Low-power-consumption open-circuit and short-circuit detection circuit for LED
By combining DC-DC conversion circuit, control circuit and voltage feedback circuit, the high power consumption and heat generation problem of vehicle RGB driver power supply under open circuit or short circuit conditions is solved, realizing low power consumption and low heat generation open and short circuit detection, ensuring that the equipment can work normally in high temperature environment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- KEBODA TECH CO LTD
- Filing Date
- 2025-05-15
- Publication Date
- 2026-04-28
AI Technical Summary
In existing technologies, vehicle-mounted RGB driver power supplies suffer from high power consumption, severe heat generation, or inaccurate status recognition when open-circuited or short-circuited, affecting the normal operation and safety of the equipment.
A combination of DC-DC conversion circuit, control circuit and voltage feedback circuit is used to achieve low-power open and short circuit detection by switching control signals. It includes NMOS transistors and filter circuits to ensure normal operation in high-temperature environments.
It achieves open and short circuit detection with low power consumption and low heat generation, ensuring that the equipment can work normally in high-temperature environments and avoiding component damage and safety hazards.
Smart Images
Figure CN224176680U_ABST
Abstract
Description
[Technical Field]
[0001] This utility model relates to the field of circuit design technology, and in particular to a low-power open / short circuit detection circuit for LEDs. [Background Technology]
[0002] For automotive RGB (i.e., three-primary-color LED) driver power supplies, open circuit or short circuit issues may occur during application. An open circuit means there is no current driving the circuit, which may cause the device to malfunction. A short circuit may cause excessive current, thereby damaging the device or causing safety hazards. As the requirements for the functionality of vehicle ambient lighting increase, the demand for high-brightness RGB is also increasing. The current of the products is also increasing, but the size requirement is decreasing, resulting in a gradual increase in heat generation. This necessitates that the product can self-detect the fault state of the RGB current control device, such as open circuit or short circuit, to ensure that the failure of the product does not affect the functionality of the entire vehicle.
[0003] Please refer to Figure 1 As shown, it is a circuit diagram of a low-power open and short circuit detection circuit for automotive RGB in the prior art. It supplies power to the anode of RGB (i.e., U3) through DCDC circuit U1, and the cathode of RGB (i.e., U3) is connected to LED driver circuit (i.e. LED Driver) U4. LED driver circuit U4 will detect the open and short circuit status of RGB (i.e., U3).
[0004] exist Figure 1 In the existing technical solution shown, the RGB (i.e., U3) and LED driver circuit U4 are powered by the DCDC circuit U1, which has the following problems:
[0005] If the output voltage of the DC-DC circuit U1 is set to be high, the power consumption of the RGB (i.e., U3) and LED driver circuit U4 will increase, resulting in more severe heat generation in the RGB (i.e., U3) and LED driver circuit U4. When the product is in a high-temperature environment, the RGB (i.e., U3) and LED driver circuit U4 may reach high temperatures and burn out components.
[0006] If the output voltage of the DC-DC circuit U1 is set too low, the LED driver circuit U4 will have the problem of not being able to accurately identify the short circuit and normal operation of RGB (i.e., U3).
[0007] Therefore, it is necessary to propose a new technical solution to address the above problems. [Utility Model Content]
[0008] One of the objectives of this invention is to provide a low-power open and short circuit detection circuit for LEDs, which can meet the requirements for detecting open and short circuit states of LEDs (e.g., RGB), and also realize the functions of low power consumption and low self-heating of LEDs (e.g., RGB) and LED driver circuits.
[0009] According to one aspect of this utility model, a low-power open / short circuit detection circuit for LEDs is provided, comprising: a DC-DC converter circuit, whose input terminal Vin_dcdc is connected to node A, whose output terminal is connected to the output power supply terminal Vbus, and whose feedback terminal FB receives a feedback voltage VFB; node A is connected to the input power supply terminal VIN; the DC-DC converter circuit converts the input DC voltage into DC voltages of different voltage levels based on the feedback voltage VFB; a control circuit, whose power supply terminal is connected to the input terminal Vin_dcdc of the DC-DC converter circuit, whose first output terminal outputs a first control signal Control-1, and whose second output terminal outputs a second control signal Control-2; and a voltage feedback circuit. When the first control signal Control-1 is valid and the second control signal Control-2 is invalid, the voltage feedback circuit provides a first feedback voltage VFB1 to the feedback terminal FB of the DC-DC converter circuit; when the first control signal Control-1 is invalid and the second control signal Control-2 is valid, the voltage feedback circuit provides a second feedback voltage VFB2 to the feedback terminal FB of the DC-DC converter circuit; the LED driver circuit has its control terminal connected to the negative terminal of the LED, its power supply terminal connected to the output power supply terminal Vbus, and the positive terminal of the LED connected to the output power supply terminal Vbus. The LED driver circuit is used to drive the LED to work normally or to detect the open circuit and short circuit status of the LED.
