DCDC Converter Overvoltage and Undervoltage Module Fault Detection Circuit and Detection Method

Abstract

The present invention discloses a fault detection circuit and method for an overvoltage and undervoltage module of a DCDC converter. The circuit includes a DC connection port, an overvoltage shutdown module, an undervoltage shutdown module, a first battery, and a load connected in series in sequence. Among them, the circuit may further include a processing unit, a detection point A provided on the line connecting the DC connection port and the overvoltage shutdown module, a detection point C provided on the line connecting the overvoltage shutdown module and the undervoltage shutdown module, and a detection point B provided on the line connecting the undervoltage shutdown module, the first battery, and the load. The processing unit controls the on-off of the switches in the overvoltage shutdown module and the undervoltage shutdown module, detects the voltages at each detection point, and determines whether the overvoltage shutdown module and the undervoltage shutdown module have the following faults according to the detected voltages: 1. The overvoltage shutdown module and the undervoltage shutdown module are open-circuited; 2. The overvoltage shutdown module and the undervoltage shutdown module are short-circuited; meeting the corresponding safety objectives at ASIL C and ASIL D levels; and having the advantages of accurate detection and high detection efficiency at the same time.

Description

Technical Field

[0001] The present invention relates to the field of automotive electronics new energy vehicle technology DCDC control, and particularly to an overvoltage and undervoltage module fault detection circuit and detection method for a DCDC converter. Background Art

[0002] In new energy vehicles, a DCDC converter can convert the high-voltage direct current of a power battery into low-voltage direct current to supply power to a first battery and a load. The functions of the overvoltage shutdown module and the undervoltage shutdown module in the DCDC converter are to protect the power supply network from the following hazards: 1. Unintended overvoltage output of the DCDC converter causes the voltage of the vehicle's 12V power supply network to be too high unexpectedly, resulting in damage to electrical appliances; 2. Internal short circuit and unintended undervoltage output in the DCDC cause undervoltage of the first battery and the vehicle's 12V power supply network or loss of DCDC power output.

[0003] Therefore, when the vehicle is powered on, it is necessary to detect the overvoltage shutdown module and the undervoltage shutdown module of the DCDC converter to verify whether the overvoltage shutdown module and the undervoltage shutdown module are short-circuited and open-circuited. To avoid the failure of the shutdown path due to the failure of the overvoltage shutdown module and the undervoltage shutdown module when over- and under-voltage hazards occur. This design can effectively improve the diagnostic coverage of latent faults of the DCDC overvoltage shutdown module and the undervoltage shutdown module.

[0004] Currently, there are two conventional methods in the industry for testing the short-circuit and open-circuit failure modes in the overvoltage shutdown module and the undervoltage shutdown module of a DCDC converter: The first is to back up and redundant the overvoltage shutdown module and the undervoltage shutdown module. This solution can meet the functional safety design with a corresponding safety target level of ASIL B, ASIL C, or ASIL D. However, this design solution will also increase the cost of hardware design and the difficulty of PCB board space layout. The second is high-voltage power-on self-check. By using the high voltage of the vehicle's DC bus, a voltage difference is formed before and after the overvoltage shutdown module and the undervoltage shutdown module, so as to detect the latent faults of the overvoltage shutdown module and the undervoltage shutdown module. This solution will extend the DCDC initialization time, resulting in too long vehicle power-on time and causing driver complaints.

[0005] Therefore, designing an accurate and efficient overvoltage and undervoltage module fault detection circuit and detection method is an urgent technical problem in the industry. Summary of the Invention

[0006] In order to solve the above-mentioned defects existing in the prior art, the present invention proposes an overvoltage and undervoltage module fault detection circuit and detection method for a DCDC converter.

[0007] The technical solution adopted by the present invention is to design an overvoltage and undervoltage module fault detection circuit for a DCDC converter, which includes a DC connection port, an overvoltage shutdown module, an undervoltage shutdown module, a first battery and a load connected in series in sequence, and further includes a processing unit, a detection point A provided on the line connecting the DC connection port and the overvoltage shutdown module, a detection point C provided on the line connecting the overvoltage shutdown module and the undervoltage shutdown module, and a detection point B on the line connecting the undervoltage shutdown module and the first battery and the load. The processing unit controls the on / off of the switches in the overvoltage shutdown module and the undervoltage shutdown module, detects the voltages at each detection point, and determines whether the overvoltage shutdown module and the undervoltage shutdown module are normal according to the detected voltages.

