CN206136376U - Backlight driving circuit - Google Patents
Backlight driving circuit Download PDFInfo
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- CN206136376U CN206136376U CN201621032554.0U CN201621032554U CN206136376U CN 206136376 U CN206136376 U CN 206136376U CN 201621032554 U CN201621032554 U CN 201621032554U CN 206136376 U CN206136376 U CN 206136376U
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Abstract
The utility model discloses a backlight driving circuit, including transformer circuit, PWM control module, the prefabricated module of drive current and the control module that adjusts luminance, the power output end of transformer circuit is connected with LED lamp strip, and the 2nd power output end and the input of the prefabricated module of drive current and dimming control module's power end of transformer circuit are connected, and the output of the prefabricated module of drive current is connected with PWM control module's the first feedback end, and dimming control module's output is connected with PWM control module's second feedback end, and PWM control module's power output 0 is connected with the hand drive of transformer circuit end, the prefabricated module of drive current is used for output current setting signal, and dimming control module is used for exporting the dimming control signal, and PWM control module is used for controlling the transformer circuit according to electric current setting signal and dimming control signal to make the drive current of the suitable size of its output. The utility model discloses technical scheme has the characteristics that the function is abundant.
Description
Technical field
This utility model is related to backlight drive circuit technical field, more particularly to a kind of backlight drive circuit.
Background technology
LED increasing makes in a television set because having the advantages that long service life, power and energy saving, driving convenient
With.Wherein, the driving of LED is divided into exchange and drives and DC driven.Exchange driving is referred to after AC rectification filtering through AC-DC
Conversion power directly to LED lamp bar, DC driven refer to AC rectification filtering after, first pass through AC-DC conversion obtain one every
Low-voltage dc voltage after, then become through DC-DC and give LED lamp bar and power.Exchange type of drive is because than DC driven mode
Lack one-stage transfor-mation and there is efficiency high, the advantage of low cost.
Fig. 1 is a kind of highly integrated monolithic constant current AC driving circuit, is a kind of application circuit of NCP1370 chips,
NCP1370 chips are single-chip microcomputer primary current constant control Mode integrating circuits, with lamp open circuit and short-circuit protection, overcurrent protection, defeated
Enter the functions such as the linear and PWM light modulations of voltage monitoring, main primary.The AC driving circuit of monolithic constant current shown in Fig. 1 is in switch
The primary of power supply takes switching current signal and carries out output constant current control, and in the primary of Switching Power Supply brightness adjustment control is carried out.Due to being
Primary control dimming mode, dim signal can not isolate civil power, therefore limit the range of application of Switching Power Supply, in TV
Isolation brightness adjustment control is realized in machine, is then also needed to the simulation dim signal with television set and digital dim signal is matched.Meanwhile,
Present driving proposes the requirement for wanting prefabricated electric current to meet different lamp bar driving currents, and the circuit shown in Fig. 1 can not be realized
Analog- and digital- light modulation isolation control and prefabricated electric current meet the function of different lamp bar driving currents.
Utility model content
Main purpose of the present utility model is to provide a kind of backlight drive circuit, it is intended to enrich the work(of the backlight drive circuit
Energy.
For achieving the above object, the utility model proposes backlight drive circuit include transformer circuit, with exchange it is defeated
Enter end, driven moved end, the first power output end and second source outfan, first power output end is connected with LED lamp bar；
PWM control modules, with drive output, the first feedback end, the second feedback end, the drive output and transformator electricity
The driven moved end connection on road；Driving current Prefabricated block, the input of the driving current Prefabricated block and the transformer circuit
The connection of second source outfan, the first feedback end of the outfan of the driving current Prefabricated block and the PWM control modules
Connection；The driving current Prefabricated block, to output current setting signal, so that the PWM control modules control the transformation
The output current of the first power output end of device circuit；And, dimming controlling module, with power end, simulation light modulation pwm signal
Input and digital dimming pwm signal end, the power end of the dimming controlling module is defeated with the second source of the transformer circuit
Go out end connection, the outfan of the dimming controlling module is connected with the second feedback end of the PWM control modules；The brightness adjustment control mould
Block, for exporting corresponding dimming control signal to described according to the simulation of input light modulation pwm signal and digital dimming pwm signal
PWM control modules carry out brightness adjustment control.
Preferably, the transformer circuit includes transformator, boost voltage output unit and driving voltage output unit, institute
Transformator is stated including primary side winding, vice-side winding and assists winding, the boost voltage output unit include the first diode, the
One electric capacity and mu balanced circuit；The first end of the primary side winding is the ac input end of the transformer circuit, the former limit around
Second end of group is the driven moved end of the transformer circuit；The input of the vice-side winding and the driving voltage output unit
End connection, the outfan of the driving voltage output unit is the first power output end of the transformer circuit；The auxiliary
The first end of winding is connected with the anode of first diode, the negative electrode of first diode, the of first electric capacity
The input interconnection of one end and the mu balanced circuit, the second end of first electric capacity and the ground connection termination of the mu balanced circuit
Ground, the outfan of the mu balanced circuit is the second source outfan of the transformer circuit.
Preferably, the mu balanced circuit includes first resistor, second resistance, 3rd resistor and the first voltage stabilizing adjustment pipe, institute
The first end for stating first resistor is the input of the mu balanced circuit, and the second end of the first resistor, first voltage stabilizing are adjusted
The first end interconnection of the negative electrode of homogeneous tube and the second resistance, its connecting node is the outfan of the mu balanced circuit；Described
The first end interconnection of the reference pole, the second end of the second resistance and the 3rd resistor of one voltage stabilizing adjustment pipe, described first
The anode of voltage stabilizing adjustment pipe is connected with the second end of the 3rd resistor, and its connecting node is the earth terminal of the mu balanced circuit.