[0010] Compared with the prior art, this utility model can not only meet the requirements of LED (e.g., RGB) open circuit and short circuit state detection, but also realize the functions of low power consumption and low self-heating of LED (e.g., RGB) and LED driving circuit. [Attached Image Description]
[0011] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Among them:
[0012] Figure 1 This is a circuit diagram of a low-power open / short circuit detection circuit for automotive RGB in the prior art.
[0013] Figure 2 This is a circuit diagram of a low-power open / short circuit detection circuit for LEDs in one embodiment of the present invention.
Detailed Implementation Methods
[0014] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0015] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that excludes other embodiments. Unless otherwise specified, the terms coupling, connection, linking, and interconnection used herein to indicate electrical connection mean direct or indirect connection. For example, A being connected to B includes both a direct electrical connection between A and B and a connection between A and B via electrical components or circuits.
[0016] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "back", "positive", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0017] Please refer to Figure 2 As shown, it is a circuit diagram of a low-power open / short circuit detection circuit for LEDs in one embodiment of the present invention. Figure 2 The low-power open / short circuit detection circuit for LEDs shown includes a DC-DC converter circuit (i.e., DC-DC) U1, a control circuit (i.e., MCU) U2, a voltage feedback circuit 210, and an LED driver circuit (i.e., LED Driver) U4.
[0018] The input terminal Vin_dcdc of the DC-DC converter circuit (i.e., DC-DC) U1 is connected to node A, its output terminal is connected to the output power supply terminal Vbus, its feedback terminal FB receives the feedback voltage VFB, node A is connected to the input power supply terminal VIN, and the DC-DC converter circuit (i.e., DC-DC) U1 converts the input DC voltage into DC voltage outputs of different voltage levels based on the feedback voltage VFB.
[0019] The power supply terminal Vin_mcu of the control circuit (i.e., MCU) U2 is connected to the input terminal Vin_dcdc of the DC-DC converter circuit (i.e., DC-DC) U1. Its first output terminal outputs the first control signal Control-1, and its second output terminal outputs the second control signal Control-2.
[0020] When the first control signal Control-1 is valid and the second control signal Control-2 is invalid, the voltage feedback circuit 210 provides a first feedback voltage VFB1 to the feedback terminal FB of the DC-DC converter circuit (i.e., DC-DC) U1; when the first control signal Control-1 is invalid and the second control signal Control-2 is valid, the voltage feedback circuit 210 provides a second feedback voltage VFB2 to the feedback terminal FB of the DC-DC converter circuit (i.e., DC-DC) U1.
[0021] The control terminal of the LED driver circuit (i.e., LED Driver) U4 is connected to the negative terminal of LED220, and its power supply terminal Vin_LEDDriver is connected to the output power supply terminal Vbus. The positive terminal of LED220 is connected to the output power supply terminal Vbus. The LED driver circuit (i.e., LED Driver) U4 is used to drive LED220 to work normally or to detect the open circuit and short circuit status of LED220.
[0022] When the first control signal Control-1 is valid and the second control signal Control-2 is invalid, the voltage feedback circuit 210 provides a first feedback voltage VFB1 to the feedback terminal FB of the DC-DC converter circuit (i.e., DC-DC) U1. The DC-DC converter circuit (i.e., DC-DC) U1 outputs a first output power supply voltage Vbus1 based on the first feedback voltage VFB1. At this time, the LED driver circuit (i.e., LED Driver) U4 detects the open-circuit and short-circuit states of the LED 220. When the first control signal Control-1 is invalid and the second control signal Control-2 is valid, the voltage feedback circuit 210 provides a second feedback voltage VFB2 to the feedback terminal FB of the DC-DC converter circuit (i.e., DC-DC) U1. The DC-DC converter circuit (i.e., DC-DC) U1 outputs a second output power supply voltage Vbus2 based on the second feedback voltage VFB2. At this time, the LED driver circuit (i.e., LED Driver) U4 drives the LED 220 to work normally. The first output power supply voltage Vbus1 is greater than the second output power supply voltage Vbus2.