[0008] The detection circuit further includes a buck module and a detection switch. The output end of the buck module is connected to the detection point C, the input end is connected to the detection point B and one end of the detection switch, and the other end of the detection switch is connected to the detection point A. The processing unit controls the on / off of the detection switch, and the buck module can reduce the voltage of the first battery by N volts and send it to the detection point C under the control of the processing unit.

[0009] The voltage of the first battery is 12V DC, and the N volts is 2V.

[0010] The present invention also designs a detection method for an overvoltage and undervoltage module fault detection circuit of a DCDC converter. The detection circuit adopts the above-mentioned overvoltage and undervoltage module fault detection circuit for a DCDC converter. The detection method includes controlling the on / off of the switches in the detection switch, the overvoltage shutdown module and the undervoltage shutdown module, controlling whether the buck module works, detecting the voltages at each detection point, determining whether the overvoltage shutdown module and the undervoltage shutdown module are normal according to the detected voltages, and uploading fault information when the overvoltage shutdown module or the undervoltage shutdown module fails.

[0011] The detection method includes: First, control the detection switch, the overvoltage shutdown module and the undervoltage shutdown module to conduct, and the buck module stops working, and determine whether the overvoltage shutdown module and the undervoltage shutdown module are open-circuited; then, control the overvoltage shutdown module and the undervoltage shutdown module to disconnect, the buck module works, and determine whether the overvoltage shutdown module and the undervoltage shutdown module are short-circuited; secondly, control the overvoltage shutdown module to conduct, the undervoltage shutdown module and the detection switch to disconnect, the buck module works, and determine whether the overvoltage shutdown module is open-circuited; thirdly, control the overvoltage shutdown module and the detection switch to disconnect, the undervoltage shutdown module to conduct, the buck module works, and determine whether the undervoltage shutdown module is open-circuited.

[0012] The detection method includes the following detection steps:

[0013] Step 2: Prohibit the buck module from working, control the detection switch to conduct, and control the overvoltage shutdown module and the undervoltage shutdown module to conduct;

[0014] Step 3: Detect the voltages at detection points A, B, and C, and calculate the voltages of Uab, Uac, and Ubc; where Uab is the voltage at detection point A minus the voltage at detection point B, Uac is the voltage at detection point A minus the voltage at detection point C, and Ubc is the voltage at detection point B minus the voltage at detection point C;

[0015] Step 4: Determine whether the voltages of Uab, Uac, and Ubc are equal to 0V. If any one of the voltages is not equal to 0V, go to Step 5; if all voltages are equal to 0V, go to Step 6;

[0016] Step 5: Flag that an open circuit fault has occurred in the overvoltage shutdown module and the undervoltage shutdown module, and go to Step 20;

[0017] Step 6: Control the overvoltage shutdown module and the undervoltage shutdown module to disconnect, control the buck module to work, and control the detection switch to conduct;

[0018] Step 7: Detect the voltages at detection points A, B, and C, and calculate the voltages of Uab, Uac, and Ubc;

[0019] Step 8: Determine whether the voltage of Uac is greater than or equal to 2V and whether the voltage of Ubc is greater than or equal to 2V; if the voltage of Uac is greater than or equal to 2V and the voltage of Ubc is greater than or equal to 2V, go to Step 11; if the voltage of Uac is less than 2V, go to Step 9; if the voltage of Ubc is less than 2V, go to Step 10;

[0020] Step 9: Flag a short circuit fault in the overvoltage shutdown module, and go to Step 20;

[0021] Step 10: Flag a short circuit fault in the undervoltage shutdown module, and go to Step 20;

[0022] Step 11: Control the overvoltage shutdown module to conduct, the undervoltage shutdown module and the detection switch to disconnect, and the buck module to work;

[0023] Step 12: Detect the voltages at detection points A, B, and C, and calculate the voltages of Uba and Uca; where Uba is the voltage at detection point B minus the voltage at detection point A, and Uca is the voltage at detection point C minus the voltage at detection point A;

[0024] Step 13: Determine whether the voltage of Uba is greater than or equal to 2V and the voltage of Uca is equal to 0V. If so, go to Step 15; if the voltage of Uba is less than 2V or the voltage of Uca is not equal to 0V, go to Step 14;

