Vehicle-mounted LED open / short circuit detection circuit

Abstract

The application provides a vehicle-mounted LED open short circuit detection circuit, wherein a first control unit and a second control unit are connected with the same communication bus, and the first control unit and the second control unit share the same communication node. The first multiplexing switch comprises a communication interface, an output interface, a detection interface and a control signal interface; the second multiplexing switch comprises a communication interface, an output interface, a detection interface and a control signal interface; the input end of the first signal conversion circuit receives the output control signal of the first control unit, and the output end is connected with the communication interface of the second multiplexing switch; the input end of the second signal conversion circuit receives the output control signal of the second control unit, and the output end is connected with the communication interface of the first multiplexing switch. Compared with the prior art, the application solves the problem that two device ends cannot simultaneously send messages to one LIN node when there is only one LIN node and the MCU IO port is insufficient.

Description

[0001] The present application relates to the technical field of vehicle-mounted LED detection, and particularly relates to a vehicle-mounted LED open / short circuit detection circuit.

[0002] The normal vehicle-mounted atmosphere lamp needs to have the following functions: when an RGB (Red, Green, Blue) open circuit or short circuit fault occurs, the fault needs to be uploaded to a vehicle machine, and the open / short circuit is detected. Since the number of LIN (Local Interconnect Network, i.e. local area interconnection network) nodes of the vehicle-mounted atmosphere lamp is limited, and the lower end device needs to send relevant information to the vehicle machine through LIN communication, when there is only one LIN node, but there are two LIN devices at the lower end, and the two LIN devices (or slave devices) do not have communication functions, there is a problem: the two devices at the lower end cannot simultaneously send LIN messages to the bus.

[0003] Therefore, it is necessary to provide a new technical scheme to solve the above problems.

[0004] One of the purposes of the present application is to provide a vehicle-mounted LED open / short circuit detection circuit, which solves the problem that when there is only one LIN node, and the MCU IO port is not enough, the two device ends cannot simultaneously send messages to the bus.

[0005] ​​​According to one aspect of the present application, the present application provides a vehicle-mounted LED open short circuit detection circuit, which comprises a first control unit, a second control unit, a first multiplexing switch, a second multiplexing switch, a first signal conversion circuit and a second signal conversion circuit. The first control unit and the second control unit are connected with the same communication bus, and the first control unit and the second control unit share the same communication node on the communication bus; the first multiplexing switch comprises a communication interface, an output interface, m detection interfaces and n control signal interfaces, the m detection interfaces are connected with a first light emitting diode array, the output interface is connected with a sampling interface of the first control unit, and the first control unit outputs n-bit control signals to the n control signal interfaces of the first multiplexing switch; the second multiplexing switch comprises a communication interface, an output interface, m detection interfaces and n control signal interfaces, the m detection interfaces are connected with a second light emitting diode array, the output interface is connected with a sampling interface of the second control unit, and the second control unit outputs n-bit control signals to the n control signal interfaces of the second multiplexing switch; an input end of the first signal conversion circuit receives the n-bit control signals output by the first control unit, an output end of the first signal conversion circuit is connected with the communication interface of the second multiplexing switch, and the first signal conversion circuit outputs corresponding first fault indication signals to the communication interface of the second multiplexing switch through the output end based on the n-bit control signals output by the first control unit; an input end of the second signal conversion circuit receives the n-bit control signals output by the second control unit, an output end of the second signal conversion circuit is connected with the communication interface of the first multiplexing switch, and the second signal conversion circuit outputs corresponding second fault indication signals to the communication interface of the first multiplexing switch through the output end based on the n-bit control signals output by the second control unit, wherein m and n are positive integers.

[0006] Compared with the prior art, the present application realizes simple communication between two MCUs, thereby designing a circuit capable of normally reporting LED open short circuit faults under the premise that two MCUs (Microcontroller Unit) only use one LIN node address and there is no redundant MCU GPIO (General-purpose input / output), thereby ingeniously solving the factors of insufficient LIN nodes and insufficient MCU resources. BRIEF DESCRIPTION OF DRAWINGS

[0007] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0008] Figure 1 This is a partial circuit diagram of an on-board LED open / short circuit detection circuit in one embodiment of the present invention;

[0009] Figure 2 This is a schematic diagram of another part of the vehicle-mounted LED open / short circuit detection circuit in one embodiment of the present invention.

Detailed Implementation Methods

[0010] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0011] 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 invention. The phrase "in one embodiment" appearing in different places throughout 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.

[0012] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "front", "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 invention 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 invention.

[0013] Please refer to Figure 1 The diagram shown is a partial circuit diagram of an on-board LED open / short circuit detection circuit in one embodiment of the present invention; please refer to... Figure 2 As shown, it is another part of the circuit diagram of the vehicle-mounted LED open / short circuit detection circuit in one embodiment of the present invention. Figure 1 and Figure 2The vehicle-mounted LED open / short circuit shown includes a first control unit 110, a second control unit 120, a first multiplexer 130, a second multiplexer 140, a first signal conversion circuit 150, and a second signal conversion circuit 160.

[0014] like Figure 1 As shown, the first control unit 110 and the second control unit 120 are connected to the same communication bus, and the first control unit 110 and the second control unit 120 share the same communication node on the communication bus.

