WO2019061221A1

WO2019061221A1 - Switch direct-current boost circuit and terminal backlight module

Info

Publication number: WO2019061221A1
Application number: PCT/CN2017/104207
Authority: WO
Inventors: 徐家林; 刘静江
Original assignee: 深圳传音制造有限公司
Priority date: 2017-09-29
Filing date: 2017-09-29
Publication date: 2019-04-04

Abstract

A switch direct-current boost circuit and a terminal backlight module. The circuit comprises: a boost control unit (14), an energy storage inductor (11), a resistance-controlled power supply (16) and a load drive circuit (12), wherein the boost control unit (14) comprises a switch circuit and a feedback circuit; an input end of the energy storage inductor (11) is connected to a power supply (10), and an output end thereof is respectively connected to a switch node port of the boost control unit (14) and an input end of the load drive circuit (12); a power supply input end of the boost control unit (14) is connected to the power supply, the switch node port thereof is further connected to the input end of the load drive circuit (12), an enable end thereof is connected to an enable pulse, and a feedback end thereof is connected to one end of a load; a resistance-controlled end of the boost control unit (14) is connected to a positive electrode of the resistance-controlled power supply (16); and an output end of the load drive circuit (12) is connected to the other end of the load. The feedback resistance value of a power supply module is determined by means of adjusting and controlling a current, such that the design flexibility of a switch direct-current boost circuit can be improved, and the applicability thereof can be improved.

Description

Switching DC boost circuit and terminal backlight module

Technical field

The present application relates to the field of electronic technologies, and in particular, to a switching DC boost circuit and a terminal backlight module.

Background technique

With the continuous development of science and technology, the performance of various mobile terminal devices has also been continuously improved, which makes the performance of power modules of terminal devices more important. In order to improve the performance of the power module, the application of the feedback loop in the current power module has become very common.

In the prior art, for a switching DC boost circuit in a power module, a feedback loop generally requires a voltage divider resistor with a fixed external resistance. However, when the load changes the requirements of the power supply, it is often necessary to adjust the resistance of the feedback voltage dividing resistor of the switching DC boost circuit. Since the feedback loop is a voltage-dividing resistor with a fixed external resistance, the resistance of the voltage-dividing resistor can only be adjusted by replacing the voltage-dividing resistor, so that the performance of the switching DC-boost circuit is poor and the applicability is low.

Summary of the invention

The embodiment of the invention provides a switching DC boosting circuit and a terminal backlight module, which can improve the design flexibility of the switching DC boosting circuit by using the resistance of the current regulating power module feedback resistor, and has higher applicability.

The first aspect provides a switching DC boost circuit, which may include: a boost control unit, a storage inductor, a control resistor, and a load drive circuit, wherein the boost control unit includes a switch circuit and a feedback circuit.

The input end of the energy storage inductor is connected to the input power source VCC, and the output end of the energy storage inductor is respectively connected to the switch node port of the boost control unit and the input end of the load drive circuit.

The power input end of the boost control unit is connected to the input power source VCC, and the switch node port of the boost control unit is also connected to the input end of the load drive circuit. The enable end of the boost control unit is connected to an enable pulse, and the feedback end of the boost control unit is connected to one end of the load.

The control end of the boost control unit is connected to the positive pole of the control power supply, wherein the current outputted by the control power supply can flow into the feedback circuit through the control end of the boost control unit. The feedback circuit can determine the resistance of the feedback resistor according to the current output by the control resistor, and the feedback circuit includes at least the feedback resistor. The output of the above load driving circuit is connected to the other end of the load.

In some possible implementations, the boost control unit includes: a switch circuit and a feedback circuit.

The switch node port of the switch circuit is connected to the switch node port of the boost control unit, and the power input end of the switch circuit is connected to the power input end of the boost control unit. The enable end of the switch circuit is connected to the enable end of the boost control unit, and the feedback end of the switch circuit is respectively connected to one end of the feedback circuit and the feedback end of the boost control unit, and the other end of the feedback circuit and the boost control unit The control terminals are connected.

In some possible implementations, the switch circuit may be an integrated chip for determining a boost control unit switch node according to the enable pulse and a feedback signal input from a feedback end of the boost control unit. The opening time or closing time of the port.

In some possible implementations, the load driving circuit includes: a Zener diode D1 and a capacitor C1.