[0025] Step 14: Flag an open circuit fault in the overvoltage shutdown module, and go to Step 20;

[0026] Step 15: Control the overvoltage shutdown module and the detection switch to disconnect, and the undervoltage shutdown module to conduct, and the buck module operates;

[0027] Step 16: Detect the voltages at detection points A, B, and C, and calculate the voltages of Uab and Ucb; where Ucb is the voltage at detection point C minus the voltage at detection point B;

[0028] Step 17: Determine whether to transfer to Step 19 when the voltage of Uab is greater than or equal to 2V and the voltage of Ucb is equal to 0V; if the voltage of Uab is less than 2V or the voltage of Ucb is not equal to 0V, then transfer to Step 18;

[0029] Step 18: Flag an open-circuit fault of the undervoltage shutdown module, and transfer to Step 20;

[0030] Step 19: Flag that the overvoltage shutdown module and the undervoltage shutdown module are normal;

[0031] Step 20: Report the status of the overvoltage shutdown module and the undervoltage shutdown module.

[0032] During the detection process, the above detection steps are executed more than twice.

[0033] The beneficial effects of the technical solution provided by the present invention are:

[0034] The present invention can cover the following failure modes of the overvoltage shutdown module and the undervoltage shutdown module: 1. Open circuit of the overvoltage shutdown module and the undervoltage shutdown module; 2. Short circuit of the overvoltage shutdown module and the undervoltage shutdown module; meeting the corresponding safety goals of ASIL C and ASIL D levels; and having the advantages of accurate detection and high detection efficiency. Description of the Drawings

[0035] The present invention will be described in detail below in conjunction with embodiments and drawings, where:

[0036] Figure 1 is the circuit state diagram for judging whether the overvoltage shutdown module and the undervoltage shutdown module are open-circuited;

[0037] Figure 2 is the circuit state diagram for judging whether the overvoltage shutdown module and the undervoltage shutdown module are short-circuited;

[0038] Figure 3 is the circuit state diagram for judging whether the overvoltage shutdown module is open-circuited;

[0039] Figure 4 is the circuit state diagram for judging whether the undervoltage shutdown module is open-circuited;

[0040] Figure 5 is the control flow chart of the preferred embodiment;

[0041] Figure 6It is a circuit diagram of a preferred embodiment. Detailed implementation manners

[0042] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0043] The objective of the present invention is to provide a method for detecting latent faults in the overvoltage shutdown module and undervoltage shutdown module of a DCDC converter and meeting the corresponding safety objectives at ASIL C and ASIL D levels.

[0044] The present invention discloses a fault detection circuit for the overvoltage and undervoltage modules of a DCDC converter. Referring to Figure 6 the preferred embodiment shown, the detection circuit includes a DC connection port, an overvoltage shutdown module, an undervoltage shutdown module, a first battery, and a load connected in series in sequence. It further includes a processing unit, a detection point A provided on the line connecting the DC connection port and the overvoltage shutdown module, a detection point C provided on the line connecting the overvoltage shutdown module and the undervoltage shutdown module, and a detection point B provided on the line connecting the undervoltage shutdown module, the first battery, and the load. The processing unit controls the on / off of the switches in the overvoltage shutdown module and the undervoltage shutdown module, detects the voltages at each detection point, and determines whether the overvoltage shutdown module and the undervoltage shutdown module are normal according to the detected voltages. It should be noted that in actual use, the first battery is also connected to the vehicle's 12V network. Detection is performed before the vehicle is powered on, and the first battery supplies power to the overvoltage and undervoltage modules so that the processing unit can detect the voltages at each detection point.

[0045] It should be noted that in the application of the present invention in a new energy vehicle DCDC converter, the DC connection port can be connected to a second battery and a high / low voltage converter. Among them, the first battery can include an in-vehicle low-voltage battery, and the second battery can include a high-voltage battery.

[0046] Referring to Figure 1 the application of the present invention in a DCDC converter shown, the detection circuit further includes a buck module and a detection switch. The output end of the buck module is connected to the detection point C, the input end is connected to the detection point B and one end of the detection switch, and the other end of the detection switch is connected to the detection point A. The processing unit controls the on / off of the detection switch, and the buck module can reduce the voltage of the first battery by N volts and send it to the detection point C under the control of the processing unit.