[0023] exist Figure 2In the specific embodiment shown, LED220 is RGB, and the three positive terminals of RGB are all connected to the output power supply terminal Vbus, and the three negative terminals of RGB are respectively connected to the control terminals RED_CONTROL, GREEN_CONTROL, and BLUE_CONTROL of the LED driver circuit (i.e., LED Driver) U4.
[0024] exist Figure 2 In the specific embodiment shown, the voltage feedback circuit 210 includes resistors R1, R2, and R4, and switching transistors Q1 and Q2. One end of resistor R1 is connected to the output power supply terminal Vbus, and the other end is connected to node D. Node D is connected to the feedback terminal FB of the DC-DC converter circuit (i.e., DC-DC) U1. The first connection terminal of switching transistor Q1 is connected to node D via resistor R2, and its second connection terminal is grounded. Its control terminal is connected to the first output terminal (or the first control signal Control-1) of the control circuit (i.e., MCU) U2. The first connection terminal of switching transistor Q2 is connected to node D via resistor R4, and its second connection terminal is grounded. Its control terminal is connected to the second output terminal (or the second control signal Control-2) of the control circuit (i.e., MCU) U2. The voltage at node D is the feedback voltage VFB output by the voltage feedback circuit 210.
[0025] exist Figure 2 In the specific embodiment shown, switch Q1 is an NMOS transistor, and the first connection terminal, the second connection terminal, and the control terminal of switch Q1 are the drain, source, and gate of the NMOS transistor, respectively; switch Q2 is an NMOS transistor, and the first connection terminal, the second connection terminal, and the control terminal of switch Q2 are the drain, source, and gate of the NMOS transistor, respectively.
[0026] exist Figure 2 In the specific embodiment shown, the voltage feedback circuit 210 further includes resistors R3 and R5, and capacitors C1, C5, and C6. One end of resistor R3 is connected to node B, and the other end is connected to the control terminal of the switching transistor Q1. One end of capacitor C5 is connected to node B, and the other end is grounded. Node B is connected to the first output terminal (or the first control signal Control-1) of the control circuit (i.e., MCU) U2. One end of resistor R5 is connected to node C, and the other end is connected to the control terminal of the switching transistor Q2. One end of capacitor C6 is connected to node C, and the other end is grounded. Node C is connected to the second output terminal (or the second control signal Control-2) of the control circuit (i.e., MCU) U2. One end of capacitor C1 is connected to the output power supply terminal Vbus, and the other end is connected to node D. Capacitors C5 and C6 are filter capacitors; resistors R3 and R5 are current-limiting resistors, limiting the gate current of MOSFETs Q1 and Q2; and capacitor C1 is a feedback capacitor, adjusting the loop stability of the DC-DC converter circuit (i.e., DC-DC) U1.
[0027] When the first control signal Control-1 is valid (e.g., the first control signal Control-1 is high) and the second control signal Control-2 is invalid (e.g., the second control signal Control-2 is low), the switch Q1 is turned on and the switch Q2 is turned off. Resistors R1 and R2 are connected in series between the output power supply terminal Vbus and the ground terminal. The voltage feedback circuit 210 provides the first feedback voltage VFB1 to the feedback terminal FB of the DC-DC converter circuit (i.e., DC-DC) U1. At this time, the DC-DC converter circuit (i.e., DC-DC) U1 outputs the first output power supply voltage Vbus1 based on the first feedback voltage VFB1. The voltage value of Vbus1 is set relatively high (the specific voltage value needs to be configured according to the actual design situation, and needs to meet the requirements of the LED driver circuit (i.e., LED Driver) U4 to detect the open circuit and short circuit status of LED220).
[0028] When the first control signal Control-1 is invalid (e.g., the first control signal Control-1 is low) and the second control signal Control-2 is valid (e.g., the second control signal Control-2 is high), the switch Q1 is turned off and the switch Q2 is turned on. Resistors R1 and R4 are connected in series between the output power supply terminal Vbus and the ground terminal. The voltage feedback circuit 210 provides the second feedback voltage VFB2 to the feedback terminal FB of the DC-DC converter circuit (i.e., DC-DC) U1. At this time, the DC-DC converter circuit (i.e., DC-DC) U1 outputs the second output power supply voltage Vbus2 based on the second feedback voltage VFB2. The voltage value of Vbus2 is set to a low value (the specific voltage value needs to be configured according to the actual design situation, and needs to meet the normal operating voltage requirements of LED220 and LED driver circuit (i.e., LEDDriver) U4).
