CN203520836U - Backlight driving circuit and liquid crystal display device - Google Patents
Backlight driving circuit and liquid crystal display device Download PDFInfo
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- CN203520836U CN203520836U CN201320638752.1U CN201320638752U CN203520836U CN 203520836 U CN203520836 U CN 203520836U CN 201320638752 U CN201320638752 U CN 201320638752U CN 203520836 U CN203520836 U CN 203520836U
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Abstract
The utility model discloses a backlight driving circuit and a liquid crystal display device. The backlight driving circuit includes a direct-current voltage input end, a switching signal control end, a duty ratio signal control end, an LED module switching circuit, a small signal control circuit and a constant current control integrated circuit; a first switch-on end of the switching circuit receives direct current voltage input; a second switch-on end of the switching circuit is connected with the input end of the LED module; two input ends of the small signal control circuit are respectively connected with the switching signal control end and the duty ratio signal control end; the output end of the small signal control circuit is connected with a switch-on trigger end of the switching circuit; the switching on and switching off of the switching circuit can be controlled according to signals inputted by the switching signal control end and the duty ratio signal control end, such that the switching on and switching off of the direct-current voltage input end and the LED module can be controlled. With the backlight driving circuit and the liquid crystal display device of the utility model adopted, power consumption and cost can be greatly decreased, and therefore, a low-power consumption and low-cost backlight design can be realized.
Description
Technical field
The utility model relates to field of backlights, particularly a kind of backlight drive circuit and liquid crystal indicator.
Background technology
At present, display device (for example LCD TV) normally adopts civil power input to power, therefore, first LCD TV turns direct current by interchange, converting electric main to one can be to the DC source of each functional module power supply, and then each functional module is obtained required separately voltage or electric current again from DC source.
As shown in Figure 1, Fig. 1 is the circuit diagram of prior art backlight drive circuit, existing backlight drive circuit adopts a power supply conversion topologies circuit 100 first to convert the direct current output of Switching Power Supply to a magnitude of voltage that backlight LED light string is required conventionally, then needs a special-purpose constant current control integration circuit U 1A to complete the control function to the control of power supply conversion topologies circuit 100 and constant current driving.Accumulation of energy inductance L 1 in the power supply conversion topologies circuit 100 of existing backlight drive circuit and the cost of fast diode D1 are higher, make the cost of Integral back light drive circuit higher, and metal-oxide-semiconductor T1A is operated under upper frequency, high current and high voltage state, and power consumption is very large.Along with further developing of LED chip and encapsulation technology, the development of LED device has efficiently become inexorable trend, and the driving of low-power consumption also becomes inevitable.The employing of LED efficiently, LED drive current is reduced gradually, the power consumption of LED itself reduces greatly, because the switch power consumption of power supply conversion topologies circuit 100 self is constant, therefore the switch power consumption of power supply conversion topologies circuit 100 self has just raise at the proportion of whole power-supply system, and useless power consumption raises.The switch power consumption of too high power supply conversion topologies circuit 100 self and too high LED-backlit cost, hindered the low-power consumption of LED-backlit and design cheaply.
Utility model content
Fundamental purpose of the present utility model is for providing a kind of more low-power consumption, backlight drive circuit and liquid crystal indicator more cheaply.
The utility model proposes a kind of backlight drive circuit, comprise DC voltage input end, switching signal control end, duty cycle signals control end, LED module and on-off circuit, small-signal control circuit and constant current control integration circuit, wherein,
The first conduction terminal of described on-off circuit connects described DC voltage input end, receives DC voltage input; The second conduction terminal of described on-off circuit connects the input end of described LED module; The first input end of described small-signal control circuit connects described switching signal control end, the second input end of described small-signal control circuit connects described duty cycle signals control end, the output terminal of described small-signal control circuit connects the conducting trigger end of described on-off circuit, described small-signal control circuit is according to conducting and the shutoff of on-off circuit described in the signal controlling of described switching signal control end and the input of described duty cycle signals control end, to control connection and the cut-out of described DC voltage input end and described LED module;
Described constant current control integration circuit connects the output terminal of described LED module, and the electric current of controlling in described LED module keeps constant.