Preferably, the mu balanced circuit includes that the 4th resistance, the 5th resistance, the 6th resistance, first switch pipe and second are steady
Pressure adjustment pipe, the first end of the 4th resistance is connected with the colelctor electrode of the first switch pipe, and its connecting node is described steady
The input of volt circuit；The emitter stage of the first switch pipe is connected with the first end of the 5th resistance, and its connecting node is
The outfan of the mu balanced circuit；Second end of the 5th resistance, the first end of the 6th resistance and second voltage stabilizing
The reference pole interconnection of adjustment pipe, the negative electrode of second voltage stabilizing adjustment pipe, the second end of the 4th resistance and described first open
The base stage interconnection of pipe is closed, the anode of the second voltage stabilizing adjustment pipe is connected with the second end of the 6th resistance, its connecting node
For the earth terminal of the mu balanced circuit.
Preferably, the driving current Prefabricated block includes potentiometer and the first follow circuit；The input of the potentiometer
End is connected with the power end of first follow circuit, and its connecting node is the input of the driving current Prefabricated block；Institute
The adjustment end for stating potentiometer is connected with the input of first follow circuit, and the outfan of first follow circuit is described
The outfan of driving current Prefabricated block；The earth terminal ground connection of the outfan of the potentiometer and first follow circuit.
Preferably, first follow circuit includes the 7th resistance, the 8th resistance, second switch pipe and the 3rd switching tube,
The base stage of the second switch pipe is the input of first follow circuit；The colelctor electrode of the second switch pipe and described
The first end connection of eight resistance, its connecting node is the power end of first follow circuit；Second end of the 8th resistance
It is connected with the emitter stage of the 3rd switching tube, its connecting node is the outfan of first follow circuit；Described 3rd opens
Close the first end interconnection of the base stage, the emitter stage of the second switch pipe and the 7th resistance of pipe, the of the 7th resistance
Two ends are connected with the colelctor electrode of the 3rd switching tube, and its connecting node is the earth terminal of first follow circuit.
Preferably, first follow circuit includes the 9th resistance, the 4th switching tube and the 5th switching tube, and the described 4th opens
The base stage for closing pipe is the input of first follow circuit；The emitter stage of the 4th switching tube and the of the 9th resistance
Two ends connect, and the first end of the 9th resistance be connected with the colelctor electrode of the 5th switching tube, and its connecting node is described the
The power end of one follow circuit, the outfan of extremely described first follow circuit of transmitting of the 5th switching tube, the described 4th
The earth terminal of extremely described first follow circuit of the current collection of switching tube.
Preferably, the PWM control modules include control chip, the 6th switching tube and sampling resistor；The control chip
Light modulation foot be the PWM control modules the first feedback end and the second feedback end；The driving foot of the control chip with it is described
The grid connection of the 6th switching tube, the source electrode of the 6th switching tube is grounded by the sampling resistor, the 6th switching tube
Drain electrode for the PWM control modules drive output.
Preferably, the dimming controlling module include the tenth resistance, the 11st resistance, the 12nd resistance, the 13rd resistance,
14th resistance, the first optocoupler, the second optocoupler, the second electric capacity and the second follow circuit；The negative electrode and anode of first optocoupler
For being input into digital dimming pwm signal, the colelctor electrode of first optocoupler is connected with the outfan of first follow circuit, institute
The light modulation foot interconnection of the emitter stage, the first end of the tenth resistance and the control chip of the first optocoupler is stated, the described tenth is electric
The second end ground connection of resistance；Second end of the 11st resistance is connected with the source electrode of the 6th switching tube, and the described 11st is electric
The first end interconnection of the first end of resistance, the feedback foot of the control chip and the 12nd resistance, the 12nd resistance
Second end is connected with the outfan of second follow circuit, the power end of second follow circuit and the 13rd resistance
First end be connected with the outfan of the mu balanced circuit, the input of second follow circuit, the 14th resistance
The first end interconnection of the second end and second electric capacity, the second end of the 13rd resistance, the first of the 14th resistance
End and second optocoupler emitter stage interconnection, the earth terminal of second follow circuit, the second end of second electric capacity and
The grounded emitter of second optocoupler, the negative electrode and anode of second optocoupler are used for input simulation light modulation pwm signal.
Preferably, the dimming controlling module includes the 7th switching tube, the 15th resistance, the 16th resistance, the 17th electric
Resistance, the 18th resistance, the 3rd electric capacity, the 4th electric capacity, the 3rd optocoupler, the 4th optocoupler and the 3rd follow circuit；3rd optocoupler
Negative electrode and anode be used to be input into the of digital dimming pwm signal, the emitter stage of the 3rd optocoupler and the 18th resistance
One end is connected with the light modulation foot of the control chip, the second end ground connection of the 18th resistance；The collection of the 3rd optocoupler
Electrode is connected with the outfan of the 3rd follow circuit, and the power end of the 3rd follow circuit is defeated with the mu balanced circuit
Go out end connection, the first of the input of the 3rd follow circuit, the second end of the 17th resistance and the 4th electric capacity
End interconnection, the colelctor electrode of the first end, the second end of the 16th resistance and the 7th switching tube of the 17th resistance
Interconnection, the colelctor electrode interconnection of the base stage, the second end of the 15th resistance and the 4th optocoupler of the 7th switching tube, institute
The first end of first end, the first end of the 15th resistance and the 3rd electric capacity of the 16th resistance is stated with described first
The outfan connection of follow circuit, the earth terminal of the 3rd follow circuit, the second end of the 4th electric capacity, the described 7th open
The emitter stage of pipe and the grounded emitter of the 4th optocoupler are closed, the negative electrode and anode of the 4th optocoupler are used for input simulation and adjust
Light pwm signal.