[0029] Figure 2 The low-power open / short circuit detection circuit for LEDs shown also includes a first filter circuit 230 and a second filter circuit 240.
[0030] The first filter circuit 230 is connected between node A and the input terminal Vin_dcdc of the DC-DC converter circuit (i.e., DC-DC) U1. The first filter circuit 230 includes a capacitor. The first filter circuit 230 is a filter circuit for the input power supply terminal VIN, ensuring that the EMC (Electromagnetic Compatibility) test results meet standard requirements; it is an unavoidable part of the circuit design. Figure 2In the specific embodiment shown, the first filter circuit 230 includes an inductor L1, a capacitor C3, and a capacitor C4. One end of the inductor L1 is connected to node A, and the other end is connected to the input terminal Vin_dcdc of the DC-DC converter circuit (i.e., DC-DC) U1. One end of the capacitor C3 is connected to node A, and the other end is grounded. One end of the capacitor C4 is connected to the input terminal Vin_dcdc of the DC-DC converter circuit (i.e., DC-DC) U1, and the other end is grounded. It should be noted that in other embodiments, the first filter circuit 230 may also be other filter circuits including capacitors.
[0031] The second filter circuit 240 is connected between the output terminal of the DC-DC converter U1 and the output power supply terminal Vbus. The second filter circuit 240 is a filter circuit for the output power supply terminal Vbus, which reduces the ripple of the output voltage of the DC-DC converter U1 and is an unavoidable part of the circuit design. Figure 2 In the specific embodiment shown, the second filter circuit 240 includes an inductor L2 and a capacitor C2. One end of the inductor L2 is connected to the output terminal of the DC-DC converter circuit (i.e., DC-DC) U1, and the other end is connected to the output power supply terminal Vbus. One end of the capacitor C2 is connected to the output power supply terminal Vbus, and the other end is grounded. In other embodiments, the second filter circuit 240 may also be other filter circuits including capacitors.
[0032] Figure 2 The low-power open / short circuit detection circuit for LEDs shown also includes a reverse protection diode D1. The positive terminal of the reverse protection diode D1 is connected to the input power supply terminal VIN, and its negative terminal is connected to node A. When the power supply terminal of the circuit is reverse-connected, the reverse protection diode D1 provides reverse connection protection.
[0033] In one embodiment of this utility model, when the power supply is turned on (or the system is turned on), the control circuit (i.e., MCU) U2 controls the first control signal Control-1 to output a high level (i.e., the first control signal Control-1 is valid) and the second control signal Control-2 to output a low level (i.e., the second control signal Control-2 is invalid). At this time, MOSFET Q1 is turned on and MOSFET Q2 is turned off (or turned off), so the output voltage of the output power supply terminal Vbus is Vbus1. At this time, the output voltage of the DC-DC converter circuit (i.e., DC-DC) U1 is relatively high. The LED driver circuit (i.e., LED Driver) U4 detects the open circuit and short circuit status of LED220 (e.g., RGB). When the detected voltage is less than the open circuit threshold, it is determined that LED220 (e.g., RGB) is open. When the detected voltage is greater than the short circuit threshold, it is determined that LED220 (e.g., RGB) is short-circuited. When the detected voltage is between the open circuit threshold and the short circuit threshold, LED220 (e.g., RGB) is in normal working state. The control circuit (i.e., MCU) U2 controls the first control signal Control-1 to output a high level and the second control signal Control-2 to output a low level for 1 second (the specific time is set according to the actual design). Subsequently, the control circuit (i.e., MCU) U2 controls the first control signal Control-1 to output a low level (i.e., the first control signal Control-1 is invalid) and the second control signal Control-2 to output a high level (i.e., the second control signal Control-2 is valid). At this time, MOSFET Q1 is turned off (or turned off), and MOSFET Q2 is turned on. Therefore, the output voltage of the output power supply terminal Vbus is Vbus2. At this time, the output voltage of the DC-DC converter circuit (i.e., DC-DC) U1 is relatively low, which can meet the normal operation of LED220 (e.g., RGB) and LED driver circuit (i.e., LED Driver) U4. At this time, the power consumption of LED220 (e.g., RGB) and LED driver circuit (i.e., LED Driver) U4 is small, and the heat generation is not serious, which can meet the normal operation of the product in high temperature environment. In other words, when the system is powered on, the control circuit (i.e., MCU) U2 controls the first control signal Control-1 to be active and the second control signal Control-2 to be inactive for a predetermined time, so that the LED driver circuit (i.e., LED Driver) U4 can detect the open and short circuit states of the LED220 (e.g., RGB). After the system is powered on, the control circuit (i.e., MCU) U2 controls the first control signal Control-1 to be inactive and the second control signal Control-2 to be active, so that the LED driver circuit (i.e., LED Driver) U4 can drive the LED220 (e.g., RGB) to work normally. This scheme only performs open and short circuit detection on the LED220 (e.g., RGB) when powered on.
