CN218513149U - Backlight driving circuit and display device - Google Patents

Abstract

The utility model provides a backlight drive circuit and display device, wherein, the backlight drive circuit includes switching power supply circuit, signal port, switch circuit, charging and discharging circuit and backlight driver chip, switch circuit and charging and discharging circuit set gradually through the front end at backlight driver chip, during the standby, switching circuit turn-offs, backlight driver chip does not have standby power consumption, and simultaneously, when switch circuit turn-offs or display device fall the electricity, charging and discharging circuit provides the long power signal of predetermineeing, backlight driver chip can preserve relevant data when predetermineeing long, avoid data to burn the storage many times, the drive work volume has been simplified, and simultaneously, the consumption of backlight driver circuit has been reduced.

Description

Backlight driving circuit and display device

Technical Field

The utility model belongs to the technical field of display device, especially, relate to a backlight drive circuit and display device.

Background

At present, a display device, such as a television, an all-in-one computer, and the like, generally includes a display panel and a backlight module, where the backlight module includes a backlight source and a backlight source driving circuit for driving the backlight source to work, where the backlight source driving circuit includes a switching power supply circuit and a backlight source driving chip, and the backlight source driving chip outputs a switching control signal to the switching power supply circuit, so that the switching power supply circuit outputs a working power supply with a corresponding size to the backlight source, and the backlight source provides a light source with a corresponding brightness to the display panel.

The backlight driving chip is powered by the auxiliary power end, and is switched to a low power consumption state when the display device is in standby state, but the power end of the backlight driving chip continuously provides a working power supply, so that the backlight driving chip still occupies certain power consumption, which is not beneficial to the requirement of low power consumption of the display device.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a backlight drive circuit aims at solving the problem that has the consumption and can't instant storage data when falling the electricity when traditional backlight driver chip standby.

The utility model provides a first aspect of the embodiment provides a backlight drive circuit, backlight drive circuit sets up in display device, backlight drive circuit includes:

the input end of the switching power supply circuit is used for inputting a main power supply, the output end of the switching power supply circuit is used for outputting a working power supply to the backlight source, and the switching power supply circuit is triggered by a switching control signal to convert and output the working power supply;

the display device comprises a signal port and a power supply control unit, wherein the signal port comprises a first port for inputting an auxiliary power supply and a second port for inputting a power on/off signal, the power on/off signal is a first level signal when the display device is started, the power on/off signal is a second level signal when the display device is in a standby state, and the first level signal and the second level signal are level signals with opposite polarities;

the input end of the switch circuit is connected with the first port, the controlled end of the switch circuit is connected with the second port, the switch circuit is triggered to be switched on by the first level signal, and the switch circuit is triggered to be switched off by the second level signal;

the power supply end of the charge-discharge circuit is connected with the output end of the switch circuit, and the charge-discharge circuit triggers charge work when being powered on and triggers discharge work when being powered off;

and the backlight source driving chip is respectively connected with the second port, the output end of the charging and discharging circuit, the output end of the switching circuit and the controlled end of the switching power supply circuit, and is triggered by an input power supply signal and an on-off signal to output the switch control signal.

Optionally, the switch circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor, a first electronic switch tube, and a second electronic switch tube;

the first end of the first resistor, the first end of the first capacitor and the first end of the first electronic switching tube are connected together to form the input end of the switching circuit, the second end of the first resistor, the first end of the second resistor and the first end of the second electronic switching tube are connected together, the controlled end of the second electronic switching tube is connected with the first end of the third resistor, the first end of the third resistor forms the controlled end of the switching circuit, the second end of the second electronic switching tube is grounded, the second end of the second resistor, the second end of the first capacitor, the controlled end of the first electronic switching tube and the first end of the fourth resistor are connected together, the second end of the fourth resistor is connected with the first end of the second capacitor, and the second end of the second capacitor and the second end of the first electronic switching tube are connected to form the output end of the switching circuit.

