Electric leakage detection system and electric leakage detection method

Abstract

To provide an electric leakage detection system and an electric leakage detection method applied to a circuit board including a plurality of traces.SOLUTION: The system includes a plurality of parallel switch loops, a voltage generator, a controller, and a decision device. Providing a plurality of parallel switch loops, each switch loop being disposed with a first switch, a second switch, and a probe connected to a node between the first switch and the second switch, the probe corresponding to one of the plurality of traces of the circuit board, inputting a voltage to the first switch of each of the plurality of parallel switch loops, controlling conduction of each of the first switch and the second switch of each of the plurality of parallel switch loops to generate an electrical signal between two of the plurality of traces of the circuit board, and receiving the electrical signal and determining whether the electrical signal exceeds a preset threshold.SELECTED DRAWING: Figure 2

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Taiwan Patent Application No. 113126483, filed with the Taiwan Intellectual Property Office on July 15, 2024, the disclosure of which is incorporated herein by reference in its entirety. [Technical Field]

[0002] The present invention relates to a leakage current detection system and a leakage current detection method, and more particularly to a system and method applicable to a circuit board that can quickly and accurately determine whether a leakage current exists in the circuit board and identify the node where a leakage current occurs between two nodes. [Background technology]

[0003] As technology advances, electronic products tend to be smaller, lighter, and more multi-functional. To achieve these goals, circuit boards are stacked with multiple trace layers, resulting in a very high density of traces within the structure. However, due to the high density of traces, such designs are prone to short circuits and electrical leakage between traces, which can lead to abnormal circuit board operation.

[0004] FIG. 1 is a schematic diagram of a conventional leakage current detection device for a circuit board. After manufacturing a circuit board with a large number of traces (wiring), it is necessary to test for abnormal impedances between these traces (e.g., to test for unintended connections or connections that should be made) and determine whether these traces are set as designed. The leakage current detection device 10 shown in FIG. 1 can be used to calculate the electrical characteristics between any two nodes (such as nodes 101, 102, 103, and 104) based on Ohm's law and determine whether an abnormality exists. For example, in FIG. 1, output terminal 11 of leakage current detection device 10 supplies a detection voltage to node 101. If there is a leakage current between node 101 and any of nodes 102, 103, and 104, a current signal is measured at input terminal 12. The voltage or resistance value between node 101 and any of node 102, node 103, and node 104 is calculated according to Ohm's law, and it can be determined whether the leakage current phenomenon between node 101 and any of node 102, node 103, and node 104 reaches the criteria for determining a circuit board failure.

[0005] However, when testing for short circuits or leakage current between these traces, it is necessary to test the abnormal relationship between one trace and all other traces. Therefore, if a circuit board has tens of thousands of traces, completing electrical tests on all of these traces will take a long time due to the large amount of testing. Therefore, how to quickly and accurately determine whether a circuit board has a leakage current and identify the node where the leakage current occurs between two nodes has become a major challenge in the industry.

[0006] Therefore, there is a need to provide a system and method for detecting electrical leakage that can quickly and accurately determine whether there is electrical leakage on a circuit board and identify the node where the electrical leakage occurs between two nodes. DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0007] SUMMARY OF THE INVENTION An object of the present invention is to provide a system and method for detecting electric leakage that can quickly and accurately determine whether there is an electric leakage on a circuit board and identify the node where the electric leakage occurs between two nodes. [Means for solving the problem]

[0008] To achieve the above object, in one aspect, the present disclosure provides a leakage current detection system for a circuit board, the leakage current detection system for a circuit board including a plurality of traces including: a plurality of parallel switch loops, each of which has a first switch, a second switch, and a probe connected to a node between the first switch and the second switch, the probe corresponding to one of the plurality of traces of the circuit board; a voltage source configured to input a voltage to the first switch of each of the plurality of parallel switch loops; a controller configured to control conduction of the first switch and the second switch of each of the plurality of parallel switch loops to generate an electrical signal between two of the plurality of traces of the circuit board; and a determination device connected to the second switch, configured to receive the electrical signal, and determine whether the electrical signal exceeds a predetermined threshold.

