Fault diagnosis circuit, diagnosis method thereof and vehicle

Abstract

The invention provides a fault diagnosis circuit, a diagnosis method thereof and a vehicle, the method is applied to the vehicle, the fault diagnosis circuit comprises a first acquisition module, a second acquisition module, a first operational circuit, a second operational circuit and a diagnosis module, the first acquisition module is used for acquiring a first segment voltage of a to-be-detected circuit; the second acquisition module is used for acquiring a second segment voltage of the to-be-detected circuit; the first operational circuit is used for calculating a first difference value between the first segment voltage and the second segment voltage; the second operational circuit is used for calculating a second difference value between the second segment voltage and the first segment voltage; the diagnosis module is used for identifying whether the to-be-detected circuit has a fault according to the first difference value and the second difference value. Therefore, the problems of difficult short circuit detection and high cost of the serially connected LEDs are solved, and reliable and high-precision LED fault diagnosis is realized with lower hardware cost on the premise of not increasing complex chips.

Description

Technical Field

[0001] This application relates to the field of vehicles, and more specifically, to fault diagnosis circuits and diagnostic methods thereof, and vehicles. Background Technology

[0002] As automotive intelligence continues to improve, users are placing higher demands on the functional safety and reliability of vehicle lights. Vehicle light controllers need to possess precise fault diagnosis capabilities for individual LEDs (Light Emitting Diodes). Especially in high-end models, where multi-string high-current LED arrays are widely used, there is an urgent need for a high-precision, low-cost, and high-efficiency single-LED short-circuit / open-circuit detection solution to balance functional safety, system efficiency, and development costs.

[0003] Related technologies use DC-DC converters (DC-DC converters) in conjunction with subsequent linear constant current chips or matrix switch chips to monitor the current or voltage of LEDs by grouping them. This requires the introduction of analog chips, MCUs (Microcontroller Units), and communication interfaces. Especially in high-current or multi-particle applications, the cost of the Bill of Materials (BOM) increases significantly, and the system complexity is high. Summary of the Invention

[0004] This application provides a fault diagnosis circuit and its diagnostic method, as well as a vehicle. This method can solve the problems of difficult and costly detection of short circuits in series LEDs. Without adding complex chips, it achieves reliable and high-precision LED fault diagnosis at a lower hardware cost.

[0005] Firstly, a fault diagnosis circuit is provided, including: The first acquisition module has its two ends connected to the first detection point and the second detection point of the circuit under test, and is used to acquire the first segment voltage of the circuit under test. The second acquisition module has its two ends connected to the second and third detection points of the circuit under test, and is used to acquire the second segment voltage of the circuit under test. A first arithmetic circuit, which is connected to the first acquisition module and the second acquisition module respectively, is used to calculate the first difference between the first segment voltage and the second segment voltage. The second operational circuit is connected to the first acquisition module and the second acquisition module respectively, and is used to calculate the second difference between the second segment voltage and the first segment voltage. The diagnostic module has a first input terminal connected to the output terminal of the first arithmetic circuit and a second input terminal connected to the output terminal of the second arithmetic circuit, and is used to identify whether the circuit under test has a fault based on the first difference and the second difference.

[0006] The above technical solution involves acquiring two segment voltages in the circuit under test through the first and second acquisition modules, respectively. Then, the first and second calculation circuits calculate the difference between the first and second segment voltages, and the difference between the second and first segment voltages, respectively. Since the two LEDs on the same board have the same BIN level and operating temperature, their single-LED voltage drop height is consistent under normal conditions. Therefore, the two voltages should be equal when there is no fault, and the difference should be close to zero. Once a single LED in a segment is short-circuited, the total voltage of that segment will decrease significantly, causing a significant asymmetrical deviation between the two differences. Based on this, the diagnostic module can identify which segment is faulty, thus achieving reliable and high-precision LED fault diagnosis at a low hardware cost without adding complex chips.

[0007] In conjunction with the first aspect, in some possible implementations, the aforementioned fault diagnosis circuit includes: A power supply module is connected to the first acquisition module, the second acquisition module, the first arithmetic circuit, the second arithmetic circuit, and the diagnostic module, respectively. The power supply module is used to supply power to the first acquisition module, the second acquisition module, the first arithmetic circuit, the second arithmetic circuit, and the diagnostic module.

[0008] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the first acquisition module includes: A first resistor, one end of which is connected to the first detection point of the circuit to be tested; The second resistor has one end connected to the other end of the first resistor, and the other end of the second resistor is connected to a grounding node. A third resistor, one end of which is connected to the second detection point of the circuit to be tested; The fourth resistor, one end of the second resistor is connected to the other end of the third resistor; The first operational amplifier has its non-inverting input connected to the connection node between the first resistor and the second resistor, its inverting input connected to the connection node between the third resistor and the fourth resistor, its ground terminal connected to the ground node, its power supply terminal connected to the power supply module, and its output terminal connected to both the first operational circuit and the second operational circuit.