Optionally, the charging and discharging circuit comprises at least one third capacitor;

the first end of at least one third capacitor is connected in parallel to form a power supply end of the charge and discharge circuit, and the second end of at least one third capacitor is grounded.

Optionally, the switching power supply circuit comprises a BUCK circuit and/or a BOOST circuit.

Optionally, the backlight driving circuit further includes a unidirectional conducting circuit for unidirectional input and output;

the input end of the one-way conduction circuit is connected with the output end of the switch circuit, and the output end of the one-way conduction circuit, the power supply end of the charge-discharge circuit and the power supply end of the backlight source driving chip are connected in common.

Optionally, the unidirectional conducting circuit comprises a fifth resistor and a first diode;

the first end of the fifth resistor forms the input end of the unidirectional conduction circuit, the second end of the fifth resistor is connected with the anode of the first diode, and the cathode of the first diode forms the output end of the unidirectional conduction circuit.

Optionally, the backlight driving circuit further includes:

the voltage sampling circuit, the signal input part of voltage sampling circuit with switching power supply circuit's output is connected, the signal output part of voltage sampling circuit with backlight driver chip's signal end is connected, voltage sampling circuit is used for the sampling switching power supply circuit's output voltage to output voltage sampled signal extremely backlight driver chip.

Optionally, the voltage sampling circuit comprises a sixth resistor and a seventh resistor;

the first end of the sixth resistor forms a signal input end of the voltage sampling circuit, the second end of the sixth resistor and the first end of the seventh resistor are connected in common to form a signal output end of the voltage sampling circuit, and the second end of the seventh resistor is grounded.

Optionally, the second port is further used for inputting a current regulation signal;

the backlight source driving circuit further comprises an eighth resistor, a ninth resistor, a second diode and a third diode;

the first end of the eighth resistor is connected to the second port, the second end of the eighth resistor, the first end of the ninth resistor, the anode of the second diode and the anode of the third diode are connected in common, the second end of the ninth resistor is grounded, the cathode of the second diode is connected to the signal end of the backlight source driving chip and used for outputting the power on/off signal, and the cathode of the third diode is connected to the signal end of the backlight source driving chip and used for outputting the current regulation signal.

A second aspect of the embodiments of the present invention provides a display device, including a backlight and the backlight driving circuit as described above.

Compared with the prior art, the embodiment of the utility model beneficial effect who exists is: the backlight driving circuit is characterized in that the switching circuit and the charging and discharging circuit are sequentially arranged at the front end of the backlight driving chip, during standby, the switching circuit is switched off, the backlight driving chip has no standby power consumption, and meanwhile, when the switching circuit is switched off or the display device is powered off, the charging and discharging circuit provides a preset long power signal, the backlight driving chip can store related data in the preset long time, the data is prevented from being repeatedly burnt and stored, the driving workload is simplified, and meanwhile, the power consumption of the backlight driving circuit is reduced.

Drawings

Fig. 1 is a schematic block diagram of a backlight driving circuit according to an embodiment of the present invention;

fig. 2 is a first circuit schematic diagram of a backlight driving circuit according to an embodiment of the present invention;

fig. 3 is a schematic diagram of a second module of a backlight driving circuit according to an embodiment of the present invention;

fig. 4 is a second circuit schematic diagram of a backlight driving circuit according to an embodiment of the present invention;

fig. 5 is a schematic diagram of a third module of a backlight driving circuit according to an embodiment of the present invention;

FIG. 6 is a circuit diagram of a voltage sampling circuit in the backlight driving circuit shown in FIG. 5;

fig. 7 is a third circuit schematic diagram of a backlight driving circuit according to an embodiment of the present invention;

fig. 8 is a schematic block diagram of a display device according to an embodiment of the present invention.

Detailed Description

In order to make the technical problem, technical solution and advantageous effects to be solved by the present invention more clearly understood, the following description is given in conjunction with the accompanying drawings and embodiments to illustrate the present invention in further detail. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.