The utility model proposes backlight drive circuit in, on the one hand, dimming controlling module can simultaneously receives input
Simulation light modulation pwm signal and digital dimming pwm signal, and dimming control signal corresponding with light modulation pwm signal is exported to PWM controls
Molding block carries out brightness adjustment control.On the other hand, driving current Prefabricated block can be with output current setting signal to PWM control modules
Carry out transformer circuit output current prefabricated.Therefore, the utility model proposes backlight drive circuit can realize simulate sum
Word light modulation isolation control and prefabricated electric current meet the function of different lamp bar driving currents.Relative to prior art, with function
Abundant the characteristics of.
Description of the drawings
In order to be illustrated more clearly that this utility model embodiment or technical scheme of the prior art, below will be to embodiment
Or the accompanying drawing to be used needed for description of the prior art is briefly described, it should be apparent that, drawings in the following description are only
It is some embodiments of the present utility model, for those of ordinary skill in the art, in the premise for not paying creative work
Under, other accompanying drawings can be obtained with the structure according to these accompanying drawings.
Fig. 1 is the electrical block diagram of backlight drive circuit in prior art；
Fig. 2 is the high-level schematic functional block diagram of the embodiment of this utility model backlight drive circuit one；
Fig. 3 is the electrical block diagram of the backlight drive circuit first embodiment shown in Fig. 2；
Fig. 4 is the electrical block diagram of mu balanced circuit first embodiment in Fig. 3；
Fig. 5 is the electrical block diagram of mu balanced circuit second embodiment in Fig. 3；
Fig. 6 is the electrical block diagram of the first follow circuit first embodiment in Fig. 3；
Fig. 7 is the electrical block diagram of the first follow circuit second embodiment in Fig. 3；
Fig. 8 is the electrical block diagram of the backlight drive circuit second embodiment shown in Fig. 2.
Drawing reference numeral explanation：
The realization of this utility model purpose, functional characteristics and advantage will be described further referring to the drawings in conjunction with the embodiments.
Specific embodiment
Below in conjunction with the accompanying drawing in this utility model embodiment, the technical scheme in this utility model embodiment is carried out
Clearly and completely describe, it is clear that described embodiment is only a part of embodiment of the present utility model, rather than all
Embodiment.Based on the embodiment in this utility model, those of ordinary skill in the art are not making creative work premise
Lower obtained every other embodiment, belongs to the scope of this utility model protection.
In addition, the description for being related to " first ", " second " etc. in this utility model is only used for describing purpose, and it is not understood that
To indicate or implying its relative importance or the implicit quantity for indicating indicated technical characteristic.Thus, define " first ",
At least one this feature can be expressed or be implicitly included to the feature of " second ".In addition, the technical side between each embodiment
Case can be combined with each other, but must can be implemented as basis with those of ordinary skill in the art, when the combination of technical scheme
It will be understood that the combination of this technical scheme is not present when appearance is conflicting or cannot realize, also not in this utility model requirement
Protection domain within.
The utility model proposes a kind of backlight drive circuit, the backlight drive circuit is applied to display device or illumination sets
It is standby, it is particularly suited for television set, drive LED lamp bar work therein.
With reference to Fig. 2, in one embodiment, the utility model proposes backlight drive circuit include transformer circuit 100, tool
There are ac input end VI, driven moved end, the first power output end and second source outfan, the first power output end and LED
Bar connects；PWM control modules 200, with drive output, the first feedback end, the second feedback end, drive output and transformator
The driven moved end connection of circuit 10；Driving current Prefabricated block 300, the input and transformation of the driving current Prefabricated block 300
The second source outfan connection of device circuit 100, outfan and the PWM control modules 200 of the driving current Prefabricated block 300
First feedback end connects；The driving current Prefabricated block 300, to output current setting signal, so that PWM control modules 200
The output current of the first power output end of control transformer circuit 100；And, dimming controlling module 400, with power end,
Simulation light modulation pwm signal input and digital dimming pwm signal end, power end and the transformator electricity of the dimming controlling module 400
The second source outfan connection on road 100, the outfan of the dimming controlling module 400 and the second feedback of PWM control modules 200
End connection；The dimming controlling module 400, for right according to the simulation of input light modulation pwm signal and the output of digital dimming pwm signal
The dimming control signal answered to PWM control modules 200 carry out brightness adjustment control.
Before backlight drive circuit drives LED lamp bar work, can first clear and definite LED lamp bar specifications parameter, and pass through
The size of the driving current of the first power output end output of the prefabricated voltage device circuit 10 of driving current Prefabricated block 300, is allowed to
Match with LED lamp bar to be driven.
By backlight drive circuit incoming transport electricity, based on the control of PWM control modules 200, the output of transformer circuit 100 is closed
The driving voltage and driving current of suitable size is to LED lamp bar, LED lamp bar work.
Hereafter, the brightness of LED lamp bar is if desired adjusted, is then input into corresponding simulation light modulation PWM to dimming controlling module 400
Signal and digital dimming pwm signal are capable of achieving, very easy.
Due to the utility model proposes backlight drive circuit in, on the one hand, dimming controlling module 400 can connect simultaneously
The simulation light modulation pwm signal and digital dimming pwm signal of input are received, and is exported and digital dimming pwm signal and simulation light modulation PWM
The corresponding dimming control signal of signal carries out brightness adjustment control to PWM control modules 200.On the other hand, driving current Prefabricated block
The 300 power output end output currents that transformer circuit 100 can be carried out with output current setting signal to PWM control modules 200
It is prefabricated.Therefore, the utility model proposes backlight drive circuit can realize it is analog- and digital- light modulation isolation control and it is prefabricated
Electric current meets the function of different lamp bar driving currents.Relative to prior art, the characteristics of with feature richness.