[0015] exist Figure 1 In the specific embodiment shown, the first control unit 110 is MCU1, and the second control unit 120 is MCU2; the communication bus is a LIN bus; and the communication nodes are LIN nodes. There is only one LIN bus in the vehicle body domain, and the LIN bus allocates LIN nodes to downstream devices. The downstream devices will reply with relevant messages after receiving the bus message. For example... Figure 1 As shown, the first control unit 110 and the second control unit 120 share the same LIN node address. If they send messages simultaneously, a problem will occur, and the bus will be unable to receive messages. Therefore, when one control unit sends a LIN message to the bus, the other control unit must wait; they cannot send messages simultaneously.

[0016] like Figure 2 As shown, the first multiplexer 130 is U1, and the second multiplexer 140 is U2. U1 and U2 are two TMUX1308 multiplexers. The first multiplexer 130 includes a communication interface S6, an output interface D, and m detection interfaces (in... Figure 2 In the specific embodiment shown, m = 6, and the 6 detection interfaces are the detection interfaces S0, S1, S2, S3, S4, and S5 of U1, and n control signal interfaces (in... Figure 2 In the specific embodiment shown, n=3, and the three control signal interfaces are the control signal interfaces A2, A0, and A1 of U1. Among them, m detection interfaces (e.g., detection interfaces S0, S1, S2, S3, S4, and S5 of U1) are connected to the first light-emitting diode array (not shown), and the output interface D is connected to the sampling interface MCU1_Vadc of the first control unit 110. The first control unit 110 outputs n-bit control signals (in... Figure 2 In the specific embodiment shown, n = 3, and the 3 control signals (MCU1_A2, MCU1_A0, MCU1_A1) are respectively given to the n control signal interfaces of the first multiplexer 130 (e.g., control signal interfaces A2, A0, A1 of U1), where m and n are both positive integers. Figure 2In the illustrated embodiment, the output interface D of the first multiplexing switch 130 is connected to ground through the series connection of the voltage dividing resistors R11 and R12 in turn, and the connection node between the voltage dividing resistors R11 and R12 is connected to the sampling interface MCU1_Vadc of the first control unit 110.

[0017] The second multiplexing switch 140 includes a communication interface S6, an output interface D, m detection interfaces (in the illustrated embodiment, the m detection interfaces are the detection interfaces S0, S1, S2, S3, S4, S5 of the U2 respectively), and n control signal interfaces (in the illustrated embodiment, the n control signal interfaces are the control signal interfaces A2, A0, A1 of the U2 respectively). Figure 2 In the illustrated embodiment, m = 6, and the 6 detection interfaces are the detection interfaces S0, S1, S2, S3, S4, S5 of the U2 respectively, and n = 3, and the 3 control signal interfaces are the control signal interfaces A2, A0, A1 of the U2 respectively. Figure 2 In the illustrated embodiment, m = 6, and the 6 detection interfaces are the detection interfaces S0, S1, S2, S3, S4, S5 of the U2 respectively, and n = 3, and the 3 control signal interfaces are the control signal interfaces A2, A0, A1 of the U2 respectively. Figure 2 In the illustrated embodiment, n = 3, and the 3 control signals are MCU2_A2, MCU2_A0, MCU2_A1 respectively. Figure 2 In the illustrated embodiment, the output interface D of the second multiplexing switch 140 is connected to ground through the series connection of the voltage dividing resistors R7 and R8 in turn, and the connection node between the voltage dividing resistors R7 and R8 is connected to the sampling interface MCU2_Vadc of the second control unit 120.

[0018] The input end of the first signal conversion circuit 150 receives the n control signals (for example, MCU1_A2, MCU1_A0, MCU1_A1) output by the first control unit 110, and the output end thereof is connected to the communication interface S6 of the second multiplexing switch 140. The first signal conversion circuit 150 outputs a corresponding first fault indication signal to the communication interface S6 of the second multiplexing switch 140 through the output end thereof based on the n control signals (for example, MCU1_A2, MCU1_A0, MCU1_A1) output by the first control unit 110.

[0019] The input end of the second signal conversion circuit 160 receives the n-bit control signal (for example, MCU2_A2, MCU2_A0, MCU2_A1) output by the second control unit 120, and the output end is connected with the communication interface S6 of the first multiplexing switch 130. The second signal conversion circuit 160 outputs the corresponding second fault indication signal to the communication interface S6 of the first multiplexing switch 130 through the output end based on the n-bit control signal (for example, MCU2_A2, MCU2_A0, MCU2_A1) output by the second control unit 120.

[0020] The following is based on Figure 1 and Figure 2 The working principle of the vehicle-mounted LED open-short circuit detection circuit provided by the application is specifically introduced.

