WO2020168815A1

WO2020168815A1 - Protection circuit of power supply apparatus, method, and device

Info

Publication number: WO2020168815A1
Application number: PCT/CN2019/127716
Authority: WO
Inventors: 郑凌霄
Original assignee: 广州视源电子科技股份有限公司
Priority date: 2019-02-20
Filing date: 2019-12-24
Publication date: 2020-08-27
Also published as: CN109755923B; CN109755923A

Abstract

A protection circuit of a power supply apparatus, comprising: a power output module (110), a voltage reducing module (120), a control module (130), a load module (140), a detection module (150), and a feedback module (160); a first terminal of the power output module (110) is connected to a first terminal of the control module (130), a second terminal of the power output module (110) is respectively connected to a first terminal of the voltage reducing module (120) and a positive terminal of the load module (140), and a third terminal of the power output module (110) is respectively connected to a second terminal of the voltage reducing module (120) and a first terminal of the detection module (150); a second terminal of the detection module (150) is connected to a negative terminal of the load module (140), a third terminal of the detection module (150) is connected to a first terminal of the feedback module (160), and a second terminal of the feedback module (160) is connected to the first terminal of the control module (130); when the load module (140) fails, the detection module (150) outputs a failure signal to the feedback module (160) such that the feedback module (160) outputs a feedback signal to the control module (130) so as to trigger the control module (130) to stop outputting control signals to the power output module (110).

Description

Protection circuit, method and equipment of power supply device

This disclosure claims the priority of a Chinese patent application filed with the Chinese Patent Office with an application number of 201910126971.3 on February 20, 2019. The entire content of the above application is incorporated into this disclosure by reference.

Technical field

This application relates to the technical field of power supply control, for example, to a protection circuit, method, and equipment of a power supply device.

Background technique

When a short-to-ground fault occurs on the negative terminal of a TV (television, TV) backlight strip, the voltage applied to the TV backlight strip is equal to the input voltage of the BUCK circuit, which increases the TV backlight current. Constant current, at the same time, the TV backlight strip will burn out due to excessive current. Therefore, in order to avoid excessive current from burning the backlight strip, technicians connect the cathode of the diode to the cathode of the TV backlight strip and the anode of the diode to 12V. When the negative pole of the TV backlight strip is short-circuited to ground, the 12V voltage is short-circuited to the ground terminal through the diode, so that the output capacitor in the BUCK circuit is quickly discharged below the backlight strip voltage to prevent the backlight strip from being damaged.

However, when the backlight strip has an open circuit failure, the diode connected to the 12V voltage and the inductor, power tube, diode and output capacitor in the original BUCK circuit form a boost converter (BOOST) circuit, which increases the voltage across the output capacitor , Causing power failure and damage.

Summary of the invention

The present application provides a protection circuit, method, and equipment for a power supply device, which implements overcurrent protection when a load module fails, so as to avoid damage to the power supply.

In the first aspect, this application provides a protection circuit for a power supply device, including: a power output module, a step-down module, a control module, a load module, a detection module, and a feedback module; wherein,

The first end of the power output module is connected to the output end of the control module, and the second end of the power output module is respectively connected to the first end of the step-down module and the positive end of the load module, so The third end of the power output module is respectively connected to the second end of the step-down module and the first end of the detection module; the negative end of the load module is respectively connected to the second end of the detection module and the The third end of the step-down module is connected, the third end of the detection module is connected to the first end of the feedback module, and the second end of the feedback module is connected to the first end of the control module;

When the load module fails, the detection module outputs a fault signal to the feedback module, and the feedback module outputs a feedback signal to the control module according to the fault signal, so as to trigger the control module according to the feedback The signal stops outputting the control signal to the power output module.

The power output module includes: a power output unit and an overvoltage protection unit;

The first end of the power output unit is connected to the first end of the control module, and the second end of the power output unit is respectively connected to the first end of the step-down module and the positive end of the load module; The third end of the power output unit is respectively connected to the second end of the step-down module, the first end of the overvoltage protection unit, and the first end of the detection module; the first end of the overvoltage protection unit One end is connected to the third end of the control module;

When the voltage value of the third terminal of the power output unit exceeds the preset voltage value, the overvoltage protection unit outputs an overvoltage protection signal to the control module to trigger the control module to stop outputting the control signal.