With reference to Fig. 3 to Fig. 8, in a preferred embodiment, above-mentioned transformer circuit 100 includes that transformator T, boost voltage are defeated
Go out unit (figure is not marked) and driving voltage output unit (driving voltage output unit as shown in Fig. 3 or Fig. 8), transformator
T includes primary side winding NP, vice-side winding NS and assists winding NAUX, boost voltage output unit include the first diode D1, the
One electric capacity C1 and mu balanced circuit 110；The first end of primary side winding NP for transformer circuit 100 ac input end VI, former limit around
Second end of group NP is the driven moved end of transformer circuit 100；Vice-side winding NS connects with the input of driving voltage output unit
Connect, the outfan of driving voltage output unit is the first power output end of transformer circuit 100；The first of assists winding NAUX
End is connected with the anode of the first diode D1, the negative electrode of the first diode D1, the first end of the first electric capacity C1 and mu balanced circuit 110
Input P1 interconnection, the earth terminal P2 ground connection GND of second end of the first electric capacity C1 and mu balanced circuit 110, mu balanced circuit 110
Outfan P3 is the second source outfan of transformer circuit 100.
When the ac input end VI incoming transport power supplys of transformer circuit 100：Transformer secondary winding NS passes through former limit
Winding NP obtains an alternating current, and the alternating current is input into LED lamp bar Jing after driving voltage output unit carries out rectifying and wave-filtering process,
Power to LED lamp bar.Transformator assists winding NS obtains an alternating current, the alternating current the first diodes of Jing by primary side winding NP
It is input into mu balanced circuit 110 after D1 rectifications, the first electric capacity C1 Filtering Processing, mu balanced circuit 110 carries out the unidirectional current of input surely
Export after pressure process.It is noted that unidirectional current is exported again Jing after the process of mu balanced circuit 110, the first electric capacity C1 can be eliminated
Impact of the fluctuation of both end voltage to subsequent conditioning circuit.
With reference to Fig. 4, in a preferred embodiment, above-mentioned mu balanced circuit 110 include first resistor R1, second resistance R2, the
Three resistance R3 and the first voltage stabilizing adjustment pipe IC1, the first end of first resistor R1 is the input P1 of mu balanced circuit 110, and first is electric
The first end interconnection at second end, the negative electrode of the first voltage stabilizing adjustment pipe IC1 and second resistance R2 of resistance R1, its connecting node is voltage stabilizing
The outfan P3 of circuit 110；First voltage stabilizing adjusts reference pole, the second end of second resistance R2 and 3rd resistor R3 of pipe IC1
First end is interconnected, and the anode of the first voltage stabilizing adjustment pipe IC1 is connected with the second end of 3rd resistor R3, and its connecting node is voltage stabilizing electricity
The earth terminal P2 on road 110.
When the input P1 of mu balanced circuit 110 has power input, the voltage that 3rd resistor R3 is divided is more than or equal to
First voltage stabilizing adjusts the cut-in voltage of pipe IC1, and the first voltage stabilizing adjustment pipe IC1 is opened, and falls to being adjusted in the first voltage stabilizing the reference of pipe IC1
Pole tension is constant for X1.It is preferred that X1 is 2.5V, so, the voltage of the outfan P3 of mu balanced circuit 110 is just stable in 2.5 (1+
R2/R3) V, realizes voltage stabilizing function.
With reference to Fig. 5, in a preferred embodiment, above-mentioned mu balanced circuit 110 include the 4th resistance R4, the 5th resistance R5, the
Six resistance R6, first switch pipe Q2 and the second voltage stabilizing adjustment pipe IC2, the first end of the 4th resistance R4 and the collection of first switch pipe Q1
Electrode connects, and its connecting node is the input P1 of mu balanced circuit 110；The emitter stage of first switch pipe Q1 and the 5th resistance R5's
First end connects, and its connecting node is the outfan P4 of mu balanced circuit 110；Second end of the 5th resistance R5, the 6th resistance R6
The reference pole interconnection of first end and the second voltage stabilizing adjustment pipe IC2, the second voltage stabilizing adjustment negative electrode of pipe IC2, the of the 4th resistance R4
The base stage interconnection of two ends and first switch pipe Q1, the anode of the second voltage stabilizing adjustment pipe IC2 is connected with second end of the 6th resistance R6,
Its connecting node is the earth terminal P2 of mu balanced circuit 110.
When the input P1 of mu balanced circuit 110 has power input, first switch pipe Q1 conductings, the 6th resistance R6 point
Voltage adjusts the cut-in voltage of pipe IC2 more than or equal to the second voltage stabilizing, and the second voltage stabilizing adjustment pipe IC2 is opened, fallen steady second
The voltage constant of the reference pole of pressure adjustment pipe IC2 is X2.It is preferred that X2 is 2.5V, and so, the outfan P3 of mu balanced circuit 110
Voltage it is just stable in 2.5 (1+R2/R3) V, realize voltage stabilizing function.
With reference to Fig. 3 to Fig. 8, in a preferred embodiment, driving current Prefabricated block 300 include potentiometer W and first with
With circuit 10；The input of potentiometer W is connected with the power end P7 of the first follow circuit 10, and its connecting node is that driving current is pre-
The input of molding block 300；The adjustment end of potentiometer W is connected with the input P4 of the first follow circuit 10, the first follow circuit
10 outfan P6 is the outfan of driving current Prefabricated block 300；The outfan of potentiometer W and the first follow circuit 10 connect
Ground terminal P5 is grounded GND.
In the present embodiment, the electricity between the adjustment end and outfan of potentiometer W is adjusted by adjusting the adjustment end of potentiometer W
Pressure, to adjust the voltage of the input P4 in the first follow circuit 10, so as to adjust the output voltage of the first follow circuit 10.
It is understood that when potentiometer W adjustment ends are adjusted to the outfan of potentiometer W, falling in the input of the first follow circuit 10
The voltage of end P4 is zero；When potentiometer W adjustment ends are adjusted to the input of potentiometer, fall in the input of the first follow circuit 10
The voltage of end P4 is V3, so, with the position change of potentiometer W adjustment ends, the output voltage correspondence of the first follow circuit 10
Change, and the scope of its output voltage zero between V3.Additionally, first is arranged in driving current Prefabricated block 300 following
Circuit 10 can reduce the internal resistance of output voltage.