[0009] In another aspect, the present disclosure further provides a method for detecting electrical leakage in a circuit board, the circuit board including a plurality of traces, the method comprising the following steps: first, providing a plurality of parallel switch loops; each of the plurality of parallel switch loops including a first switch, a second switch, and a probe connected to a node between the first switch and the second switch; the probe corresponding to one of the plurality of traces on the circuit board; next, inputting a voltage to a first switch of each of the plurality of parallel switch loops; next, controlling the conduction of the first switch and the second switch of each of the plurality of parallel switch loops to generate an electrical signal between each two of the plurality of traces on the circuit board; next, receiving the electrical signal and determining whether the electrical signal exceeds a predetermined threshold value.

[0010] In another aspect, the present disclosure further provides a method for detecting electrical leakage in a circuit board, the circuit board including a plurality of traces, the method for detecting electrical leakage comprising the following steps: first, providing a plurality of parallel switch loops; each of the plurality of parallel switch loops including a first switch and a second switch; electrically connecting the plurality of parallel switch loops to a plurality of traces; turning on a first switch in each of the plurality of parallel switch loops and the remaining second switches in each of the plurality of switch loops; inputting a voltage; and determining whether an electrical signal exceeding a predetermined threshold exists between a trace corresponding to each of the first switches and a trace corresponding to the remaining second switches.

[0011] In summary, the leakage current detection system and leakage current detection method of the present disclosure can quickly and accurately determine whether there is a leakage current on a circuit board and identify the node where the leakage current occurs between two nodes. [Brief explanation of the drawings]

[0012] The above embodiments and advantages of the present invention will become more readily apparent to those skilled in the art after reviewing the following detailed description and accompanying drawings. [Figure 1] FIG. 1 is a schematic diagram of a conventional leakage detection device for a circuit board. [Figure 2] 1 is a schematic diagram of a leakage detection system according to an embodiment of the present invention and a circuit board to be measured. [Figure 3] 3 is an equivalent circuit diagram of the earth leakage detection system and the circuit board of FIG. 2. [Figure 4] 3 is a schematic diagram showing a measurement process of a circuit board by the leakage current detection system of FIG. 2. [Figure 5] 3 is another schematic diagram showing the measurement process of the circuit board by the leakage current detection system of FIG. 2. [Figure 6] 2 is a flowchart of a leakage detection method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] When reading the following detailed description, please refer to all figures of the present invention. All figures of the present invention illustrate different embodiments of the present invention by illustrating examples, and help those skilled in the art understand how to implement the present invention. These examples provide sufficient embodiments to demonstrate the spirit of the present invention, and each embodiment is consistent with other embodiments, and new embodiments can be implemented through any combination thereof. In other words, the present invention is not limited to the embodiments disclosed in this specification.

[0014] 2 is a schematic diagram of a ground fault detection system and a circuit board to be measured according to one embodiment of the present invention. In FIG. 2, the ground fault detection system 20 is applicable to a circuit board 30. In one embodiment, the circuit board 30 includes a plurality of traces and may be a printed circuit board, an integrated circuit chip carrier, or a display panel, although the present invention is not limited to these examples.

[0015] 2, the leakage current detection system 20 of the present invention includes a switch device 21, a voltage source 22, a controller 23, and a determination device 24. The switch device 21 includes multiple parallel switch loops. Each switch loop includes a first switch 211, a second switch 212, and probes Pin_1, Pin_2..., Pin_n-1, Pin_n, and Pin_n+1 connected to a node 213 between the first switch 211 and the second switch 212. The probes Pin_1, Pin_2..., Pin_n-1, and Pin_n correspond to test points P_1, P_2..., P_n-1, and P_n of multiple traces on a circuit board 30. The probe Pin_n+1 corresponds to test point 31 in a power / ground zone (VCC / GND) 32 of the circuit board 30. The voltage source 22 is configured to input a voltage to each first switch 211 of the multiple parallel switch loops in the switch device 21. The controller 23 is configured to control the conduction of the first switch 211 and the second switch 212 of each switch loop, thereby generating an electrical signal such as a voltage or current value between two corresponding traces of the multiple traces on the circuit board 30. The determination device 24 mainly includes a microprocessor and a detection resistor Ri (see FIG. 3), which forms a resistive voltage divider with the insulation resistance of the circuit board, and the microprocessor detects the divided voltage and performs data processing. In FIGS. 2 and 3, the determination device 24 is connected to the second switch 212 to receive the electrical signal and determine whether the electrical signal exceeds a preset threshold. If the electrical signal is greater than the preset threshold, it can be determined that a leakage current has occurred in the circuit board 30. In one embodiment, the leakage current detection system 20 may further include a signal amplifier (not shown) electrically connected to the controller 23 and configured to amplify the electrical signal detected by the multiple parallel switch loops and transmit the amplified signal to the determination device 24.