The detection module includes: a transistor unit and a diode unit; the first end of the transistor unit is connected to the third end of the power output module, and the second end of the transistor unit is connected to the first end of the feedback module , The third terminal of the transistor unit is connected to the first terminal of the diode unit, and the second terminal of the diode unit is connected to the negative terminal of the load module;

Wherein, when the load module fails, the detection module outputs a fault signal to the feedback module, including: when the load module fails, the voltage signal of the third terminal of the power output module passes through the diode The unit transmits to the negative terminal of the load module, and triggers the transistor unit to generate a fault signal, and output the fault signal to the feedback module.

The fault signal includes a short-circuit fault signal or an open-circuit fault signal, the short-circuit fault signal is generated when the load module has a short-circuit fault, and the open-circuit fault signal is generated when the load module has an open-circuit fault.

The transistor unit includes a first transistor and a first resistor. The first end of the first transistor is respectively connected to the third end of the power output module and the first end of the first resistor. The second end of the transistor is connected to the first end of the feedback module, and the third end of the first transistor is respectively connected to the first end of the diode unit and the second end of the first resistor.

The transistor unit further includes a first capacitor, wherein the first end of the first capacitor is connected to the first end of the first transistor and the first end of the first resistor respectively, and the first capacitor The second end of is connected to the second end of the first transistor and the second end of the first resistor.

The diode unit includes a first diode and a second resistor, a first end of the second resistor is connected to a third end of the transistor unit, and a second end of the second resistor is connected to the first and second resistors. The anode of the pole tube is connected; the second end of the first diode is connected to the negative end of the load module.

The feedback module includes: an optocoupler unit and a resistance unit, the first end of the optocoupler unit is connected to the second end of the transistor unit, and the second end of the optocoupler unit is connected to the first end of the resistance unit. The second end of the resistance unit is connected to the second end of the control module.

The optocoupler unit includes: a light emitting diode, a phototransistor, and a third resistor. A first end of the third resistor is connected to a second end of the transistor unit, and a second end of the third resistor is connected to the light emitting diode. The anode connection of the diode;

The collector of the phototransistor is connected to the first end of the resistance unit.

The step-down module includes: a step-down unit and a step-down control unit; the first end of the step-down unit is respectively connected to the positive end of the load module and the second end of the power output module, and the step-down unit The second end of the unit is connected to the negative end of the load module and the second end of the detection module, the third end of the step-down unit is connected to the first end of the step-down control unit, and the drop The second end of the voltage control unit is respectively connected to the first end of the detection module and the third end of the power output module.

In a second aspect, the present application provides a protection method for a power supply device, including: when a load module fails, a detection module outputs a fault signal to a feedback module; the feedback module outputs a feedback signal to a control module according to the fault signal ; The control module stops outputting control signals to the power output module according to the feedback signal.

In a third aspect, the present application also provides a device that includes the protection circuit of the power supply device as described in the first aspect.

The present application provides a protection circuit, method, and equipment for a power supply device, including: a power output module, a step-down module, a control module, a load module, a detection module, and a feedback module; the first end of the power output module and the second end of the control module One end is connected, the second end of the power output module is connected to the first end of the step-down module and the positive end of the load module, and the third end of the power output module is connected to the second end of the step-down module and the first end of the detection module. Connection; the second end of the detection module is connected to the negative end of the load module, the third end of the detection module is connected to the first end of the feedback module, and the second end of the feedback module is connected to the first end of the control module; when the load module fails , The detection module outputs a fault signal to the feedback module, so that the feedback module outputs a feedback signal to the control module, and triggers the control module to stop outputting the control signal to the power output module. This application realizes overcurrent protection when the load module fails to avoid damage to the power supply .

Description of the drawings

Fig. 1 is a schematic block diagram of a protection circuit of a power supply device in an embodiment of the present application;

2 is a schematic block diagram of a protection circuit of a power supply device in an optional embodiment of the present application;

3 is a schematic structural diagram of a protection circuit of a power supply device in an optional embodiment of the present application;

Fig. 4 is a flowchart of steps of a method for protecting a source device in an embodiment of the present application.

detailed description

The application will be further described in detail below with reference to the drawings and embodiments. It is understandable that the specific embodiments described here are only used to explain the application, but not to limit the application. In addition, it should be noted that, for ease of description, the drawings only show a part of the structure related to the present application instead of all of the structure.

FIG. 1 is a principle block diagram of a protection circuit of a power supply device in an embodiment of the present application; this embodiment can be applied to the case of protecting a power supply device, and the protection circuit of the power supply device is set in equipment. The device can be a TV.