[0021] The first control unit 110 outputs the n-bit control signal (or the n-bit control signal indicating polling sampling) indicating the non-open-short circuit fault (in the specific embodiment shown in Figure 2 In the specific embodiment shown in FIG. 1, n=3, and the 3-bit control signal indicating polling sampling is from 000 to 110) to the n control signal interfaces (for example, the control signal interfaces A2, A0 and A1 of U1) of the first multiplexing switch 130, so as to poll and sample the communication interface S6 and the m detection interfaces (for example, the detection interfaces S0, S1, S2, S3, S4 and S5 of U1) of the first multiplexing switch 130 through the n control signal interfaces (for example, the control signal interfaces A2, A0 and A1 of U1) of the first multiplexing switch 130. The first control unit 110 determines whether the first light-emitting diode array (not shown) has an open-short circuit fault based on the polling and sampling of the m detection interfaces (for example, the detection interfaces S0, S1, S2, S3, S4 and S5 of U1) of the first multiplexing switch 130. If the first light-emitting diode array (not shown) is detected to have an open-short circuit fault, the first control unit 110 outputs the n-bit control signal (in the specific embodiment shown in Figure 2 In the specific embodiment shown in FIG. 1, n=3, and the 3-bit control signal indicating the open-short circuit fault is 111). In other words, the m detection interfaces (for example, the detection interfaces S0, S1, S2, S3, S4 and S5 of U1) of the first multiplexing switch 130 are used to identify the open-short circuit fault of RGB.

[0022] The second control unit 120 outputs the n-bit control signal (or the n-bit control signal indicating polling sampling) indicating the non-open-short circuit fault (in the specific embodiment shown in Figure 2In the illustrated embodiment, n = 3, indicating that the 3-bit control signal representing the polling sampling is from 000 to 110) to the n control signal interfaces (e.g., control signal interfaces A2, A0, A1 of U2) of the second multiplexing switch 140, so as to poll sample the m detection interfaces (e.g., detection interfaces S0, S1, S2, S3, S4, S5 of U2) and the communication interface S6 of the second multiplexing switch 140 through the n control signal interfaces (e.g., control signal interfaces A2, A0, A1 of U2) of the second multiplexing switch 140. The second control unit 120 determines whether the second light-emitting diode array (not shown) has an open / short circuit fault based on the polling sampling of the m detection interfaces (e.g., detection interfaces S0, S1, S2, S3, S4, S5 of U2) of the second multiplexing switch 140; if the second light-emitting diode array (not shown) is detected to have an open / short circuit fault, the second control unit 120 outputs an n-bit control signal representing the open / short circuit fault (in the illustrated embodiment, n = 3, indicating that the 3-bit control signal representing the open / short circuit fault is 111). Figure 2 In other words, the m detection interfaces (e.g., detection interfaces S0, S1, S2, S3, S4, S5 of U2) of the second multiplexing switch 140 are used to identify the open / short circuit fault of RGB.

[0023] When the first control unit 110 outputs an n-bit control signal representing an open / short circuit fault (e.g., a 3-bit control signal 111 representing an open / short circuit fault), the first signal conversion circuit 150 outputs a first fault indication signal at a first logic level (in the illustrated embodiment, the first logic level is a low level) to the communication interface S6 of the second multiplexing switch 140, and the first fault indication signal at the first logic level indicates that the first control unit 110 detects an open / short circuit fault. Figure 2 When the first control unit 110 outputs an n-bit control signal representing an open / short circuit fault (e.g., a 3-bit control signal 111 representing an open / short circuit fault), the first signal conversion circuit 150 outputs a first fault indication signal at a first logic level (in the illustrated embodiment, the first logic level is a low level) to the communication interface S6 of the second multiplexing switch 140, and the first fault indication signal at the first logic level indicates that the first control unit 110 detects an open / short circuit fault. Figure 2 When the first control unit 110 outputs an n-bit control signal representing an open / short circuit fault (e.g., a 3-bit control signal 111 representing an open / short circuit fault), the first signal conversion circuit 150 outputs a first fault indication signal at a first logic level (in the illustrated embodiment, the first logic level is a low level) to the communication interface S6 of the second multiplexing switch 140, and the first fault indication signal at the first logic level indicates that the first control unit 110 detects an open / short circuit fault.

[0024] When the second control unit 120 outputs an n-bit control signal representing an open / short circuit fault (e.g., a 3-bit control signal 111 representing an open / short circuit fault), the second signal conversion circuit 160 outputs a second fault indication signal at a first logic level (in the illustrated embodiment, the first logic level is a low level) to the communication interface S6 of the first multiplexing switch 130, and the second fault indication signal at the first logic level indicates that the second control unit 120 detects an open / short circuit fault. Figure 2In the illustrated embodiment, the first logic level is a low logic level), the second fault indication signal at the first logic level indicates that the second control unit 120 detected an open-short fault; when the second control unit 120 outputs an n-bit control signal indicative of a non-open-short fault (e.g., a 3-bit control signal 000-110 indicative of a polling sample), the second signal conversion circuit 160 outputs a second fault indication signal at a second logic level (in the illustrated embodiment, the second logic level is a high logic level) to the communication interface S6 of the first multiplexing switch 130. Figure 2 In the illustrated embodiment, the second logic level is a high logic level), the second fault indication signal at the second logic level indicates that the second control unit 120 did not detect an open-short fault.