[0009] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the second acquisition module includes: The fifth resistor, one end of which is connected to the second detection point of the circuit to be tested; The sixth resistor has one end connected to the other end of the fifth resistor, and the other end of the sixth resistor is connected to a grounding node; The seventh resistor, one end of which is connected to the third detection point of the circuit to be tested; The eighth resistor, one end of which is connected to the other end of the seventh resistor; The second operational amplifier has its non-inverting input connected to the connection node between the fifth and sixth resistors, its inverting input connected to the connection node between the seventh and eighth resistors, its ground terminal connected to the other end of the sixth resistor, its power supply terminal connected to the power supply module, and its output terminal connected to both the first and second operational circuits.

[0010] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the first operational circuit includes: The ninth resistor, one end of which is connected to the second acquisition module; The tenth resistor has one end connected to the other end of the ninth resistor, and the other end of the tenth resistor is connected to a grounding node. The eleventh resistor, one end of which is connected to the first acquisition module; The twelfth resistor, one end of which is connected to the other end of the eleventh resistor; The third operational amplifier has its non-inverting input connected to the connection point between the ninth and tenth resistors, its inverting input connected to the connection point between the eleventh and twelfth resistors, its ground terminal connected to a grounding node, and its power supply terminal connected to a power supply module.

[0011] In combination with the first aspect and the above implementation methods, in some possible implementation methods, the second operational circuit includes: The thirteenth resistor, one end of which is connected to the first acquisition module; The fourteenth resistor has one end connected to the other end of the thirteenth resistor, and the other end of the fourteenth resistor is connected to a grounding node. The fifteenth resistor, one end of which is connected to the second acquisition module; The sixteenth resistor, one end of which is connected to the other end of the fifteenth resistor; The fourth operational amplifier has its non-inverting input connected to the connection point between the thirteenth and fourteenth resistors, its inverting input connected to the connection point between the fifteenth and sixteenth resistors, its ground terminal connected to the grounding stage, and its power supply terminal connected to the power supply module.

[0012] In combination with the first aspect and the above implementation methods, in some possible implementations, the diagnostic module includes: The first diode, one end of which is connected to the first operational circuit; The second diode has one end connected to the second operational circuit, and the other end connected to the other end of the first diode.

[0013] Secondly, a vehicle is provided, including: the fault diagnosis circuit as described above.

[0014] Thirdly, a diagnostic method for a fault diagnosis circuit is provided, applied to the fault diagnosis circuit as described above, wherein the method includes the following steps: Obtain the first segment voltage and the second segment voltage of the circuit under test; Calculate the first difference between the first segment voltage and the second segment voltage, and the second difference between the second segment voltage and the first segment voltage; The presence of a fault in the circuit under test is identified based on the first difference and the second difference.

[0015] In conjunction with the third aspect, in some possible implementations, identifying whether the circuit under test is faulty based on the first difference and the second difference includes: Calculate the third difference between the first difference and the second difference; Based on the first detection point, the second detection point, and the third detection point, the theoretical difference between the first segment voltage and the second segment voltage is determined; If the third difference is equal to the theoretical difference, then the circuit under test is determined to be fault-free. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a fault diagnosis circuit provided according to an embodiment of this application; Figure 2This is a schematic diagram of a fault diagnosis circuit provided according to an embodiment of this application; Figure 3 This is a schematic diagram of a fault diagnosis circuit according to an embodiment of this application; Figure 4 This is a schematic diagram of a diagnostic method for a fault diagnosis circuit provided according to an embodiment of this application. Detailed Implementation

[0017] The technical solutions in this application will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more than two.

[0018] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0019] The following description, with reference to the accompanying drawings, describes a fault diagnosis circuit, its diagnostic method, and a vehicle according to embodiments of this application. Addressing the difficulties and high costs associated with detecting short circuits in series-connected LEDs mentioned in the background art, this application provides a fault diagnosis circuit, comprising: a first acquisition module, a second acquisition module, a first arithmetic circuit, a second arithmetic circuit, and a diagnostic module. The first acquisition module acquires a first segment voltage of the circuit under test; the second acquisition module acquires a second segment voltage of the circuit under test; the first arithmetic circuit calculates a first difference between the first segment voltage and the second segment voltage; the second arithmetic circuit calculates a second difference between the second segment voltage and the first segment voltage; and the diagnostic module identifies whether a fault exists in the circuit under test based on the first and second differences. This solves the problems of difficulty and high cost in detecting short circuits in series-connected LEDs, achieving reliable and high-precision LED fault diagnosis at a lower hardware cost without adding complex chips.

[0020] Figure 1 This is a schematic diagram of a fault diagnosis circuit provided in an embodiment of this application.

[0021] For example, such as Figure 1 As shown, the fault diagnosis circuit 10 includes: a first acquisition module 100, a second acquisition module 200, a first arithmetic circuit 300, a second arithmetic circuit 400, and a diagnosis module 500.

[0022] The first acquisition module 100 has its two ends connected to the first detection point and the second detection point of the circuit under test, and is used to acquire the first segment voltage of the circuit under test.

[0023] The second acquisition module 200 is connected at both ends to the second and third detection points of the circuit under test, and is used to acquire the second segment voltage of the circuit under test.

[0024] The first operational circuit 300 is connected to the first acquisition module 100 and the second acquisition module 200 respectively, and is used to calculate the first difference between the first segment voltage and the second segment voltage.