The positive electrodes of the Zener diodes D1 are respectively connected to the switch node ports of the boost control unit and the output terminals of the energy storage inductors. The negative electrode of the Zener diode D1 is connected to one end of the capacitor C1 and one end of the load, and the other end of C1 is grounded.

In some possible implementations, the above switching DC boost circuit further includes: a capacitor C2.

One end of the capacitor C2 is respectively connected to the input terminal of the positive electrode and the storage inductor of the input power source VCC, and the other end is grounded.

The second aspect provides a terminal backlight module, wherein the terminal backlight module includes a switching DC boost circuit connected between a power source and a load, wherein the switch DC boost circuit includes: a boost control unit The energy storage inductor and the load drive circuit, wherein the boost control unit comprises a switch circuit and a feedback circuit.

In some possible implementations, the switch circuit is an integrated chip, and the integrated chip is configured to have a feedback signal according to the enable pulse and a feedback end input of the boost control unit, and determine the boost control unit switch node port. The opening time or closing time.

In the embodiment of the present invention, the switch DC boost circuit includes: a boost control unit, a storage inductor, a control resistor, and a load drive circuit, wherein the boost control unit includes a switch circuit and a feedback circuit. The input end of the energy storage inductor is connected to the input power source VCC, and the output end of the energy storage inductor is respectively connected to the switch node port of the boost control unit and the input end of the load drive circuit. The power input end of the boost control unit is connected to the input power source VCC, and the switch node port of the boost control unit is also connected to the input end of the load driving circuit, and the enable end of the boost control unit is connected to the enable pulse, and the boosting The feedback end of the control unit is connected to one end of the load. The control end of the boost control unit is connected to the positive pole of the control power supply, and the feedback circuit can determine the feedback current according to the current output by the control power supply. The resistance of the resistor, the feedback circuit includes at least the feedback resistor described above. The output of the above load driving circuit is connected to the other end of the load. By adopting the embodiment of the invention, determining the feedback resistance value of the power module by regulating the current can improve the design flexibility of the switching DC boost circuit and improve its applicability.

DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the present invention. Other drawings may also be obtained from those of ordinary skill in the art in light of the inventive work.

1 is a schematic diagram of a switching DC boost circuit according to an embodiment of the present invention;

2 is another schematic diagram of a switching DC voltage boosting circuit according to an embodiment of the present invention;

3 is a schematic diagram of a switching circuit of a switching DC boost circuit according to an embodiment of the present invention;

4 is a schematic structural diagram of a terminal backlight module according to an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described in the following with reference to the accompanying drawings. It is apparent that the described embodiments are only a part of the embodiments of the invention, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

In a specific implementation, the load described in this embodiment may include a light-emitting type load such as a light emitting diode (LED) lamp, a liquid crystal display (LCD) screen, or a small motor. The above load is only an example, not an exhaustive one, and is not limited herein.

FIG. 1 is a schematic diagram of a switching DC boost circuit according to an embodiment of the present invention. The switching DC voltage boosting circuit described in the embodiments of the present invention includes: a power source VCC10, a storage inductor 11, a load driving circuit 12, an enable pulse 13, a boost control unit 14, a load 15, and a control power supply 16. The boost control unit 15 may include a switch circuit and a feedback circuit.

In a specific implementation, the positive electrode of the power source 10 is respectively connected to the power input end of the boost control unit 14 and the input end of the energy storage inductor 11 . An output end of the energy storage inductor 11 is respectively connected to an input end of the load driving circuit 12 and a switch node port of the boost control unit 14, and an output end of the load driving circuit 12 is connected to one end of the load 15 and a load 15 The other end is connected to the feedback end of the boost control unit. The enable terminal of the boost control unit 14 is connected to the enable pulse 13, and the switch node port of the boost control unit 14 is also connected to the input terminal of the load drive circuit 12. The control terminal of the boost control unit 14 is connected to the positive terminal of the controlled-resistance power supply 16. The grounding end of the power supply 10 is connected to the grounding end of the boosting control unit 14 and grounded.

The working principle of the switching DC voltage boosting circuit described in the embodiment of the present invention will be specifically described below with reference to FIG.