[0025] When the first control unit 110 detects an open-short fault and the first control unit 110 detects a second fault indication signal at a first logic level (in the illustrated embodiment, the first logic level is a low logic level) received by the communication interface of the first multiplexing switch 130, it indicates that both the first control unit 110 and the second control unit 120 detected an open-short fault, and at this time, only the first control unit 110 or the second control unit 120 can send a first message to the LIN bus. In one embodiment, the first message includes that both the first control unit 110 and the second control unit 120 detected an open-short fault. Figure 2 When the first control unit 110 does not detect an open-short fault and the first control unit 110 detects a second fault indication signal at a second logic level (in the illustrated embodiment, the second logic level is a high logic level) received by the communication interface of the first multiplexing switch 130, it indicates that both the first control unit 110 and the second control unit 120 did not detect an open-short fault, and at this time, only the first control unit 110 or the second control unit 120 can send a second message to the LIN bus. In one embodiment, the second message includes that both the first control unit 110 and the second control unit 120 did not detect an open-short fault.

[0026] Figure 2 When the first control unit 110 does not detect an open-short fault and the first control unit 110 detects a second fault indication signal at a first logic level (in the illustrated embodiment, the first logic level is a low logic level) received by the communication interface of the first multiplexing switch 130, it indicates that the first control unit 110 did not detect an open-short fault and the second control unit 120 detected an open-short fault, and at this time, only the second control unit 120 can send a third message to the LIN bus. In one embodiment, the third message includes that the first control unit 110 did not detect an open-short fault and the second control unit 120 detected an open-short fault.

[0027] In the illustrated embodiment, the first logic level is a low logic level), the second fault indication signal at the first logic level indicates that the second control unit 120 detected an open-short fault; when the second control unit 120 outputs an n-bit control signal indicative of a non-open-short fault (e.g., a 3-bit control signal 000-110 indicative of a polling sample), the second signal conversion circuit 160 outputs a second fault indication signal at a second logic level (in the illustrated embodiment, the second logic level is a high logic level) to the communication interface S6 of the first multiplexing switch 130. Figure 2

[0028] ​​Similarly, when the second control unit 120 detects an open / short circuit fault and the second control unit 120 detects that the first fault indication signal received by the communication interface of the second multiplexer 140 is at the first logic level (in... Figure 2 In the specific embodiment shown, when the first logic level is low, it indicates that both the first control unit 110 and the second control unit 120 have detected an open / short circuit fault. In this case, either the first control unit 110 or the second control unit 120 can send a first message to the LIN bus. In one embodiment, the first message includes the fact that both the first control unit 110 and the second control unit 120 have detected an open / short circuit fault.

[0029] When the second control unit 120 does not detect an open / short circuit fault and the second control unit 120 detects that the first fault indication signal received by the communication interface of the second multiplexer 140 is at the second logic level (in Figure 2 In the specific embodiment shown, when the second logic level is high, it indicates that neither the first control unit 110 nor the second control unit 120 has detected an open or short circuit fault. In this case, either the first control unit 110 or the second control unit 120 can send a second message to the LIN bus. In one embodiment, the second message includes the statement that neither the first control unit 110 nor the second control unit 120 has detected an open or short circuit fault.

[0030] When the second control unit 120 does not detect an open / short circuit fault and the second control unit 120 detects that the first fault indication signal received by the communication interface of the second multiplexer 140 is at the first logic level (in Figure 2 In the specific embodiment shown, when the first logic level is low, it indicates that the second control unit 120 has not detected an open / short circuit fault, but the first control unit 110 has detected an open / short circuit fault. In this case, only the first control unit 110 can send the fourth message to the LIN bus. In one embodiment, the fourth message includes the statement that the second control unit 120 has not detected an open / short circuit fault, but the first control unit 110 has detected an open / short circuit fault.

[0031] like Figure 2 As shown, the first signal conversion circuit 150 includes n diodes (in Figure 2In the specific embodiment shown, n=3, the three diodes are diodes D1, D2, and D3, resistors R1, R2, R3, R9, and R10, and the first MOSFET Q1. In this circuit, resistors R1 and R2 are connected in series between the input voltage terminal VIN and the ground terminal; resistors R3, R9, and R10 are connected in series between the input voltage terminal VIN and the ground terminal; the cathodes of n diodes (e.g., diodes D1, D2, and D3) are respectively connected to the n control signal interfaces (e.g., control signal interfaces A1, A0, and A2 of U1) of the first multiplexer 130, and the anodes of the n diodes (e.g., diodes D1, D2, and D3) are all connected to the connection node between resistors R1 and R2; the control terminal of the first MOSFET Q1 is connected to the connection node between resistors R1 and R2, its first connection terminal is connected to the connection node between resistors R3 and R9, and its second connection terminal is grounded; the connection node between resistors R9 and R10 serves as the output terminal of the first signal conversion circuit 150 and is connected to the communication interface S6 of the second multiplexer 140.

[0032] like Figure 2 As shown, the second signal conversion circuit 160 includes an additional n diodes ((in Figure 1 In the specific embodiment shown, n=3, and the other 3 diodes are diodes D4, D5, and D6, resistors R4, R5, and R6, and the second MOSFET Q2. Resistors R4 and R5 are connected in series between the input voltage terminal VIN and the ground terminal. The cathodes of the other n diodes (e.g., diodes D4, D5, and D6) are respectively connected to the n control signal interfaces of the second multiplexer 140 (e.g., control signal interfaces A1, A0, and A2 of U2), and the anodes of the other n diodes (e.g., diodes D4, D5, and D6) are all connected to the connection node between resistors R4 and R5. The control terminal of the second MOSFET Q2 is connected to the connection node between resistors R4 and R5, its first connection terminal is connected to the input voltage terminal VIN via resistor R6, and its second connection terminal is grounded. The connection node between the second MOSFET Q2 and resistor R6 serves as the output terminal of the second signal conversion circuit 160 and is connected to the communication interface S6 of the first multiplexer 130.