As shown in FIG. 1, the protection circuit of the power supply device provided by the embodiment of the present application mainly includes: a power output module 110, a step-down module 120, a control module 130, a load module 140, a detection module 150 and a feedback module 160.

The first end of the power output module 110 is connected to the first end of the control module 130, and the second end of the power output module 110 is connected to the first end of the step-down module 120 and the load module 140, respectively. The positive terminal of the power output module 110 is connected to the second terminal of the step-down module 120 and the first terminal of the detection module 150 respectively; the negative terminal of the load module 140 is connected to the The second end of the detection module 150 is connected to the third end of the step-down module 120, the third end of the detection module 150 is connected to the first end of the feedback module 160, and the The second end is connected to the first end of the control module 130.

When the load module 140 fails, the detection module 150 outputs a fault signal to the feedback module 160, and the feedback module 160 outputs a feedback signal to the control module 130 according to the fault signal to trigger the control The module 130 stops outputting the control signal to the power output module 110 according to the feedback signal.

In this embodiment, the power output module 110 performs voltage conversion on the received voltage signal according to the control signal generated by the control module 130, and converts it into two different voltage signals. Among them, two different voltage signals are output through the second terminal and the third terminal of the power output module 110 respectively. The second terminal of the power output module 110 inputs the output voltage signal to the positive terminal of the load module 140 after the step-down conversion of the buck module, and the voltage signal output by the third terminal of the power output module 110 is 12V. Since the third end of the power output module 110 is respectively connected to the second end of the step-down module 120 and the first end of the detection module 150, the third end of the power output module 110 is respectively the second end of the step-down module 120 and the detection module The first terminal of 150 provides a 12V power supply voltage. It should be noted that when the load module 140 is working normally, the third terminal of the power output module 110 provides a 12V power supply voltage for the second terminal of the step-down module 120 to reduce the voltage. The module 120 works normally and outputs the rated voltage to the load module 140. When the load module 140 fails, the third terminal of the power output module 110 provides the first terminal of the detection module 150 with a power supply voltage of 12V, so that the detection module detects the failure signal.

When the load module 140 fails, the third terminal of the power output module 110 provides a 12V supply voltage for the first terminal of the detection module 150, so that the detection module 150 detects the fault signal, and outputs the fault signal to the feedback module 160 for feedback The module 160 outputs a feedback signal to the control module 130 according to the fault signal to trigger the control module 130 to stop outputting the control signal to the power output module 110 according to the feedback signal, thereby turning off the power output module 110, and the second and third ends of the power output module 110 At this time, the first terminal and the second terminal of the step-down module 120 have no voltage signal input, and the working state is stopped, so that when the load module 140 fails, the power supply device will stop working and avoid damage to the power supply. The problem to achieve over-current protection.

In summary, the protection circuit of the power supply device provided in this embodiment includes: a power output module, a step-down module, a control module, a load module, a detection module, and a feedback module. When the load module fails, the detection module can be used to feed the feedback module The fault signal is output, so that the feedback module outputs the feedback signal to the control module, which triggers the control module to stop outputting the control signal to the power output module, which realizes the overcurrent protection when the load module fails and avoids damage to the power supply.

On the basis of the foregoing embodiment, this embodiment further optimizes the protection circuit of the power supply device. Fig. 2 is a functional block diagram of a protection circuit of a power supply device in an optional embodiment of the present application.

As shown in FIG. 2, the power output module 110 includes a power output unit 111 and an overvoltage protection unit 112; a first end of the power output unit 111 is connected to a first end of the control module 130, and the power The second end of the output unit 111 is respectively connected to the first end of the step-down module 120 and the positive end of the load module 140; the third end of the power output unit 111 is respectively connected to the first end of the step-down module 120 The two ends, the first end of the overvoltage protection unit 112 and the first end of the detection module 150 are connected; the first end of the overvoltage protection unit 112 is connected to the second end of the control module 130. When the voltage value of the third terminal of the power output unit 111 exceeds the preset voltage value, the overvoltage protection unit 112 outputs an overvoltage protection signal to the control module to trigger the control module 130 to stop outputting the control signal.

