Vehicle-mounted relay diagnosis circuit and test equipment

Abstract

The invention belongs to the related technical field of diagnosis circuits, and particularly relates to a vehicle-mounted relay diagnosis circuit and test equipment. A first switching circuit, namely a low-side driving circuit body, and a second switching circuit, namely a load circuit, are arranged in a low-side driving circuit; the first switch circuit is provided with a first sampling circuit, and the first sampling circuit collects a signal of a first output end and outputs a first sampling signal through a first sampling output end. A second sampling circuit is arranged on the second switch circuit, and the second sampling circuit collects a signal of a second driving end and outputs a second sampling signal through a second sampling output end; and the diagnosis circuit diagnoses the low-side driving circuit according to the first sampling signal and the second sampling signal. Therefore, the low-side driving circuit can distinguish the ground short circuit and open circuit of the low-side driving circuit and the ground short circuit and open circuit of the load end of the low-side driving circuit through the first sampling signal and the second sampling signal.

Description

Technical Field

[0001] The present invention belongs to the technical field related to diagnostic circuits, and in particular relates to a vehicle-mounted relay diagnostic circuit and testing equipment. Background Art

[0002] In the process of using the vehicle relay, the low-side circuit is often used for driving. In actual use, circuit failure is inevitable. Therefore, when returning the relay to the factory for repair, the circuit needs to be tested as a whole to determine the specific fault problem.

[0003] In actual use, common circuit faults include short circuit to ground and open circuit faults. When judging circuit faults, it is further divided into four types: short circuit to ground of the low-side circuit itself, open circuit fault of the low-side circuit itself, short circuit to ground of the low-side circuit peripheral load circuit, and short circuit to ground of the low-side peripheral load circuit. When detecting these four faults, the sampling level is low level.

[0004] Therefore, in the prior art, it is not possible to directly distinguish the above four types of circuit failures. Summary of the invention

[0005] Based on the above problems, the present invention proposes a vehicle-mounted relay diagnostic circuit, which sets two diagnostic circuits, one for detecting a short circuit to ground and an open circuit in a low-side drive circuit, and the other for detecting a short circuit to ground and an open circuit in a load circuit, so as to distinguish and detect four fault problems, thereby accurately locating circuit problems.

[0006] The content of the present invention is achieved through the following content:

[0007] In a first aspect, the present invention provides a low-side driver diagnostic circuit, comprising:

[0008] The low-side driving circuit includes a first switch circuit and a second switch circuit. The first switch circuit is provided with a first control end and a first output end, and the second switch circuit is provided with a second control end and a second driving end. The first control end is connected to an external signal, the first output end is drivingly connected to the second control end, and the second driving end is drivingly connected to a load device.

[0009] A first sampling circuit is provided with a first sampling terminal and a first sampling output terminal, the first sampling terminal is connected to the first output terminal, the first sampling circuit collects a signal at the first output terminal and outputs a first sampling signal through the first sampling output terminal;

[0010] A second sampling circuit is provided with a second sampling end and a second sampling output end, the second sampling end is connected to the second driving end, the second sampling circuit collects the signal of the second driving end and outputs the second sampling signal through the second sampling output end;

[0011] and a diagnosis circuit connected to the first sampling output terminal and the second sampling output terminal, and diagnosing the low-side driving circuit according to the first sampling signal and the second sampling signal.

[0012] The invention provides a first switch circuit, i.e., the main body of the low-side drive circuit, and a second switch circuit, i.e., the load circuit, in the low-side drive circuit; a first sampling circuit is provided on the first switch circuit, the first sampling circuit collects the signal of the first output terminal and outputs the first sampling signal through the first sampling output terminal; a second sampling circuit is provided on the second switch circuit, the second sampling circuit collects the signal of the second drive terminal and outputs the second sampling signal through the second sampling output terminal; and a diagnostic circuit is provided, the diagnostic circuit diagnoses the low-side drive circuit according to the first sampling signal and the second sampling signal. The low-side drive circuit can distinguish the short circuit and open circuit to the ground of the low-side drive circuit itself and the short circuit and open circuit to the ground of the load terminal of the low-side drive circuit through the first sampling signal and the second sampling signal.

