Load short circuit detection circuit, circuit board and backlight module
By designing a load short-circuit detection circuit, using transistors and sensing signal components to detect load short-circuits, and triggering protection measures, the overheating damage caused by load short-circuits in LED backlit TVs is solved, and effective protection of load and circuits is achieved.
Patent Information
- Application Number
- CN202420548861.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-20
- Publication Date
- 2025-03-25
- Estimated Expiration
- 2034-03-20
AI Technical Summary
In LED backlit TVs, when the negative end of the backlight strip is short-circuited to the ground, the constant current detection circuit fails, resulting in excessive current flow of the strip and overheating and damage, and the prior art cannot effectively detect and trigger protection measures.
A load short circuit detection circuit is designed, including transistors, switch control components, load connection components, sensing signal transmission components, sensing signal reception components and signal indication components. When the load is short-circuited, the load connection component is turned on, the transistor is turned on, the sensing signal transmitting component outputs the sensing signal, and the sensing signal receiving component is sensed and turned on, so that the signal indicator component outputs the disconnection signal, triggering the load protection chip to disconnect the load power supply.
Effectively detect load short circuit to ground, trigger protection measures, prevent light strips from overheating and damage, and protect circuit devices.
Smart Images
Figure CN222671928U_ABST
Abstract
Description
Technical Field
[0001] The present specification relates to the field of circuit protection technology, and in particular to a load short-circuit detection circuit, a circuit board, and a backlight module. Background Art
[0002] In the application field of LED backlight TV, the output end of the LED load module needs to be connected to the constant current driver chip. However, when the negative end of the backlight strip LED is short-circuited to the ground, the constant current detection circuit fails, and the backlight strip flows several times more than the strip's bearing current, causing the strip to overheat and be damaged. Utility Model Content
[0003] The present specification provides a load short circuit detection circuit, a circuit board and a backlight module. The circuit is simple and can detect a load short circuit fault to ground, thereby triggering protection measures for the load and protecting circuit components from damage.
[0004] In a first aspect, an embodiment of the present specification provides a load short circuit detection circuit, including a first voltage output terminal, a transistor, a switch control component, a load connection component, a sensor signal transmitting component, a sensor signal receiving component and a signal indication component;
[0005] One end of the switch control component is connected to the first voltage output end, the other end of the switch control component is respectively connected to the emitter and base of the transistor, the base of the transistor is connected to one end of the load connection component, the other end of the load connection component is connected to the negative electrode of the load, the collector of the transistor is connected to one end of the sensor signal transmitting component, the other end of the sensor signal transmitting component is grounded, the sensor signal transmitting component and the sensor signal receiving component are inductively connected to each other, one end of the sensor signal receiving component is connected to one end of the signal indicating component, and the other end of the signal indicating component is connected to the load protection chip;
[0006] When the load is short-circuited, the load connection component is turned on, the base voltage of the transistor is less than the emitter voltage of the transistor, so that the transistor is turned on, and the output voltage of the first voltage output end is loaded to the sensor signal transmitting component via the transistor, enabling the sensor signal transmitting component to output the sensor signal, and the sensor signal receiving component is turned on after sensing the sensor signal, so that the signal indication component outputs a disconnect indication signal to the load protection chip, and the disconnect indication signal enables the load protection chip to disconnect the load power supply drive circuit.
[0007] In the second aspect, an embodiment of the present specification provides a backlight module, including a light bar load, a drive circuit powered by the load, a load protection chip and the above-mentioned load short-circuit detection circuit, one end of the load short-circuit detection circuit is connected to the negative pole of the load, the other end of the load short-circuit detection circuit is connected to one end of the load protection chip, and the other end of the load protection chip is connected to the drive circuit.
[0008] In a third aspect, an embodiment of the present specification provides a circuit board, and the circuit board stores the load short-circuit detection circuit mentioned above.
[0009] In the embodiments of the present specification, by connecting one end of the load connecting component to the negative electrode of the load and connecting the other end of the load connecting component to the base of the transistor, when a short circuit occurs in the load, the load connecting component is turned on, thereby controlling the transistor to be turned on, and outputting the output voltage of the first voltage output end to the sensing signal transmitting component connected to the collector of the transistor. The sensing signal transmitting component transmits a sensing signal to turn on the sensing signal receiving component, thereby causing the signal indicating component to output a disconnection indicating signal to the load protection chip, triggering the load protection chip to disconnect the load power supply driving circuit, causing the load to stop working, thereby protecting the load and the circuit. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.