[0016] In the circuit board 30 of FIG. 2, an insulation resistance Rpcb_H exists between any two test points P_1, P_2, ..., P_n, and an insulation resistance Rpcb_V exists between each test point P_1, P_2, ..., P_n and the power / ground zone (VCC / GND) 32. FIG. 3 is an equivalent circuit diagram of the leakage current detection system and the circuit board. In FIG. 3, the insulation resistance Rpcb_H and the insulation resistance Rpcb_V are connected in parallel to form an equivalent resistance R_pcb. Considering the detection resistance Ri of the determination device 24, the voltage VRi is obtained as VRi = 250V * [Ri / (R_pcb + Ri)]. Next, the determination device 24 measures VRi, and if it determines that VRi is lower than a preset threshold, the circuit board passes the test. Conversely, if the measured VRi value exceeds the preset threshold, it is determined that there is a leakage current in the circuit board. In one embodiment, the earth leakage detection system 20 may further include an analog-to-digital conversion circuit (not shown) electrically connected to the determination device 24, converting the electrical signal detected by the determination device 24 into a digital signal, and then transmitting it to a display (not shown) for user inspection.

[0017] When a first switch 211 of one of the multiple parallel switch loops in the switch device 21 of the ground leakage detection system 20 of FIG. 2 is turned on and a second switch 212 of the other switch loop is turned on, the determination device 24 determines whether an electrical signal between a trace corresponding to the first switch 211 of one of the multiple parallel switch loops and a trace corresponding to a second switch 212 of the remaining switch loops exceeds a preset threshold. For example, see FIG. 4. FIG. 4 is a schematic diagram showing a measurement process of a circuit board using the ground leakage detection system of FIG. 2. In FIG. 4, of the multiple first switches 211 in FIG. 2, only the first switch 211 corresponding to probe Pin_1 is turned on, and the other switches are turned off. Of the multiple second switches 212 in FIG. 2, only the second switch 212 corresponding to probe Pin_1 is turned off, and the other switches are turned on. At this point, test points P_2, ..., P_n on the circuit board 30 are connected to test points 31 on the power / ground zone 32 via probes Pin_2, ..., Pin_n, and Pin_n+1. There is an insulation resistance Rpcb_H only between test point P_1 and test point P_2, and there is an insulation resistance Rpcb_V between test point P_1 and power / ground zone 32. These can be connected in parallel to form an equivalent resistance R_pcb, as shown in FIG. 3 . If the detected VRi value exceeds a preset threshold, it is determined that there is a leakage current on the circuit board. Next, the group of second switches 212 that are currently turned on can be left on, and the other group can be turned off. If the detected VRi value exceeds the preset threshold, it is determined that there is a leakage current on the circuit board. The group of second switches 212 that are currently turned on can be further divided into two groups, each of which can be turned on or off to determine whether the detected VRi value exceeds the preset threshold, and which two traces between them generate an electrical signal that exceeds the preset threshold.If the detected VRi value at this point does not exceed the set threshold, the group of second switches 212 that are off can be further divided into two groups, each set to on or off, to determine whether the detected VRi value exceeds the set threshold, and to check which two traces between them generate an electrical signal that exceeds the set threshold.

[0018] 5 is another schematic diagram showing the measurement process of a circuit board by the leakage current detection system of FIG. 2. In FIG. 5, among the plurality of first switches 211 in FIG. 2, the first switches 211 corresponding to probes Pin_1, ..., Pin_m are turned on, and the first switches 211 corresponding to probes Pin_m+1, ..., Pin_n are turned off. Among the plurality of second switches 212 in FIG. 2, the second switches 212 corresponding to probes Pin_1, ..., Pin_m are turned off, and the second switches 212 corresponding to probes Pin_m+1, ..., Pin_n are turned on. At this point, test points P_m+1, ..., P_n on the circuit board 30 are connected to test points 31 in the power / ground zone 32 via probes Pin_m+1, ..., Pin_n. There is an insulation resistance Rpcb_H only between test point P_m and test point P_m+1, and there is an insulation resistance Rpcb_V between test point P_1 and the power / ground zone 32. These can be connected in parallel to form an equivalent resistance R_pcb, as shown in FIG. 3. If the detected VRi value exceeds a preset threshold, it is determined that there is a ground fault on the circuit board. The group of second switches 212 that are turned on can then be kept on, and the other group can be turned off. If the detected VRi value exceeds the preset threshold, it is determined that there is a ground fault on the circuit board. The group of second switches 212 that are turned on can then be further divided into two groups, each of which can be turned on or off. It is then determined whether the detected VRi value exceeds the preset threshold, and which two traces generate an electrical signal between them that exceeds the preset threshold. If the detected VRi value does not exceed the preset threshold at this time, the group of second switches 212 that are off is further divided into two groups, which are set to on or off, respectively, to determine whether the detected VRi value exceeds the preset threshold, and to check which two traces generate an electrical signal between them that exceeds the preset threshold.