[0013] In some embodiments, the first sampling circuit further includes a third switch circuit, the third switch circuit being provided with a first voltage input terminal, a diagnosis enable terminal, and a switch output terminal;

[0014] The first voltage input terminal is connected to the first control voltage terminal, the diagnosis enable terminal is connected to the second control voltage terminal, the first control voltage and the second control voltage are connected to the input power supply; and the switch output terminal is connected to the first control terminal.

[0015] The first voltage input terminal is connected to the first output terminal through the switch output terminal through the diagnostic enable terminal on the switch circuit to provide a pull-up voltage. When detecting a short circuit to ground and an open circuit, the first sampling circuit will affect the detection result of the short circuit to ground and the open circuit, and the switch circuit will not affect the main circuit when not detected through the diagnostic enable terminal.

[0016] In some embodiments, the third switch circuit includes a first transistor, a second transistor, a first resistor, and a second resistor; the first transistor is an NPN transistor, and the second transistor is a PNP transistor;

[0017] The base of the first transistor, one end of the first resistor, and the diagnosis enable terminal are connected; the emitter of the first transistor is connected to the base of the second transistor; the emitter of the second transistor is connected to the first voltage input terminal, the collector of the second transistor is connected to one end of the second resistor, and the other end of the second resistor is the switch output terminal; the collector of the first transistor and the other end of the first resistor are connected at the same potential.

[0018] The third switch circuit controls the on and off of the two transistors through the diagnostic enable terminal, and connects the first voltage input terminal to the first output terminal, so that when the first output terminal is open-circuited, the first voltage input terminal is used as a pull-up voltage, so that the open-circuit sampling will collect a high level, and when it is short-circuited to the ground, the sampling value is a low level.

[0019] In some implementations, a first sampling circuit is provided between the first sampling terminal and the first sampling output terminal, and the first sampling circuit includes a third resistor, a fourth resistor, and a first capacitor;

[0020] One end of the third resistor is the first sampling end, and the other end of the third resistor is connected to one end of the fourth resistor, one end of the first capacitor, and the first sampling output end; the other end of the fourth resistor and the other end of the first capacitor are grounded.

[0021] The first sampling circuit is mainly used to collect the level value or voltage value of the low-side driving circuit to determine the fault of the bottom-side driving circuit.

[0022] In some embodiments, the second switching circuit includes a driving switch, including a second voltage input terminal, a third voltage input terminal, a load output terminal, and a first input terminal; the second voltage input terminal and the third voltage input terminal are connected to an external power supply, the first input terminal is connected to the first output terminal, and the load output terminal is a second driving terminal and is connected to a load device.

[0023] A driving switch is provided in the driving circuit, which distinguishes the current in the circuit when it is open circuit or short circuit to ground, so as to connect the third voltage input terminal with the load output terminal, so that the second sampling signal collected by the second sampling circuit generates different level values ​​when it is short circuit to ground or open circuit, so as to distinguish the two faults.

[0024] In some implementations, the driving switch includes a relay or a multiplexer.

[0025] Through a relay or a multiplexer, when a short circuit or an open circuit occurs to the ground, the change in current causes the internal switch of the relay to close, thereby turning on the third voltage input terminal and causing a difference between a high level and a low level to appear when detecting a short circuit or an open circuit to the ground.

[0026] In some embodiments, the second sampling circuit is provided with a second sampling circuit, and the second sampling circuit is arranged between the second sampling terminal and the second sampling output terminal; the second sampling terminal is connected to the load output terminal and is connected to the load device driver.

[0027] The second sampling circuit collects the signal at the load output end through the second sampling signal, and the second acquisition signal is specifically set at the load output end to distinguish and detect the short circuit and open circuit to ground of the load end circuit, and further distinguish the fault of the low-side drive circuit, so as to realize the separate detection of the four faults.

[0028] In some embodiments, the second sampling circuit includes a fifth resistor and a sixth resistor;

[0029] One end of the fifth resistor is the second sampling end and is connected to the second sampling end, the other end of the fifth resistor is connected to one end of the sixth resistor, and the other end of the sixth resistor is grounded and connected to the second sampling output end.