[0011] Figure 1 A schematic diagram of a load short circuit detection circuit provided in an embodiment of this specification;
[0012] Figure 2 A schematic diagram of a load short circuit detection circuit provided in an embodiment of this specification;
[0013] Figure 3 A schematic diagram of a load short circuit detection circuit provided in an embodiment of this specification;
[0014] Figure 4 A schematic diagram of a load short circuit detection circuit provided in an embodiment of this specification;
[0015] Figure 5 A schematic diagram of a load short circuit detection circuit provided in an embodiment of this specification;
[0016] Figure 6 A schematic diagram of a load short circuit detection circuit provided in an embodiment of this specification;
[0017] Figure 7 A schematic diagram of a load short circuit detection circuit provided in an embodiment of this specification;
[0018] Figure 8A schematic diagram of a load short circuit detection circuit provided in an embodiment of this specification;
[0019] Fig. 9 A schematic diagram of a load short circuit detection circuit provided in an embodiment of this specification;
[0020] Description of the drawings: Q1, transistor; 00, first voltage output terminal; 10, switch control component; 20, load connection component; 30, sensor signal transmitting component; 40, sensor signal receiving component; 50, signal indication component; 60, load protection chip; 70, load. DETAILED DESCRIPTION
[0021] In order to make the features and advantages of this specification more obvious and easy to understand, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the drawings in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this specification.
[0022] In the prior art, when a constant output current is used to drive a load, a constant current detection circuit is used to detect the current of the backlight strip. When the backlight strip is short-circuited to the ground, there is still current forming a complete loop through the ground, so the constant current detection circuit can still detect the current. Therefore, the constant current detection circuit cannot detect the short circuit to the ground. Therefore, when the load is short-circuited to the ground, the protection circuit for the load cannot be triggered, causing damage to electronic components.
[0023] In order to solve the above technical problems, the embodiments of this specification provide a backlight module, including a light bar load, a load-powered driving circuit, a load protection chip, and a load short-circuit detection circuit, one end of the load short-circuit detection circuit is connected to the negative electrode of the load, the other end of the load short-circuit detection circuit is connected to one end of the load protection chip, and the other end of the load protection chip is connected to the driving circuit. The load-powered driving circuit is used to supply power to the light bar load, the load short-circuit detection circuit is used to detect whether the light bar load is short-circuited to the ground, and the load protection chip is used to disconnect the load-powered driving circuit according to the disconnection indication signal output by the load short-circuit detection circuit, so as to achieve short-circuit protection for the light bar load.
[0024] like Figure 1 As shown, the embodiment of this specification provides a load short circuit detection circuit, which includes a first voltage output terminal 00, a transistor Q1, a switch control component 10, a load connection component 20, a sensor signal transmitting component 30, a sensor signal receiving component 40 and a signal indication component 50;
[0025] One end of the switch control component 10 is connected to the first voltage output terminal 00, and the other end of the switch control component 10 is respectively connected to the emitter and base of the transistor Q1, the base of the transistor Q1 is connected to one end of the load connection component 20, the other end of the load connection component 20 is connected to the negative electrode of the load 70, the collector of the transistor Q1 is connected to one end of the sensor signal transmitting component 30, the other end of the sensor signal transmitting component 30 is grounded, the sensor signal transmitting component 30 and the sensor signal receiving component 40 are inductively connected to each other, one end of the sensor signal receiving component 40 is connected to one end of the signal indicating component 50, and the other end of the signal indicating component 50 is connected to the load protection chip 60;
[0026] When the load 70 is not short-circuited, the circuit from the load connection component 20 to the load 70 is not conductive, and the voltage at the end of the load connection component 20 connected to the base of the transistor Q1 and the voltage at the end of the switch control component 10 connected to the emitter of the transistor Q1 are both the voltage output by the first voltage output terminal 00. Therefore, there is no voltage difference between the base and emitter of the transistor Q1, the collector and emitter of the transistor Q1 are not conductive, and the signal indication component 50 outputs a conductive indication signal to the load protection chip 60.
[0027] When the load 70 is short-circuited to the ground, the load connection component 20 is turned on, the base voltage of the transistor Q1 is less than the emitter voltage of the transistor Q1, so that the transistor Q1 is turned on, and the output voltage of the first voltage output terminal 00 is loaded to the sensor signal transmitting component 30 through the transistor Q1, and the sensor signal transmitting component 30 is turned on, so that the sensor signal receiving component 40 is turned on after receiving the sensing signal, so that the signal indicating component 50 outputs a disconnection indicating signal to the load protection chip 60. Among them, the disconnection indicating signal is a low-level signal compared to the conduction indicating signal.