[0019] Therefore, in combination with the leakage current detection system 20 shown in FIG. 2, the present invention provides a leakage current detection method as shown in FIG. 6. The leakage current detection method is applicable to a circuit board 30 including a plurality of traces. In FIG. 6, the leakage current detection method includes the following steps. First, in step S61, a plurality of parallel switch loops are prepared. In each switch loop, probes Pin_1, Pin_2..., Pin_n-1, Pin_n, and Pin_n+1 are arranged, connected to a first switch 211, a second switch 212, and a node 213 between the first switch 211 and the second switch 212. The probes Pin_1, Pin_2..., Pin_n-1, and Pin_n correspond to test points P_1, P_2..., P_n-1, and P_n of the plurality of traces on the circuit board 30. In step S62, a voltage is input to the first switch 211 of each of the plurality of parallel switch loops. In step S63, the conduction of the first switch 211 and the second switch 212 of each of the plurality of parallel switch loops is controlled to generate an electrical signal between each two of the plurality of traces on the circuit board 30. In step S64, the electrical signal is received, and it is determined whether the electrical signal exceeds a preset threshold.

[0020] In one embodiment, controlling the on or off of the first switch 211 and the second switch 212 of each switch loop in step S63 may include turning on the first switch 211 of one of the multiple parallel switch loops and turning on the remaining second switches 212, and determining whether the electrical signal between the trace corresponding to the first switch 211 and the trace corresponding to the remaining second switches 212 exceeds a preset threshold.

[0021] In one embodiment, when an electrical signal between a trace corresponding to a first switch and a trace corresponding to a second switch exceeds a preset threshold, one group of second switches is set on and the other group is set off, and it is detected whether an electrical signal between a trace corresponding to a first switch and a trace corresponding to a second switch exceeds the preset threshold, and it is determined which two traces have an electrical signal that exceeds the preset threshold.

[0022] As described above, it can be seen that the leakage current detection system and leakage current detection method of the present invention can quickly and accurately determine whether or not there is a leakage current on a circuit board and identify the node where the leakage current is occurring.

[0023] At least the following aspects can be understood from the above-described embodiment. [1] According to one aspect, a leakage current detection system for a circuit board including a plurality of traces includes a plurality of parallel switch loops, each of the plurality of switch loops having a first switch, a second switch, and a probe connected to a node between the first switch and the second switch, the probe corresponding to one of the plurality of traces of the circuit board; a voltage source arranged to input a voltage to the first switch of each of the plurality of parallel switch loops; a controller arranged to control conduction of each of the first switch and the second switch of each of the plurality of parallel switch loops to generate an electrical signal between two of the plurality of traces of the circuit board; and a determination device connected to the second switch to receive the electrical signal and arranged to determine whether the electrical signal exceeds a predetermined threshold. [2] According to form [1], the determination device includes a detection resistor arranged to form a resistive voltage divider together with an insulation resistor of the circuit board, and a microprocessor connected to the detection resistor, which detects the divided voltage provided by the resistive voltage divider and performs data processing. [3] According to the aspect [1] or [2], the device further comprises an analog-to-digital conversion circuit electrically connected to the determination device and configured to convert the electrical signal detected by the determination device into a digital signal and transmit the digital signal to a display. [4] According to any one of the aspects [1] to [3], the device further comprises a signal amplifier electrically connected to the controller, which amplifies the electrical signals detected by the plurality of parallel switch loops. [5] According to any one of the aspects [1] to [4], when the first switch of one of the plurality of parallel switch loops is on and the remaining second switches are on, the determination device determines whether the electrical signal between the trace corresponding to the first switch and the trace corresponding to the remaining second switch of the plurality of parallel switch loops exceeds the preset threshold. [6] According to any one of the aspects [1] to [5], all the second switches are divided into two groups, the first group is set to on, and the second group is set to off, and it is determined in which group the electrical signal occurs, and the group division operation is repeated until it is determined between which two specific traces an electrical signal exceeding the preset threshold exists. [7] According to one aspect, a method for detecting leakage current in a circuit board including a plurality of traces includes the steps of: providing a plurality of parallel switch loops, each switch loop including a first switch, a second switch, and a probe connected to a node between the first switch and the second switch, the probe corresponding to one of the plurality of traces on the circuit board; inputting a voltage to the first switch of each of the plurality of parallel switch loops; controlling the conduction of each of the first switch and the second switch of each of the plurality of parallel switch loops to generate an electrical signal between two of the plurality of traces on the circuit board; and receiving the electrical signal and determining whether the electrical signal exceeds a predetermined threshold. [8] According to form [7], the step of determining whether the electrical signal exceeds the preset threshold includes a step of detecting a divided voltage provided by a resistive voltage divider composed of an insulation resistor of the circuit board and a resistive voltage divider, and a step of performing data processing. [9] According to the embodiment [7] or [8], the method further comprises converting the electrical signal into a digital signal and transmitting the digital signal to a display.