The detection module 150 includes a transistor unit 152 and a diode unit 151; the first terminal of the transistor unit 152 is connected to the third terminal of the power output module 110, and the second terminal of the transistor unit 152 is connected to the feedback The first terminal of the module 160 is connected, the third terminal of the transistor unit 152 is connected to the first terminal of the diode unit 151, and the second terminal of the diode unit 151 is connected to the negative terminal of the load module;

Wherein, when the load module 140 fails, the detection module 150 outputs a fault signal to the feedback module 160, including: when the load module 140 fails, the voltage at the third terminal of the power output module 110 The signal is transmitted to the negative terminal of the load module through the diode unit 151, and triggers the transistor unit 152 to generate a fault signal and output the fault signal to the feedback module 160.

The feedback module 160 includes an optocoupler unit 161 and a resistance unit 162. The first end of the optocoupler unit 161 is connected to the second end of the transistor unit 152, and the second end of the optocoupler unit 161 is connected to the second end of the transistor unit 152. The first end of the resistance unit 162 is connected, and the second end of the resistance unit 162 is connected to the second end of the control module 130.

The step-down module 120 includes: a step-down unit 121 and a step-down control unit 122; the first end of the step-down unit 121 is respectively connected to the positive end of the load module 140 and the second end of the power output module 110 Connected, the second end of the step-down unit 121 is respectively connected to the negative end of the load module 140 and the second end of the detection module 150, and the third end of the step-down unit 121 is connected to the step-down control The first end of the unit 122 is connected, and the second end of the step-down control unit 122 is connected to the first end of the detection module 150 and the third end of the power output module 110 respectively.

The fault signal includes: a short circuit fault signal or an open circuit fault signal, the short circuit fault signal is generated when a short circuit fault occurs in the load module, and the open circuit fault signal is generated when an open circuit fault occurs in the load module.

Specifically, when a short-circuit fault occurs in the load module 140, the detection module 150 can detect the short-circuit fault, that is, the diode unit 151 turns on after detecting the short-circuit fault, triggers the transistor unit 152 to turn on, and generates a corresponding short-circuit fault signal. The short-circuit fault signal is transmitted to the optocoupler unit 161, so that the optocoupler unit 161 is turned on, so that the first input end of the control module 130 is grounded through the optocoupler unit 161 and the resistance unit 162, thereby making the output end of the control module stop Output control signal.

Similarly, when an open-circuit fault occurs in the load module 140, the fourth transistor Q4 and the twentieth resistor R20 of the load module 140 and the step-down module form a loop with the ground terminal, and the voltage value of the second terminal of the power output module to the ground is equal to the drop The voltage value between the positive terminal and the negative terminal of the pressure module makes the potential value of the negative terminal of the step-down module 120 0V, which is equivalent to being connected to GND. The detection module 150 can detect the open circuit fault, that is, the diode unit 151 turns on after detecting the open circuit fault, triggers the transistor unit 152 to turn on, and generates a corresponding open circuit fault signal, which can then be transmitted to the optocoupler unit 161 , The optocoupler unit 161 is turned on, so that the first input terminal of the control module 130 is grounded through the optocoupler unit 161 and the resistance unit 162, and the output terminal of the control module can be triggered to stop outputting control signals.

The power output unit 111 includes: a resonator unit 1111, a first commutator unit 1112, and a second commutator unit 1113; the first output end of the resonator unit 1111 is connected to the input end of the first commutator unit 1112, and the resonator unit 1111 The second output terminal of the rectifier unit is connected to the input terminal of the second rectifier unit 1113; the output terminal of the first rectifier unit 1112 is connected to the positive terminal of the load module 140 and the first terminal of the step-down unit 121; the second rectifier unit 1113 The output terminals of are respectively connected to the second terminal of the step-down control unit 122 and the first terminal of the diode unit 151.

In this embodiment, the power output unit 111 adopts a resonance circuit with LLC topology. It should be noted that this embodiment only describes the power output unit 111, and is not limited. You can set a suitable power output according to the actual situation of the circuit. unit.

In addition, the first commutator unit 1112 adopts a bridge rectification topology, and the second commutator unit 1113 adopts a full-wave rectification topology. It should be noted that this embodiment only applies to the first commutator unit 1112 and the second rectifier unit 1112. The structure of the subunit 1113 is described without limitation, and a suitable rectifier unit can be set according to the actual situation of the circuit.

The control module 130 includes: a first control chip 131, a first drive unit 132, and a second drive unit 133; the first end of the first drive unit 132 is connected to the third end of the first control chip 131, and the first drive unit 132 The second terminal is connected to the first input terminal of the resonator unit 1111. The first end of the second driving unit 133 is connected to the fourth end of the first control chip 131, and the second end of the second driving unit 132 is connected to the second input end of the resonator unit 1111. It should be noted that, in this embodiment, the first end of the power output module includes the first input end of the resonator unit 1111 and the second input end of the resonator unit 1111.