[0025] The second operational circuit 400 is connected to the first acquisition module 100 and the second acquisition module 200 respectively, and is used to calculate the second difference between the second segment voltage and the first segment voltage.

[0026] The diagnostic module 500 has a first input terminal connected to the output terminal of the first arithmetic circuit 300 and a second input terminal connected to the output terminal of the second arithmetic circuit 400. It is used to identify whether there is a fault in the circuit under test based on the first difference and the second difference.

[0027] It is understandable that the circuit under test consists of at least two LEDs connected in series, corresponding to the first detection point to the second detection point (upper half) and the second detection point to the third detection point (lower half), respectively. Under normal operating conditions, since the LEDs on the same board have the same BIN rating, similar operating temperature, and the same driving current, if the number of LEDs in the two segments is equal, their forward voltage drops should be basically the same, that is, the voltage of the first segment is approximately equal to the voltage of the second segment.

[0028] The first acquisition module 100 and the second acquisition module 200 respectively acquire the voltages U1 and U2 of the two segments in real time. The first arithmetic circuit 300 calculates the difference A1 between U1 and U2, and the second arithmetic circuit 300 calculates the difference A2 between U1 and U2. Under fault-free conditions, U1 and U2 are approximately equal, and A1 and A2 are equal in magnitude but opposite in sign, exhibiting symmetrical characteristics. When one or more LEDs in one segment are short-circuited, the number of effective LEDs in that segment decreases, and the total voltage drop decreases. For example, if the upper half of the segment is short-circuited... If the lower half is short-circuited, then U1 is less than U2, A1 is less than 0, and A2 is greater than 0; if the lower half is short-circuited, then U2 is less than U1, A1 is greater than 0, and A2 is less than 0. There will always be one path with a positive and significant difference, and the other path will be close to zero or negative. The subsequent stage only detects the positive signal and sends it to the OR gate, which can realize fault alarm under single power supply. This avoids the problem of traditional single subtractor schemes requiring dual power supplies and absolute value circuits due to positive and negative output voltages, greatly simplifying the hardware and reducing costs, while still effectively identifying single LED short-circuit faults.

[0029] It should be noted that the fault diagnosis circuit 10 may further include a compensation unit, wherein the compensation unit may be connected to the segment with fewer LEDs in the first segment and the second segment, and the proportional gain of the compensation unit is determined by the ratio of the number of components in the first segment to the number of components in the second segment.

[0030] like Figure 2 As shown, it is recommended that the two LEDs be divided equally in the whole string. For strings with an odd number of LEDs, a compensation unit can be used to complete the load or an amplifier ratio can be used to compensate the output, so that the voltages of U1 and U2 are output to subtractor 1.

[0031] In addition, those skilled in the art should note that the voltage difference within the BIN of an LED is generally 0.2 to 0.25V. Therefore, the maximum error of the difference between two LEDs is (0.2 to 0.25)*n / 2, where n is the number of LED strings. The maximum number of strings is recommended to be less than half of the voltage drop of a single LED to ensure that the deviation of the LED voltage BIN will not affect the circuit result. For example, taking a 3V LED as an example, the number of LED strings should be within 12, which is also in line with the maximum number of strings commonly used in automotive headlight designs.

[0032] Optionally, in some embodiments, the fault diagnosis circuit 10 described above includes a power supply module.

[0033] The power supply module is connected to the first acquisition module 100, the second acquisition module 200, the first arithmetic circuit 300, the second arithmetic circuit 400 and the diagnostic module 500 respectively. The power supply module is used to supply power to the first acquisition module 100, the second acquisition module 200, the first arithmetic circuit 300, the second arithmetic circuit 400 and the diagnostic module 500.

[0034] Specifically, this embodiment considers that the normal power supply range of the vehicle lighting system is 9–16V. If a dual power supply is used, the first or second operational circuit can be reduced, but an additional negative voltage generation circuit is required, increasing cost and complexity. If a high-voltage single power supply is used, the scaling processing of the second segment voltage signal can be eliminated, but it exceeds the standard automotive voltage range, which also increases the power supply design cost. Therefore, preferably, this embodiment adopts a single power supply architecture compatible with the vehicle power supply (such as 5V or a suitable voltage after LDO regulation). The power supply module provides stable and low-cost power to each operational amplifier and logic circuit through voltage regulators such as LDOs. This avoids the cost increase caused by negative or high voltage and supports a pure positive voltage detection structure using two subtractors plus OR gates, achieving cost-effective fault diagnosis.

[0035] Optionally, in some embodiments, the first acquisition module 100 includes: a first resistor R1 to a fourth resistor R4 and a first operational amplifier U1.

[0036] Wherein, one end of the first resistor R1 is connected to the first detection point of the circuit under test; one end of the second resistor R2 is connected to the other end of the first resistor R1, and the other end of the second resistor R2 is connected to the grounding node; one end of the third resistor R3 is connected to the second detection point of the circuit under test; one end of the second resistor R2 is connected to the other end of the third resistor R3; the non-inverting input terminal of the first operational amplifier U1 is connected to the connection node between the first resistor R1 and the second resistor R2; the inverting input terminal of the first operational amplifier U1 is connected to the connection node between the third resistor R3 and the fourth resistor R4; the grounding terminal of the first operational amplifier U1 is connected to the grounding node; the power supply terminal of the first operational amplifier U1 is connected to the power supply module; and the output terminal of the first operational amplifier U1 is connected to the first operational circuit 300 and the second operational circuit 400 respectively.