The embodiment of the utility model provides a first aspect provides a backlight drive circuit 1, and backlight drive circuit 1 sets up in display device for provide working power supply to backlight 2, so that backlight 2 provides the light source to the display panel that corresponds luminance, and wherein, backlight 2 can be for corresponding display module assembly, for example LED module, OLED module etc. and concrete structure is not limited.

The backlight driving circuit 1 includes:

the backlight control circuit comprises a switching power supply circuit 10, wherein the input end of the switching power supply circuit 10 is used for inputting a main power supply VCC1, the output end of the switching power supply circuit 10 is used for outputting a working power supply to a backlight source 2, and the switching power supply circuit 10 is triggered by a switching control signal to convert and output the working power supply;

the display device comprises a signal port 20, wherein the signal port 20 comprises a first port P1 for inputting an auxiliary power VCC2 and a second port P2 for inputting an ON/OFF signal, wherein the ON/OFF signal is a first level signal when the display device is powered ON, the ON/OFF signal is a second level signal when the display device is standby, and the first level signal and the second level signal are level signals with opposite polarities;

the input end of the switch circuit 30 is connected with the first port P1, the controlled end of the switch circuit 30 is connected with the second port P2, the switch circuit 30 is triggered to be switched on by a first level signal, and the switch circuit 30 is triggered to be switched off by a second level signal;

the power supply end of the charge-discharge circuit 40 is connected with the output end of the switch circuit 30, and the charge-discharge circuit 40 triggers charge work when the power is on and triggers discharge work when the power is off;

and the backlight source driving chip 50 is respectively connected with the second port P2, the output end of the charging and discharging circuit 40, the output end of the switching circuit 30 and the controlled end of the switching power supply circuit 10, and the backlight source driving chip 50 is triggered by the input power supply signal and the ON/OFF signal to output a switching control signal.

In this embodiment, the switching power supply circuit 10 performs power conversion on the input main power supply VCC1 according to the received switching control signal, and outputs a working power supply adapted to the backlight 2, and when the backlight driving chip 50 stops outputting the switching control signal, the switching power supply circuit 10 stops working, and stops outputting the working power supply to the backlight 2, and the backlight driving chip 50 is powered by the auxiliary power supply VCC 2.

During normal operation, the preceding stage module of the backlight source driving circuit 1 outputs a main power source VCC1, an auxiliary power source VCC2 and an ON/OFF signal ON/OFF, at this time, the ON/OFF signal ON/OFF is a first level signal, the switch circuit 30 is controlled to be turned ON, and transmits the auxiliary power source VCC2 to the charge and discharge circuit 40 and the backlight source driving chip 50, the charge and discharge circuit 40 stores energy for charging, the backlight source driving chip 50 receives the auxiliary power source VCC2 and the first level signal synchronously, and the backlight source driving chip 50 triggers and outputs an ON/OFF control signal to the switch power source circuit 10, so that the switch power source circuit 10 outputs a working power source adapted to the backlight source 2.

Meanwhile, at the beginning of standby, the switch circuit 30 receives the second level signal, the switch circuit 30 is triggered to turn off, the charge and discharge circuit 40 releases energy and discharges, the backlight driving chip 50 receives the auxiliary power VCC2 for a preset time period, and power down protection work such as data storage can be performed in the time period, so that multiple burning storage of data is avoided, the driving workload is simplified, and when the terminal voltage of the charge and discharge circuit 40 is smaller than the lower limit value of the working voltage of the backlight driving chip 50, the backlight driving chip 50 stops working.

And, in the subsequent standby state, the switch circuit 30 keeps the off state, and the backlight driving chip 50 has no standby power consumption, thereby reducing the power consumption of the backlight driving circuit 1.

And in a shutdown state, the preceding-stage module stops outputting the main power supply VCC1 and the auxiliary power supply VCC2, and the backlight source driving circuit 1 stops working.