[0033] When the first control unit 110 outputs the n-bit control signal representing the open-short circuit fault (for example, the 3-bit control signal 111 representing the open-short circuit fault), the first MOS transistor Q1 is turned on, and at this time, the first fault indication signal output by the first signal conversion circuit 150 is at a low level (which can be referred to as a first logic level of the first fault indication signal); when the first control unit 110 outputs the n-bit control signal representing the non-open-short circuit fault (for example, the 3-bit control signal 000-110 representing the polling sampling), the first MOS transistor Q1 is turned off, and at this time, the first fault indication signal output by the first signal conversion circuit 150 is at a high level (which can be referred to as a second logic level of the first fault indication signal).

[0034] When the second control unit 120 outputs the n-bit control signal representing the open-short circuit fault (for example, the 3-bit control signal 111 representing the open-short circuit fault), the second MOS transistor Q2 is turned on, and at this time, the second fault indication signal output by the second signal conversion circuit 160 is at a low level (which can be referred to as a first logic level of the second fault indication signal); when the second control unit 120 outputs the n-bit control signal representing the non-open-short circuit fault (for example, the 3-bit control signal 000-110 representing the polling sampling), the second MOS transistor Q2 is turned off, and at this time, the second fault indication signal output by the second signal conversion circuit 160 is at a high level (which can be referred to as a second logic level of the second fault indication signal).

[0035] As shown in Figure 2 , the n-bit control signal representing the open-short circuit fault output by the first control unit 110 is n 1s, the first MOS transistor Q1 is an NMOS transistor, the first connection end, the second connection end, and the control end of the first MOS transistor Q1 are the drain, the source, and the gate of the NMOS transistor, respectively; the n-bit control signal representing the open-short circuit fault output by the second control unit is n 1s, the second MOS transistor Q2 is an NMOS transistor, the first connection end, the second connection end, and the control end of the second MOS transistor Q2 are the drain, the source, and the gate of the NMOS transistor, respectively; the first logic level of the first fault indication signal output by the first signal conversion circuit 150 is a low level, and the second logic level thereof is a high level; the first logic level of the second fault indication signal output by the second signal conversion circuit 160 is a low level, and the second logic level thereof is a high level.

[0036] In ​In the shown embodiment, m is equal to 6 and n is equal to 3. The first multiplexing switch 130 includes 6 detection interfaces, i.e., detection interfaces S0, S1, S2, S3, S4, S5 of U1, for identifying open / short circuit faults of the first LED array; the first multiplexing switch 130 includes 3 control signal interfaces, i.e., control signal interfaces A2, A0, A1 of U1; the first control unit 110 outputs 3-bit control signals, i.e., MCU1_A2, MCU1_A0, MCU1_A1. The second multiplexing switch 140 includes 6 detection interfaces, i.e., detection interfaces S0, S1, S2, S3, S4, S5 of U2, for identifying open / short circuit faults of the second LED array; the second multiplexing switch 140 includes 3 control signal interfaces, i.e., control signal interfaces A2, A0, A1 of U2; the second control unit 120 outputs 3-bit control signals, i.e., MCU2_A2, MCU2_A0, MCU2_A1. The first signal conversion circuit 150 includes 3 diodes, i.e., diodes D1, D2, D3. The second signal conversion circuit 160 includes another 3 diodes, i.e., diodes D4, D5, D6.

[0037] The first control unit 110 outputs 3-bit control signals (or 3-bit control signals representing polling sampling) representing non-open / short circuit faults, for example, outputs 3-bit control signals 000-110 representing polling sampling to the 3 control signal interfaces (i.e., control signal interfaces A2, A0, A1 of U1) of the first multiplexing switch 150 in sequence, so as to poll sample the 6 detection interfaces (e.g., detection interfaces S0, S1, S2, S3, S4, S5 of U1) and one communication interface S6 of the first multiplexing switch 130 through the output interface D of the first multiplexing switch 130. If an open / short circuit fault of the first LED array (not shown) is detected, the 3-bit control signals output by the first control unit 110 are set to 111, that is, the 3-bit control signals representing open / short circuit faults output by the first control unit 110 are 111.

[0038] When the first control unit 110 outputs the 3-bit control signal 111 representing an open-short circuit fault, the voltage at the connection node between the resistor R1 and the resistor R2 is high, so that the first MOS transistor Q1 is turned on, at this time, the voltage at the connection node between the resistor R9 and the resistor R10 is low, that is, the first fault indication signal output by the first signal conversion circuit 150 is low (which can be referred to as a first logic level); when the first control unit 110 outputs the 3-bit control signal representing a non-open-short circuit fault (or the 3-bit control signal representing polling sampling), for example, outputs the 3-bit control signal representing polling sampling 000-110 in turn, the voltage at the connection node between the resistor R1 and the resistor R2 is low, so that the first MOS transistor Q1 is turned off, at this time, the voltage at the connection node between the resistor R9 and the resistor R10 is high, that is, the first fault indication signal output by the first signal conversion circuit 150 is high (which can be referred to as a second logic level).