[0037] It should be noted that the first detection point is the voltage sampling node located at the upstream end of the LED string under test (closest to the positive terminal of the power supply or the output terminal of the constant current source), which is usually set at the beginning of the upper half of the LED string; the second detection point is the intermediate connection node located between the upper and lower halves of the LED string under test, that is, the common connection point between the end of the upper half of the LED string and the beginning of the lower half of the LED string; the third detection point is the voltage sampling node located at the downstream end of the LED string under test (closest to the ground terminal or the return terminal of the constant current source), which is usually set at the end of the lower half of the LED string and is generally connected to ground or a current sensing resistor; the first acquisition module can be a subtractor.

[0038] Combination Figure 2 and Figure 3 As shown, the first acquisition module 100 is composed of a first resistor R1 to a fourth resistor R4 and a first operational amplifier U1. It is used to calculate the difference between the first detection point and the second detection point to obtain the first segmented voltage, preferably low, with R1=R3, R2=R4, and the operational amplifier ratio is R2:R1.

[0039] The first acquisition module 100 is an operational amplifier-based non-inverting proportional subtractor. It receives the voltages of the first detection point and the second detection point, and outputs the difference between the first detection point and the second detection point to obtain the first segment voltage. This difference represents the total voltage drop of the upper LED segment. If the difference is greater than 5V, it is recommended to reduce the difference proportionally to less than 5V to reduce the cost of the operational amplifier power supply circuit. The output of the first acquisition module 100 is: k*(V1-V2), where k is the scaling ratio, which is adjusted by the external resistor of the operational amplifier, V1 is the voltage of the first detection point, and V2 is the voltage of the second detection point.

[0040] Therefore, since the total voltage drop of the LED string in the vehicle headlights can be high under high current (e.g., exceeding 5V when multiple LEDs are connected in series), and the output range of the operational amplifier (op-amp) is limited if a low-cost single-supply power supply (e.g., 5V LDO) is used, the original voltage difference may exceed the allowable range of the op-amp's power supply. Therefore, when the original voltage difference might exceed the op-amp's power supply range, the difference is proportionally reduced to ensure that the output signal is always within the voltage range that subsequent comparators or diagnostic circuits can handle (e.g., 0–5V). This avoids the need for high-voltage or dual-supply op-amps, effectively reducing the complexity of the power supply module and the overall BOM cost. This design achieves an optimal balance between hardware cost and signal compatibility while ensuring fault sensitivity.

[0041] Optionally, in some embodiments, the second acquisition module 200 includes: a fifth resistor R5 to an eighth resistor R8 and a second operational amplifier U2.

[0042] Among them, one end of the fifth resistor R5 is connected to the second detection point of the circuit under test; one end of the sixth resistor R6 is connected to the other end of the fifth resistor R5, and the other end of the sixth resistor R6 is connected to the ground node; one end of the seventh resistor R7 is connected to the third detection point of the circuit under test; one end of the eighth resistor R8 is connected to the other end of the seventh resistor R7; the non-inverting input terminal of the second operational amplifier U2 is connected to the connection node between the fifth resistor R5 and the sixth resistor R6, the inverting input terminal of the second operational amplifier U2 is connected to the connection node between the seventh resistor R7 and the eighth resistor R8, the ground terminal of the second operational amplifier U2 is connected to the other end of the sixth resistor R6, the power supply terminal of the second operational amplifier U2 is connected to the power supply module, and the output terminal of the second operational amplifier U2 is connected to the first operational circuit 300 and the second operational circuit 400 respectively.

[0043] Combination Figure 2 and Figure 3 As shown, the second acquisition module 200 is an operational amplifier that is built into an in-phase amplifier to proportionally reduce the voltage of U2. This ratio is consistent with the scaling ratio of the subtractor 1 to ensure that the voltage comparison between U2 and U1 is performed in an equal proportion.

[0044] Specifically, the second detection point is connected to one end of R5. R5 and R6 are connected in series and then grounded, forming a voltage divider sampling of the voltage to ground at the second detection point. The third detection point is connected to one end of R7. R7 and R8 are connected in series and then grounded, used to sample the voltage to ground at the third detection point. The second operational amplifier U2 is configured as a differential amplifier: its non-inverting input is connected to the node between R5 and R6 (reflecting the potential of the second detection point), and its inverting input is connected to the node between R7 and R8 (reflecting the potential of the third detection point). When R5 = R7 and R6 = R8, the output of U2 is the proportionally scaled voltage difference: k*U2, where k is the scaling ratio, the same as the scaling value of subtractor 1. This output signal is simultaneously sent to the first operational circuit 300 and the second operational circuit 400 as one of the basic inputs for calculating the first segment voltage and the second segment voltage. The entire module is powered by a single power supply (such as 5V regulated by an LDO), eliminating the need for negative voltage. This ensures the accuracy of the ground reference voltage sampling while avoiding complex power supply design, meeting the requirements of low cost and high reliability in automotive applications.