The switching power supply circuit 10 may adopt a corresponding power conversion circuit, and optionally, the switching power supply circuit 10 includes a BUCK circuit and/or a BOOST circuit, and the BUCK circuit and/or the BOOST circuit may be selected according to the BUCK-BOOST requirement.

The signal port 20 is directly connected with the front module by plugging or magnetic attraction and the like, and acquires an auxiliary power supply VCC2 and a startup and shutdown signal ON/OFF, thereby simplifying the port structure and facilitating the connection of the backlight source driving circuit 1 with the front module.

The charging and discharging circuit 40 may select an energy storage circuit with a corresponding structure, such as an energy storage battery and an energy storage capacitor, optionally, as shown in fig. 2, the charging and discharging circuit 40 includes at least one third capacitor C3;

the first end of at least one third capacitor C3 is connected in parallel to form a power supply end of the charging and discharging circuit 40, the second end of at least one third capacitor C3 is grounded, the third capacitor C3 performs energy storage charging and energy release discharging work, and the third capacitor C3 can select a capacitor with a corresponding type and capacity, such as a super capacitor.

The main power supply VCC1 and the auxiliary power supply VCC2 are correspondingly designed according to power supply requirements, for example, the main power supply VCC1 is selected to be 55V, the auxiliary power supply VCC2 is selected to be 12V, and the specific size is not limited.

The first level signal and the second level signal are selected according to the type of the switch circuit 30, and optionally, the first level signal is at a high level and the second level signal is at a low level.

Compared with the prior art, the embodiment of the utility model beneficial effect who exists is: the backlight driving circuit 1 is characterized in that the switch circuit 30 and the charge and discharge circuit 40 are sequentially arranged at the front end of the backlight driving chip 50, during standby, the switch circuit 30 is turned off, the backlight driving chip 50 has no standby power consumption, and meanwhile, when the switch circuit 30 is turned off or the display device is powered off, the charge and discharge circuit 40 provides a power signal with preset duration, the backlight driving chip 50 can store related data within preset duration, the data is prevented from being repeatedly burned and stored, the driving workload is simplified, and meanwhile, the power consumption of the backlight driving circuit 1 is reduced.

Referring to fig. 2, optionally, the switch circuit 30 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, a second capacitor C2, a first electronic switch Q1, and a second electronic switch Q2;

the first end of the first resistor R1, the first end of the first capacitor C1 and the first end of the first electronic switch tube Q1 are connected in common to form an input end of the switch circuit 30, the second end of the first resistor R1, the first end of the second resistor R2 and the first end of the second electronic switch tube Q2 are connected in common, the controlled end of the second electronic switch tube Q2 is connected with the first end of the third resistor R3, the first end of the third resistor R3 forms a controlled end of the switch circuit 30, the second end of the second electronic switch tube Q2 is grounded, the second end of the second resistor R2, the second end of the first capacitor C1, the controlled end of the first electronic switch tube Q1 and the first end of the fourth resistor R4 are connected in common, the second end of the fourth resistor R4 is connected with the first end of the second capacitor C2, and the second end of the first electronic switch tube Q1 are connected to form an output end of the switch circuit 30.

In this embodiment, the first electronic switch Q1 is turned off when receiving a low level and turned on when receiving a high level, the second electronic switch Q2 is turned on when receiving a high level and turned off when receiving a low level, the first electronic switch Q1 may select a corresponding type of switch, such as a PMOS transistor or a PNP triode, optionally, the first electronic switch Q1 is a PMOS transistor, similarly, the second electronic switch Q2 may select a corresponding type of switch, such as an NMOS transistor or an NPN triode, optionally, the second electronic switch Q2 is an NPN triode.

During normal operation, preceding stage module output main power VCC1 of backlight drive circuit 1, auxiliary power VCC2 and switching ON/OFF signal ON/OFF, at this moment, switching ON/OFF signal ON/OFF is the first level signal of high level, second electronic switch pipe Q2 and first electronic switch pipe Q1 all switch ON, and transmit auxiliary power VCC2 to charge-discharge circuit 40 and backlight drive chip 50, charge-discharge circuit 40 charges the energy storage, backlight drive chip 50 then receives auxiliary power VCC2 and the first level signal of high level in step, backlight drive chip 50 triggers output switch control signal to switching power supply circuit 10, so that switching power supply circuit 10 outputs the working power supply of backlight 2 adaptation.