[0047] In the preferred embodiment, the voltage of the first battery can be DC 12V, and N volts is 2V. It should be noted that the voltage of the first battery can also be DC 24V or DC 48V, and the above N can also be 4V. The embodiments of the present invention are not limited thereto.

[0048] The present invention also discloses a detection method for a DCDC converter overvoltage and undervoltage module fault detection circuit. The detection circuit adopts the above-mentioned DCDC converter overvoltage and undervoltage module fault detection circuit. The detection method includes controlling the on / off of switches in the detection switch, overvoltage shutdown module, and undervoltage shutdown module, controlling whether the buck module works, detecting the voltages at each detection point, judging whether the overvoltage shutdown module and the undervoltage shutdown module are normal according to the detected voltages, and uploading fault information when the overvoltage shutdown module or the undervoltage shutdown module fails.

[0049] The detection method includes: First, control the detection switch, overvoltage shutdown module, and undervoltage shutdown module to conduct, and the buck module stops working, and judge whether the overvoltage shutdown module and the undervoltage shutdown module are open-circuited; Then, control the overvoltage shutdown module and the undervoltage shutdown module to disconnect, the buck module works, and judge whether the overvoltage shutdown module and the undervoltage shutdown module are short-circuited; Secondly, control the overvoltage shutdown module to conduct, the undervoltage shutdown module and the detection switch to disconnect, the buck module works, and judge whether the overvoltage shutdown module is open-circuited; Thirdly, control the overvoltage shutdown module and the detection switch to disconnect, the undervoltage shutdown module to conduct, the buck module works, and judge whether the undervoltage shutdown module is open-circuited.

[0050] The following combines Figure 5 the flowchart of the preferred embodiment shown to elaborate in detail the detection steps of the detection method:

[0051] Step 1, start, the first battery provides a detection power supply of 12V;

[0052] Step 2, (refer to Figure 1 the circuit state diagram shown for judging whether the overvoltage shutdown module and the undervoltage shutdown module are open-circuited) prohibit the buck module from working, control the detection switch to conduct, and control the overvoltage shutdown module and the undervoltage shutdown module to conduct;

[0053] Step 3, detect the voltages at detection point A, detection point B, and detection point C, and calculate the voltages of Uab, Uac, and Ubc; Uab is the voltage at detection point A minus the voltage at detection point B, Uac is the voltage at detection point A minus the voltage at detection point C, and Ubc is the voltage at detection point B minus the voltage at detection point C;

[0054] Step 4, judge whether the voltages of Uab, Uac, and Ubc are equal to 0V. If any one of the voltages is not equal to 0V, go to Step 5 (there is a fault); if all voltages are equal to 0V, go to Step 6 (no fault, continue detection);

[0055] Step 5, mark that the overvoltage shutdown module and the undervoltage shutdown module have an open-circuit fault, and go to Step 20 (report the fault and exit);

[0056] Step 6, (refer to Figure 2As shown in the circuit state diagram for determining whether the overvoltage shutdown module and undervoltage shutdown module are short-circuited, control the overvoltage shutdown module and undervoltage shutdown module to disconnect, control the buck module to operate, and control the detection switch to conduct;

[0057] Step 7: Detect the voltages at detection points A, B, and C, and calculate the voltages of Uab, Uac, and Ubc;

[0058] Step 8: Determine whether the voltage of Uac is greater than or equal to 2V and whether the voltage of Ubc is greater than or equal to 2V; if the voltage of Uac is greater than or equal to 2V and the voltage of Ubc is greater than or equal to 2V, go to Step 11 (no fault, continue detection); if the voltage of Uac is less than 2V, go to Step 9 (there is a fault); if the voltage of Ubc is less than 2V, go to Step 10 (there is a fault);

[0059] Step 9: Flag a short-circuit fault in the overvoltage shutdown module, and go to Step 20 (report the fault and exit);

[0060] Step 10: Flag a short-circuit fault in the undervoltage shutdown module, and go to Step 20 (report the fault and exit);

[0061] Step 11: (Refer to Figure 3 As shown in the circuit state diagram for determining whether the overvoltage shutdown module is open-circuited, control the overvoltage shutdown module to conduct, the undervoltage shutdown module and the detection switch to disconnect, and the buck module to operate;

