12, the 9th resistance r11 respectively
The other end connect the 4th N-shaped mos pipe q6 drain electrode, the source ground of the 4th N-shaped mos pipe q6, the grid of the 4th N-shaped mos pipe q6
The switching signal from mainboard is accessed in pole, and the colelctor electrode of third transistor q7 connects one end of the 11st resistance r13, the 11st electricity
The other end of resistance r13 connects one end of the 4th transistor q8 colelctor electrode and the 12nd resistance r14, the base of the 4th transistor q8 respectively
Pole connects the negative pole of Zener diode zd1 and the other end of the 12nd resistance r14 respectively, and the emitter stage of the 4th transistor q8 is respectively
Connect one end of the 3rd electric capacity c3, the other end ground connection of the 3rd electric capacity c3, the plus earth of Zener diode zd1, with the 4th crystalline substance
The emitter stage of body pipe q8 is as the outfan of power supply conversion and control circuit.
6. according to claim 5 a kind of single feed back direct-push dc light modulation 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.
7. according to claim 1 a kind of single feed back direct-push dc light modulation LED lamp tube drive circuit it is characterised in that: described
Reference voltage generating circuit includes the 5th transistor q9 and three-terminal shunt regulator u1, and the colelctor electrode of described 5th transistor q9 divides
Lian Jie not power conversion and the outfan of control circuit and one end of the 17th resistance r19, and the base stage of the 5th transistor q9 is respectively
Connect the other end of the 17th resistance r19 and the cathode terminal of three-terminal shunt regulator u1, the emitter stage of the 5th transistor q9 is respectively
Connect one end of one end, one end of the 13rd resistance r15 and the 4th electric capacity c4 of the 15th resistance r17, the 13rd resistance r15
The other end connect one end of the 14th resistance r16, the reference edge of three-terminal shunt regulator u1 connects the 15th resistance r17 respectively
The other end and the 16th resistance r18 one end, the anode tap of three-terminal shunt regulator u1, the other end of the 16th resistance r18,
The other end of the other end of the 4th electric capacity c 4 and the 14th resistance r16 is grounded respectively, the emitter stage of the 5th transistor q9 output the
One reference voltage, the other end of the 13rd resistance r15 exports the second reference voltage.
8. according to claim 7 a kind of single feed back direct-push dc light modulation LED lamp tube drive circuit it is characterised in that: described
The reference voltage of the reference edge of three-terminal shunt regulator u1 is 2.5v, and described three-terminal shunt regulator u1 is tl431 manostat.
9. according to claim 7 a kind of single feed back direct-push dc light modulation LED lamp tube drive circuit it is characterised in that: described
5th transistor q9 is npn transistor.
10. according to claim 1 a kind of single feed back direct-push dc light modulation 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 a compensating electric capacity are in series.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620737529.6U CN205912292U (en) | 2016-07-13 | 2016-07-13 | Straight pushing -type DC of single feedback LED fluorescent tube drive circuit that adjusts luminance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620737529.6U CN205912292U (en) | 2016-07-13 | 2016-07-13 | Straight pushing -type DC of single feedback LED fluorescent tube drive circuit that adjusts luminance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205912292U true CN205912292U (en) | 2017-01-25 |
Family
ID=57805407
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620737529.6U Withdrawn - After Issue CN205912292U (en) | 2016-07-13 | 2016-07-13 | Straight pushing -type DC of single feedback LED fluorescent tube drive circuit that adjusts luminance |
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| Country | Link |
|---|---|
| CN (1) | CN205912292U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105960070A (en) * | 2016-07-13 | 2016-09-21 | 福建捷联电子有限公司 | Single-feedback direct-push type DC light-dimming LED tube driving circuit |
| CN107770914A (en) * | 2017-11-03 | 2018-03-06 | 赛尔富电子有限公司 | A kind of LED lamp power supply |
| CN113316289A (en) * | 2020-02-26 | 2021-08-27 | 苏州佳世达电通有限公司 | LED power supply circuit |
| CN114815941A (en) * | 2021-01-27 | 2022-07-29 | 北京京东方光电科技有限公司 | Voltage regulation and control circuit |
-
2016
- 2016-07-13 CN CN201620737529.6U patent/CN205912292U/en not_active Withdrawn - After Issue
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105960070A (en) * | 2016-07-13 | 2016-09-21 | 福建捷联电子有限公司 | Single-feedback direct-push type DC light-dimming LED tube driving circuit |
| CN105960070B (en) * | 2016-07-13 | 2017-09-29 | 福建捷联电子有限公司 | A kind of single feedback direct-push DC dimming LED lamp tube drive circuits |
| CN107770914A (en) * | 2017-11-03 | 2018-03-06 | 赛尔富电子有限公司 | A kind of LED lamp power supply |
| CN107770914B (en) * | 2017-11-03 | 2023-10-10 | 赛尔富电子有限公司 | LED lamp power supply |
| CN113316289A (en) * | 2020-02-26 | 2021-08-27 | 苏州佳世达电通有限公司 | LED power supply circuit |
| CN114815941A (en) * | 2021-01-27 | 2022-07-29 | 北京京东方光电科技有限公司 | Voltage regulation and control circuit |
| CN114815941B (en) * | 2021-01-27 | 2023-11-17 | 北京京东方光电科技有限公司 | Voltage regulation circuit |
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