[0045] Those skilled in the art will understand that, since the first and second segment voltages are greater than the operational amplifier's supply voltage, the scaling factor of subtractor 1 and proportional amplifier 1 is set to 1 / 9 to limit the voltages at the non-inverting and inverting terminals of the operational amplifier to less than 4.5V. Alternatively, the first and second segment voltages can be proportionally divided using a set of voltage-dividing resistors before being supplied to the subtractor and proportional amplifier. This method carries less risk, but requires careful selection of the values ​​for the voltage-dividing resistors and the operational amplifier's feedback resistor to ensure accurate sampling voltage.

[0046] Optionally, in some embodiments, the first operational circuit 300 includes: a ninth resistor R9 to a twelfth resistor R12 and a third operational amplifier U3.

[0047] Among them, one end of the ninth resistor R9 is connected to the second acquisition module 200; one end of the tenth resistor R10 is connected to the other end of the ninth resistor R9, and the other end of the tenth resistor R10 is connected to the grounding node; one end of the eleventh resistor R11 is connected to the first acquisition module 100; one end of the twelfth resistor R12 is connected to the other end of the eleventh resistor R11; the non-inverting input terminal of the third operational amplifier U3 is connected to the connection point between the ninth resistor R9 and the tenth resistor R10, the inverting input terminal of the third operational amplifier U3 is connected to the connection point between the eleventh resistor R11 and the twelfth resistor R12, the grounding terminal of the third operational amplifier U3 is connected to the grounding node, and the power supply terminal of the third operational amplifier U3 is connected to the power supply module.

[0048] Specifically, the first operational circuit 300 consists of a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, and a third operational amplifier U3. Its core function is to calculate and output the difference between the first segment voltage and the second segment voltage, i.e., U1-U2 (or its scaled-down form). The output of the second acquisition module 200 (representing the lower half voltage drop U2) is connected to one end of R9. R9 and R10 are connected in series and then grounded, forming a voltage divider sampling of the U2 signal. The output of the first acquisition module 100 (representing the upper half voltage drop U1) is connected to one end of R11. R11 and R12 are connected in series and then grounded, used to sample the U1 signal. The third operational amplifier U3 is configured as a differential amplifier: its non-inverting input is connected to the node between R9 and R10 (corresponding to the U2 voltage divider), and its inverting input is connected to the node between R11 and R12 (corresponding to the U1 voltage divider).

[0049] When the resistor matching conditions R9=R11 and R10=R12 are met, the output voltage of U3 is -k(U1-U2), which is an inverted amplified signal (the scaling factor is adjustable). This design allows for scaling the difference by adjusting the external resistors. For example, when the original voltage difference is too large, the output amplitude can be reduced to match the input range of subsequent comparators or diagnostic modules (e.g., limited to 0–5V), thereby avoiding the use of high-voltage or dual-supply op-amps and reducing power supply complexity and system cost. The entire circuit is powered by a single power supply module, has a simple structure, and is suitable for low-cost fault diagnosis applications in automotive 9–16V environments.

[0050] Those skilled in the art will understand that the proportional subtractor built with operational amplifiers calculates the difference between the first and second detection points output by subtractor 1 proportionally to the difference between the second and first detection points. The difference in voltage drop across the upper and lower LED segments indicates whether there is an LED fault. If the scaling factor of the difference in the previous stage is small, it can be appropriately amplified in this stage to facilitate subsequent circuit design. The difference has the following conditions: when the LED is fault-free, the voltage difference between the two segments is close to 0, and the output of the first operational circuit 300 is close to 0V; when the lower half of the LED is short-circuited, the output value is positive; when the upper half of the LED is short-circuited, the output value is negative; when the LED is open-circuited, the output value is positive.

[0051] In summary, if a single operational amplifier is used to represent the difference, a dual positive and negative power supply is required, and an absolute value circuit needs to be designed in the subsequent stage to correct the output for subsequent fault handling. This is costly. Therefore, this invention uses two sets of subtractors, namely the first operational circuit 300 and the second operational circuit 400. When an anomaly occurs, at least one set of subtractors outputs a high level, while the other set outputs close to 0V, greatly saving costs.

[0052] In actual operation, the ninth resistor R9, the tenth resistor R10, the eleventh resistor R11, the twelfth resistor R12, and the third operational amplifier U3 form a subtractor used to calculate the voltage difference between the two LED segments. R9=R11, R10=R12, R13=R15, R14=R16, and the operational amplifier ratio is R10:R19=R13:R14. If the subtraction output value is too small after scaling the previous stage, the ratio can be increased to facilitate control by the subsequent stage.

[0053] Optionally, in some embodiments, the second operational circuit 400 includes: thirteenth resistors R13 to sixteenth resistors R16 and a fourth operational amplifier U4.