Meanwhile, at the beginning of standby, the switch circuit 30 receives a second level signal with a low level, the second electronic switch tube Q2 and the first electronic switch tube Q1 are both turned off, the switch circuit 30 triggers to turn off, the auxiliary power supply VCC2 is cut off from being output to the backlight driving chip 50, the charge and discharge circuit 40 releases energy and discharges, the backlight driving chip 50 receives the auxiliary power supply VCC2 with a preset duration, and power-down protection work such as data storage can be carried out in the time period, multiple burning storage of data is avoided, driving workload is simplified, and when the terminal voltage of the charge and discharge circuit 40 is smaller than the lower limit value of the working voltage of the backlight driving chip 50, the backlight driving chip 50 stops working.

As shown in fig. 3, in order to prevent the switching circuit 30 from being abnormal due to the power signal fed back to the switching circuit 30 reversely when the charging and discharging circuit 40 discharges, optionally, the backlight driving circuit 1 further includes a unidirectional conducting circuit 60 for unidirectional input and output;

the input end of the unidirectional circuit 60 is connected to the output end of the switch circuit 30, and the output end of the unidirectional circuit 60, the power end of the charge/discharge circuit 40 and the power end of the backlight driving chip 50 are connected together.

During normal operation, the switching circuit 30 is turned on, the unidirectional conducting circuit 60 maintains the unidirectional conducting state, and the auxiliary power VCC2 is output to the rear charging and discharging circuit 40 and the backlight driving chip 50 through the switching circuit 30 and the unidirectional conducting circuit 60.

And in the standby state, the switch circuit 30 and the one-way conduction circuit 60 are both kept in the cut-off state, no power supply signal is reversely fed back to the switch circuit 30 by the charge and discharge circuit 40, the switch circuit 30 is kept in normal on-off state, and the working reliability of the switch circuit 30 is improved.

Optionally, as shown in fig. 4, in order to simplify the circuit structure, the unidirectional circuit 60 includes a fifth resistor R5 and a first diode D1;

the first end of the fifth resistor R5 forms the input end of the unidirectional circuit 60, the second end of the fifth resistor R5 is connected to the anode of the first diode D1, the cathode of the first diode D1 forms the output end of the unidirectional circuit 60, and the first diode D1 realizes the unidirectional operation.

Optionally, as shown in fig. 5, in order to implement feedback adjustment on the operating power supply of the backlight 2, the backlight driving circuit 1 further includes:

the signal input end of the voltage sampling circuit 70 is connected to the output end of the switching power supply circuit 10, the signal output end of the voltage sampling circuit 70 is connected to the signal end of the backlight source driving chip 50, and the voltage sampling circuit 70 is configured to sample the output voltage of the switching power supply circuit 10 and output a voltage sampling signal to the backlight source driving chip 50.

In this embodiment, the backlight driving chip 50 adjusts the magnitude of the working power supply of the backlight 2 according to the voltage sampling signal feedback, when detecting that the output working voltage is decreased, the backlight driving chip 50 increases the output working voltage by changing the magnitude of the switching control signal, for example, increasing the duty ratio of the PWM control signal, whereas when detecting that the output working voltage is increased, the backlight driving chip 50 decreases the output working voltage by changing the magnitude of the switching control signal, for example, decreasing the duty ratio of the PWM control signal, so that the switching power supply circuit 10 decreases the output working voltage, thereby maintaining the output working power supply within the preset voltage range.