[0028] It should be noted that when the load 70 is short-circuited to the ground, the voltage of the load connection component 20 near the load 70 side is reduced, the circuit from the first voltage output terminal 00 through the switch control component 10 and the load connection component 20 to the load 70 is turned on, and the voltage of the base side of the load connection component 20 near the transistor Q1 is reduced, so that the emitter voltage of the transistor Q1 is greater than the base voltage, the transistor Q1 is turned on, and the output voltage of the first voltage output terminal 00 is added to the sensor signal transmitting component 30, and the sensor signal transmitting component sends a sensor signal to the sensor signal receiving component 40, and the sensor signal receiving component 40 is used to receive the signal sent by the sensor signal transmitting component 30. The load protection chip 60 obtains the first signal via the signal indication component 50 to determine that the load 70 is short-circuited to the ground. The load protection chip 60 can take protective measures for the short-circuit situation of the load 70, for example, the drive circuit that supplies power to the load 70 can be disconnected.
[0029] The transistor Q1 may also be replaced by any controllable component such as a field effect transistor with similar functions, and the specific selection may be made according to actual conditions.
[0030] Furthermore, if Figure 2 As shown, the switch control component 10 includes a first resistor R11.
[0031] One end of the first resistor R11 is connected to the base of the transistor Q1 and the first voltage output terminal 00, and the other end of the first resistor R11 is connected to the emitter of the transistor Q1 and one end of the load connection component 20. When the load is not short-circuited, the circuit from the first voltage output terminal 00 through the switch control component 10 and the load connection component 20 to the load 70 is not turned on, and no current flows through, so the first resistor R11 does not play a voltage dividing role, and the emitter and base voltages of the transistor Q1 are the same; when the load 70 is short-circuited, the circuit from the first voltage output terminal 00 through the switch control component 10 and the load connection component 20 to the load 70 is turned on, and after the voltage is divided by the first resistor R11, the base voltage of the transistor Q1 is less than the emitter voltage, and the transistor Q1 is turned on.
[0032] Furthermore, if Figure 3 As shown, the load connection component 20 includes at least one diode, a third capacitor C23 and a second resistor R24. Figure 3 The figure shows the case where the load is two LEDs and the load connection component includes two diodes D21 and D22 , wherein the diode D21 is connected to the cathode of LED1 , and the diode D22 is connected to the cathode of LED2 .
[0033] One end of the second resistor R24 is connected to the base of the transistor Q1, and the other end of the second resistor R24 is connected to the anodes of the diodes D21 and D22. The second resistor R24 is used to ensure that the transistor Q1 can be turned on, that is, the base voltage is greater than the collector voltage.
[0034] A first plate of the third capacitor C23 is connected to the second resistor R24, and a second plate of the third capacitor C23 is grounded.
[0035] The cathodes of diodes D21 and D22 are connected to the negative terminals of loads LED1 and LED2, respectively, and the anodes of diodes D21 and D22 are connected to the second resistor R24. By arranging diodes D21 and D22 in the load connection assembly 20, it can be ensured that when the load is not short-circuited, the cathode voltage is higher than the anode voltage and is in a cut-off state, that is, the base voltage of transistor Q1 is the same as the emitter voltage, so that transistor Q1 is not turned on. After at least one of LED1 and LED2 is short-circuited to the ground, the cathode of the diode is grounded, and the anode voltage of the diode is greater than the cathode voltage of the diode, so the diode is forward-conducted. Since there is a first resistor R11 between the emitter and the base of transistor Q1, there is a voltage drop between the emitter and the base, and the base voltage is lower than the emitter voltage, which meets the conduction condition of the PNP transistor, so the transistor Q1 is turned on.
[0036] It should be noted that the number of diodes may correspond to the number of loads.
[0037] Furthermore, if Figure 4 As shown, the sensing signal transmitting component 30 includes a light emitting element D31 and a third resistor R32; the sensing signal receiving component 40 includes a light receiving element Q41 and a fourth resistor R42; the light receiving element Q41 and the light emitting element D31 form an optical coupler.