[0054] Among them, one end of the thirteenth resistor R13 is connected to the first acquisition module 100; one end of the fourteenth resistor R14 is connected to the other end of the thirteenth resistor R13, and the other end of the fourteenth resistor R14 is connected to the grounding node; one end of the fifteenth resistor R15 is connected to the second acquisition module 200; one end of the sixteenth resistor R16 is connected to the other end of the fifteenth resistor R15; the non-inverting input terminal of the fourth operational amplifier U4 is connected to the connection point between the thirteenth resistor R13 and the fourteenth resistor R14, the inverting input terminal of the fourth operational amplifier U4 is connected to the connection point between the fifteenth resistor R15 and the sixteenth resistor R16, the grounding terminal of the fourth operational amplifier U4 is connected to the grounding stage, and the power supply terminal of the fourth operational amplifier U4 is connected to the power supply module.

[0055] In this embodiment, the second operational circuit 400 consists of a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, and a fourth operational amplifier U4. Its core function is to calculate and output the difference between the second segment voltage and the first segment voltage, as a complementary signal to the output of the first operational circuit 300. Specifically, the output of the first acquisition module 100 (representing the upper LED voltage drop U1) is connected to one end of R13. R13 and R14 are connected in series and then grounded, forming a voltage divider sampling of U1. The output of the second acquisition module 200 (representing the lower LED voltage drop U2) is connected to one end of R15. R15 and R16 are connected in series and then grounded, used to sample the U2 signal. The fourth operational amplifier U4 is configured as a differential amplifier: its non-inverting input is connected to the node between R13 and R14 (corresponding to the U1 voltage divider), and its inverting input is connected to the node between R15 and R16 (corresponding to the U2 voltage divider).

[0056] When the resistor matching conditions R13=R15 and R14=R16 are met, the output voltage of U4 is k(U1-U2), while the output voltage of U3 is -k(U1-U2). Therefore, the output of the second operational circuit 400 is inversely related to the output of the first operational circuit 300. This ensures that when a short circuit occurs in either the upper or lower half, one output will always show a significant positive voltage, while the other will be close to zero or negative. This dual-channel differential structure avoids the use of absolute value circuits or dual power supplies, requiring only a single-supply operational amplifier and subsequent positive detection logic to achieve highly robust fault presence detection. The entire module is powered by a unified power supply module, eliminating the need for negative or high voltage, thus meeting the design requirements of low cost and high reliability in automotive applications. Optionally, in some embodiments, the diagnostic module 500 includes a first diode and a second diode.

[0057] In this circuit, one end of the first diode is connected to the first operational circuit 300; one end of the second diode is connected to the second operational circuit 400; and the other end of the second diode is connected to the other end of the first diode.

[0058] Specifically, the diagnostic module 500 consists of a first diode D13 and a second diode D14, and uses an OR structure to achieve the combined output of fault signals. The anode (or cathode, depending on the signal polarity design) of the first diode is connected to the output terminal of the first operational circuit 300, and the anode (or the corresponding polarity terminal) of the second diode is connected to the output terminal of the second operational circuit 400. The other ends (cathode or anode) of the two diodes are connected to the diagnostic output node U0 (which can be connected to a pull-up resistor or a subsequent alarm circuit).

[0059] Therefore, the hardware diode OR logic can merge any abnormal signal into a unified fault indication signal without the need for additional logic gate chips or MCUs, which significantly simplifies the circuit, reduces costs, and is compatible with single power supply architectures.

[0060] To verify the effectiveness of the fault diagnosis circuit in this application embodiment, simulations were performed. When the LED is normal, the output Uo = 57.6mV; when a single LED in the lower half is short-circuited, the output Uo = 738.6mV; when a single LED in the upper half is short-circuited, Uo = 737.6mV; when all LEDs in the lower half are short-circuited, the output Uo = 4.37V; when all LEDs in the upper half are short-circuited, Uo = 4.36V; when there is a short circuit across the upper and lower halves (one identical LED is short-circuited in each half, resulting in the lowest output), Uo = 825mV; and when the LED is open-circuited, Uo = 4.4V. The simulation results show that under various LED fault conditions, Uo ranges from 0.7V to 4.5V. Under normal conditions, the voltage is 0.057V, showing a significant voltage difference, which can be used to control the feedback fault in the back-end circuit.

[0061] Therefore, this embodiment of the application utilizes a segmented difference method—subtracting the lower half voltage from the entire string voltage to obtain the upper half voltage—to fully leverage the characteristic that LEDs on the same circuit board have the same BIN level and similar operating temperature, significantly reducing common-mode voltage deviation during the subtraction operation. This effectively suppresses the interference of individual LED voltage drop differences on fault diagnosis, thereby achieving more accurate and robust short-circuit fault identification. The pure hardware method realizes single-LED fault diagnosis for multiple strings of LEDs, saving significant costs, especially for high-current applications, and avoiding the introduction of linear or matrix chips or software. Since the diagnostic mechanism is based on static voltage difference and does not rely on dynamic current modulation or communication handshake, it provides the possibility of detecting single or partial LED short circuits before power-on.