Preferably, described small-signal control circuit comprises the first resistance, the second resistance, the 3rd resistance, the 4th resistance, the 5th resistance, the first switching tube, second switch pipe, the 3rd switching tube and the 4th switching tube, wherein,
The trigger end of described the first switching tube connects described switching signal control end, and the first conduction terminal of described the first switching tube connects the trigger end of described second switch pipe, the second conduction terminal ground connection of described the first switching tube;
The trigger end of described second switch pipe also connects respectively one end of described the first resistance and one end of described the second resistance, and the other end of described the first resistance connects power supply, the other end ground connection of described the second resistance; The first conduction terminal of described second switch pipe connects the first conduction terminal of trigger end and described the 4th switching tube of described the 3rd switching tube, the second conduction terminal ground connection of described second switch pipe;
The trigger end of described the 3rd switching tube also connects one end of described the 3rd resistance, the other end ground connection of described the 3rd resistance; The first conduction terminal of described the 3rd switching tube connects the conducting trigger end of described on-off circuit; The second conduction terminal of described the 3rd switching tube is through described the 4th resistance eutral grounding;
The trigger end of described the 4th switching tube connects described duty cycle signals control end, and the second conduction terminal of described the 4th switching tube connects the first end of described the 5th resistance, and the other end of described the 5th resistance connects power supply.
Preferably, described small-signal control circuit also comprises the 6th resistance, the 7th resistance, the first electric capacity and the 5th switching tube, the second conduction terminal of described the 5th switching tube connects the second conduction terminal of described on-off circuit, the trigger end of described the 5th switching tube connects the input end of described LED module, and the second conduction terminal of described the 5th switching tube also connects the trigger end of described the 5th switching tube through described the 6th resistance; The first conduction terminal of described the 5th switching tube connects the trigger end of described second switch pipe through described the 7th resistance, the first conduction terminal of described the 5th switching tube is also through described the first capacity earth.
Preferably, described the first switching tube is NPN type triode, and the trigger end of described the first switching tube is base stage, and the first conduction terminal of described the first switching tube is collector, and the second conduction terminal of described the first switching tube is emitter;
Described second switch pipe is NPN type triode, and the trigger end of described second switch pipe is base stage, and the first conduction terminal of described second switch pipe is collector, and the second conduction terminal of described second switch pipe is emitter;
Described the 3rd switching tube is NPN type triode, and the trigger end of described the 3rd switching tube is base stage, and the first conduction terminal of described the 3rd switching tube is collector, and the second conduction terminal of described the 3rd switching tube is emitter;
Described the 4th switching tube is positive-negative-positive triode, and the trigger end of described the 4th switching tube is base stage, and the first conduction terminal of described the 4th switching tube is collector, and the second conduction terminal of described the 4th switching tube is emitter;
Described the 5th switching tube is positive-negative-positive triode, and the trigger end of described the 5th switching tube is base stage, and the first conduction terminal of described the 5th switching tube is collector, and the second conduction terminal of described the 5th switching tube is emitter.
Preferably, described small-signal control circuit also comprises the 8th resistance, the 9th resistance and the tenth resistance, described switching signal control end connects the trigger end of described the first switching tube through described the 8th resistance, one end of described the 9th resistance is connected to the trigger end of described the first switching tube, the other end ground connection of described the 9th resistance, described duty cycle signals control end connects the trigger end of described the 4th switching tube through described the tenth resistance.
Preferably, described on-off circuit comprises dropping resistor and PMOS pipe, the source electrode of described PMOS pipe is the first conduction terminal of described on-off circuit, the drain electrode of described PMOS pipe is the second conduction terminal of described on-off circuit, the grid of described PMOS pipe is the conducting trigger end of described on-off circuit, and described dropping resistor is connected between the source electrode and grid of described PMOS pipe.