In some possible implementations, it is assumed that all components of the circuit are in an ideal state. When the switching DC boost circuit is powered up, the feedback circuit in the boost control unit 14 is obtained according to the control terminal of the boost control unit 14. Regulation The current determines the resistance of the feedback resistor in the feedback circuit. The feedback circuit includes at least the feedback resistor, and the regulated current is an output current of the control resistor 16 . The magnitude of the output of the above-mentioned controlled-resistance power supply 16 is determined by the specification requirements of the load 15.

When the switch node port of the boost control unit 14 is in an open state, the input voltage flows into the input end of the energy storage inductor 11, and since the input is direct current, the voltage on the energy storage inductor 11 linearly rises at a certain ratio. That is, the electric energy is converted into magnetic energy inside the energy storage inductor 11 to form an energy storage circuit, which is the state of charge of the energy storage inductor 11. Before the above-described energy storage inductor 11 does not reach saturation, the stored energy is proportional to the duration (ie, charging time) of the above-described state of charge. At the same time, the load driving circuit 12 supplies power to the load, and the load 15 is in a power-on state. At this time, the feedback port of the boost control unit 14 receives the feedback signal, and according to the feedback signal and the enable end of the boost control unit. The received enable pulse 13 adjusts the charging time of the energy storage inductor 11 to control the voltage value across the energy storage inductor 11.

When the feedback circuit in the boost control unit 14 receives the operating current signal from the load 15 through the feedback terminal of the boost control unit 14, the operating current signal is converted into a feedback signal and transmitted to the boost through its internal feedback resistor. The switching circuit in the voltage control unit 14. Then, the switching circuit determines the state of the switch node port of the boost control unit 14 based on the feedback signal and the enable pulse 13 acquired by the enable terminal of the boost control unit 14, the state including both on and off. If it is determined that the state of the switch node port of the boost control unit 14 is closed, the output end of the energy storage inductor 11 starts to supply the stored power to the load drive circuit 12, and the voltage value provided by the load drive circuit 12 to the load 15 at this time. To be greater than the voltage value provided by the load drive circuit 12 to the load 15 when the storage inductor 11 is in the charging state, the entire switching DC boost circuit implements the voltage boost function.

In the embodiment of the present invention, the switching DC voltage boosting circuit includes: a boosting control unit, an energy storage inductor, and a load driving circuit, wherein the boosting control unit includes a switching circuit and a feedback circuit. The input end of the energy storage inductor is connected to the input power source VCC, and the output end of the energy storage inductor is respectively connected to the switch node port of the boost control unit and the input end of the load drive circuit. The power input end of the boost control unit is connected to the input power source VCC, and the switch node port of the boost control unit is also connected to the input end of the load driving circuit, and the enable end of the boost control unit is connected to the enable pulse, and the boosting The feedback end of the control unit is connected to one end of the load. The control end of the boost control unit is connected to the positive pole of the control power supply, and the feedback circuit can determine the resistance of the feedback resistor according to the current output by the control power supply. The feedback circuit includes at least the feedback resistor. The output of the load drive circuit is connected to the other end of the load. By adopting the embodiment of the invention, the feedback resistance value of the power module can be determined by regulating the current, thereby improving the design flexibility of the switching DC boost circuit and improving the applicability thereof.

FIG. 2 is another schematic diagram of a switching DC boost circuit according to an embodiment of the present invention. The switching DC voltage boosting circuit described in the embodiment of the present invention comprises: a power source VCC20, a storage inductor 21, a load driving circuit 22, a boosting control unit 23, an enable pulse 26, a control power supply 27, and a load 28. The boost control unit 23 includes a switch circuit 24 and a feedback circuit 25.

In some possible implementations, the switching DC boost circuit may further include a capacitor C2, and the capacitor C2 forms an LC filter circuit with the energy storage inductor 21, and filters the DC output of the power source 20 to obtain a more stable charging current. . In some possible implementations, the load driving circuit 22 described above may include a Zener diode D1 and a capacitor C1.

In a specific implementation, the positive electrode of the power source 20 has one end of the capacitor C2, an input end of the storage inductor 21, and a power input terminal 1 of the boost control unit 23, and the other end of the capacitor C2 is grounded. The above energy storage inductor The output terminals of 21 are respectively connected to the switch node port of the above-described boost control unit 23 and the positive electrode of the Zener diode D1 in the load drive circuit 22. The negative electrode of the Zener diode D1 is connected to one end of the load and one end of the capacitor C1 in the load drive circuit 22, and the other end of the C1 is grounded. The other end of the load 28 is connected to the feedback end of the boost control unit 23, and the enable end of the boost control unit 23 is connected to the enable pulse 26, and the control end thereof is connected to the positive terminal of the control power supply 27.