[0062] Step 12: Detect the voltages at detection points A, B, and C, and calculate the voltages of Uba and Uca; Uba is the voltage at detection point B minus the voltage at detection point A, and Uca is the voltage at detection point C minus the voltage at detection point A;

[0063] Step 13: Determine whether the voltage of Uba is greater than or equal to 2V and when the voltage of Uca is equal to 0V, go to Step 15 (no fault, continue detection); if the voltage of Uba is less than 2V or the voltage of Uca is not equal to 0V, go to Step 14 (there is a fault);

[0064] Step 14: Flag an open-circuit fault in the overvoltage shutdown module, and go to Step 20 (report the fault and exit);

[0065] Step 15: (Refer to Figure 4 As shown in the circuit state diagram for determining whether the undervoltage shutdown module is open-circuited, control the overvoltage shutdown module and the detection switch to disconnect, the undervoltage shutdown module to conduct, and the buck module to operate;

[0066] Step 16: Detect the voltages at detection points A, B, and C, and calculate the voltages of Uab and Ucb; Ucb is the voltage at detection point C minus the voltage at detection point B;

[0067] Step 17: Determine whether the voltage of Uab is greater than or equal to 2V and the voltage of Ucb is equal to 0V. If so, go to Step 19 (no fault); if the voltage of Uab is less than 2V or the voltage of Ucb is not equal to 0V, then go to Step 18 (fault).

[0068] Step 18: Flag the open - circuit fault of the undervoltage shutdown module and go to Step 20 (report the fault and exit).

[0069] Step 19: Flag that the overvoltage shutdown module and the undervoltage shutdown module are normal.

[0070] Step 20: Report the status of the overvoltage shutdown module and the undervoltage shutdown module.

[0071] During the detection process, after completing the morning detection steps once, detect again. In a preferred embodiment, the detection steps are performed two or more times to improve the accuracy of detection.

[0072] The above embodiments are only for illustration and not for limitation. Any equivalent modification or change without departing from the spirit and scope of this application shall be included in the scope of the claims of this application.

[0073] Figures 1 - 6 It is only used to explain the embodiments of the present invention and should not limit the protection scope of the present invention.

Claims

1. A fault detection circuit for overvoltage and undervoltage modules of a DC-DC converter, which is applied to new energy vehicles and includes a DC connection port, an overvoltage shutdown module, an undervoltage shutdown module, a first battery, and a load connected in series in sequence. It is characterized in that, It further includes: a processing unit, a detection point A provided on the line connecting the DC connection port and the overvoltage shutdown module, a detection point C provided on the line connecting the overvoltage shutdown module and the undervoltage shutdown module, and a detection point B on the line connecting the undervoltage shutdown module, the first battery and the load. The processing unit controls the on / off of the switches in the overvoltage shutdown module and the undervoltage shutdown module, detects the voltages at each detection point, and determines whether the overvoltage shutdown module and the undervoltage shutdown module are normal according to the detected voltages; It further includes a buck module and a detection switch; the output end of the buck module is connected to the detection point C, the input end is connected to the detection point B and one end of the detection switch, and the other end of the detection switch is connected to the detection point A; the processing unit controls the on / off of the detection switch, and the buck module can reduce the voltage of the first battery by N volts and send it to the detection point C under the control of the processing unit; the DC connection port is connected to a high-voltage battery, and the first battery is a low-voltage battery. Detection is performed before the vehicle is powered on, and the first battery supplies power to the overvoltage shutdown module and the undervoltage module.

2. The overvoltage and undervoltage module fault detection circuit of the DCDC converter according to claim 1, characterized in that, The voltage of the first battery is 12V DC, and N volts is 2V.

3. A detection method for a DCDC converter overvoltage and undervoltage module fault detection circuit, characterized in that, The detection circuit is the DCDC converter overvoltage and undervoltage module fault detection circuit according to any one of claims 1 or 2. The detection method includes controlling the on / off of the switches in the detection switch, the overvoltage shutdown module and the undervoltage shutdown module, controlling whether the buck module works, detecting the voltages at each detection point, determining whether the overvoltage shutdown module and the undervoltage shutdown module are normal according to the detected voltages, and uploading fault information when the overvoltage shutdown module or the undervoltage shutdown module fails.