Preferably, described LED module comprises the LED lamp string of one or more parallel connections, the input end of each LED lamp string connects the input end of described LED module, the corresponding constant flow channel that connects corresponding described constant current control integration circuit of output terminal of each LED lamp string, the quantity of the constant flow channel that the output terminal of each LED lamp string connects is identical.
Preferably, also comprise a plurality of and described LED lamp string voltage dependent resistor (VDR) one to one, the output terminal of described LED lamp string is also through its corresponding voltage dependent resistor (VDR) ground connection.
Preferably, described constant current control integration circuit is TLC5928 chip, and the 23 pin of described constant current control integration circuit is through a resistance eutral grounding.
The utility model also provides a kind of liquid crystal indicator, comprises backlight drive circuit as above.
Backlight drive circuit of the present utility model and liquid crystal indicator, DC voltage input end receives the DC voltage input of a LED module conducting that can make, this DC voltage can be supplied by Switching Power Supply, adopt DC voltage input end directly to LED module, to power, save booster circuit, reduced cost; And, by small-signal control circuit gauge tap circuit turn-on and shutoff, the frequency of operation of on-off circuit is identical with the frequency of the pulse signal of duty cycle signals control end input, frequency of operation with respect to on-off element of the prior art, the frequency of operation of the on-off circuit of the present embodiment significantly reduces, and the power consumption of on-off circuit reduces greatly.The backlight drive circuit of the present embodiment, the control of on-off circuit is controlled by small-signal control circuit, constant current control integration circuit is without the control circuit of integrated gauge tap circuit, the special-purpose constant current control integration circuit using with respect to existing backlight drive circuit, the constant current control integration circuit cost of the present embodiment reduces.Low-power consumption, backlight design have cheaply been realized.
Accompanying drawing explanation
Fig. 1 is the circuit diagram of prior art backlight drive circuit;
Fig. 2 is the structural representation of the utility model backlight drive circuit the first embodiment;
Fig. 3 is the circuit diagram of the utility model backlight drive circuit the second embodiment;
Fig. 4 is the circuit diagram of the utility model backlight drive circuit the 3rd embodiment.
The realization of the utility model object, functional characteristics and advantage, in connection with embodiment, are described further with reference to accompanying drawing.
Embodiment
Should be appreciated that specific embodiment described herein is only in order to explain the utility model, and be not used in restriction the utility model.
As shown in Figure 2, Fig. 2 is the structural representation of the utility model backlight drive circuit the first embodiment.
The backlight drive circuit that this embodiment proposes, comprise DC voltage input end 10, switching signal control end 20, duty cycle signals control end 30, LED module 40, on-off circuit 50, small-signal control circuit 60 and constant current control integration circuit 70, wherein, the first conduction terminal 1 of on-off circuit 50 connects DC voltage input end 10, receives DC voltage input; The second conduction terminal 2 of on-off circuit 50 connects the input end of LED module 40; The first input end connecting valve signal controlling end 20 of small-signal control circuit 60, the second input end of small-signal control circuit 60 connects duty cycle signals control end 30, the conducting trigger end 3 of the output terminal connecting valve circuit 50 of small-signal control circuit 60, small-signal control circuit 60 is according to conducting and the shutoff of the signal control switch circuit 50 of switching signal control end 20 and 30 inputs of duty cycle signals control end, to control connection and the cut-out of DC voltage input end 10 and LED module 40; Constant current control integration circuit 70 connects the output terminal of LED module 40, and the electric current of controlling in LED module 40 keeps constant.
The principle of work of the backlight drive circuit of the present embodiment is: DC voltage input end 10 provides voltage for LED module 40, and small-signal control circuit 60 is according to the duty of the signal controlling small-signal control circuit 60 of switching signal control end 20 inputs (work or do not work); Small-signal control circuit 60 is according to the frequency of the pulse signal of duty cycle signals control end 30 inputs, the conducting state of gauge tap circuit 50 and the switching frequency of off state, thereby control the conducting state of LED module 40 and the switching frequency of dissengaged positions, control conducting state time and the dissengaged positions time of LED module 40; Constant current control integration circuit 70 is controlled LED module 40 and when conducting state, is kept the current constant of LED module 40 inside.