The power input terminal of the boost control unit 23 is connected to the power input terminal 1 of the switch circuit 24, and the switch node port of the boost control unit 23 is connected to the switch node port 1 of the switch circuit 24, and the boost control unit 23 is connected. The enable terminal is coupled to the enable terminal 1 of the switch circuit 24. The feedback terminal of the boost control unit 23 is connected to the feedback terminal 1 of the switch circuit 24 and the input terminal of the feedback circuit 25, respectively, and the other end of the feedback circuit 25 is connected to the control terminal of the boost control unit 23. In some feasible implementation manners, the ports may be directly connected, or may be connected through a conditioning circuit such as a filter circuit or an amplifying circuit, and are not limited herein. The function of the above conditioning circuit is to ensure the stability of signal transmission between ports.

Optionally, please refer to FIG. 3 together. FIG. 3 is a schematic diagram of a switch circuit of a switching DC boost circuit according to an embodiment of the present invention. The switch circuit 24 described above may include a pre-processing circuit 241, an error amplifier 242, a comparator 243, a switch controller 244, a comparison signal acquisition unit 245, and a switch trigger 246. The first end of the pre-processing circuit 241 is the enable end 1 of the switch circuit 24, and the other end is connected to one end of the error amplifier 242. The error amplifier 242 has one end connected to the feedback terminal 1 of the switching circuit 25 and the other end connected to one end of the comparator 243. The comparator 243 has one end connected to one end of the switch controller 244 and the other end connected to one end of the comparison signal acquisition unit 245. One end of the switch controller 244 is connected to the comparison signal acquisition unit 245, and the other end is connected to one end of the switch trigger 246. One end of the switch trigger 246 is the switch node port 1 of the switch circuit 24, and the other end is connected to one end of the comparison signal acquisition unit 245.

In some possible implementations, it is assumed that all components of the circuit are in an ideal state. After the power supply 20 starts to supply power, the feedback circuit 25 in the boost control unit 23 determines the resistance of the feedback resistor in the feedback circuit 25 through the control current obtained by the control terminal of the boost control unit 23, wherein the feedback circuit 25 The feedback resistor is included at least, and the regulated current is the output current of the controlled-resistance power supply 27. The magnitude of the output of the above-mentioned controlled-resistance power supply 27 is determined by the specification requirements of the load 28.

When the switch node port of the switch circuit 24 is in an open state, the current output by the power source 20 flows into the input end of the energy storage inductor 21. Since the input is direct current, the voltage across the energy storage inductor 21 rises linearly at a certain ratio. That is, the electric energy is converted into magnetic energy inside the energy storage inductor 21 to form an energy storage circuit, which is the state of charge of the storage inductor 21, and the voltage across the storage inductor 21 is a charging voltage. Before the storage inductor 21 does not reach saturation, the charging voltage is proportional to the duration of the charging state (ie, charging time). At the same time, the positive voltage of the Zener diode D1 is greater than the negative voltage, and is in a conducting state. The power supply current flows through the Zener diode, and the capacitor C1 is charged while the load is being driven, so that the voltage across the capacitor C1 rises, and finally a stable state is obtained. At this time, the operating voltage of the load 28 is equal to the voltage across the capacitor C1.

When the load 28 is in the working state, the current during operation will provide a feedback signal to the feedback terminal of the switch circuit 24 through the feedback circuit 25 determined by the resistance value, and the enable terminal of the switch circuit 24 can receive the enable pulse. 26 is processed by the pre-processing circuit 241 described above to obtain an internal reference voltage. Then passed through the above error amplifier 242 The difference between the feedback signal and the internal reference voltage is obtained and amplified, and the error signal output by the error amplifier 252 is compared with the comparison signal output by the comparison signal acquisition unit 245 through the comparator 243. The switch controller 244 outputs a trigger signal to the switch trigger 246 according to the comparison result output by the comparator 243. The switch trigger 246 determines the state of the switch node port of the switch circuit 24 according to the trigger signal, and the state of the switch node port may include Open and close.