[0030] Through the second sampling circuit, when the circuit is open, the data is collected as a low level state, and when the circuit is short-circuited to the ground, the data is collected as a high level state, thereby distinguishing the faults of the open circuit and the short circuit to the ground.

[0031] In some embodiments, the first switch circuit includes a control switch and a diode; the control switch is a field effect transistor, one end of the first control terminal is connected to one end of the diode, and the other end is connected to the gate of the control field effect transistor to achieve conduction of the first control terminal.

[0032] The control switch realizes the on-off of the first control terminal through the field effect tube and the anti-reverse diode, and further controls the gate of the field effect tube, so that the first control terminal controls the field effect tube to be turned on.

[0033] In a second aspect, the present invention proposes a test device, comprising any one of the low-side driver diagnostic circuits mentioned in the first aspect, the test device being provided with a test plug terminal, wherein the plurality of test plug terminals are respectively connected to a first input terminal, a first sampling terminal, and a second sampling terminal; so that the first sampling circuit and the second sampling circuit are connected to the low-side driver circuit.

[0034] By providing a plug-in terminal on the test equipment, the first sampling circuit and the second sampling circuit can be plugged into the low-side driving circuit, so as to further prevent the diagnostic circuit from affecting the normal operation of the low-side driving circuit when in use.

[0035] The beneficial effects of the vehicle-mounted relay diagnostic circuit and test equipment of the present invention are:

[0036] The invention provides a first switch circuit, i.e., the main body of the low-side drive circuit, and a second switch circuit, i.e., the load circuit, in the low-side drive circuit; a first sampling circuit is provided on the first switch circuit, the first sampling circuit collects the signal of the first output terminal and outputs the first sampling signal through the first sampling output terminal; a second sampling circuit is provided on the second switch circuit, the second sampling circuit collects the signal of the second drive terminal and outputs the second sampling signal through the second sampling output terminal; and a diagnostic circuit is provided, the diagnostic circuit diagnoses the low-side drive circuit according to the first sampling signal and the second sampling signal. The low-side drive circuit can distinguish the short circuit and open circuit to the ground of the low-side drive circuit itself and the short circuit and open circuit to the ground of the load terminal of the low-side drive circuit through the first sampling signal and the second sampling signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A circuit framework diagram of a vehicle-mounted relay diagnostic circuit of the present invention;

[0038] Figure 2 A circuit for a vehicle-mounted relay diagnostic circuit of the present invention Figure 1 ;

[0039] Figure 3 A circuit for a vehicle-mounted relay diagnostic circuit of the present invention Figure 2 ;

[0040] Figure 4 A circuit for a vehicle-mounted relay diagnostic circuit of the present invention Figure 3 ;

[0041] Figure 5 The invention provides a testing device.

[0042] Reference numerals:

[0043] R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor;

[0044] C1, first capacitor;

[0045] Q1, the first transistor; Q2, the second transistor; Q3, the control switch;

[0046] D1, diode;

[0047] MCU_control, the first control terminal; output, the first output terminal; EN, the diagnostic enable terminal;

[0048] U1, relay; U1_1, second voltage input terminal; U1_2, third voltage input terminal; U1_3, first input terminal; U1_4, load output terminal;

[0049] MCU_1, first sampling output terminal; MCU_2, second sampling output terminal;

[0050] VCC_1, first control voltage; VCC_2, second control voltage; VCC_3, first voltage input terminal;

[0051] A. The third switching circuit; B. The first sampling circuit; C. The second sampling circuit. DETAILED DESCRIPTION

[0052] The preferred embodiments of the present application are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present application can be more easily understood by those skilled in the art, thereby making a clearer definition of the protection scope of the present application.

[0053] Please refer to the drawings, where the same component symbols represent the same components, and the principles of the present application are illustrated by implementing them in an appropriate computing environment. The following description is based on the illustrated specific embodiments of the present application, which should not be considered as limiting other specific embodiments of the present application that are not described in detail herein.

[0054] The term "module" as used herein may be a software or hardware object executed on the computing system. The different components, modules, engines, and services described herein may be implementation objects on the computing system. The apparatus and methods described herein may be implemented in software, or in hardware, and all are within the scope of protection of this application.