The voltage sampling circuit 70 may adopt a structure of a voltage dividing resistor circuit, a transformer, and the like, and optionally, as shown in fig. 6, in order to simplify the line structure, the voltage sampling circuit 70 includes a sixth resistor R6 and a seventh resistor R7;

the first end of the sixth resistor R6 forms a signal input end of the voltage sampling circuit 70, the second end of the sixth resistor R6 and the first end of the seventh resistor R7 are connected together to form a signal output end of the voltage sampling circuit 70, the second end of the seventh resistor R7 is grounded, the sixth resistor R6 and the seventh resistor R7 form a voltage dividing resistor circuit, the working voltage output by the switching power supply circuit 10 is divided and sampled, and a voltage sampling signal with a corresponding magnitude is output to the backlight source driving chip 50, and the backlight source driving chip 50 adjusts the magnitude of the working power supply of the backlight source 2 according to the voltage sampling signal feedback, so that the output working power supply is maintained within a preset voltage range.

As shown in fig. 7, optionally, the second port P2 is also used for inputting the current adjusting signal ADJ;

the backlight driving circuit 1 further includes an eighth resistor R8, a ninth resistor R9, a second diode D2, and a third diode D3;

the first end of the eighth resistor R8 is connected to the second port P2, the second end of the eighth resistor R8, the first end of the ninth resistor R9, the anode of the second diode D2, and the anode of the third diode D3 are connected together, the second end of the ninth resistor R9 is grounded, the cathode of the second diode D2 is connected to the signal end of the backlight driver chip 50 and is configured to output an ON/OFF signal, and the cathode of the third diode D3 is connected to the signal end of the backlight driver chip 50 and is configured to output a current adjustment signal ADJ.

In this embodiment, the eighth resistor R8 and the ninth resistor R9 form a voltage dividing resistor circuit, the second port P2 generates a current adjusting signal ADJ and an ON/OFF signal ON/OFF with corresponding magnitudes by inputting voltage signals with different voltage levels, and outputs the current adjusting signal ADJ and the ON/OFF signal ON/OFF to the backlight driving chip 50 through the second diode D2 and the third diode D3, and meanwhile, the backlight driving chip 50 further outputs a switch control signal with a corresponding magnitude to the switching power supply circuit 10 according to the received current adjusting signal ADJ, so as to adjust the magnitude of the working current output to the backlight 2.

The utility model discloses still provide a display device, as shown in fig. 1, this display device includes backlight 2 and backlight drive circuit 1, and above-mentioned embodiment is referred to this backlight drive circuit 1's concrete structure, because this display device has adopted all technical scheme of above-mentioned all embodiments, consequently has all beneficial effects that the technical scheme of above-mentioned embodiment brought at least, and the repeated description is no longer repeated here one by one.

The display device may be a television, an all-in-one computer, or the like, and the display device includes a display panel and a backlight module, where the backlight module includes a backlight source 2 and a backlight source driving circuit 1 for driving the backlight source to work, where the backlight source driving circuit 1 includes a switching power supply circuit 10 and a backlight source driving chip 50, and the backlight source driving chip 50 outputs a switch control signal to the switching power supply circuit 10, so that the switching power supply circuit 10 outputs a working power supply with a corresponding size to the backlight source 2, and the backlight source 2 provides a light source with a corresponding brightness to the display panel.

The above-mentioned embodiments are only used for illustrating the technical solution of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.

Claims (10)

1. A backlight driving circuit, the backlight driving circuit is disposed in a display device, the backlight driving circuit comprising:

the input end of the switching power supply circuit is used for inputting a main power supply, the output end of the switching power supply circuit is used for outputting a working power supply to the backlight source, and the switching power supply circuit is triggered by a switching control signal to convert and output the working power supply;

the display device comprises a signal port and a control unit, wherein the signal port comprises a second port, a first port and a second port, the second port is used for inputting an on-off signal, the first port is used for inputting an auxiliary power supply, the on-off signal is a first level signal when the display device is started, the on-off signal is a second level signal when the display device is in a standby state, and the first level signal and the second level signal are level signals with opposite polarities;