The backlight drive circuit of the present embodiment, DC voltage input end 10 receives one can be to the DC voltage input of LED module 40 power supplies, this DC voltage can be supplied by Switching Power Supply, adopt DC voltage input end 10 directly to LED module 40 power supplies, save power supply conversion topologies circuit, reduced cost; And, by small-signal control circuit 60 gauge tap circuit 50 turn-on and turn-off, the frequency of operation of on-off circuit 50 is identical with the frequency of the pulse signal of duty cycle signals control end 30 inputs, frequency of operation with respect to on-off element of the prior art, the frequency of operation of the on-off circuit 50 of the present embodiment significantly reduces, and the power consumption of on-off circuit 50 reduces greatly.The backlight drive circuit of the present embodiment, the control of on-off circuit 50 is controlled by small-signal control circuit 60, constant current control integration circuit 70 control circuits without integrated gauge tap circuit 50, the special-purpose constant current control integration circuit using with respect to existing backlight drive circuit, constant current control integration circuit 70 costs of the present embodiment.The backlight drive circuit of the present embodiment has been realized low-power consumption, backlight design cheaply.
Further, as shown in Figure 3, Fig. 3 is the circuit diagram of the utility model backlight drive circuit the second embodiment, and the present embodiment is based on the first embodiment.The small-signal control circuit 60 of the present embodiment comprises the first resistance R 1, the second resistance R 2, the 3rd resistance R 3, the 4th resistance R 4, the 5th resistance R 5, the first switching tube Q1, second switch pipe Q2, the 3rd switching tube Q3 and the 4th switching tube Q4, wherein, the trigger end connecting valve signal controlling end 20 of the first switching tube Q1, the first conduction terminal of the first switching tube Q1 connects the trigger end of second switch pipe Q2, the second conduction terminal ground connection of the first switching tube Q1; The trigger end of second switch pipe Q2 also connects respectively one end of the first resistance R 1 and one end of the second resistance R 2, and the other end of the first resistance R 1 connects power supply VCC, the other end ground connection of the second resistance R 2; The first conduction terminal of second switch pipe Q2 connects the trigger end of the 3rd switching tube Q3 and the first conduction terminal of the 4th switching tube Q4, the second conduction terminal ground connection of second switch pipe Q2; The trigger end of the 3rd switching tube Q3 also connects one end of the 3rd resistance R 3, the other end ground connection of the 3rd resistance R 3; The second conduction terminal of conducting trigger end 3, the three switching tube Q3 of the first conduction terminal connecting valve circuit 50 of the 3rd switching tube Q3 is through the 4th resistance R 4 ground connection; The trigger end of the 4th switching tube Q4 connects the first end of the second conduction terminal connection the 5th resistance R 5 of duty cycle signals control end 30, the four switching tube Q4, and the other end of the 5th resistance R 5 connects power supply VCC.
In the present embodiment, the first switching tube Q1 is NPN type triode, and the trigger end of the first switching tube Q1 is base stage, and the first conduction terminal of the first switching tube Q1 is collector, and the second conduction terminal of the first switching tube Q1 is emitter; Second switch pipe Q2 is NPN type triode, and the trigger end of second switch pipe Q2 is base stage, and the first conduction terminal of second switch pipe Q2 is collector, and the second conduction terminal of second switch pipe Q2 is emitter; The 3rd switching tube Q3 is NPN type triode, and the trigger end of the 3rd switching tube Q3 is base stage, and the first conduction terminal of the 3rd switching tube Q3 is collector, and the second conduction terminal of the 3rd switching tube Q3 is emitter; The 4th switching tube Q4 is positive-negative-positive triode, and the trigger end of the 4th switching tube Q4 is base stage, and the first conduction terminal of the 4th switching tube Q4 is collector, and the second conduction terminal of the 4th switching tube Q4 is emitter.Be appreciated that the first switching tube Q1, second switch pipe Q2, the 3rd switching tube Q3 and the 4th switching tube Q4 of the present embodiment are not limited only to the switching tube of the above-mentioned type, can also be for thering is switching tube or other devices of identical function.