With reference to Fig. 6, in a preferred embodiment, above-mentioned first follow circuit 10 include the 7th resistance R7, the 8th resistance R8,
Second switch pipe Q2 and the 3rd switching tube Q3, the base stage of second switch pipe Q2 is the input P4 of the first follow circuit 10；Second
The colelctor electrode of switching tube Q2 is connected with the first end of the 8th resistance R8, and its connecting node is the power end of the first follow circuit 10
P7；Second end of the 8th resistance R8 is connected with the emitter stage of the 3rd switching tube Q3, and its connecting node is the first follow circuit 10
Outfan P6；The first end of emitter stage and the 7th resistance R7 that the base stage of the 3rd switching tube Q3, second open hanging tube Q2 is interconnected, and the 7th
Second end of resistance R7 is connected with the colelctor electrode of the 3rd switching tube Q3, and its connecting node is the earth terminal of the first follow circuit 10
P5。
When the input input high level of the first follow circuit 10, second switch pipe Q2 conductings, the 3rd switching tube Q3's
Base stage is high level, and the base voltage of the 3rd switching tube Q3 is driven high, the 3rd switching tube Q3 cut-offs, the transmitting of the 3rd switching tube Q3
Pole tension is driven high, the output high level of the first follow circuit 10.When the input P4 of the first follow circuit 10 exports low level,
Second switch pipe Q2 ends, and the base voltage of the 3rd switching tube Q3 is pulled low, the 3rd switching tube Q3 conductings, the 3rd switching tube Q3's
Emitter voltage is driven high, the output low level of the first follow circuit 10.So, the first follow circuit 10 is achieved that voltage follow
Function.
With reference to Fig. 7, in a preferred embodiment, above-mentioned first follow circuit 10 includes the 9th resistance R9, the 4th switching tube
Q4 and the 5th switching tube Q5, the base stage of the 4th switching tube Q4 is the input P4 of the first follow circuit 10；4th switching tube Q4's
Emitter stage is connected with second end of the 9th resistance R9, and the first end of the 9th resistance R9 is connected with the colelctor electrode of the 5th switching tube Q5,
Its connecting node is the power end P7 of the first follow circuit 10, and the 5th switching tube Q5's launches the defeated of extremely the first follow circuit 10
Go out and hold P6, the earth terminal P5 of current collection extremely first follow circuit 10 of the 4th switching tube Q4.
When the input P4 input high levels of the first follow circuit 10, the 4th switching tube Q4 cut-offs, the 5th switching tube Q5
Base voltage be driven high, the 5th switching tube Q5 conductings, the emitter voltage of the 5th switching tube Q5 is driven high, the first follow circuit
10 output high level.When the input P4 input low levels of the first follow circuit 10, the 4th switching tube Q4 conductings, the 5th switch
The base voltage of pipe Q5 is pulled low, and the 5th switching tube Q5 cut-offs, the emitter voltage of the 5th switching tube Q5 is pulled low, and first follows
Circuit 10 exports low level.So, the first follow circuit 10 is achieved that voltage follow function.
With reference to Fig. 3 to Fig. 8, in a preferred embodiment, above-mentioned PWM control modules 200 include control chip the 210, the 6th
Switching tube Q6 and sampling resistor RS；The light modulation foot DIM of control chip 210 is first feedback end and second of PWM control modules 200
Feedback end；The driving foot DRV of control chip 210 is connected with the grid of the 6th switching tube Q6, and the source electrode of the 6th switching tube Q6 passes through
Sampling resistor RS is grounded GND, and the drain electrode of the 6th switching tube Q6 is the drive output of PWM control modules 200.
When the driving foot DRV of control chip 210 exports high level, the 6th switching tube Q6 conductings, PWM control modules 200
Output drive signal；When the driving foot DRV of control chip 210 exports low level, the 6th switching tube Q6 cut-offs, PWM control moulds
The not output drive signal of block 200.It is noted that in the present embodiment, the model of control chip 210 is preferably NCP1370, when
When the dutycycle or amplitude of the PWM ripples that the light modulation foot DIM of control chip 210 is received change, it drives foot DRV outputs
The dutycycle of PWM ripples change.
With reference to Fig. 3, in a preferred embodiment, above-mentioned dimming controlling module 400 includes the tenth resistance R10, the 11st electric
It is resistance R11, the 12nd resistance R12, the 13rd resistance R13, the 14th resistance R14, the first optocoupler U1, the second optocoupler U2, second electric
Hold C2 and the second follow circuit 20；The negative electrode B1 and anode A 1 of the first optocoupler U1 is used to be input into digital dimming pwm signal, the first light
The colelctor electrode of coupling U1 is connected with the outfan of the first follow circuit 10, the emitter stage of the first optocoupler U1, the first of the tenth resistance R10
The light modulation foot DIM interconnection of end and control chip 210, the second end ground connection GND of the tenth resistance R10；The second of 11st resistance R11
End is connected with the source electrode of the 6th switching tube Q6, the first end of the 11st resistance R11, the feedback foot CS and the tenth of control chip 210
The first end interconnection of two resistance R12, second end of the 12nd resistance R12 is connected with the outfan of the second follow circuit 20, and second
The first end of the power end of follow circuit 20 and the 13rd resistance R13 is connected with the outfan of mu balanced circuit 110, and second follows electricity
The first end interconnection of the input on road 20, second end of the 14th resistance R14 and the second electric capacity C2, the of the 13rd resistance R13
The emitter stage interconnection at two ends, the first end of the 14th resistance R14 and the second optocoupler U2, the earth terminal of the second follow circuit 20, the
Second end of two electric capacity C2 and the grounded emitter GND of the second optocoupler U2, the negative electrode B2 and anode A 2 of the second optocoupler U2 is for defeated
Enter simulation light modulation pwm signal.