[0038] The light-emitting element D31 is connected to the collector of the transistor Q1 via the third resistor R32; the output end of the light-receiving element Q41 is grounded via the fourth resistor R42, the controlled end of the signal indication component 50 is connected to the output end of the light-receiving element Q41, and the input end of the light-receiving element Q41 is connected to the second voltage output end 01. The third resistor R32 is used to divide the voltage of the first voltage output end 00 to protect the light-emitting element 31 and prevent the light-emitting element 31 from being burned out. It can be understood that after the output voltage from the collector passes through the first voltage output end 00, the third resistor R32 can prevent the light-receiving element D41 from being directly grounded after being turned on. The second voltage output end 01 is the output voltage of the load protection chip 60, for example, it can be a 5V voltage output from the load protection chip 60. The fourth resistor R42 is used to prevent the output end of the light-receiving element Q41 from being directly grounded when the light-receiving element Q41 is turned on, so as to provide the signal indication component 50 with an output level.
[0039] It can be understood that the optical coupler is used to achieve isolation between high voltage and low voltage to prevent high voltage from being connected to low voltage. The voltage on the sensor signal receiving component 40 side is high voltage, and the voltage on the sensor signal transmitting component 30 side is low voltage. Therefore, the use of the optical coupler can improve the safety performance of the staff operating the sensor signal transmitting component 30 side. In addition, the light receiving element Q41 and the light emitting element D31 can also be other electronic devices that can transmit electrical signals between two isolated circuits.
[0040] Furthermore, if Figure 5 As shown, the sensing signal transmitting component 30 further includes a fifth resistor R33;
[0041] One end of the fifth resistor R33 is connected to the anode of the light emitting element D31 , and the other end of the fifth resistor R33 is connected to the cathode of the light emitting element D31 .
[0042] The fifth resistor R33 is used for voltage stabilization. When the light receiving element is turned on, the voltage across the fifth resistor R33 is constant, thereby ensuring that the voltage across the light emitting element D31 is equal to the voltage of the fifth resistor R33, and the light can be stably emitted.
[0043] Furthermore, if Figure 6 As shown, the sensing signal receiving component 40 further includes a sixth resistor R43;
[0044] One end of the sixth resistor R43 is connected to the light receiving element, and the other end of the sixth resistor R43 is connected to the second voltage output terminal O1.
[0045] The sixth resistor R43 is used for voltage division to prevent the light receiving element Q41 from being burned out.
[0046] Furthermore, if Figure 7 As shown, the switch control component 10 includes a first capacitor C12;
[0047] One end of the first capacitor C12 is connected to the first voltage output end, and the other end of the first capacitor C12 is grounded.
[0048] The first capacitor C12 is used for filtering to improve voltage stability.
[0049] Furthermore, if Figure 8 As shown, the switch control component 10 also includes a voltage stabilizing diode D14 and a second capacitor C13;
[0050] One end of the voltage zener diode D14 is connected to the collector of the transistor Q1, and the other end of the voltage zener diode D14 is connected to the base of the transistor Q1;
[0051] One end of the second capacitor C13 is connected to the collector of the transistor Q1 , and the other end of the second capacitor C13 is connected to the base of the transistor Q1 .
[0052] The voltage stabilizing diode D14 is used for voltage stabilization, and the second capacitor C13 is used for filtering to ensure that when the diode D21 and / or the diode D22 is turned on, a voltage drop is generated between the base and the emitter of the transistor Q1, thereby ensuring that the transistor Q1 can be turned on.
[0053] Furthermore, if Fig. 9 As shown, the signal indication component 50 includes a switch circuit 51 and a sampling circuit 52 .
[0054] The sampling circuit 52 includes a first voltage divider circuit 521 and a second voltage divider circuit 522 and a sampling node 52A disposed between the first voltage divider circuit 521 and the second voltage divider circuit 522. The first voltage divider circuit 521 and the second voltage divider circuit 522 are connected in series between the third voltage output terminal 02 and the ground. The sampling node 52A is used to connect to the sampling terminal of the load protection chip 60.
[0055] The input end of the switch circuit 51 is connected to the sampling node 52A, the output end of the switch circuit 51 is grounded, and the controlled end of the switch circuit 51 is connected to the sensor signal receiving component 40;
[0056] When the load 70 is short-circuited to ground, the switch circuit 51 is turned on according to the optical signal emitted by the sensor signal receiving component 40 to change the voltage of the sampling node 52A, so that the load protection chip 60 can detect the first signal to determine that the load is short-circuited to ground.