Further, on-off circuit 50 comprises dropping resistor R11 and PMOS pipe T, the source electrode of PMOS pipe T is the first conduction terminal 1 of on-off circuit 50, the drain electrode of PMOS pipe T is the second conduction terminal 2 of on-off circuit 50, the grid of PMOS pipe T is the conducting trigger end 3 of on-off circuit 50, and dropping resistor R11 is connected between the source electrode and grid of PMOS pipe T.Certainly, the PMOS of the present embodiment pipe T also available other switching tubes replaces, and realizes identical function, and concrete connected mode may be different, according to the type of concrete switching tube, determine.
The principle of work of the small-signal control circuit 60 of the present embodiment is:
When one, switching signal control end 20 is high level, the first switching tube Q1 conducting, the trigger end of second switch pipe Q2 is low level, second switch pipe Q2 cut-off.Now: 1, when duty cycle signals control end 30 is low level, the 4th switching tube Q4 conducting, the trigger end of the 3rd switching tube Q3 is high level, the 3rd switching tube Q3 conducting; The 3rd switching tube Q3 conducting makes DC voltage input end 10 arrive ground through dropping resistor R11 and the 4th resistance R 4, between the source electrode of PMOS pipe T and grid, produce pressure drop (this pressure drop size is the voltage swing at dropping resistor R11 two ends), the voltage of the grid of PMOS pipe T is lower than the voltage of PMOS pipe T source electrode, PMOS pipe T conducting, DC voltage input end 10 is communicated with LED module 40 to LED module 40 power supplies.2, when duty cycle signals control end 30 is high level, the 4th switching tube Q4 cut-off, the trigger end of the 3rd switching tube Q3 is low level, the 3rd switching tube Q3 cut-off, PMOS pipe T cut-off, DC voltage input end 10 disconnects with LED module 40.
When two, switching signal control end 20 is low level, the first switching tube Q1 cut-off, the trigger end of second switch pipe Q2 is high level, second switch pipe Q2 conducting, the trigger end of the 3rd switching tube Q3 is low level, the 3rd switching tube Q3 cut-off, PMOS pipe T cut-off, DC voltage input end 10 disconnects with LED module 40, and LED module 40 is in off state.Now, no matter duty cycle signals control end 30 is low level or high level, and PMOS pipe T is in cut-off state, and LED module 40 is constant in off state.
Further, as shown in Figure 4, Fig. 4 is the circuit diagram of the utility model backlight drive circuit the 3rd embodiment, and the present embodiment is based on the second embodiment.Small-signal control circuit 60 also comprises the 6th resistance R 6, the 7th resistance R 7, the first capacitor C 1 and the 5th switching tube Q5, the second conduction terminal 2 of the second conduction terminal connecting valve circuit 50 of the 5th switching tube Q5, the trigger end of the 5th switching tube Q5 connects the input end of LED module 40, and the second conduction terminal of the 5th switching tube Q5 also connects the trigger end of the 5th switching tube Q5 through the 6th resistance R 6; The trigger end of the first conduction terminal of the 5th switching tube Q5 seven resistance R 7 connection second switch pipe Q2 through ground, the first conduction terminal of the 5th switching tube Q5 is also through the first capacitor C 1 ground connection.The 6th resistance R 6 of the present embodiment, the 7th resistance R 7 and the 5th switching tube Q5 form the holding circuit of the present embodiment backlight drive circuit, when the electric current of DC voltage input end 10 input is excessive, it is large that the pressure reduction at the 6th resistance R 6 two ends becomes, the second conduction terminal of the 5th switching tube Q5 and the pressure reduction between first end become large, when this pressure reduction reaches the forward voltage of the 5th switching tube Q5, the 5th switching tube Q5 conducting, a part for excessive electric current flows through the 7th resistance R 7 and the second resistance R 2 arrives ground, the trigger end that makes second switch pipe Q2 is high level, second switch pipe Q2 conducting, thereby make PMOS cut-off, be that on-off circuit 50 disconnects, DC voltage input end 10 disconnects with LED module 40, LED module 40 is protected, prevent overcurrent burning out LED module 40.