the input end of the switch circuit is connected with the first port, the controlled end of the switch circuit is connected with the second port, the switch circuit is triggered to be switched on by the first level signal, and the switch circuit is triggered to be switched off by the second level signal;

the power supply end of the charge-discharge circuit is connected with the output end of the switch circuit, and the charge-discharge circuit triggers charge work when being powered on and triggers discharge work when being powered off;

and the backlight source driving chip is respectively connected with the second port, the output end of the charging and discharging circuit, the output end of the switching circuit and the controlled end of the switching power supply circuit, and is triggered by an input power supply signal and an on-off signal to output the switching control signal.

2. The backlight driving circuit according to claim 1, wherein the switching circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor, a first electronic switch and a second electronic switch;

the first end of the first resistor, the first end of the first capacitor and the first end of the first electronic switching tube are connected together to form the input end of the switching circuit, the second end of the first resistor, the first end of the second resistor and the first end of the second electronic switching tube are connected together, the controlled end of the second electronic switching tube is connected with the first end of the third resistor, the first end of the third resistor forms the controlled end of the switching circuit, the second end of the second electronic switching tube is grounded, the second end of the second resistor, the second end of the first capacitor, the controlled end of the first electronic switching tube and the first end of the fourth resistor are connected together, the second end of the fourth resistor is connected with the first end of the second capacitor, and the second end of the second capacitor and the second end of the first electronic switching tube are connected to form the output end of the switching circuit.

3. The backlight driver circuit of claim 1, wherein the charge and discharge circuit comprises at least one third capacitor;

the first end of at least one third capacitor is connected in parallel to form a power supply end of the charging and discharging circuit, and the second end of at least one third capacitor is grounded.

4. The backlight driving circuit according to claim 1, wherein the switching power supply circuit includes a BUCK circuit and/or a BOOST circuit.

5. The backlight driving circuit according to claim 1, wherein the backlight driving circuit further comprises a unidirectional on circuit for unidirectional input and output;

the input end of the one-way conduction circuit is connected with the output end of the switch circuit, and the output end of the one-way conduction circuit, the power supply end of the charge-discharge circuit and the power supply end of the backlight source driving chip are connected in common.

6. The backlight driver circuit of claim 5, wherein the unidirectional conducting circuit comprises a fifth resistor and a first diode;

the first end of the fifth resistor forms the input end of the unidirectional conducting circuit, the second end of the fifth resistor is connected with the anode of the first diode, and the cathode of the first diode forms the output end of the unidirectional conducting circuit.

7. The backlight driving circuit according to claim 1, further comprising:

the voltage sampling circuit, the signal input part of voltage sampling circuit with switching power supply circuit's output is connected, the signal output part of voltage sampling circuit with backlight driver chip's signal end is connected, voltage sampling circuit is used for the sampling switching power supply circuit's output voltage to output voltage sampling signal extremely backlight driver chip.

8. The backlight driving circuit according to claim 7, wherein the voltage sampling circuit includes a sixth resistor and a seventh resistor;

the first end of the sixth resistor forms a signal input end of the voltage sampling circuit, the second end of the sixth resistor and the first end of the seventh resistor are connected in common to form a signal output end of the voltage sampling circuit, and the second end of the seventh resistor is grounded.

9. The backlight driver circuit of claim 8, wherein the second port is further for inputting a current adjustment signal;

the backlight source driving circuit further comprises an eighth resistor, a ninth resistor, a second diode and a third diode;

the first end of the eighth resistor is connected to the second port, the second end of the eighth resistor, the first end of the ninth resistor, the anode of the second diode and the anode of the third diode are connected in common, the second end of the ninth resistor is grounded, the cathode of the second diode is connected to the signal end of the backlight source driving chip and used for outputting the power on/off signal, and the cathode of the third diode is connected to the signal end of the backlight source driving chip and used for outputting the current regulation signal.

10. A display device comprising a backlight and the backlight driving circuit according to any one of claims 1 to 9.

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