[0057] Furthermore, if Fig. 9 As shown, the switch circuit includes a switch element Q511;
[0058] The gate of the switch element Q511 is connected to the input end of the switch circuit 51 , the drain of the switch element Q511 is connected to the controlled end of the switch circuit 51 , and the source of the switch element Q511 is connected to the output end of the switch circuit 51 .
[0059] Among them, the first voltage divider circuit 521 and the second voltage divider circuit 522 divide the voltage output from the third voltage output terminal 02 so that there is a voltage at the sampling node 52A. When the LED is working normally, the load detection chip 60 can obtain the first voltage (high level) of the sampling node 52A to obtain a conduction indication signal. When the LED is short-circuited, the light-emitting element D31 emits light, the photosensitive element Q41 receives the light emitted by the light-emitting element D31 and is in a conduction state, and the drain D and the source S of the switch element Q511 are connected. At this time, the high level output from the third voltage output terminal 02 is grounded via the switch circuit 51, short-circuiting the first voltage divider circuit 521, and pulling down the voltage of the sampling node 52A, so that the load detection chip 60 can obtain the second voltage (low level) of the sampling node 52A that is different from the first voltage, thereby obtaining a disconnection indication signal. Therefore, when the load protection chip 60 detects a high level, it indicates that the LED is working normally, and when it detects a low level, it indicates that the LED is in a short-circuit state to the ground.
[0060] It should be noted that the switch element Q511 can be an NPN transistor, a PNP transistor, a relay, etc.
[0061] Furthermore, if Fig. 9As shown, the first voltage divider circuit 521 includes a seventh resistor R5211, one end of the seventh resistor R5211 is connected to the sampling node 52A, and the other end of the seventh resistor R5211 is connected to the input end of the switch circuit 51;
[0062] and / or;
[0063] The second voltage divider circuit 522 includes an eighth resistor R5221 , one end of the eighth resistor R5221 is connected to the sampling node 52A, and the other end of the eighth resistor R5221 is connected to the third voltage output terminal O2 .
[0064] Optionally, the first voltage-dividing circuit may include a plurality of parallel resistors, and the second voltage-dividing circuit may include a plurality of series resistors, so as to divide the output voltage of the third voltage output terminal 02 .
[0065] By adopting the embodiment of the present specification, one end of the load connecting component is connected to the negative electrode of the load, and the other end of the load connecting component is connected to the base of the transistor. When a short circuit occurs in the load, the load connecting component is turned on, thereby controlling the transistor to be turned on, and the output voltage of the first voltage output end is output to the sensing signal transmitting component connected to the collector of the transistor. The sensing signal is output through the sensing signal transmitting component, and the sensing signal receiving component receives the sensing signal emitted by the sensing signal transmitting component and is turned on, so that the load protection chip obtains the disconnection indication signal (low-level signal) via the signal indication component to determine that a ground short circuit occurs in the load, trigger the load protection chip to work, turn off the load power supply drive circuit, and stop the load from working, thereby protecting the load and the circuit.
[0066] The present invention also provides a circuit board according to an embodiment of the present invention. The circuit board includes the Figure 1-Figure 9 The load short circuit detection circuit of the embodiment shown, the specific circuit structure and implementation method can be found in Figure 1-Figure 9 The specific description of the embodiment shown is not repeated here. It is understandable that the circuit board can be a complete circuit board or can be formed by splicing multiple circuit boards.
[0067] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium, and when the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, the storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.
[0068] The above disclosure is only the preferred embodiment of the present application, which certainly cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application are still within the scope covered by the present application.
Claims
1. A load short circuit detection circuit, characterized in that: It includes a first voltage output terminal, a triode, a switch control component, a load connection component, a sensor signal transmitting component, a sensor signal receiving component and a signal indicating component; One end of the switch control component is connected to the first voltage output end, the other end of the switch control component is respectively connected to the emitter and base of the transistor, the base of the transistor is connected to one end of the load connection component, the other end of the load connection component is connected to the negative electrode of the load, the collector of the transistor is connected to one end of the sensor signal transmitting component, the other end of the sensor signal transmitting component is grounded, the sensor signal transmitting component and the sensor signal receiving component are inductively connected to each other, one end of the sensor signal receiving component is connected to one end of the signal indicating component, and the other end of the signal indicating component is connected to the load protection chip; When the load is short-circuited, the load connecting component is turned on, the base voltage of the transistor is less than the emitter voltage of the transistor, so that the transistor is turned on, and the output voltage of the first voltage output end is loaded to the sensing signal transmitting component via the transistor, enabling the sensing signal transmitting component to output a sensing signal, and the sensing signal receiving component is turned on after sensing the sensing signal, so that the signal indicating component outputs a disconnection indicating signal to the load protection chip, and the disconnection indicating signal enables the load protection chip to disconnect the load power supply driving circuit.