Further, small-signal control circuit 60 also comprises the 8th resistance R 8, the 9th resistance R 9 and the tenth resistance R 10, switching signal control end 20 connects the trigger end of the first switching tube Q1 through the 8th resistance R 8, one end of the 9th resistance R 9 is connected to the trigger end of the first switching tube Q1, the other end ground connection of the 9th resistance R 9, duty cycle signals control end 30 connects the trigger end of the 4th switching tube Q4 through the tenth resistance R 10.The effect of the 8th resistance R 8 and the 9th resistance R 9 is to prevent the damage of the overflow of switching signal control end 20 to the first switching tube Q1, and same the tenth resistance R 10 is also the damage of overflow to the 4th switching tube Q4 that prevents duty cycle signals control end 30.
Concrete, the 5th switching tube Q5 is positive-negative-positive triode, and the trigger end of the 5th switching tube Q5 is base stage, and the first conduction terminal of the 5th switching tube Q5 is collector, and the second conduction terminal of the 5th switching tube Q5 is emitter.The 5th switching tube Q5 that is appreciated that the present embodiment is not limited only to positive-negative-positive triode, can also be for having switching tube or other devices of identical function.
Further, LED module 40 comprises the LED lamp string 41 of one or more parallel connections, the input end of each LED lamp string 41 connects the input end of LED module 40, the corresponding constant flow channel out that connects corresponding constant current control integration circuit 70 of output terminal of each LED lamp string 41, the quantity of the constant flow channel out that the output terminal of each LED lamp string 41 connects is identical, so that the electric current in each LED lamp string 41 is identical.Backlight drive circuit also comprises a plurality of and LED lamp string 41 voltage dependent resistor (VDR) ZR one to one, and the output terminal of LED lamp string 41 is also through its corresponding voltage dependent resistor (VDR) ZR ground connection.In the present embodiment, take 4 lamp connection in series-parallel and 4 voltage dependent resistor (VDR) ZR is example.Voltage dependent resistor (VDR) ZR is as overvoltage protection; when the voltage (being the voltage of LED lamp string 41 output terminals) of constant flow channel out reaches the forward voltage of voltage dependent resistor (VDR) ZR; voltage dependent resistor (VDR) ZR conducting, the electric current in loop increases, and the pressure reduction at the 6th resistance R 6 two ends increases; make the 5th switching tube Q5 conducting; and then make second switch pipe Q2 conducting, and PMOS pipe T cut-off, on-off circuit 50 disconnects; DC voltage input end 10 and LED module 40 are disconnected, realize holding circuit.
Concrete, in the present embodiment, constant current control integration circuit 70 adopts TLC5928 chip, and the 23 pin of constant current control integration circuit 70 is through resistance R 12 ground connection.The 23 pin R-EXT of TLC5928 chip is reference pin, by the resistance of regulating resistance R12, and magnitude of voltage that can regulating constant circulation road out, thus regulate the current value in LED lamp string 41.Precision between TLC5928 chip constant flow channel out is 1%, and constant current accuracy is high; And TLC5928 chip is programmable chip, can realize serial data communication with CLK pin by SDI pin, SDO pin and be connected, both can receive the data that arrange of mainboard chip, these data levels can be linked to other chip again; The work of constant flow channel out is coordinated by the level state of LE pin and OE pin to control; This chip (TLC5928 chip) can arrange the output of constant flow channel out from hardware and software two aspects, meet flexibly the constant current demand of lamp string; And compare with the special-purpose constant current control integration circuit in existing backlight drive circuit, cost is lower, cost be about the former (special-purpose constant current control integration circuit) 1/3rd.
The utility model also provides a kind of liquid crystal indicator, comprises backlight drive circuit, and this backlight drive circuit can comprise that earlier figures 2 is to all technical schemes in embodiment illustrated in fig. 4, and its concrete structure can, with reference to previous embodiment, not repeat at this.Owing to having adopted the scheme of aforementioned backlight drive circuit, liquid crystal indicator of the present utility model is compared to existing liquid crystal indicator, and cost and power consumption all significantly reduce, and realizes low-power consumption, design cheaply.