[0055] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0056] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0057] Embodiment 1:

[0058] like Figure 1-2 As shown, a low-side driver diagnostic circuit includes:

[0059] The low-side driving circuit includes a first switch circuit and a second switch circuit. The first switch circuit is provided with a first control terminal MCU_control and a first output terminal output, and the second switch circuit is provided with a second control terminal and a second driving terminal. The first control terminal MCU_control is connected to an external signal, the first output terminal output is drivingly connected to the second control terminal, and the second driving terminal is drivingly connected to a load device.

[0060] The first sampling circuit is provided with a first sampling terminal and a first sampling output terminal MCU_1, the first sampling terminal is connected to the first driving terminal, the first acquisition circuit acquires the signal of the first output terminal output and outputs the first sampling signal through the first sampling output terminal MCU_1;

[0061] The second sampling circuit is provided with a second sampling terminal and a second sampling output terminal MCU_2, the second sampling terminal is connected to the second driving terminal, the second acquisition circuit acquires the signal of the second driving terminal and outputs the second sampling signal through the second sampling output terminal MCU_2;

[0062] And a diagnosis circuit is connected to the first sampling output terminal MCU_1 and the second sampling output terminal MCU_2, and diagnoses the low-side driving circuit according to the first sampling signal and the second sampling signal.

[0063] Specifically, the low-side driving circuit is between the first control terminal MCU_control and the first output terminal output of the low-side driving circuit, and the load device connected through the first output terminal output is the load circuit. Under normal circumstances, the low-side driving circuit controls the first control terminal MCU_control to be turned on and off through the MCU, and then the specific problem of the circuit is determined through the diagnostic circuit of the MCU. When the circuits at both ends of the low-side driving circuit and the load circuit detect problems, if a single diagnostic circuit is used to collect a single acquisition signal, the problem location will be inaccurate, because the two circuits show the same situation when the problem occurs, so it is impossible to distinguish the specific circuit part where the problem occurs. At the same time, when the low-side driving circuit and the load circuit are detected, the connection parts of the sampling circuits of the two are different, so two diagnostic circuits are required for detection. Therefore, when detecting the low-side driving circuit, a first sampling circuit can be set, which is set at the first output terminal output, to detect short circuit to ground and open circuit through the first sampling signal sampled by the first sampling output terminal MCU_1, and the method can be through the voltage value and level value of the first output terminal output when the short circuit to ground or the open circuit changes to distinguish the short circuit to ground and the open circuit. When detecting the load circuit, since the load circuit driven by the low-side driving circuit is usually in the form of having a second switch circuit and connected to the load, the characteristics of the second switch circuit can be used, and the current value makes the second switch circuit on and off, so that the output voltage of the second switch circuit changes, thereby distinguishing the two situations of short circuit and open circuit to ground of the load circuit. The above method can be realized by using a current threshold on-off device. The current values ​​of the short circuit and open circuit are mainly used to cause the on-off of the switch circuit to be different. According to this method, it can be detected whether the switch circuit is on and off, or an on-off signal is set at the output end of the switch circuit. When the second switch circuit is turned on, the on-off signal is output, and the on-off signal can be used as the second sampling signal sampled by the second sampling output end MCU_2 to determine the current circuit state. And by setting a diagnostic circuit, the diagnostic circuit can be an MCU, the first sampling signal and the second sampling signal are input into the MCU, and the MCU determines the level signal, or the diagnostic circuit can be a processing chip with a digital signal, or a single-chip microcomputer.

[0064] The beneficial effect of this embodiment is that a first switch circuit, i.e., the low-side drive circuit body, and a second switch circuit, i.e., the load circuit, are provided; a first sampling circuit is provided on the first switch circuit, the first sampling circuit collects the signal of the first output terminal output and outputs the first sampling signal through the first sampling output terminal MCU_1; a second sampling circuit is provided on the second switch circuit, the second sampling circuit collects the signal of the second drive terminal and outputs the second sampling signal through the second sampling output terminal MCU_2; and a diagnostic circuit is connected to the first sampling output terminal MCU_1 and the second sampling output terminal MCU_2, and the low-side drive circuit is diagnosed according to the first sampling signal and the second sampling signal. So that the low-side drive circuit can distinguish the short circuit and open circuit to the ground of the low-side drive circuit itself through the first sampling signal and the second sampling signal; and at the same time, the short circuit and open circuit to the ground of the load terminal of the low-side drive circuit can also be distinguished. Thus, the circuit problem can be accurately located.