This embodiment is on the basis of the above-mentioned embodiment to describe the specific components in each module and the connection relationship between the components. Fig. 3 is a schematic structural diagram of a protection circuit of a power supply device in an optional embodiment of the present application.

As shown in Figure 3, the components included in each module in the protection circuit of the power supply device and the connection relationship between the components are as follows:

The transistor unit 152 includes a first transistor Q1 and a first resistor R1. The first terminal of the first transistor Q1 is connected to the third terminal of the power output module 110 and the first resistor R1. The second end of the first transistor Q1 is connected to the first end of the feedback module 160, and the third end of the first transistor is connected to the first end of the diode unit and the first resistor respectively. The second end of the connection.

The transistor unit 152 further includes a first capacitor C1, wherein the first terminal of the first capacitor C1 is respectively connected to the first terminal of the first transistor Q1 and the first terminal of the first resistor R1, and the The second end of the first capacitor C1 is connected to the second end of the first transistor Q1 and the second end of the first resistor R1.

In this embodiment, optionally, the first transistor Q1 is a PNP transistor. The first end of the first transistor Q1 is the emitter of the PNP type transistor, the second end of the first transistor Q1 is the collector of the PNP type transistor, and the third end of the first transistor Q1 is the PNP type transistor. The base. It should be noted that in this embodiment, only the types of transistors are described and not limited, and other types of transistors can be used for specific use occasions and effects of the circuit. Illustratively, the transistors can be bipolar transistors, field effect transistors, etc. .

The diode unit 151 includes a first diode D1 and a second resistor R2, a first end of the second resistor R2 is connected to a third end of the transistor unit 152, and a second end of the second resistor R2 It is connected to the anode of the first diode D1; the second end of the first diode D1 is connected to the negative end of the load module 140.

The photocoupler unit 161 includes a light emitting diode PC2A, a phototransistor PC2B, and a third resistor R3. The first end of the third resistor R3 is connected to the second end of the transistor unit 152. The second end is connected to the anode of the light emitting diode PC2A; the collector of the phototransistor PC2B is connected to the first end of the resistance unit. The emitter of the phototransistor PC2B is grounded.

The step-down unit 121 includes: a fourth transistor Q4, a second diode D2, a second inductor L2, and a first electrolytic capacitor E1; wherein the cathode of the second diode D2 is respectively connected to the output of the first rectifier unit 1112 Terminal and the first terminal of the first electrolytic capacitor E1, the anode of the second diode D2 is respectively connected to the first terminal of the first transistor Q1 and the first terminal of the second inductor L2; the second terminal of the second inductor L2 Respectively connected to the second end of the first electrolytic capacitor E1 and the negative end of the load module 140, the second end of the fourth transistor Q4 and the first end of the step-down control unit 122; the first end of the first electrolytic capacitor E1 and the load The positive terminal of the module 140 is connected, and the second terminal of the first electrolytic capacitor E1 is connected to the negative terminal of the load module 140.

Optionally, the fourth transistor Q4 is a metal oxide semiconductor field effect transistor (Metal Oxide Semiconductor, MOS). The first end of the fourth transistor Q4 is the drain of the MOS transistor, the second end of the fourth transistor Q4 is the source of the MOS transistor, and the third end of the fourth transistor Q4 is the gate of the MOS transistor. .

The resonator unit 1111 includes: a second transistor Q2, a third transistor Q3, a transformer T1, a ninth capacitor C9, and a first inductor L1; the first terminal of the second transistor Q2 is connected to the input voltage, and the first terminal of the second transistor Q2 Terminals are respectively connected to the first terminal of the third transistor Q3 and the first terminal of the first inductor L1, the second terminal of the first inductor L1 is connected to the first terminal of the primary winding of the transformer T1, and the transformer The first end of the primary winding of the ninth capacitor C9 is connected to the first end, and the second end of the ninth capacitor C9 is connected to the second end of the third transistor Q3.

The first end of the secondary first winding of the transformer T1 is connected to the first end of the first rectifier unit 1112, that is, the anode of the third diode D3, and the first end of the secondary first winding of the transformer T1 The two ends are connected to the second end of the first rectifier unit 1112, that is, the cathode of the sixth diode D6. The first end of the secondary second winding of the transformer T1 is connected to the first end of the second rectifier unit 1113, that is, the anode of the seventh diode D7, and the first end of the secondary second winding of the transformer T1 The two ends are connected to the second end of the second rectifier unit 1113, that is, the cathode of the eighth diode D8.