[0062] In summary, this application provides a fault diagnosis circuit, comprising: a first acquisition module, a second acquisition module, a first arithmetic circuit, a second arithmetic circuit, and a diagnosis module. The first acquisition module acquires a first segment voltage of the circuit under test; the second acquisition module acquires a second segment voltage of the circuit under test; the first arithmetic circuit calculates a first difference between the first segment voltage and the second segment voltage; the second arithmetic circuit calculates a second difference between the second segment voltage and the first segment voltage; and the diagnosis module identifies whether a fault exists in the circuit under test based on the first and second differences. This solves the problems of difficult and costly short-circuit detection of series LEDs, achieving reliable and high-precision LED fault diagnosis at a lower hardware cost without adding complex chips.

[0063] This application also provides a vehicle, including: the fault diagnosis circuit as described above.

[0064] This application also provides a diagnostic method for a fault diagnosis circuit, which is applied to the fault diagnosis circuit described above.

[0065] like Figure 4 As shown, the diagnostic method for this fault diagnosis circuit includes the following steps: In step S101, the first segment voltage and the second segment voltage of the circuit to be tested are obtained.

[0066] In step S102, the first difference between the first segment voltage and the second segment voltage, and the second difference between the second segment voltage and the first segment voltage are calculated.

[0067] In step S103, the presence of a fault in the circuit under test is identified based on the first difference and the second difference.

[0068] Optionally, in some embodiments, identifying whether the circuit under test is faulty based on the first difference and the second difference includes: calculating a third difference between the first difference and the second difference; determining the theoretical difference between the first segment voltage and the second segment voltage based on the first detection point, the second detection point, and the third detection point; and determining that the circuit under test is faulty if the third difference is equal to the theoretical difference.

[0069] Specifically, the system first obtains the first and second differences, and then calculates the third difference. Simultaneously, based on the physical design of the LED string (e.g., both the upper and lower sections contain 5 LEDs of the same model), it is determined that the voltage drop across the two sections should be equal under normal operating conditions; therefore, the theoretical difference is 0. If the measured third difference, after proportional conversion, equals the theoretical difference, the LED string is determined to have no short-circuit or open-circuit fault; if the third difference significantly deviates from 0 (e.g., exceeds a preset threshold), a fault is determined to exist.

[0070] Therefore, by introducing a third difference and comparing it with the theoretical difference, the embodiments of this application avoid the misjudgment that may be caused by relying solely on a single threshold comparison. This fully utilizes the characteristics of consistent LEDBIN and temperature on the same board, making the theoretical difference highly reliable. At the same time, the construction of the third difference enhances the amplitude of the fault signal, improving the signal-to-noise ratio and detection sensitivity.

[0071] It should be noted that the foregoing explanation of the fault diagnosis circuit embodiment also applies to the fault diagnosis method of the fault diagnosis circuit in this embodiment, and will not be repeated here.

[0072] According to the fault diagnosis circuit method proposed in this application, the first segment voltage and the second segment voltage of the circuit under test are obtained, and a first difference between the first segment voltage and the second segment voltage and a second difference between the second segment voltage and the first segment voltage are calculated. The presence of a fault in the circuit under test is then identified based on the first difference and the second difference. This solves the problems of difficult and costly detection of short circuits in series LEDs, achieving reliable and high-precision LED fault diagnosis at a lower hardware cost without adding complex chips.

[0073] Furthermore, embodiments of this application also protect an apparatus that may include a memory and a processor, wherein the memory stores executable program code, and the processor is used to call and execute the executable program code to perform the diagnostic method of the fault diagnosis circuit provided in embodiments of this application.

[0074] This embodiment can divide the device into functional modules based on the above method example. For example, each module can correspond to a separate function, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware. It should be noted that the module division in this embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0075] It should be noted that all relevant content of each step involved in the above method embodiments can be referenced from the functional description of the corresponding functional module, and will not be repeated here.

[0076] It should be understood that the device provided in this embodiment is used to perform the diagnostic method of the fault diagnosis circuit described above, and therefore can achieve the same effect as the above implementation method.

[0077] When using integrated units, the device may include a processing module and a storage module. When applied to an automobile, the processing module can be used to control and manage the vehicle's movements. The storage module can be used to support the vehicle in executing program code, etc.

[0078] The processing module may be a processor or a controller, which can implement or execute various exemplary logic blocks, modules, and circuits as disclosed in this application. The processor may also be a combination of computing functions, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc., and the storage module may be a memory.

[0079] In addition, the device provided in the embodiments of this application may specifically be a chip, component or module. The chip may include a connected processor and a memory. The memory is used to store instructions. When the processor calls and executes the instructions, the chip can execute the diagnostic method of the fault diagnosis circuit provided in the above embodiments.

[0080] This embodiment also provides a computer-readable storage medium storing computer program code. When the computer program code is run on a computer, the computer executes the above-described related method steps to implement a fault diagnosis circuit diagnosis method provided in the above embodiment.

[0081] This embodiment also provides a computer program product that, when run on a computer, causes the computer to perform the aforementioned related steps to implement a fault diagnosis circuit diagnosis method provided in the above embodiment.

[0082] In this embodiment, the device, computer-readable storage medium, computer program product, or chip are all used to execute the corresponding methods provided above. Therefore, the beneficial effects they can achieve can be referred to the beneficial effects in the corresponding methods provided above, and will not be repeated here.