It is noted that in the present embodiment, the model of control chip 210 is preferably NCP1370.Additionally, second follows
Circuit 20 can be with identical with the circuit structure of the first follow circuit 10, it is also possible to different, is not limited herein.
Digital dimming pwm signal is input into the light modulation foot DIM of control chip 210 by the first optocoupler U1, realizes that numeral is adjusted
Light function.The resistance R13 copped waves of Jing the 13rd after the second optocoupler U2 outputs of simulation light modulation pwm signal are processed, and are added in the first light
The square-wave signal of the colelctor electrode of coupling U1 becomes d. c. voltage signal simultaneously Jing after the 14th resistance R14 and the second electric capacity C2 Integral Processings
The second follow circuits of Jing 20 are exported.The DC voltage is added to the feedback foot CS of control chip 210, mould by the 12nd resistance R12
The dutycycle for intending light modulation pwm signal can change the voltage at the second electric capacity C2 two ends when changing, the change of the voltage can change the
The change of 11 resistance R11 both end voltages, so as to realize simulating dimming function.
With reference to Fig. 8, in a preferred embodiment, dimming controlling module 400 includes the 7th switching tube Q7, the 15th resistance
R15, the 16th resistance R16, the 17th resistance R17, the 18th resistance R18, the 3rd electric capacity C3, the 4th electric capacity C4, the 3rd optocoupler
U3, the 4th optocoupler U4 and the 3rd follow circuit 30；The negative electrode B3 and anode A 3 of the 3rd optocoupler U3 is used to be input into digital dimming PWM letters
Number, the emitter stage of the 3rd optocoupler U3 and the first end of the 18th resistance R18 are connected with the light modulation foot DIM of control chip 210, and
The second end ground connection GND of 18 resistance R18；The colelctor electrode of the 3rd optocoupler U3 is connected with the outfan of the 3rd follow circuit 30, the
The power end of three follow circuits 30 is connected with the outfan of mu balanced circuit 110, the input of the 3rd follow circuit 110, the 17th
The first end interconnection of second end of resistance R17 and the 4th electric capacity C4, the first end of the 17th resistance R17, the 16th resistance R16
The colelctor electrode interconnection of the second end and the 7th switching tube Q7, the base stage of the 7th switching tube Q7, second end of the 15th resistance R15 and the
The colelctor electrode interconnection of four optocoupler U4, the first end of the 16th resistance R16, the first end of the 15th resistance R15 and the 3rd electric capacity C3
First end be connected with the outfan of the first follow circuit 10, the earth terminal of the 3rd follow circuit 30, the of the 4th electric capacity R4
The grounded emitter at two ends, the emitter stage of the 7th switching tube Q7 and the 4th optocoupler U4, the negative electrode B4 and anode A 4 of the 4th optocoupler U4
For input simulation light modulation pwm signal.
It is noted that in the present embodiment, the model of control chip is preferably NCP1370.In addition the 3rd follow circuit
30 can be with identical with the circuit structure of the first follow circuit 10, it is also possible to different, is not limited herein
Digital dimming pwm signal is input into the light modulation foot DIM of control chip 210 by the 3rd optocoupler U3, realizes that numeral is adjusted
Light function.The resistance R15 copped waves of Jing the 15th after the 4th optocoupler U4 outputs of simulation light modulation pwm signal are processed, and are added in the 7th and are opened
The square-wave signal for closing the colelctor electrode of pipe Q7 becomes d. c. voltage signal Jing after the 17th resistance R17 and the 4th electric capacity C4 Integral Processings
And the follow circuits 30 of Jing the 3rd are exported.The optocoupler U3 of d. c. voltage signal Jing the 3rd are input to the light modulation foot of control chip 210
DIM, the dutycycle of simulation light modulation pwm signal can change the change of the output voltage of the 3rd follow circuit 30 when changing, so as to realize
Simulation dimming function.
Hereinafter, with reference to Fig. 2 to Fig. 7, the operation principle of this utility model backlight drive circuit first embodiment is illustrated：
The output second after the first diode D1 rectifications, the first electric capacity C1 filtering of assists winding NAUX of transformator T is electric
Source voltage, the second source voltage obtains a voltage-stabilized source after mu balanced circuit 110, and it is electric that it can eliminate first
Hold impact of the fluctuation of C1 both end voltages to subsequent conditioning circuit.The regulated power supply can obtain one after potentiometer W partial pressures can
The output voltage of tune, the output voltage can control the digital dimming of LED lamp bar through the first optocoupler U1 again, and can pass through
Potentiometer W is setting driving output current.Simulation light modulation pwm signal is exported through the 13rd resistance R13 by the second optocoupler U2
To output voltage copped wave, the square-wave signal for being added in the first optocoupler U1 colelctor electrodes is accumulated through the 14th resistance R14 and the second electric capacity C2
Get DC voltage, the DC voltage obtains the very low voltage of internal resistance after the second follow circuit 20, the voltage leads to
The feedback foot CS that the 12nd resistance R12 is added to NCP1370 is crossed, it is electric that simulation dimming control signal dutycycle can change second when changing
Hold C2 both end voltages, the change in voltage can cause the change of the 11st resistance R11 both end voltages, open such that it is able to change the 6th
The switching current value of pipe Q6 is closed, therefore can realize simulating dimming function.
Hereinafter, with reference to Fig. 2, Fig. 4 to Fig. 8, the operation principle of this utility model backlight drive circuit second embodiment is illustrated：
The output second after the first diode D1 rectifications, the first electric capacity C1 filtering of assists winding NAUX of transformator T is electric
Source voltage, the second source voltage obtains a voltage-stabilized source after mu balanced circuit 110, and it is electric that it can eliminate first
Hold impact of the fluctuation of C1 both end voltages to subsequent conditioning circuit.The regulated power supply can obtain one after potentiometer W partial pressures can
The output voltage of tune, the output voltage again as the power supply of dimming controlling module 400, therefore, it can change brightness adjustment control mould
The output voltage of block 400, also just can be with the electric current of prefabricated output.The voltage obtains low internal resistance through the 3rd follow circuit 30 again
Voltage, then can just realize the simulation light modulation to exporting and digital dimming through the 3rd optocoupler U3.