It should be noted that the transformer T1 adopts a three-winding transformer, in which the first end of the primary winding, the first end of the secondary first winding and the first end of the secondary second winding are terminals with the same name.

The resonator unit 1111 also includes: an excitation inductance Lr, not shown in the figure, a first end of the excitation inductance Lr is connected to the first end of the primary winding of the transformer T1, and a second end of the excitation inductance Lr is connected to the primary of the transformer T1 The second end of the winding. The magnetizing inductance Lr is the magnetizing inductance of the transformer T1.

Wherein, the first rectifier subunit 1112 is a bridge rectifier current, including: a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, and a second electrolytic capacitor E2; Among them, the cathode of the third diode D3 is connected to the cathode of the fourth diode D4, the anode of the third diode D3 is connected to the cathode of the fifth diode D5; the anode of the fourth diode D4 is connected to the The cathode of the six diode D6 is connected, the anode of the fifth diode D5 is connected to the anode of the sixth diode D6, and the positive end of the second electrolytic capacitor E2 is connected to the cathode of the third diode and The first terminal of the step-down module and the negative terminal of the second electrolytic capacitor E2 are grounded and connected to the anode of the sixth diode D6. Since the output of the power output module is alternating current, the function of the first rectifier unit is to convert the alternating current output by the power output module into direct current to supply power to the step-down module.

The second rectifier unit 1113 is a full-wave rectifier circuit. In an embodiment, the second rectifier unit 1113 includes: a seventh diode D7, an eighth diode D8, a third electrolytic capacitor E3, and a fourth electrolytic capacitor E4. Wherein, the cathode of the seventh diode D7 is connected to the cathode of the eighth diode D8; wherein, after the third electrolytic capacitor E3 and the fourth electrolytic capacitor E4 are connected in parallel, one end is grounded, and the other end is connected to the second end of the step-down module Two ends.

In this embodiment, the load module 150 may be a backlight LED (Light Emitting Diode, LED) lamp, where the negative terminal LED- of the LED lamp and the positive terminal LED+ of the LED lamp can be used as the backlight LED of an electronic device (such as a TV). The driver interface of the lamp. At the same time, the control IC of the control module 130 is an LLC topology control chip. The first driving unit 132 includes: a fifth resistor R5, a sixth resistor R6, and a ninth diode D9; the second driving unit 133 includes: an eighth resistor R8, a ninth resistor R9, and a tenth diode D10. The working principle of the power failure protection circuit is specifically as follows: the LLC topology control chip of the control module 130, the first driving unit 132 connected to it drives the second transistor Q2, and the second driving unit 133 drives the third transistor Q3 to make the first The second transistor Q2 and the third transistor Q3 are turned on alternately; then, the resonance unit 1201 composed of the transformer T1, the first inductor L1 and the first capacitor C1 resonantly transfers energy to the secondary of the transformer T1. At the same time, the second inductor L2, the second diode D2, the first electrolytic capacitor E1, and the fourth transistor Q4 form a BUCK step-down circuit, which is also a step-down unit 121. Meanwhile, the first main control chip U1 is a BUCK circuit control chip, that is, a control chip of the step-down control unit 122. The current flowing through the TV backlight LED lamp generates a voltage on the twentieth resistor R20 through the fourth transistor Q4. The generated voltage is sampled by the FB pin of the first main control chip U1 and compared with the internal reference to adjust the first main The duty cycle of the GATE pin of the control chip U1 is used to drive the fourth transistor Q4 to achieve the purpose of constant current and voltage reduction.

When the connection line of the backlight LED lamp is aging and broken or the TV set is assembled in the factory, when the negative terminal of the LED lamp is short-circuited to GND, the first diode D1 is turned on and the second rectifier unit 1113 The output 12V voltage flows into the ground terminal through the first resistor R1, the second resistor R2 and the first diode D1. The base of the first transistor Q1 gets a current signal, so that the emitter and collector of the first transistor Q1 are turned on. The anode of the light-emitting diode PC2A is turned on by a voltage of 12V to generate a light signal. After the phototransistor PC2B couples the light signal, the emitter and collector of the phototransistor PC2B are turned on, and the second end of the control module passes through the fourth resistor R4 and the photosensitive After the transistor PC2B is grounded, the protection function pin of the control IC is pulled low. The IC is protected and stops outputting control signals, that is, it stops outputting control signals to the second transistor Q2 and the third transistor Q3, causing the power output module to stop working.