The working principle of the circuit in the open state of the switch node has been described above, and will not be described here. If the state of the above-mentioned switch node is closed, the above-mentioned energy storage inductor 21 stops charging, and based on the voltage holding characteristic of the inductor, the charging voltage of the storage inductor 21 is slowly lowered until it is zero. Since the switch node port is in the closed state, the above-described storage inductor 21 discharge current flows through the load drive circuit 22 to the load. At this time, C1 in the load driving circuit 22 starts to supply power to the load 28, and due to the action of the Zener diode, it does not discharge to the ground, ensuring that the sum of the voltage across C1 and the charging voltage of the storage inductor 21 is the load 28 The operating voltage is used to achieve the voltage boost function.

Specifically, after the circuit is powered on, the feedback circuit determines the magnitude of the feedback resistance value in the feedback circuit 25 according to the control circuit obtained by the control terminal of the boost control unit 23, and then provides a feedback signal to the switch circuit 24, the switch The circuit 24 determines the state of the switch node port of the boost control unit 23 and the time that the state is maintained by the feedback signal and the enabled enable pulse 26 described above. When the above-mentioned switch node port is in an open state, the energy storage inductor 21 is in a state of charge, and its charging voltage is proportional to the maintenance time of the state of the switch node port. When the switch node port is in the closed state, the storage inductor 21 is in a discharged state, and the operating voltage of the load 28 is the sum of the voltage across C1 and the charging voltage of the storage inductor 21.

In the embodiment of the present invention, the switching DC voltage boosting circuit includes: a boosting control unit, an energy storage inductor, and a load driving circuit, wherein the boosting control unit includes a switching circuit and a feedback circuit. The input end of the energy storage inductor is connected to the input power source VCC, and the output end of the energy storage inductor is respectively connected to the switch node port of the boost control unit and the input end of the load drive circuit. The power input end of the boost control unit is connected to the input power source VCC, and the switch node port of the boost control unit is also connected to the input end of the load driving circuit, and the enable end of the boost control unit is connected to the enable pulse, and the boosting The feedback end of the control unit is connected to one end of the load. The control end of the boost control unit is connected to the positive pole of the control power supply, and the feedback circuit can determine the resistance of the feedback resistor according to the current output by the control power supply. The feedback circuit includes at least the feedback resistor. The output of the load drive circuit is connected to the other end of the load. By adopting the embodiment of the invention, determining the feedback resistance value of the power module by regulating the current can improve the design flexibility of the switching DC boost circuit and improve its applicability.

FIG. 4 is a schematic structural diagram of a terminal backlight module according to an embodiment of the present invention. The terminal backlight module includes a power source 30, a signal source 31, a switching DC boost circuit 32, and a backlight 33.

Specifically, after the power source 30 supplies power to the terminal backlight module, the switch DC boost circuit 32 determines the magnitude of the voltage provided by the backlight 33 according to the control signal provided by the signal source 31 and the feedback signal provided by the backlight 33. For the specific principle of the determination, reference may be made to the working principle of the switching DC voltage boosting circuit described in the embodiment of the above-mentioned switching DC voltage boosting circuit, and details are not described herein again. After the switching DC boosting circuit 32 determines the magnitude of the voltage supplied from the backlight 33, the backlight 33 is supplied with the above voltage, and the backlight 33 is turned on.

The switching DC boost circuit in the terminal backlight module described in this embodiment can determine that the backlight provides a matching voltage according to the control signal provided by the signal source and the feedback signal provided by the load, and does not need to be renewed after the backlight is replaced. Designing a switching DC boost circuit to improve the applicability of the switching DC boost circuit and improve the terminal backlight module design Flexibility.

The above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention. It should be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the appended claims.