Preferred embodiment of the present utility model is the foregoing is only, the scope of the claims of the present utility model is not thereby limited,
It is every under inventive concept of the present utility model, the equivalent structure made using this utility model description and accompanying drawing content is become
Change, or directly/be used in other related technical fields indirectly and be included in scope of patent protection of the present utility model.
Claims (10)
1. a kind of backlight drive circuit, it is characterised in that include：
Transformer circuit, with ac input end, driven moved end, the first power output end and second source outfan, described
One power output end is connected with LED lamp bar；
PWM control modules, with drive output, the first feedback end, the second feedback end, the drive output and the transformation
The driven moved end connection of device circuit；
Driving current Prefabricated block, the input of the driving current Prefabricated block is exported with the second source of the transformer circuit
End connection, the outfan of the driving current Prefabricated block is connected with the first feedback end of the PWM control modules；The driving current
Prefabricated block, to output current setting signal, so that the PWM control modules control the first power supply of the transformer circuit
The output current of outfan；And,
Dimming controlling module, with power end, simulation light modulation pwm signal input and digital dimming pwm signal end, the light modulation control
The power end of molding block is connected with the second source outfan of the transformer circuit, the outfan of the dimming controlling module and institute
State the second feedback end connection of PWM control modules；The dimming controlling module, for according to input simulation light modulation pwm signal and
Digital dimming pwm signal exports corresponding dimming control signal and carries out brightness adjustment control to the PWM control modules.
2. backlight drive circuit as claimed in claim 1, it is characterised in that the transformer circuit includes transformator, auxiliary
Voltage output unit and driving voltage output unit, the transformator includes primary side winding, vice-side winding and assists winding, described
Boost voltage output unit includes the first diode, the first electric capacity and mu balanced circuit；The first end of the primary side winding is described
The ac input end of transformer circuit, the second end of the primary side winding is the driven moved end of the transformer circuit；The pair
Side winding is connected with the input of the driving voltage output unit, and the outfan of the driving voltage output unit is the change
First power output end of transformer circuits；The first end of the assists winding is connected with the anode of first diode, described
The input interconnection of the negative electrode of the first diode, the first end of first electric capacity and the mu balanced circuit, first electric capacity
The second end and the mu balanced circuit earth terminal ground connection, the outfan of the mu balanced circuit is the second of the transformer circuit
Power output end.
3. backlight drive circuit as claimed in claim 2, it is characterised in that the mu balanced circuit include first resistor, second
Resistance, 3rd resistor and the first voltage stabilizing adjustment pipe, the first end of the first resistor is the input of the mu balanced circuit, described
The first end interconnection at the second end of first resistor, the negative electrode of first voltage stabilizing adjustment pipe and the second resistance, its connection section
Point is the outfan of the mu balanced circuit；First voltage stabilizing adjusts reference pole, the second end of the second resistance and the institute of pipe
The first end interconnection of 3rd resistor is stated, the anode of the first voltage stabilizing adjustment pipe is connected with the second end of the 3rd resistor, its
Connecting node is the earth terminal of the mu balanced circuit.
4. backlight drive circuit as claimed in claim 2, it is characterised in that the mu balanced circuit include the 4th resistance, the 5th
Resistance, the 6th resistance, first switch pipe and the second voltage stabilizing adjustment pipe, first end and the first switch pipe of the 4th resistance
Colelctor electrode connection, its connecting node is the input of the mu balanced circuit；The emitter stage of the first switch pipe and described
The first end connection of five resistance, its connecting node is the outfan of the mu balanced circuit；It is second end of the 5th resistance, described
The reference pole interconnection of the first end of the 6th resistance and second voltage stabilizing adjustment pipe, second voltage stabilizing adjusts negative electrode, the institute of pipe
State the second end of the 4th resistance and the base stage interconnection of the first switch pipe, the anode of second voltage stabilizing adjustment pipe and described the
The second end connection of six resistance, its connecting node is the earth terminal of the mu balanced circuit.
5. backlight drive circuit as claimed in claim 2, it is characterised in that the driving current Prefabricated block includes potentiometer
And first follow circuit；The input of the potentiometer is connected with the power end of first follow circuit, and its connecting node is
The input of the driving current Prefabricated block；The adjustment end of the potentiometer connects with the input of first follow circuit
Connect, the outfan of first follow circuit is the outfan of the driving current Prefabricated block；The outfan of the potentiometer
And the earth terminal ground connection of first follow circuit.
6. backlight drive circuit as claimed in claim 5, it is characterised in that first follow circuit include the 7th resistance,
8th resistance, second switch pipe and the 3rd switching tube, the base stage of the second switch pipe is the input of first follow circuit
End；The colelctor electrode of the second switch pipe is connected with the first end of the 8th resistance, and its connecting node is followed for described first
The power end of circuit；Second end of the 8th resistance is connected with the emitter stage of the 3rd switching tube, and its connecting node is institute
State the outfan of the first follow circuit；The base stage of the 3rd switching tube, the emitter stage of the second switch pipe and the described 7th
The first end interconnection of resistance, the second end of the 7th resistance is connected with the colelctor electrode of the 3rd switching tube, its connecting node
For the earth terminal of first follow circuit.
7. backlight drive circuit as claimed in claim 5, it is characterised in that first follow circuit include the 9th resistance,
4th switching tube and the 5th switching tube, the base stage of the 4th switching tube is the input of first follow circuit；Described
The emitter stage of four switching tubes is connected with the second end of the 9th resistance, and the first end of the 9th resistance and the described 5th is switched
The colelctor electrode connection of pipe, its connecting node is the power end of first follow circuit, and the transmitting of the 5th switching tube is extremely
The outfan of first follow circuit, the earth terminal of extremely described first follow circuit of current collection of the 4th switching tube.