When the wiring of the LED light is not in good contact with the socket on the power board and disconnected, or the whole machine factory has misoperation and plugging and unplugging, it will cause the LED light to open circuit fault. At this time, because the fourth transistor Q4 is still working, the negative terminal LED of the LED lamp can form a loop through the fourth transistor Q4 and the twentieth resistor R20 to the ground terminal, so that the voltage across the first electrolytic capacitor E1 is equal to the second electrolytic capacitor. The voltage across the capacitor E2. At this time, the negative terminal LED- potential of the LED lamp is 0V, which is equivalent to being connected to GND. At this time, the first diode D1 is turned on and the second rectifier unit 1113 outputs the 12V voltage. The first resistor R1, the second resistor R2 and the first diode D1 flow into the ground terminal, and the base of the first transistor Q1 obtains a current signal, so that the emitter and the collector of the first transistor Q1 are turned on; the light emitting diode PC2A The anode is turned on by a voltage of 12V to generate a light signal. After the phototransistor PC2B couples the light signal, the emitter and collector of the phototransistor PC2B are turned on, and the second end of the control module is grounded through the fourth resistor R4 and the phototransistor PC2B , The protection function pin of the control IC is pulled low, the IC is protected, and the output control signal is stopped, that is, it stops outputting the control signal to the second transistor Q2 and the third transistor Q3, causing the power output module to stop working.

On the basis of the foregoing embodiment, an embodiment of the present application provides a method for protecting a power supply device. As shown in FIG. 4, the protection method of the power supply device may specifically include the following steps:

Step 402: When the load module fails, the detection module outputs a fault signal to the feedback module.

When the load module fails, the detection module can detect the failure of the load module and generate a corresponding fault signal, and output the fault signal to the feedback module to trigger the feedback module to output a feedback signal to the control module.

Step 404: The feedback module outputs a feedback signal to the control module according to the fault signal.

After the feedback module receives the fault signal output by the detection module, it can generate a feedback signal according to the fault signal and output the feedback signal to the control module to trigger the control module to stop the output of the control signal through the feedback signal.

Step 406: The control module stops outputting the control signal to the power output module according to the feedback signal.

After detecting the feedback signal output by the feedback module, the control module can stop outputting the control signal to the power output module based on the feedback signal to shut down the power output module, so that the power supply device stops working and avoids the problem of power failure and damage.

It can be seen that when the load module fails, the embodiment of the present application can output a fault signal to the feedback module through the detection module, so that the feedback module outputs a feedback signal to the control module, thereby triggering the control module to stop outputting the control signal to the power output module, thereby realizing the load Over-current protection when the module fails to avoid damage to the power supply and achieve the purpose of power protection.

In a specific implementation, the power output module in the embodiment of the present application may include: a power output unit and an overvoltage protection unit. The protection method of the power supply device may further include: when the voltage value of the third terminal of the power output unit exceeds a preset voltage value, the overvoltage protection unit outputs an overvoltage protection signal to the control module to trigger the control module Stop outputting the control signal.

In the embodiment of the present application, optionally, the detection module may include: a transistor unit and a diode unit. When the load module fails, the detection module outputs a fault signal to the feedback module, which may specifically include: when the load module fails, the voltage signal of the third terminal of the power output module is transmitted to the load through the diode unit in the detection module The negative terminal of the module triggers the transistor unit in the detection module to generate a fault signal and output the fault signal to the feedback module.

The fault signal may include: a short-circuit fault signal or an open-circuit fault signal, the short-circuit fault signal is generated when the load module has a short-circuit fault, and the open-circuit fault signal is generated when the load module has an open-circuit fault.

The protection method of the power supply device described above can be executed by the protection circuit of the power supply device provided by any embodiment of the present application, and has the functional modules and beneficial effects corresponding to the protection circuit of the power supply device.

An embodiment of the present application also provides a device, which includes any protection circuit of the power supply device as provided in the foregoing embodiment. The device can execute the protection method of the power supply device provided in any embodiment of the present application, and has the corresponding functional modules and beneficial effects of the protection circuit of the power supply device.