[0065] Embodiment 2:

[0066] Please refer to Figure 2 , and combined with Figure 3-4 Based on Example 1, this example further optimizes and explains the circuit structure proposed in Example 1.

[0067] In some embodiments, the first sampling circuit further includes a third switch circuit A, and the third switch circuit A is provided with a first voltage input terminal VCC_3, a diagnosis enable terminal EN, and a switch output terminal;

[0068] The first voltage input terminal VCC_3 is connected to the first control voltage VCC_1 terminal, the diagnosis enable terminal EN is connected to the second control voltage VCC_2 terminal, the first control voltage VCC_1 and the second control voltage VCC_2 are connected to the input power supply; the switch output terminal is connected to the first control terminal MCU_control.

[0069] Specifically, the first sampling circuit mainly includes a third switch circuit A and a first sampling circuit B. The third switch circuit A is used to connect the pull-up voltage or other signals to affect the detection result of the open circuit and the short circuit to the ground in the first sampling circuit B. The third switch circuit A can also disconnect the circuit when the short circuit and the open circuit are not detected, so as to reduce the influence of the pull-up voltage on the circuit, so that the first sampling circuit can exist as a bypass. The third switch circuit A can be applied to the on-off mode with switch properties such as the on-off of the transistor D1, the on-off of the MOS tube, and the on-off of the relay U1, wherein the transistor D1 can be all PNP, or all NPN, or a combination of NPN and PNP. It can be switched through the diagnostic enable terminal EN, and the diagnostic enable terminal EN can be opened when a short circuit and an open circuit are detected, so that the first sampling circuit is connected to the low-side drive circuit. The level value of the sampling circuit through the first sampling circuit B, after being affected by the third switch circuit A, the level value of the short circuit to the ground and the open circuit presents different level states, so it can be distinguished.

[0070] The beneficial effect of this method is that the first voltage input terminal VCC_3 is connected to the first output terminal output through the switch output terminal through the diagnostic enable terminal EN on the third switch circuit A to provide a pull-up voltage. When detecting a short circuit to ground and an open circuit, the first sampling circuit B will affect the detection result of the short circuit to ground and the open circuit, and the third switch circuit A will not affect the main circuit when not being detected through the diagnostic enable terminal EN.

[0071] In some embodiments, the third switch circuit A includes a first transistor Q1, a second transistor Q2, a first resistor R1, and a second resistor R2; the first transistor Q1 is an NPN transistor, and the second transistor Q2 is a PNP transistor;

[0072] The base of the first transistor Q1, one end of the first resistor R1, and the diagnosis enable terminal EN are connected; the emitter of the first transistor Q1 is connected to the base of the second transistor Q2; the emitter of the second transistor Q2 is connected to the first voltage input terminal VCC_3, the collector of the second transistor Q2 is connected to one end of the second resistor R2, and the other end of the second resistor R2 is the switch output terminal; the collector of the first transistor Q1 and the other end of the first resistor R1 are connected to the same potential.

[0073] Specifically, the third switch circuit A is formed by turning on and off the first transistor Q1 and the second transistor Q2. The first transistor Q1 is turned on and off by controlling the base of the first transistor Q1. When the first transistor Q1 is turned on and off, the second transistor Q2 is controlled to be turned on and off. The first transistor Q1 is an NPN transistor D1, and the second transistor Q2 is a PNP transistor D1. By mixing the two transistors D1, the reliability of the switch can be improved.

[0074] The beneficial effect of this method is that the third switch circuit A controls the on and off of the two transistors D1 through the diagnostic enable terminal EN, and connects the first voltage input terminal VCC_3 to the first output terminal output, so that when the first output terminal output is open, the first voltage input terminal VCC_3 is used as a pull-up voltage, so that the open circuit sampling will collect a high level, and when it is short-circuited to the ground, the sampling value is a low level. And by changing the resistance values ​​of the first resistor R1 and the second resistor R2, it is achieved that the 9-16V voltage can meet the high and low level thresholds. In some embodiments, the first resistor R1 and the second resistor R2 can be 4.7K.