[0034] In another embodiment of this utility model, the detection cycle can also be configured according to actual needs, so that the control circuit (i.e., MCU) U2 performs open circuit and short circuit state detection in each cycle. The working principle is the same as the above scheme, and the specific cycle needs to be set according to actual needs. Specifically, the control circuit (i.e., MCU) U2 is configured with a detection cycle. In the first predetermined time of each detection cycle, the control circuit (i.e., MCU) U2 controls the first control signal Control-1 to be valid and the second control signal Control-2 to be invalid, so that the LED driver circuit (i.e., LED Driver) U4 performs open circuit and short circuit state detection on the LED220 (e.g., RGB). In the second predetermined time of each detection cycle, the control circuit (i.e., MCU) U2 controls the first control signal Control-1 to be invalid and the second control signal Control-2 to be valid, so that the LED driver circuit (i.e., LED Driver) U4 drives the LED220 (e.g., RGB) to work normally.
[0035] In summary, this invention can meet the requirements for detecting open and short circuit states of LEDs (e.g., RGB), and can also achieve low power consumption and low self-heating of LEDs (e.g., RGB) and LED driving circuits.
[0036] It should be noted that any modifications made by those skilled in the art to the specific embodiments of this utility model do not depart from the scope of the claims of this utility model. Accordingly, the scope of the claims of this utility model is not limited to the foregoing specific embodiments.
Claims
1. A low-power open / short circuit detection circuit for LEDs, characterized in that, It includes: A DC-DC converter circuit has its input terminal Vin_dcdc connected to node A, its output terminal connected to the output power supply terminal Vbus, and its feedback terminal FB receiving a feedback voltage VFB. Node A is connected to the input power supply terminal VIN. The DC-DC converter circuit converts the input DC voltage into DC voltage outputs of different voltage levels based on the feedback voltage VFB. The control circuit has its power supply terminal connected to the input terminal Vin_dcdc of the DC-DC conversion circuit, its first output terminal outputs a first control signal Control-1, and its second output terminal outputs a second control signal Control-2. The voltage feedback circuit provides a first feedback voltage VFB1 to the feedback terminal FB of the DC-DC converter when the first control signal Control-1 is valid and the second control signal Control-2 is invalid; and provides a second feedback voltage VFB2 to the feedback terminal FB of the DC-DC converter when the first control signal Control-1 is invalid and the second control signal Control-2 is valid. The LED driver circuit has its control terminal connected to the negative terminal of the LED, its power supply terminal connected to the output power supply terminal Vbus, and the positive terminal of the LED connected to the output power supply terminal Vbus. The LED driver circuit is used to drive the LED to work normally or to detect the open circuit and short circuit status of the LED.
2. The low-power open / short circuit detection circuit for LEDs according to claim 1, characterized in that, When the voltage feedback circuit provides a first feedback voltage VFB1 to the feedback terminal FB of the DC-DC converter circuit, the DC-DC converter circuit outputs a first output power supply voltage Vbus1 based on the first feedback voltage VFB1. At this time, the LED driving circuit detects the open circuit and short circuit status of the LED. When the voltage feedback circuit provides a second feedback voltage VFB2 to the feedback terminal FB of the DC-DC converter circuit, the DC-DC converter circuit outputs a second output power supply voltage Vbus2 based on the second feedback voltage VFB2. At this time, the LED driver circuit drives the LED to operate normally. Wherein, the first output power supply voltage Vbus1 is greater than the second output power supply voltage Vbus2.