[0039] The second control unit 120 outputs the 3-bit control signal representing a non-open-short circuit fault (or the 3-bit control signal representing polling sampling), for example, outputs the 3-bit control signal representing polling sampling 000-110 in turn to the 3 control signal interfaces of the second multiplexing switch 160 (that is, the control signal interfaces A2, A0, A1 of U2), so as to poll and sample the 6 detection interfaces (for example, the detection interfaces S0, S1, S2, S3, S4, S5 of U2) and one communication interface S6 of the second multiplexing switch 140 through the output interface D of the second multiplexing switch 140. If an open-short circuit fault of the second light-emitting diode array (not shown) is detected, the 3-bit control signal output by the second control unit 120 is set to 111, that is, the 3-bit control signal representing an open-short circuit fault output by the second control unit 120 is 111.

[0040] When the second control unit 120 outputs the 3-bit control signal 111 representing an open-short circuit fault, the voltage at the connection node between the resistor R4 and the resistor R5 is high, so that the second MOS transistor Q2 is turned on, at this time, the voltage at the connection node between the resistor R6 and the second MOS transistor Q2 is low, that is, the second fault indication signal output by the second signal conversion circuit 160 is low (which can be referred to as a first logic level); when the second control unit 120 outputs the 3-bit control signal representing a non-open-short circuit fault (or the 3-bit control signal representing polling sampling), for example, outputs the 3-bit control signal representing polling sampling 000-110 in turn, the voltage at the connection node between the resistor R4 and the resistor R5 is low, so that the second MOS transistor Q2 is turned off, at this time, the voltage at the connection node between the resistor R6 and the second MOS transistor Q2 is high, that is, the second fault indication signal output by the second signal conversion circuit 160 is high (which can be referred to as a second logic level).

[0041] As can be seen from the above, when the first control unit 110 detects the open short circuit fault, the second control unit 120 will detect that the level of the communication interface S6 of the second multiplex switch 140 changes from high to low during the polling sampling; when the second control unit 120 detects the open short circuit fault, the first control unit 110 will detect that the level of the communication interface S6 of the first multiplex switch 130 changes from high to low during the polling sampling.

[0042] In ​ and ​ In the specific embodiment shown in the figure, when the first control unit 110 detects the open short circuit fault and the first control unit 110 detects that the level of the communication interface S6 of the first multiplex switch 130 changes from high to low, it indicates that both the first control unit 110 and the second control unit 120 detect the open short circuit fault, at this time, only the first control unit 110 or the second control unit 120 can send a message to the LIN bus, and the message includes that both the first control unit 110 and the second control unit 120 detect the open short circuit fault. When the first control unit 110 does not detect the open short circuit fault and the first control unit 110 detects that the level of the communication interface S6 of the first multiplex switch 130 is high, it indicates that both the first control unit 110 and the second control unit 120 do not detect the open short circuit fault, at this time, only the first control unit 110 or the second control unit 120 can send a message to the LIN bus, and the message includes that both the first control unit 110 and the second control unit 120 do not detect the open short circuit fault. When the first control unit 110 does not detect the open short circuit fault and the first control unit 110 detects that the level of the communication interface of the first multiplex switch 130 changes from high to low, it indicates that the first control unit 110 does not detect the open short circuit fault, and the second control unit 120 detects the open short circuit fault, at this time, only the second control unit 120 which detects the open short circuit fault can send a message to the LIN bus, and the message includes that the first control unit 110 does not detect the open short circuit fault, and the second control unit 120 detects the open short circuit fault.

[0043] Similarly, when the second control unit 120 detects the open short circuit fault and the second control unit 120 detects that the level of the communication interface S6 of the second multiplexing switch 140 changes from high to low, it indicates that the first control unit 110 and the second control unit 120 both detect the open short circuit fault, at this time, only the first control unit 110 or the second control unit 120 can send a message to the LIN bus, and the message includes that the first control unit 110 and the second control unit 120 both detect the open short circuit fault. When the second control unit 120 does not detect the open short circuit fault and the second control unit 120 detects that the level of the communication interface S6 of the second multiplexing switch 140 is high, it indicates that the first control unit 110 and the second control unit 120 both do not detect the open short circuit fault, at this time, only the first control unit 110 or the second control unit 120 can send a message to the LIN bus, and the message includes that the first control unit 110 and the second control unit 120 both do not detect the open short circuit fault. When the second control unit 120 does not detect the open short circuit fault and the second control unit 120 detects that the level of the communication interface S6 of the second multiplexing switch 140 is low, it indicates that the second control unit 120 does not detect the open short circuit fault and the first control unit 110 detects the open short circuit fault, at this time, only the first control unit 110 which detects the open short circuit fault can send a message to the LIN bus, and the message includes that the second control unit 120 does not detect the open short circuit fault and the first control unit 110 detects the open short circuit fault.