[10] According to any one of the aspects [7] to [9], the method further includes a step of amplifying the electrical signals detected by the plurality of parallel switch loops.

[11] According to any one of the aspects [7] to

[10] , the method further includes a step of turning on the first switch of one of the plurality of parallel switch loops, turning on the remaining second switches, and determining whether the electrical signal between the trace corresponding to the first switch and the trace corresponding to the remaining second switch exceeds the preset threshold.

[12] According to any one of the aspects [7] to

[11] , the method further includes the steps of dividing all the second switches into two groups, setting the first group to on and the second group to off, and determining in which group the electrical signal occurs; and repeating the group division operation until it is determined between which two specific traces an electrical signal exceeding the preset threshold exists.

[13] According to one aspect, a method for detecting electrical leakage in a circuit board including a plurality of traces includes the steps of: providing a plurality of parallel switch loops, each of which has a first switch and a second switch disposed therein; electrically connecting the plurality of parallel switch loops to the plurality of traces; turning on the first switch of one of the plurality of parallel switch loops and turning on the second switches of the remaining plurality of parallel switch loops; and inputting a voltage between the trace corresponding to the first switch and the trace corresponding to the remaining second switch to determine whether an electrical signal exceeding a predetermined threshold exists between the trace corresponding to the first switch and the trace corresponding to the remaining second switch.

[14] According to form

[13] , the method further includes the steps of dividing all the second switches into two groups, setting the first group to on and the second group to off, and determining in which group the electrical signal occurs; and repeating the group division operation until it is determined between which two specific traces an electrical signal exceeding the preset threshold exists.

[15] According to the aspect

[13] or

[14] , the step of determining whether the electrical signal exceeds the preset threshold includes the steps of detecting a divided voltage provided by a resistive voltage divider composed of an insulation resistor of the circuit board and a resistive voltage divider, and performing data processing.

[16] According to any one of the aspects

[13] to

[15] , the method further includes converting the electrical signal into a digital signal and transmitting the digital signal to a display.

[17] According to any one of the aspects

[13] to

[16] , the method further includes a step of amplifying the electrical signals detected by the plurality of parallel switch loops.

[0024] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention. [Explanation of symbols]

[0025] 10: Leakage detection device 11: Output terminal 12: Input terminal 20: Electrical leakage detection system 21: Switch device 22: Voltage source 23: Controller 24: Judgment device 30: Circuit board 31, P_1, P_2..., P_n-1, P_n: Test points 32: Power / Ground Zone 101, 102, 103, 104, 213: Nodes 211: First Switch 212: Second switch Pin_1, Pin_2…, Pin_n-1, Pin_n, Pin_n+1: Probe Ri: detection resistor R_pcb: equivalent resistance Rpcb_H, Rpcb_V: Insulation resistance S61~S64: Step

Claims

1. 1. A ground fault detection system for a circuit board including a plurality of traces, comprising: a plurality of parallel switch loops, each of which has a first switch, a second switch, and a probe connected to a node between the first switch and the second switch, the probe corresponding to one of the plurality of traces of the circuit board; a voltage source arranged to input a voltage to the first switch of each of the plurality of parallel switch loops; a controller configured to control conduction of each of the first switches and the second switches in each of the plurality of parallel switch loops to generate an electrical signal between two of the plurality of traces of the circuit board; and a determination device connected to the second switch to receive the electrical signal and determine whether the electrical signal exceeds a preset threshold.