[0075] In some embodiments, a first sampling circuit is disposed between the first sampling terminal and the first output terminal output, and the first sampling circuit includes a third resistor R3, a fourth resistor R4, and a first capacitor C1;

[0076] One end of the third resistor R3 is the first sampling end, and the other end of the third resistor R3 is connected to one end of the fourth resistor R4 and one end of the first capacitor C1; the other end of the fourth resistor R4 and the other end of the first capacitor C1 are grounded.

[0077] Specifically, the first sampling circuit B performs voltage division through the third resistor R3, and the fourth resistor R4 and the first capacitor C1 perform filtering to improve the accuracy of sampling and acquisition. Further, additional resistors and capacitors can be added, and the sizes of unused capacitors and resistors can be set to achieve filtering and noise separation for different bands. The beneficial effect of this method is that the first sampling circuit B is mainly used to collect the level value or voltage value of the low-side drive circuit to determine the fault of the bottom-side drive circuit. Among them, the third resistor R3 and the fourth resistor R4 can be 47K, and by changing the resistance values ​​of the first resistor R1 and the second resistor R2, it is achieved that the voltage of 9 to 16V can meet the high and low level thresholds. The first capacitor C1 can be 100PF.

[0078] In some embodiments, the second switching circuit includes a driving switch, including a second voltage input terminal U1_1, a third voltage input terminal U1_2, a load output terminal U1_4, and a first input terminal U1_3; the second voltage input terminal U1_1 and the third voltage input terminal U1_2 are connected to an external power supply, the first input terminal U1_3 is connected to the first output terminal output, and the load output terminal U1_4 is a second driving terminal and is connected to a load device.

[0079] Specifically, when the output load circuit does not have a driving switch or a third switch circuit A, a driving switch can be added, and the driving switch is mainly turned on and off by the change of current. Through the current on and off, the driving switch can be turned on and off by using the inconsistency of the circuit current of the two faults of open circuit and short circuit to ground when the level detection is consistent, and then the two faults can be distinguished. In order to further achieve the distinction, a second voltage input terminal U1_1 is set, and the second voltage input terminal U1_1 can be a constant voltage, such as 12V, etc., or it can be an external control power supply. The second voltage input terminal U1_1 mainly meets the start-up voltage of the driving switch, and a third voltage input terminal U1_2 is also set. The third voltage input terminal U1_2 can be an electrical signal, which can be a constant voltage, such as 12V, etc., so that when the relay U1 is turned on, a certain signal can be output, such as a voltage signal, a constant voltage value, an electrical signal, etc. The second sampling signal can be collected by the second sampling circuit C connected to the output end of the driving switch to distinguish between open circuit and short circuit to ground. Based on the above circuit design, when the circuit is open, the driving switch is not turned on, so that the second sampling signal is low level. When the ground is short-circuited, the relay U1 is turned on, thereby collecting a high level from the second sampling signal.

[0080] The beneficial effect of this method is that a driving switch is provided in the driving circuit, and the current in the circuit is distinguished by an open circuit and a short circuit to ground, so that the third voltage input terminal U1_2 is connected with the load output terminal U1_4, so that the second sampling signal collected by the second sampling circuit C generates different level values ​​when it is short-circuited to ground or open-circuited to ground to distinguish the two faults.

[0081] In some embodiments, the driving switch includes a relay U1 and a multiplexer.

[0082] Specifically, through the relay U1 and the multiplexer, when there is a short circuit to ground or an open circuit, due to the different currents of the two faults in the circuit, the relay U1 can be opened when there is a short circuit, but not opened when there is an open circuit, so that the output end of the relay U1 can produce a differential output, and then judge the two faults of the load circuit being short circuit to ground and the load circuit being open.

[0083] The beneficial effect of this method is that, through the relay U1 or the multiplexer, when the circuit is short-circuited to the ground or open-circuited, the change in current causes the internal switch of the relay U1 to close, thereby turning on the third voltage input terminal U1_2 and causing a difference between a high level and a low level to appear when detecting a short-circuit to the ground or an open circuit.