The foregoing is only preferred embodiment of the present utility model; not thereby limit the scope of the claims of the present utility model; every equivalent structure or conversion of equivalent flow process that utilizes the utility model instructions and accompanying drawing content to do; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present utility model.
Claims (10)
1. a backlight drive circuit, is characterized in that, comprises DC voltage input end, switching signal control end, duty cycle signals control end, LED module, on-off circuit, small-signal control circuit and constant current control integration circuit, wherein,
The first conduction terminal of described on-off circuit connects described DC voltage input end, receives DC voltage input; The second conduction terminal of described on-off circuit connects the input end of described LED module; The first input end of described small-signal control circuit connects described switching signal control end, the second input end of described small-signal control circuit connects described duty cycle signals control end, the output terminal of described small-signal control circuit connects the conducting trigger end of described on-off circuit, described small-signal control circuit is according to conducting and the shutoff of on-off circuit described in the signal controlling of described switching signal control end and the input of described duty cycle signals control end, to control connection and the cut-out of described DC voltage input end and described LED module;
Described constant current control integration circuit connects the output terminal of described LED module, and the electric current of controlling in described LED module keeps constant.
2. backlight drive circuit according to claim 1, it is characterized in that, described small-signal control circuit comprises the first resistance, the second resistance, the 3rd resistance, the 4th resistance, the 5th resistance, the first switching tube, second switch pipe, the 3rd switching tube and the 4th switching tube, wherein
The trigger end of described the first switching tube connects described switching signal control end, and the first conduction terminal of described the first switching tube connects the trigger end of described second switch pipe, the second conduction terminal ground connection of described the first switching tube;
The trigger end of described second switch pipe also connects respectively one end of described the first resistance and one end of described the second resistance, and the other end of described the first resistance connects power supply, the other end ground connection of described the second resistance; The first conduction terminal of described second switch pipe connects the first conduction terminal of trigger end and described the 4th switching tube of described the 3rd switching tube, the second conduction terminal ground connection of described second switch pipe;
The trigger end of described the 3rd switching tube also connects one end of described the 3rd resistance, the other end ground connection of described the 3rd resistance; The first conduction terminal of described the 3rd switching tube connects the conducting trigger end of described on-off circuit; The second conduction terminal of described the 3rd switching tube is through described the 4th resistance eutral grounding;
The trigger end of described the 4th switching tube connects described duty cycle signals control end, and the second conduction terminal of described the 4th switching tube connects the first end of described the 5th resistance, and the other end of described the 5th resistance connects power supply.
3. backlight drive circuit according to claim 2, it is characterized in that, described small-signal control circuit also comprises the 6th resistance, the 7th resistance, the first electric capacity and the 5th switching tube, the second conduction terminal of described the 5th switching tube connects the second conduction terminal of described on-off circuit, the trigger end of described the 5th switching tube connects the input end of described LED module, and the second conduction terminal of described the 5th switching tube also connects the trigger end of described the 5th switching tube through described the 6th resistance; The first conduction terminal of described the 5th switching tube connects the trigger end of described second switch pipe through described the 7th resistance, the first conduction terminal of described the 5th switching tube is also through described the first capacity earth.
4. backlight drive circuit according to claim 3, it is characterized in that, described the first switching tube is NPN type triode, and the trigger end of described the first switching tube is base stage, the first conduction terminal of described the first switching tube is collector, and the second conduction terminal of described the first switching tube is emitter;
Described second switch pipe is NPN type triode, and the trigger end of described second switch pipe is base stage, and the first conduction terminal of described second switch pipe is collector, and the second conduction terminal of described second switch pipe is emitter;
Described the 3rd switching tube is NPN type triode, and the trigger end of described the 3rd switching tube is base stage, and the first conduction terminal of described the 3rd switching tube is collector, and the second conduction terminal of described the 3rd switching tube is emitter;
Described the 4th switching tube is positive-negative-positive triode, and the trigger end of described the 4th switching tube is base stage, and the first conduction terminal of described the 4th switching tube is collector, and the second conduction terminal of described the 4th switching tube is emitter;
Described the 5th switching tube is positive-negative-positive triode, and the trigger end of described the 5th switching tube is base stage, and the first conduction terminal of described the 5th switching tube is collector, and the second conduction terminal of described the 5th switching tube is emitter.