3. The low-power open / short circuit detection circuit for LEDs according to claim 2, characterized in that, The voltage feedback circuit includes resistors R1, R2, and R4, and switching transistors Q1 and Q2. One end of resistor R1 is connected to the output power supply terminal Vbus, and the other end is connected to node D. Node D is connected to the feedback terminal FB of the DC-DC conversion circuit. The first connection terminal of switch Q1 is connected to node D via resistor R2, its second connection terminal is grounded, and its control terminal is connected to the first output terminal of the control circuit. The first connection terminal of switch Q2 is connected to node D via resistor R4, its second connection terminal is grounded, and its control terminal is connected to the second output terminal of the control circuit. The voltage at node D is the feedback voltage VFB output by the voltage feedback circuit.
4. The low-power open / short circuit detection circuit for LEDs according to claim 3, characterized in that, When the first control signal Control-1 is valid and the second control signal Control-2 is invalid, the switch Q1 is turned on and the switch Q2 is turned off. When the first control signal Control-1 is invalid and the second control signal Control-2 is valid, the switch Q1 is turned off and the switch Q2 is turned on.
5. The low-power open / short circuit detection circuit for LEDs according to claim 3, characterized in that, The voltage feedback circuit also includes resistors R3 and R5, capacitors C1, C5, and C6. One end of the resistor R3 is connected to node B, and the other end is connected to the control terminal of the switch Q1; one end of the capacitor C5 is connected to node B, and the other end is grounded; node B is connected to the first output terminal of the control circuit. One end of resistor R5 is connected to node C, and the other end is connected to the control terminal of switch Q2; one end of capacitor C6 is connected to node C, and the other end is grounded; node C is connected to the second output terminal of the control circuit. One end of the capacitor C1 is connected to the output power supply terminal Vbus, and the other end is connected to the node D.
6. The low-power open / short circuit detection circuit for LEDs according to claim 3, characterized in that, The switching transistor Q1 is an NMOS transistor, and the first connection terminal, the second connection terminal, and the control terminal of the switching transistor Q1 are the drain, source, and gate of the NMOS transistor, respectively. The switch Q2 is an NMOS transistor, and the first connection terminal, the second connection terminal, and the control terminal of the switch Q2 are the drain, source, and gate of the NMOS transistor, respectively.
7. The low-power open / short circuit detection circuit for LEDs according to claim 1, characterized in that, It also includes a first filter circuit and a second filter circuit. The first filter circuit is connected between node A and the input terminal Vin_dcdc of the DC-DC converter circuit, and the first filter circuit includes a capacitor; The second filter circuit is connected between the output terminal of the DC-DC converter circuit and the output power supply terminal Vbus, and the second filter circuit includes a capacitor.
8. The low-power open / short circuit detection circuit for LEDs according to claim 7, characterized in that, The first filter circuit includes an inductor L1, a capacitor C3, and a capacitor C4. One end of the inductor L1 is connected to node A, and the other end is connected to the input terminal Vin_dcdc of the DC-DC converter circuit. One end of the capacitor C3 is connected to node A, and the other end is grounded. One end of the capacitor C4 is connected to the input terminal Vin_dcdc of the DC-DC converter circuit, and the other end is grounded. The second filter circuit includes an inductor L2 and a capacitor C2. One end of the inductor L2 is connected to the output terminal of the DC-DC conversion circuit, and the other end is connected to the output power supply terminal Vbus. One end of the capacitor C2 is connected to the output power supply terminal Vbus, and the other end is grounded.
9. The low-power open / short circuit detection circuit for LEDs according to claim 8, characterized in that, It also includes a reverse protection diode D1. The positive terminal of the anti-reverse diode D1 is connected to the input power supply terminal VIN, and its negative terminal is connected to node A.
10. The low-power open / short circuit detection circuit for LEDs according to claim 2, characterized in that, When the system is powered on, the control circuit controls the first control signal Control-1 to be valid and the second control signal Control-2 to be invalid, so that the LED driver circuit can detect the open circuit and short circuit status of the LED; after the system is powered on, the control circuit controls the first control signal Control-1 to be invalid and the second control signal Control-2 to be valid, so that the LED driver circuit can drive the LED to work normally. or The control circuit is configured with a detection cycle. During the first predetermined time of each detection cycle, the control circuit controls the first control signal Control-1 to be valid and the second control signal Control-2 to be invalid, so that the LED driving circuit can detect the open circuit and short circuit states of the LED. During the second predetermined time of each detection cycle, the control circuit controls the first control signal Control-1 to be invalid and the second control signal Control-2 to be valid, so that the LED driving circuit can drive the LED to work normally.