[0044] That is to say, when a single control unit (or MCU) detects the open short circuit fault, the other control unit (or MCU) will detect that the level of the communication interface S6 changes from high to low, and when reporting the fault, the control unit which detects the level change of the communication interface S6 will not send a LIN message, and only the single control unit which detects the open short circuit fault can send a message. When both control units do not detect the open short circuit fault, the level of the communication interface S6 is high when polling sampling, at this time, only one of the control units is fixed to send a message to the bus. When both control units detect the open short circuit fault, the level of the communication interface S6 changes from high to low when polling sampling, at this time, only one of the control units is fixed to send a message to the bus, so that the situation of sending a message to a node and appearing "fighting" is avoided.

[0045] In summary, the present application realizes simple communication between two MCUs, thereby designing a circuit which can normally report the LED open short circuit fault under the premise that two MCUs only use one LIN node address and there is no extra MCU GPIO port, thereby ingeniously solving the factors of LIN node deficiency and insufficient MCU resources.

[0046] It should be noted that any modifications to the specific embodiments of the application made by a person skilled in the art do not depart from the scope of the claims of the application. Accordingly, the scope of the claims of the application is not limited only to the foregoing specific embodiments.

Claims

1. An LED open short detection circuit for an automotive vehicle, comprising: The circuit comprises a first control unit, a second control unit, a first multiplex switch, a second multiplex switch, a first signal conversion circuit and a second signal conversion circuit, The first control unit and the second control unit are connected to the same communication bus, and the first control unit and the second control unit share the same communication node on the communication bus; The first multiplex switch comprises a communication interface, an output interface, m detection interfaces and n control signal interfaces, the m detection interfaces are connected to the first LED array, the output interface is connected to the sampling interface of the first control unit, and the first control unit outputs n-bit control signals to the n control signal interfaces of the first multiplex switch; The second multiplex switch comprises a communication interface, an output interface, m detection interfaces and n control signal interfaces, the m detection interfaces are connected to the second LED array, the output interface is connected to the sampling interface of the second control unit, and the second control unit outputs n-bit control signals to the n control signal interfaces of the second multiplex switch; The input end of the first signal conversion circuit receives the n-bit control signals output by the first control unit, the output end is connected to the communication interface of the second multiplex switch, and the first signal conversion circuit outputs corresponding first fault indication signals to the communication interface of the second multiplex switch through the output end based on the n-bit control signals output by the first control unit; The input end of the second signal conversion circuit receives the n-bit control signals output by the second control unit, the output end is connected to the communication interface of the first multiplex switch, and the second signal conversion circuit outputs corresponding second fault indication signals to the communication interface of the first multiplex switch through the output end based on the n-bit control signals output by the second control unit, wherein m and n are positive integers.

2. The vehicle-mounted LED open / short circuit detection circuit according to claim 1, characterized in that The first control unit outputs n-bit control signals representing non-open / short circuit faults to the n control signal interfaces of the first multiplex switch to poll and sample the communication interface and the m detection interfaces of the first multiplex switch through the n control signal interfaces of the first multiplex switch; The first control unit determines whether the first LED array has an open / short circuit fault based on the polling and sampling of the m detection interfaces of the first multiplex switch, and if it is detected that the first LED array has an open / short circuit fault, the first control unit outputs n-bit control signals representing open / short circuit faults; The second control unit outputs n-bit control signals representing non-open / short circuit faults to the n control signal interfaces of the second multiplex switch to poll and sample the communication interface and the m detection interfaces of the second multiplex switch through the n control signal interfaces of the second multiplex switch; The second control unit determines whether the second LED array has an open short circuit fault based on polling sampling of m detection interfaces of the second multiplexing switch, and outputs an n-bit control signal indicating an open short circuit fault if the second LED array is detected to have an open short circuit fault.

3. The vehicle-mounted LED open short circuit detection circuit according to claim 2, characterized in that, when the first control unit outputs the n-bit control signal indicating an open short circuit fault, the first signal conversion circuit outputs a first fault indication signal at a first logic level to the communication interface of the second multiplexing switch, the first fault indication signal at the first logic level indicating that the first control unit detects an open short circuit fault; when the first control unit outputs the n-bit control signal indicating a non-open short circuit fault, the first signal conversion circuit outputs a second fault indication signal at a second logic level to the communication interface of the second multiplexing switch, the second fault indication signal at the second logic level indicating that the first control unit does not detect an open short circuit fault; when the second control unit outputs the n-bit control signal indicating an open short circuit fault, the second signal conversion circuit outputs a second fault indication signal at a first logic level to the communication interface of the first multiplexing switch, the second fault indication signal at the first logic level indicating that the second control unit detects an open short circuit fault; when the second control unit outputs the n-bit control signal indicating a non-open short circuit fault, the second signal conversion circuit outputs a second fault indication signal at a second logic level to the communication interface of the first multiplexing switch, the second fault indication signal at the second logic level indicating that the second control unit does not detect an open short circuit fault.

4. The vehicle-mounted LED open short circuit detection circuit according to claim 3, characterized in that, when the first control unit detects an open short circuit fault and the first control unit detects that the second fault indication signal received by the communication interface of the first multiplexing switch is at the first logic level, only the first control unit or the second control unit sends a first message to the communication bus, when the first control unit does not detect an open short circuit fault and the first control unit detects that the second fault indication signal received by the communication interface of the first multiplexing switch is at the second logic level, only the first control unit or the second control unit sends a second message to the communication bus; when the first control unit does not detect an open short circuit fault and the first control unit detects that the second fault indication signal received by the communication interface of the first multiplexing switch is at the first logic level, only the second control unit sends a third message to the communication bus.