Claims

A protection circuit for a power supply device includes: a power output module, a step-down module, a control module, a load module, a detection module, and a feedback module; wherein,

The first end of the power output module is connected to the first end of the control module, and the second end of the power output module is connected to the first end of the step-down module and the positive end of the load module, respectively, The third end of the power output module is respectively connected to the second end of the step-down module and the first end of the detection module;

The negative terminal of the load module is respectively connected to the second terminal of the detection module and the third terminal of the step-down module, the third terminal of the detection module is connected to the first terminal of the feedback module, and, The second end of the feedback module is connected to the second end of the control module;

When the load module fails, the detection module outputs a fault signal to the feedback module, and the feedback module outputs a feedback signal to the control module according to the fault signal, so as to trigger the control module according to the feedback The signal stops outputting the control signal to the power output module.
The circuit according to claim 1, wherein the power output module comprises: a power output unit and an overvoltage protection unit;

The first end of the power output unit is connected to the first end of the control module, and the second end of the power output unit is respectively connected to the first end of the step-down module and the positive end of the load module;

The third end of the power output unit is respectively connected to the second end of the step-down module, the first end of the overvoltage protection unit, and the first end of the detection module;

The first end of the overvoltage protection unit is connected to the third end of the control module;

When the voltage value of the third terminal of the power output unit exceeds the preset voltage value, the overvoltage protection unit outputs an overvoltage protection signal to the control module to trigger the control module to stop outputting the control signal.
The circuit according to claim 1, wherein the detection module comprises: a transistor unit and a diode unit;

The first end of the transistor unit is connected to the third end of the power output module, the second end of the transistor unit is connected to the first end of the feedback module, and the third end of the transistor unit is connected to the The first end of the diode unit is connected, and the second end of the diode unit is connected to the negative end of the load module;

Wherein, when the load module fails, the detection module outputs a fault signal to the feedback module, including: when the load module fails, the voltage signal of the third terminal of the power output module passes through the diode The unit transmits to the negative terminal of the load module, and triggers the transistor unit to generate a fault signal, and output the fault signal to the feedback module.
The circuit according to claim 3, wherein the fault signal comprises: a short circuit fault signal or an open circuit fault signal, the short circuit fault signal is generated when the load module has a short circuit fault, and the open circuit fault signal is the Occurs when the load module has an open circuit fault.
The circuit according to claim 3, wherein the transistor unit comprises: a first transistor and a first resistor,

The first end of the first transistor is respectively connected to the third end of the power output module and the first end of the first resistor, and the second end of the first transistor is connected to the first end of the feedback module Connected, the third end of the first transistor is respectively connected to the first end of the diode unit and the second end of the first resistor.
The circuit according to claim 5, wherein the transistor unit further comprises: a first capacitor;

Wherein, the first end of the first capacitor is respectively connected to the first end of the first transistor and the first end of the first resistor, and the second end of the first capacitor is connected to the first end of the first transistor. The second end is connected to the second end of the first resistor.
The circuit according to claim 3, wherein the diode unit includes a first diode and a second resistor,

The first end of the second resistor is connected to the third end of the transistor unit, and the second end of the second resistor is connected to the anode of the first diode;

The second end of the first diode is connected to the negative end of the load module.
The circuit according to claim 3, wherein the feedback module comprises: an optocoupler unit and a resistance unit,

The first end of the optocoupler unit is connected to the second end of the transistor unit, the second end of the optocoupler unit is connected to the first end of the resistance unit, and the second end of the resistance unit is connected to the second end of the transistor unit. The second end of the control module is connected.
The circuit according to claim 8, wherein the optocoupler unit comprises: a light emitting diode, a phototransistor, and a third resistor,

The first end of the third resistor is connected to the second end of the transistor unit, and the second end of the third resistor is connected to the anode of the light emitting diode;

The collector of the phototransistor is connected to the first end of the resistance unit.
The circuit according to claim 1, wherein the step-down module comprises: a step-down unit and a step-down control unit;

The first end of the step-down unit is respectively connected to the positive end of the load module and the second end of the power output module, and the second end of the step-down unit is respectively connected to the negative end of the load module and the second end of the power output module. The second end of the detection module is connected, the third end of the step-down unit is connected to the first end of the step-down control unit, and the second end of the step-down control unit is connected to the first end of the detection module. Terminal and the third terminal of the power output module.
A method for protecting a power supply device includes:

When the load module fails, the detection module outputs a fault signal to the feedback module;

The feedback module outputs a feedback signal to the control module according to the fault signal;

The control module stops outputting the control signal to the power output module according to the feedback signal.
A device, wherein the device comprises the power distribution device according to any one of claims 1 to 10.