2. The circuit according to claim 1, characterized in that The switch control component includes a first resistor; One end of the first resistor is connected to the base of the transistor and the first voltage output end, and the other end of the first resistor is connected to the emitter of the transistor and one end of the load connection component.
3. The circuit according to claim 1, characterized in that The switch control component includes a first capacitor; One end of the first capacitor is connected to the first voltage output end, and the other end of the first capacitor is grounded.
4. The circuit according to claim 2, characterized in that The switch control component also includes a voltage stabilizing diode and a second capacitor; One end of the voltage stabilizing diode is connected to the collector of the transistor, and the other end of the voltage stabilizing diode is connected to the base of the transistor; One end of the second capacitor is connected to the collector of the transistor, and the other end of the second capacitor is connected to the base of the transistor.
5. The circuit according to claim 1, characterized in that The load connection component includes at least one diode, a third capacitor and a second resistor; The first electrode plate of the third capacitor is connected to the second resistor, and the second electrode plate of the third capacitor is grounded; The cathode of the diode is connected to the negative end of the load, and the anode of the diode is connected to the second resistor; One end of the second resistor is connected to the base of the transistor, and the other end of the second resistor is connected to the anode of the diode.
6. The circuit according to claim 1, characterized in that The sensor signal transmitting component includes a light emitting element and a third resistor; the sensor signal receiving component includes a light receiving element and a fourth resistor; The light-emitting element is connected to the collector of the transistor via the third resistor; the output end of the light-receiving element is grounded via the fourth resistor, the controlled end of the signal indication component is connected to the output end of the light-receiving element, and the input end of the light-receiving element is connected to the second voltage output end.
7. The circuit according to claim 6, characterized in that The sensing signal transmitting component further includes a fifth resistor; One end of the fifth resistor is connected to the anode of the light emitting element, and the other end of the fifth resistor is connected to the cathode of the light emitting element.
8. The circuit according to claim 6, characterized in that The sensing signal receiving component also includes a sixth resistor; One end of the sixth resistor is connected to the light receiving element, and the other end of the sixth resistor is connected to the second voltage output end.
9. The circuit according to claim 1, characterized in that The signal indication component includes a switch circuit and a sampling circuit; The sampling circuit includes a first voltage divider circuit and a second voltage divider circuit and a sampling node arranged between the first voltage divider circuit and the second voltage divider circuit, the first voltage divider circuit and the second voltage divider circuit are connected in series between the third voltage output terminal and the ground, and the sampling node is used to be connected to the sampling terminal of the load protection chip; The input end of the switch circuit is connected to the sampling node, the output end of the switch circuit is grounded, and the controlled end of the switch circuit is connected to the sensor signal receiving component; When the load is short-circuited, the switch circuit is turned on according to the optical signal emitted by the sensor signal receiving component, and the sampling circuit is short-circuited, so that the load protection chip receives a low-level signal.
10. The circuit according to claim 9, characterized in that The switch circuit includes a switch element; The gate of the switch element is connected to the input end of the switch circuit, the drain of the switch element is connected to the controlled end of the switch circuit, and the source of the switch element is connected to the output end of the switch circuit.
11. The circuit according to claim 9, characterized in that The first voltage divider circuit includes a seventh resistor, one end of the seventh resistor is connected to the sampling node, and the other end of the seventh resistor is connected to the input end of the switch circuit; and / or; The second voltage-dividing circuit includes an eighth resistor, one end of the eighth resistor is connected to the sampling node, and the other end of the eighth resistor is connected to the third voltage output end.
12. A backlight module, characterized in that: It includes a light bar load, a drive circuit powered by the load, a load protection chip, and a load short-circuit detection circuit as described in any one of claims 1 to 11, one end of the load short-circuit detection circuit is connected to the negative electrode of the load, the other end of the load short-circuit detection circuit is connected to one end of the load protection chip, and the other end of the load protection chip is connected to the drive circuit.
13. A circuit board, characterized in that: The circuit board includes the load short-circuit detection circuit as described in any one of claims 1-11.