5. The vehicle-mounted LED open short circuit detection circuit according to claim 4, characterized in that, when the second control unit detects an open short circuit fault and the second control unit detects that the first fault indication signal received by the communication interface of the second multiplexing switch is at a first logic level, only the first control unit or the second control unit sends the first message to the communication bus; when the second control unit does not detect an open short circuit fault and the second control unit detects that the first fault indication signal received by the communication interface of the second multiplexing switch is at a second logic level, only the first control unit or the second control unit sends the second message to the communication bus; when the second control unit does not detect an open short circuit fault and the second control unit detects that the fault indication signal received by the communication interface of the second multiplexing switch is at a first logic level, only the first control unit sends the fourth message to the communication bus.

6. The vehicle-mounted LED open short circuit detection circuit according to claim 5, wherein the first message comprises that the first control unit and the second control unit both detect an open short circuit fault; the second message comprises that the first control unit and the second control unit both do not detect an open short circuit fault; the third message comprises that the first control unit does not detect an open short circuit fault and the second control unit detects an open short circuit fault; the fourth message comprises that the second control unit does not detect an open short circuit fault and the first control unit detects an open short circuit fault.

7. The vehicle-mounted LED open short circuit detection circuit according to any one of claims 1-6, wherein the first signal conversion circuit comprises n diodes, a resistor R1, a resistor R2, a resistor R3, a resistor R9, a resistor R10 and a first MOS tube Q1, the resistor R1 and the resistor R2 are connected in series between an input voltage end VIN and a ground end in sequence; the resistor R3, the resistor R9 and the resistor R10 are connected in series between the input voltage end VIN and the ground end in sequence; the cathodes of the n diodes are connected to n control signal interfaces of the first multiplexing switch respectively, the anodes of the n diodes are connected to a connection node between the resistor R1 and the resistor R2; the control end of the first MOS tube Q1 is connected to the connection node between the resistor R1 and the resistor R2, the first connection end of the first MOS tube Q1 is connected to a connection node between the resistor R3 and the resistor R9, and the second connection end of the first MOS tube Q1 is grounded; a connection node between the resistor R9 and the resistor R10 is connected to a communication interface of the second multiplexing switch as an output end of the first signal conversion circuit. The second signal conversion circuit comprises another n diodes, a resistor R4, a resistor R5, a resistor R6 and a second MOS tube Q2, the resistor R4 and the resistor R5 are connected in series between an input voltage terminal VIN and a ground terminal in sequence; the cathodes of the another n diodes are connected with n control signal interfaces of the second multiplex switch respectively, the anodes of the another n diodes are connected with a connection node between the resistor R4 and the resistor R5; the control terminal of the second MOS tube Q2 is connected with the connection node between the resistor R4 and the resistor R5, the first connection terminal of the second MOS tube Q2 is connected with the input voltage terminal VIN through the resistor R6, and the second connection terminal of the second MOS tube Q2 is grounded; and the connection node between the second MOS tube Q2 and the resistor R6 is connected with a communication interface of the first multiplex switch as an output terminal of the second signal conversion circuit.

8. The vehicle-mounted LED open / short circuit detection circuit according to claim 7, characterized in that, when the first control unit outputs n-bit control signals representing an open / short circuit fault, the first MOS tube Q1 is turned on, and the first fault indication signal output by the first signal conversion circuit is a first logic level; when the first control unit outputs n-bit control signals representing a non-open / short circuit fault, the first MOS tube Q1 is turned off, and the first fault indication signal output by the first signal conversion circuit is a second logic level; when the second control unit outputs n-bit control signals representing an open / short circuit fault, the second MOS tube Q2 is turned on, and the second fault indication signal output by the second signal conversion circuit is a first logic level; when the second control unit outputs n-bit control signals representing a non-open / short circuit fault, the second MOS tube Q2 is turned off, and the second fault indication signal output by the second signal conversion circuit is a second logic level.

9. The vehicle-mounted LED open / short circuit detection circuit according to claim 8, characterized in that, the n-bit control signals representing an open / short circuit fault output by the first control unit are n 1s, the first MOS tube Q1 is an NMOS transistor, and the first connection terminal, the second connection terminal and the control terminal of the first MOS tube Q1 are the drain, the source and the gate of the NMOS transistor respectively; the n-bit control signals representing an open / short circuit fault output by the second control unit are n 1s, the second MOS tube Q2 is an NMOS transistor, and the first connection terminal, the second connection terminal and the control terminal of the second MOS tube Q2 are the drain, the source and the gate of the NMOS transistor respectively.

10. The vehicle-mounted LED open / short circuit detection circuit according to claim 9, characterized in that, n = 3, m = 6, the first logic level of the first fault indication signal output by the first signal conversion circuit is a low level, and the second logic level thereof is a high level; the first logic level of the second fault indication signal output by the second signal conversion circuit is a low level, and the second logic level thereof is a high level.

11. The vehicle-mounted LED open / short circuit detection circuit according to claim 1, characterized in that, the communication bus is a LIN bus; and the communication node is a LIN node.

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