8. backlight drive circuit as claimed in claim 5, it is characterised in that the PWM control modules include control chip, the
Six switching tubes and sampling resistor；The light modulation foot of the control chip is that the first feedback end of the PWM control modules and second are anti-
Feedback end；The foot that drives of the control chip is connected with the grid of the 6th switching tube, and the source electrode of the 6th switching tube passes through
The sampling resistor ground connection, the drain electrode of the 6th switching tube is the drive output of the PWM control modules.
9. backlight drive circuit as claimed in claim 8, it is characterised in that the dimming controlling module include the tenth resistance,
11st resistance, the 12nd resistance, the 13rd resistance, the 14th resistance, the first optocoupler, the second optocoupler, the second electric capacity and second
Follow circuit；
The negative electrode and anode of first optocoupler is used to be input into digital dimming pwm signal, the colelctor electrode of first optocoupler and institute
State the outfan connection of the first follow circuit, the emitter stage of first optocoupler, the first end of the tenth resistance and the control
The light modulation foot interconnection of coremaking piece, the second end ground connection of the tenth resistance；Second end and the described 6th of the 11st resistance
The source electrode connection of switching tube, the first end of the 11st resistance, the feedback foot of the control chip and the 12nd resistance
First end interconnection, the second end of the 12nd resistance is connected with the outfan of second follow circuit, described second with
It is connected with the outfan of the mu balanced circuit with the power end of circuit and the first end of the 13rd resistance, described second follows
The first end interconnection of the input of circuit, the second end of the 14th resistance and second electric capacity, the 13rd resistance
The second end, the first end of the 14th resistance and second optocoupler emitter stage interconnection, second follow circuit
The grounded emitter of earth terminal, the second end of second electric capacity and second optocoupler, the negative electrode and sun of second optocoupler
Pole is used for input simulation light modulation pwm signal.
10. backlight drive circuit as claimed in claim 8, it is characterised in that the dimming controlling module includes the 7th switch
Pipe, the 15th resistance, the 16th resistance, the 17th resistance, the 18th resistance, the 3rd electric capacity, the 4th electric capacity, the 3rd optocoupler,
Four optocouplers and the 3rd follow circuit；
The negative electrode and anode of the 3rd optocoupler is used to be input into digital dimming pwm signal, the emitter stage of the 3rd optocoupler and institute
The first end for stating the 18th resistance is connected with the light modulation foot of the control chip, the second end ground connection of the 18th resistance；
The colelctor electrode of the 3rd optocoupler is connected with the outfan of the 3rd follow circuit, the power end of the 3rd follow circuit with
The outfan connection of the mu balanced circuit, the input of the 3rd follow circuit, the second end of the 17th resistance and institute
State the first end interconnection of the 4th electric capacity, the first end of the 17th resistance, the second end of the 16th resistance and described the
The colelctor electrode interconnection of seven switching tubes, the base stage of the 7th switching tube, the second end of the 15th resistance and the 4th light
The colelctor electrode interconnection of coupling, the first end of the 16th resistance, the first end of the 15th resistance and the 3rd electric capacity
First end is connected with the outfan of first follow circuit, the earth terminal of the 3rd follow circuit, the 4th electric capacity
The second end, the emitter stage of the 7th switching tube and the 4th optocoupler grounded emitter, the negative electrode of the 4th optocoupler
And anode is used for input simulation light modulation pwm signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621032554.0U CN206136376U (en) | 2016-08-31 | 2016-08-31 | Backlight driving circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621032554.0U CN206136376U (en) | 2016-08-31 | 2016-08-31 | Backlight driving circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206136376U true CN206136376U (en) | 2017-04-26 |
Family
ID=58568165
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621032554.0U Active CN206136376U (en) | 2016-08-31 | 2016-08-31 | Backlight driving circuit |
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| Country | Link |
|---|---|
| CN (1) | CN206136376U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107613610A (en) * | 2017-09-26 | 2018-01-19 | 深圳市中科智联科技有限公司 | intelligent lighting controller |
| CN110753428A (en) * | 2019-09-19 | 2020-02-04 | 浙江凯耀照明有限责任公司 | Isolation dimming circuit built by operational amplifier |
-
2016
- 2016-08-31 CN CN201621032554.0U patent/CN206136376U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107613610A (en) * | 2017-09-26 | 2018-01-19 | 深圳市中科智联科技有限公司 | intelligent lighting controller |
| CN107613610B (en) * | 2017-09-26 | 2023-10-24 | 深圳市中科智联科技有限公司 | Intelligent lighting controller |
| CN110753428A (en) * | 2019-09-19 | 2020-02-04 | 浙江凯耀照明有限责任公司 | Isolation dimming circuit built by operational amplifier |
| CN110753428B (en) * | 2019-09-19 | 2021-06-08 | 浙江凯耀照明有限责任公司 | Isolation dimming circuit built by operational amplifier |
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Effective date of registration: 20230412 Address after: 518000 Room 201, building A, No. 1, Qian Wan Road, Qianhai Shenzhen Hong Kong cooperation zone, Shenzhen, Guangdong (Shenzhen Qianhai business secretary Co., Ltd.) Patentee after: Shenzhen Huaxi Investment Co.,Ltd. Address before: 518052 Room 201, building a, comprehensive office building of Qianhai Shenzhen Hong Kong Cooperation Zone Administration Bureau, No.1 liyumen street, Qianwan 1st Road, Qianhai Shenzhen Hong Kong cooperation zone, Shenzhen City, Guangdong Province Patentee before: SHENZHEN TCL DIGITAL TECHNOLOGY Ltd. |
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