2. The determination device a sense resistor arranged to form a resistive voltage divider with an isolation resistor of the circuit board; a microprocessor connected to the detection resistor for detecting a divided voltage provided by the resistive voltage divider and performing data processing; an analog-to-digital conversion circuit electrically connected to the determination device and configured to convert the electrical signal detected by the determination device into a digital signal and transmit the digital signal to a display; 2. The ground fault detection system of claim 1, further comprising: a signal amplifier electrically connected to the controller for amplifying the electrical signals detected by the plurality of parallel switch loops.

3. 2. The leakage current detection system of claim 1, wherein when the first switch of one of the plurality of parallel switch loops is on and the remaining second switches are on, the determination device determines whether the electrical signal between the trace corresponding to the first switch and the trace corresponding to the other remaining second switches of the plurality of parallel switch loops exceeds the preset threshold.

4. The leakage current detection system of claim 3, wherein all the second switches are divided into two groups, the first group is set to on, and the second group is set to off, and the group division operation is repeated until it is determined in which group the electrical signal occurs, and between which two specific traces an electrical signal exceeding the preset threshold exists.

5. 1. A method for detecting electrical leakage in a circuit board including a plurality of traces, comprising: providing a plurality of parallel switch loops, each of which includes a first switch, a second switch, and a probe connected to a node between the first switch and the second switch, the probe corresponding to one of the plurality of traces on the circuit board; applying a voltage to the first switch of each of the plurality of parallel switch loops; controlling conduction of each of the first switches and the second switches in each of the plurality of parallel switch loops to generate an electrical signal between two of the plurality of traces on the circuit board; receiving the electrical signal and determining whether the electrical signal exceeds a preset threshold.

6. The step of determining whether the electrical signal exceeds the preset threshold value comprises: detecting a divided voltage provided by a resistive voltage divider consisting of an insulation resistor of the circuit board and a resistive voltage divider; and performing data processing, The leakage current detection method includes: converting the electrical signal into a digital signal and transmitting it to a display; 6. The method of claim 5, further comprising the step of: amplifying the electrical signals detected by the plurality of parallel switch loops.

7. 6. The leakage current detection method of claim 5, further comprising the step of turning on the first switch of one of the plurality of parallel switch loops and turning on the second switches of the remaining ones of the plurality of parallel switch loops, and determining whether the electrical signal between the trace corresponding to the first switch and the trace corresponding to the remaining ones of the second switches exceeds the preset threshold.

8. Dividing all the second switches into two groups, setting the first group to ON and the second group to OFF, and determining which group generates the electrical signal; 8. The leakage current detection method of claim 7, further comprising the step of repeating the group division operation until determining between which two particular traces an electrical signal exceeding the preset threshold is present.

9. 1. A method for detecting electrical leakage in a circuit board including a plurality of traces, comprising: providing a plurality of parallel switch loops, each of the switch loops including a first switch and a second switch; electrically connecting the plurality of parallel switch loops to the plurality of traces; turning on the first switch of one of the plurality of parallel switch loops and turning on the second switches of the remaining plurality of parallel switch loops; and inputting a voltage between the trace corresponding to the first switch and the remaining traces corresponding to the second switches to determine whether there is an electrical signal exceeding a preset threshold.

10. Dividing all the second switches into two groups, setting the first group to ON and the second group to OFF, and determining which group generates the electrical signal; 10. The method of claim 9, further comprising the step of repeating the group division operation until determining between which two particular traces an electrical signal exceeding the preset threshold exists.

11. The step of determining whether the electrical signal exceeds the preset threshold value comprises: detecting a divided voltage provided by a resistive voltage divider consisting of an insulation resistor of the circuit board and a resistive voltage divider; and performing data processing, The leakage current detection method includes: converting the electrical signal into a digital signal and transmitting it to a display; 10. The method of claim 9, further comprising the step of: amplifying the electrical signals detected by the plurality of parallel switch loops.

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