Claims

A switching DC boosting circuit, comprising: a boosting control unit, a storage inductor and a load driving circuit, and a controlled resistance power supply, wherein the boosting control unit comprises a switching circuit and a feedback circuit;

The input end of the energy storage inductor is connected to the input power source VCC, and the output end of the energy storage inductor is respectively connected to the switch node port of the boost control unit and the input end of the load drive circuit;

The power input terminal of the boost control unit is connected to the input power source VCC, the switch node port of the boost control unit is also connected to the input end of the load driving circuit, and the enable terminal of the boost control unit is connected. An enable pulse, the feedback end of the boost control unit is connected to one end of the load;

The control end of the boost control unit is connected to the positive pole of the control power supply, wherein the current output by the control power supply flows into the feedback circuit through the control end of the boost control unit, and the feedback circuit is Determining a current of the output of the resistive power supply determines a resistance of the feedback resistor, the feedback circuit including at least the feedback resistor;

The output of the load drive circuit is connected to the other end of the load.
The switching DC voltage boosting circuit according to claim 1, wherein the boosting control unit comprises: a switching circuit and a feedback circuit;

a switch node port of the switch circuit is connected to a switch node port of the boost control unit, a power input end of the switch circuit is connected to a power input end of the boost control unit, and an enable end of the switch circuit Connected to an enable end of the boost control unit, a feedback end of the switch circuit is respectively connected to one end of the feedback circuit and a feedback end of the boost control unit, and the other end of the feedback circuit and the rise The control terminals of the pressure control unit are connected.
A switching DC boost circuit according to claim 2, wherein said switching circuit is an integrated chip for having input according to said enable pulse and said feedback terminal of said boost control unit And a feedback signal determining an opening duration or a closing duration of the switch node of the boost control unit.
The switching DC voltage boosting circuit according to claim 3, wherein the load driving circuit comprises: a Zener diode D1, a capacitor C1;

The positive poles of the Zener diode D1 are respectively connected to the switch node port of the boost control unit and the output end of the energy storage inductor, and the negative pole of the Zener diode D1 and the end of the capacitor C1 and the load end respectively connection;

The other end of the C1 is grounded.
The switching DC boost circuit of claim 4, wherein the switching DC boost circuit further comprises: a capacitor C2;

One end of the capacitor C2 is respectively connected to the input end of the input power source VCC and the energy storage inductor, and the other end of the capacitor C2 is grounded.
A terminal backlight module includes a switching DC boost circuit connected between a power source and a load, wherein the switch DC boost circuit includes: a boost control unit, a storage inductor, Controlled resistance power supply And a load driving circuit, wherein the boosting control unit comprises a switching circuit and a feedback circuit;

The input end of the energy storage inductor is connected to the input power source VCC, and the output end of the energy storage inductor is respectively connected to the switch node port of the boost control unit and the input end of the load drive circuit;

The power input terminal of the boost control unit is connected to the input power source VCC, the switch node port of the boost control unit is also connected to the input end of the load driving circuit, and the enable terminal of the boost control unit is connected. An enable pulse, the feedback end of the boost control unit is connected to one end of the load;

The control end of the boost control unit is connected to the positive pole of the control power supply, wherein the current output by the control power supply flows into the feedback circuit through the control end of the boost control unit, and the feedback circuit is Determining a current of the output of the resistive power supply determines a resistance of the feedback resistor, the feedback circuit including at least the feedback resistor;

The output of the load drive circuit is connected to the other end of the load.
The terminal backlight module according to claim 6, wherein the boost control unit comprises: a switch circuit and a feedback circuit;

a switch node port of the switch circuit is connected to a switch node port of the boost control unit, a power input end of the switch circuit is connected to a power input end of the boost control unit, and an enable end of the switch circuit Connected to an enable end of the boost control unit, a feedback end of the switch circuit is respectively connected to one end of the feedback circuit and a feedback end of the boost control unit, and the other end of the feedback circuit and the rise The control terminals of the pressure control unit are connected.
The terminal backlight module according to claim 7, wherein the switch circuit is an integrated chip, and the integrated chip is configured to have feedback according to the enable pulse and a feedback end input of the boost control unit. And determining a turn-on duration or a turn-off duration of the switch node of the boost control unit.
The terminal backlight module according to claim 8, wherein the load driving circuit comprises: a Zener diode D1, a capacitor C1;

The positive poles of the Zener diode D1 are respectively connected to the switching control unit switch node port and the energy storage inductor output end, and the cathode of the Zener diode D1 is respectively connected to one end of the capacitor C1 and one end of the load;

The other end of the C1 is grounded.
The terminal backlight module of claim 9, wherein the switching DC boost circuit further comprises: a capacitor C2;

One end of the capacitor C2 is respectively connected to the input end of the input power source VCC and the energy storage inductor, and the other end of the capacitor C2 is grounded.