[0084] In some embodiments, the second sampling circuit is provided with a second sampling circuit, and the second sampling circuit is provided between the second sampling terminal and the second sampling output terminal MCU_2; the second sampling terminal is connected to the load output terminal U1_4 and is connected to the floating device driver.

[0085] Specifically, the second sampling circuit C can be set as an analog signal acquisition terminal or a digital signal acquisition terminal, and digital acquisition or analog acquisition is set according to the third voltage input terminal U1_2, and the load output terminal U1_4 is acquired by the second sampling terminal, and the second sampling output terminal MCU_2 outputs the second sampling signal to the external signal analysis device. The beneficial effect of this method is that the second sampling circuit C uses the second sampling signal, and the second acquisition signal is specifically set on the load output terminal to acquire the signal of the load output terminal U1_4, so as to distinguish and detect the short circuit to ground and the open circuit of the load terminal circuit, and further distinguish the fault of the low-side drive circuit, so as to realize the separate detection of the four faults.

[0086] In some embodiments, the second sampling circuit C includes a fifth resistor R5 and a sixth resistor R6;

[0087] One end of the fifth resistor R5 is the second sampling end, the other end of the fifth resistor R5 is connected to one end of the sixth resistor R6, the other end of the sixth resistor R6 is grounded and connected to the second sampling output end MCU_2, and the other end of the sixth resistor R6 is grounded.

[0088] Specifically, the fifth resistor R5 can be used as a protection and filtering resistor, and the sixth resistor R6 can also be used as a filtering resistor. When designing, inductors, resistors, and capacitors can be used to add filtering in the circuit to improve the accuracy of the sampled second sampling signal. The fifth resistor R5 and the sixth resistor R6 can both be set to 47K.

[0089] Through the second sampling circuit C, when the circuit is open, the low level state is collected, and when the circuit is short-circuited to the ground, the high level state is collected, so as to distinguish the faults of the open circuit and the short circuit to the ground.

[0090] In some embodiments, the first switch circuit includes a control switch Q3 and a diode D1; the control switch Q3 is a field effect transistor, one end of which is connected to one end of the diode D1 through the first control terminal MCU_control, and the other end is connected to the gate of the control field effect transistor, so as to realize the first control terminal MCU_control is turned on.

[0091] Specifically, the first switch circuit is turned on and off by controlling the switch Q3 to realize the overall output control, and the anti-reverse diode D1 is set to prevent the current from flowing back and causing damage to the overall circuit. In addition, the field effect tube can be set to an N-MOS type, the drain of the field effect tube is connected to the first output terminal output, and the source of the field effect tube is grounded.

[0092] The control switch Q3 realizes the on-off of the first control terminal MCU_control through the field effect tube and the anti-reverse diode D1, and further controls the gate of the field effect tube to realize the conduction of the first control terminal MCU_control.

[0093] Embodiment 3:

[0094] like Figure 5 As shown, this embodiment is based on Embodiment 1 and Embodiment 2. The present invention proposes a test device, including any one of the low-side driver diagnostic circuits mentioned in the first aspect. The test device is provided with a test plug terminal, and the plurality of test plug terminals are respectively connected to the first input terminal U1_3, the first sampling terminal, and the second sampling terminal; so that the first sampling circuit and the second sampling circuit are connected to the low-side driver circuit.

[0095] Specifically, the test equipment can be provided with a machine platform, and the machine platform extends multiple test differential stages. The test plug end can be a probe, a contact, a metal clip, etc. The test plug end is extended from the first input end U1_3, the first sampling end, and the second sampling end, and can be detachably connected to the circuit to achieve the connection and separation of the first sampling circuit and the second sampling circuit. It can also achieve flexible connection of the first sampling circuit and the second sampling circuit to the circuit separately, so that the diagnosis can be more flexible and will not affect the normal circuit operation.

[0096] By providing a plug-in terminal on the test equipment, the first sampling circuit and the second sampling circuit can be plugged into the low-side driving circuit, so as to further prevent the diagnostic circuit from affecting the normal operation of the low-side driving circuit when in use.

[0097] The implementation modes of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present application.