4. The detection method of the DCDC converter overvoltage and undervoltage module fault detection circuit according to claim 3, characterized in that First, control the detection switch, the overvoltage shutdown module and the undervoltage shutdown module to conduct, and the buck module stops working, and determine whether the overvoltage shutdown module and the undervoltage shutdown module are open-circuited; Then, control the overvoltage shutdown module and the undervoltage shutdown module to disconnect, the buck module works, and determine whether the overvoltage shutdown module and the undervoltage shutdown module are short-circuited; Secondly, control the overvoltage shutdown module to conduct, the undervoltage shutdown module and the detection switch to disconnect, the buck module works, and determine whether the overvoltage shutdown module is open-circuited; Thirdly, control the overvoltage shutdown module and the detection switch to disconnect, the undervoltage shutdown module to conduct, the buck module works, and determine whether the undervoltage shutdown module is open-circuited.

5. The detection method of the overvoltage and undervoltage module fault detection circuit of the DCDC converter according to claim 4, characterized in that, It includes the following detection steps: Step 2: Prohibit the buck module from working, control the detection switch to conduct, and control the overvoltage shutdown module and the undervoltage shutdown module to conduct; Step 3: Detect the voltages at detection point A, detection point B, and detection point C, and calculate the voltages of Uab, Uac, and Ubc; Uab is the voltage at detection point A minus the voltage at detection point B, Uac is the voltage at detection point A minus the voltage at detection point C, and Ubc is the voltage at detection point B minus the voltage at detection point C; Step 4: Determine whether the voltages of Uab, Uac, and Ubc are equal to 0V. If any one of the voltages is not equal to 0V, go to Step 5; if all voltages are equal to 0V, go to Step 6; Step 5: Flag an open - circuit fault in the over - voltage shutdown module and the under - voltage shutdown module, and go to Step 20; Step 6: Control the over - voltage shutdown module and the under - voltage shutdown module to disconnect, control the buck module to work, and control the detection switch to conduct; Step 7: Detect the voltages at detection points A, B, and C, and calculate the voltages of Uab, Uac, and Ubc; Step 8: Judge whether the voltage of Uac is greater than or equal to 2V and whether the voltage of Ubc is greater than or equal to 2V; if the voltage of Uac is greater than or equal to 2V and the voltage of Ubc is greater than or equal to 2V, then go to Step 11; if the voltage of Uac is less than 2V, then go to Step 9; if the voltage of Ubc is less than 2V, then go to Step 10; Step 9: Flag a short - circuit fault in the over - voltage shutdown module, and go to Step 20; Step 10: Flag a short - circuit fault in the under - voltage shutdown module, and go to Step 20; Step 11: Control the over - voltage shutdown module to conduct, the under - voltage shutdown module and the detection switch to disconnect, and the buck module to work; Step 12: Detect the voltages at detection points A, B, and C, and calculate the voltages of Uba and Uca; Uba is the voltage at detection point B minus the voltage at detection point A, and Uca is the voltage at detection point C minus the voltage at detection point A; Step 13: Judge whether the voltage of Uba is greater than or equal to 2V and when the voltage of Uca is equal to 0V, go to Step 15; if the voltage of Uba is less than 2V or the voltage of Uca is not equal to 0V, then go to Step 14; Step 14: Flag an open - circuit fault in the over - voltage shutdown module, and go to Step 20; Step 15: Control the over - voltage shutdown module and the detection switch to disconnect, the under - voltage shutdown module to conduct, and the buck module to work; Step 16: Detect the voltages at detection points A, B, and C, and calculate the voltages of Uab and Ucb; Ucb is the voltage at detection point C minus the voltage at detection point B; Step 17: Judge whether the voltage of Uab is greater than or equal to 2V and when the voltage of Ucb is equal to 0V, go to Step 19; if the voltage of Uab is less than 2V or the voltage of Ucb is not equal to 0V, then go to Step 18; Step 18: Flag an open - circuit fault in the under - voltage shutdown module, and go to Step 20; Step 19: Flag that the over - voltage shutdown module and the under - voltage shutdown module are normal; Step 20: Report the status of the over - voltage shutdown module and the under - voltage shutdown module.

6. The detection method of the overvoltage and undervoltage module fault detection circuit of the DCDC converter according to claim 5, characterized in that, Execute the above detection steps more than twice.

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