5. backlight drive circuit according to claim 3, it is characterized in that, described small-signal control circuit also comprises the 8th resistance, the 9th resistance and the tenth resistance, described switching signal control end connects the trigger end of described the first switching tube through described the 8th resistance, one end of described the 9th resistance is connected to the trigger end of described the first switching tube, the other end ground connection of described the 9th resistance, described duty cycle signals control end connects the trigger end of described the 4th switching tube through described the tenth resistance.
6. backlight drive circuit according to claim 1, it is characterized in that, described on-off circuit comprises dropping resistor and PMOS pipe, the source electrode of described PMOS pipe is the first conduction terminal of described on-off circuit, the drain electrode of described PMOS pipe is the second conduction terminal of described on-off circuit, the grid of described PMOS pipe is the conducting trigger end of described on-off circuit, and described dropping resistor is connected between the source electrode and grid of described PMOS pipe.
7. backlight drive circuit according to claim 1, it is characterized in that, described LED module comprises the LED lamp string of one or more parallel connections, the input end of each LED lamp string connects the input end of described LED module, the corresponding constant flow channel that connects corresponding described constant current control integration circuit of output terminal of each LED lamp string, the quantity of the constant flow channel that the output terminal of each LED lamp string connects is identical.
8. backlight drive circuit according to claim 7, is characterized in that, also comprises a plurality of and described LED lamp string voltage dependent resistor (VDR) one to one, and the output terminal of described LED lamp string is also through its corresponding voltage dependent resistor (VDR) ground connection.
9. according to the backlight drive circuit described in claim 7 or 8, it is characterized in that, described constant current control integration circuit is TLC5928 chip, and the 23 pin of described constant current control integration circuit is through a resistance eutral grounding.
10. a liquid crystal indicator, is characterized in that, comprises backlight drive circuit as claimed in any one of claims 1-9 wherein.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320638752.1U CN203520836U (en) | 2013-10-16 | 2013-10-16 | Backlight driving circuit and liquid crystal display device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320638752.1U CN203520836U (en) | 2013-10-16 | 2013-10-16 | Backlight driving circuit and liquid crystal display device |
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| CN203520836U true CN203520836U (en) | 2014-04-02 |
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| CN201320638752.1U Expired - Fee Related CN203520836U (en) | 2013-10-16 | 2013-10-16 | Backlight driving circuit and liquid crystal display device |
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| CN (1) | CN203520836U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016095246A1 (en) * | 2014-12-18 | 2016-06-23 | 深圳Tcl数字技术有限公司 | Method and device for displaying window of screen |
| CN115083358A (en) * | 2022-07-05 | 2022-09-20 | 珠海格力电器股份有限公司 | Display panel backlight control circuit and control method |
| CN115083358B (en) * | 2022-07-05 | 2024-06-28 | 珠海格力电器股份有限公司 | Display panel backlight control circuit and control method |
-
2013
- 2013-10-16 CN CN201320638752.1U patent/CN203520836U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016095246A1 (en) * | 2014-12-18 | 2016-06-23 | 深圳Tcl数字技术有限公司 | Method and device for displaying window of screen |
| CN105761681A (en) * | 2014-12-18 | 2016-07-13 | 深圳Tcl数字技术有限公司 | Window display method and device for screen |
| CN115083358A (en) * | 2022-07-05 | 2022-09-20 | 珠海格力电器股份有限公司 | Display panel backlight control circuit and control method |
| CN115083358B (en) * | 2022-07-05 | 2024-06-28 | 珠海格力电器股份有限公司 | Display panel backlight control circuit and control method |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140402 Termination date: 20211016 |