Claims

1. A low-side driver diagnostic circuit, characterized in that: include: A low-side drive circuit comprises a first switch circuit and a second switch circuit, wherein the first switch circuit is provided with a first control end and a first output end, and the second switch circuit is provided with a second control end and a second drive end; the first control end is connected to an external signal, the first output end is drive-connected to the second control end, and the second drive end is drive-connected to a load device; A first sampling circuit is provided with a first sampling end and a first sampling output end, wherein the first sampling end is connected to the first output end, and the first sampling circuit collects a signal at the first output end and outputs a first sampling signal through the first sampling output end; A second sampling circuit is provided with a second sampling end and a second sampling output end, wherein the second sampling end is connected to the second driving end, and the second sampling circuit collects a signal from the second driving end and outputs a second sampling signal through the second sampling output end; and a diagnostic circuit connected to the first sampling output terminal and the second sampling output terminal, and diagnosing the low-side driving circuit according to the first sampling signal and the second sampling signal.

2. The low-side driver diagnostic circuit according to claim 1, characterized in that: The first sampling circuit further includes a third switch circuit, wherein the third switch circuit is provided with a first voltage input terminal, a diagnosis enable terminal, and a switch output terminal; The first voltage input terminal is connected to the first control voltage terminal, the diagnosis enable terminal is connected to the second control voltage terminal, the first control voltage and the second control voltage are connected to an input power supply; and the switch output terminal is connected to the first control terminal.

3. The low-side driver diagnostic circuit according to claim 2, characterized in that: The third switch circuit includes a first transistor, a second transistor, a first resistor, and a second resistor; the first transistor is an NPN transistor, and the second transistor is a PNP transistor; The base of the first transistor, one end of the first resistor, and the diagnosis enable terminal are connected; the emitter of the first transistor is connected to the base of the second transistor; the emitter of the second transistor is connected to the first voltage input terminal, the collector of the second transistor is connected to one end of the second resistor, and the other end of the second resistor is the switch output terminal; The collector of the first transistor is connected to the other end of the first resistor at the same potential.

4. The low-side driver diagnostic circuit according to claim 2, characterized in that: A first sampling circuit is provided between the first sampling terminal and the first sampling output terminal, and the first sampling circuit includes a third resistor, a fourth resistor, and a first capacitor; One end of the third resistor is the first sampling end, and the other end of the third resistor is connected to one end of the fourth resistor, one end of the first capacitor, and the first sampling output end; the other end of the fourth resistor and the other end of the first capacitor are grounded.

5. The low-side driver diagnostic circuit according to claim 2, characterized in that: The second switching circuit includes a driving switch, including a second voltage input terminal, a third voltage input terminal, a load output terminal, and a first input terminal; the second voltage input terminal and the third voltage input terminal are connected to an external power supply, the first input terminal is connected to the first output terminal, and the load output terminal is the second driving terminal and is connected to a load device.

6. The low-side driver diagnostic circuit according to claim 5, characterized in that: The driving switch includes a relay and a multiplexer.

7. The low-side driver diagnostic circuit according to claim 5, characterized in that: The second sampling circuit is provided with a second sampling circuit, and the second sampling circuit is arranged between the second sampling terminal and the second sampling output terminal; the second sampling terminal is connected to the load output terminal and is connected to the load device driving terminal.

8. The low-side driver diagnostic circuit according to claim 7, characterized in that: The second sampling circuit includes a fifth resistor and a sixth resistor; One end of the fifth resistor is the second sampling end, the other end of the fifth resistor is connected to one end of the sixth resistor and the second sampling output end, and the other end of the sixth resistor is grounded.

9. The low-side driver diagnostic circuit according to claim 1, characterized in that: The first switch circuit includes a control switch and a diode; the control switch is a field effect transistor, which is connected to the diode input end through one end of the first control end, and the diode output end is connected to control the field effect transistor gate to achieve the first control end controlling the field effect transistor to be turned on.

10. A testing device, characterized in that: The low-side driver diagnostic circuit comprises the low-side driver diagnostic circuit of any one of claims 1 to 9, wherein the test device is provided with a test plug terminal, and a plurality of the test plug terminals are respectively connected to the first output terminal, the first sampling terminal, and the second sampling terminal; so that the first sampling circuit and the second sampling circuit are connected to the low-side driver circuit.

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