[0083] Through the above description of the embodiments, those skilled in the art will understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0084] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0085] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A fault diagnosis circuit, characterized in that, include: The first acquisition module has its two ends connected to the first detection point and the second detection point of the circuit under test, and is used to acquire the first segment voltage of the circuit under test. The second acquisition module has its two ends connected to the second and third detection points of the circuit under test, and is used to acquire the second segment voltage of the circuit under test. A first arithmetic circuit, which is connected to the first acquisition module and the second acquisition module respectively, is used to calculate the first difference between the first segment voltage and the second segment voltage. The second operational circuit is connected to the first acquisition module and the second acquisition module respectively, and is used to calculate the second difference between the second segment voltage and the first segment voltage. The diagnostic module has a first input terminal connected to the output terminal of the first arithmetic circuit and a second input terminal connected to the output terminal of the second arithmetic circuit, and is used to identify whether the circuit under test has a fault based on the first difference and the second difference.

2. The circuit according to claim 1, characterized in that, include: A power supply module is connected to the first acquisition module, the second acquisition module, the first arithmetic circuit, the second arithmetic circuit, and the diagnostic module, respectively. The power supply module is used to supply power to the first acquisition module, the second acquisition module, the first arithmetic circuit, the second arithmetic circuit, and the diagnostic module.

3. The circuit according to claim 1, characterized in that, The first acquisition module includes: A first resistor, one end of which is connected to the first detection point of the circuit to be tested; The second resistor has one end connected to the other end of the first resistor, and the other end of the second resistor is connected to a grounding node. A third resistor, one end of which is connected to the second detection point of the circuit to be tested; The fourth resistor, one end of the second resistor is connected to the other end of the third resistor; The first operational amplifier has its non-inverting input connected to the connection node between the first resistor and the second resistor, its inverting input connected to the connection node between the third resistor and the fourth resistor, its ground terminal connected to the ground node, its power supply terminal connected to the power supply module, and its output terminal connected to both the first operational circuit and the second operational circuit.

4. The circuit according to claim 1, characterized in that, The second acquisition module includes: The fifth resistor, one end of which is connected to the second detection point of the circuit to be tested; The sixth resistor has one end connected to the other end of the fifth resistor, and the other end of the sixth resistor is connected to a grounding node; The seventh resistor, one end of which is connected to the third detection point of the circuit to be tested; The eighth resistor, one end of which is connected to the other end of the seventh resistor; The second operational amplifier has its non-inverting input connected to the connection node between the fifth and sixth resistors, its inverting input connected to the connection node between the seventh and eighth resistors, its ground terminal connected to the other end of the sixth resistor, its power supply terminal connected to the power supply module, and its output terminal connected to both the first and second operational circuits.

5. The circuit according to claim 1, characterized in that, The first operational circuit includes: The ninth resistor, one end of which is connected to the second acquisition module; The tenth resistor has one end connected to the other end of the ninth resistor, and the other end of the tenth resistor is connected to a grounding node. The eleventh resistor, one end of which is connected to the first acquisition module; The twelfth resistor, one end of which is connected to the other end of the eleventh resistor; The third operational amplifier has its non-inverting input connected to the connection point between the ninth and tenth resistors, its inverting input connected to the connection point between the eleventh and twelfth resistors, its ground terminal connected to a grounding node, and its power supply terminal connected to a power supply module.

6. The circuit according to claim 1, characterized in that, The second operational circuit includes: The thirteenth resistor, one end of which is connected to the first acquisition module; The fourteenth resistor has one end connected to the other end of the thirteenth resistor, and the other end of the fourteenth resistor is connected to a grounding node. The fifteenth resistor, one end of which is connected to the second acquisition module; The sixteenth resistor, one end of which is connected to the other end of the fifteenth resistor; The fourth operational amplifier has its non-inverting input connected to the connection point between the thirteenth and fourteenth resistors, its inverting input connected to the connection point between the fifteenth and sixteenth resistors, its ground terminal connected to the grounding stage, and its power supply terminal connected to the power supply module.

7. The circuit according to claim 1, characterized in that, The diagnostic module includes: The first diode, one end of which is connected to the first operational circuit; The second diode has one end connected to the second operational circuit, and the other end connected to the other end of the first diode.

8. A vehicle, characterized in that, include: The fault diagnosis circuit as described in any one of claims 1-7.

9. A diagnostic method for a fault diagnosis circuit, characterized in that, The method is applied to a fault diagnosis circuit as described in any one of claims 1-7, wherein the method includes the following steps: Obtain the first segment voltage and the second segment voltage of the circuit under test; Calculate the first difference between the first segment voltage and the second segment voltage, and the second difference between the second segment voltage and the first segment voltage; The presence of a fault in the circuit under test is identified based on the first difference and the second difference.

10. The method according to claim 9, characterized in that, The step of identifying whether the circuit under test is faulty based on the first difference and the second difference includes: Calculate the third difference between the first difference and the second difference; Based on the first detection point, the second detection point, and the third detection point, the theoretical difference between the first segment voltage and the second segment voltage is determined; If the third difference is equal to the theoretical difference, then the circuit under test is determined to be fault-free.

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