阅读说明：本技术 用于开关元件的故障诊断电路及其方法、电子设备 (Fault diagnosis circuit for switching element, method thereof and electronic device ) 是由 林田生 于 2021-01-29 设计创作，主要内容包括：本发明实施例公开了一种用于开关元件的故障诊断电路及其方法、电子设备。其中,故障诊断电路包括：第二电源、控制和诊断电路和至少一个低边电压检测电路,至少一个低边开关元件的第一端,以及第二电源的第一接地端,均与直流电源的负极电连接；低边电压检测电路的电压输入端与第二电源的电压输出端电连接；任一低边电压检测电路的低边检测端与对应的低边开关元件的第二端电连接；控制和诊断电路的至少一个第一信号输入端与至少一个低边开关元件的控制端一一对应电连接；控制和诊断电路的至少一个第一信号输出端与至少一个低边电压检测电路的第一输出端一一对应电连接。本发明实施例提供的技术方案可以实现对开关元件的故障诊断。(The embodiment of the invention discloses a fault diagnosis circuit for a switching element, a method thereof and electronic equipment. Wherein, the fault diagnosis circuit includes: the first end of the at least one low-side switching element and the first grounding end of the second power supply are electrically connected with the negative pole of the direct-current power supply; the voltage input end of the low-side voltage detection circuit is electrically connected with the voltage output end of the second power supply; the low-side detection end of any one low-side voltage detection circuit is electrically connected with the second end of the corresponding low-side switching element; at least one first signal input end of the control and diagnosis circuit is electrically connected with the control end of at least one low-side switch element in a one-to-one correspondence manner; at least one first signal output end of the control and diagnosis circuit is electrically connected with the first output end of at least one low-side voltage detection circuit in a one-to-one correspondence mode. The technical scheme provided by the embodiment of the invention can realize fault diagnosis of the switching element.)

1. A fault diagnosis circuit for a switching element, characterized in that the switching element comprises:

at least one low-side switching element, a first end of any one of the low-side switching elements being electrically connected to a negative electrode of a direct current power supply;

the failure diagnosis circuit includes:

a second power supply comprising: the first grounding end of the second power supply is electrically connected with the first end of the at least one low-side switching element;

at least one low side voltage detection circuit in one-to-one correspondence with the at least one low side switching element, any of the low side voltage detection circuits comprising: the voltage input end of the low-side voltage detection circuit is electrically connected with the voltage output end of the second power supply; a low-side detection end of any one of the low-side voltage detection circuits is electrically connected with a second end of the corresponding low-side switching element;

control and diagnostic circuitry comprising: at least one first signal input and at least one first signal output; the at least one first signal input end corresponds to the at least one low-side switch element one by one, and any first signal input end is electrically connected with the control end of the corresponding low-side switch element; the at least one first signal output end corresponds to the at least one low-side voltage detection circuit one by one, and any first signal output end is electrically connected with the first output end of the corresponding low-side voltage detection circuit; the control and diagnosis circuit is used for controlling the at least one first signal output end to output a closing signal and an opening signal, and judging whether the at least one low-side switching element has a fault or not according to the signal of the first output end of the at least one low-side voltage detection circuit.

2. The fault diagnosis circuit for a switching element according to claim 1, wherein the switching element further comprises: at least one high-side switching element, a first end of any one of the high-side switching elements being electrically connected to a positive electrode of the DC power supply;

the fault diagnosis circuit further includes: a positive voltage detection circuit and at least one high side voltage detection circuit,

the positive voltage detection circuit includes: the second detection end, the second grounding end and the second output end; the second detection end of the positive voltage detection circuit is electrically connected with the first end of the at least one high-side switching element, and the second grounding end of the positive voltage detection circuit is electrically connected with the first grounding end of the second power supply;

the at least one high side voltage detection circuit corresponds to the at least one high side switching element one to one, and any one of the high side voltage detection circuits includes: a high side detection terminal, a third ground terminal and a third output terminal; a third grounding end of the high-side voltage detection circuit is electrically connected with a first grounding end of the second power supply, and a high-side detection end of any one high-side voltage detection circuit is electrically connected with a second end of the corresponding high-side switching element;

the control and diagnostic circuitry further comprises: a second signal input, at least one third signal input, and at least one second signal output; the second signal input end is electrically connected with the second output end of the positive voltage detection circuit, the at least one third signal input end corresponds to the at least one high-side switch element one by one, and any one third signal input end is electrically connected with the control end of the corresponding high-side switch element; the at least one second signal output end corresponds to the at least one high-side voltage detection circuit one by one, and any one second signal output end is electrically connected with a third output end of the corresponding high-side voltage detection circuit; the control and diagnosis circuit is used for controlling the at least one second signal output end to output a closing signal and an opening signal, and judging whether the at least one high-side switching element has a fault or not according to the difference value of the signal of the second output end of the positive voltage detection circuit and the signal of the third output end of the at least one high-side voltage detection circuit.

3. The fault diagnosis circuit for a switching element according to claim 2, wherein any one of the high-side voltage detection circuits further comprises: a first resistance and a second resistance, wherein the first resistance and the second resistance are connected,

the first end of the first resistor is electrically connected with the high-side detection end of the high-side voltage detection circuit; the second end of the first resistor and the first end of the second resistor are electrically connected with the third output end of the high-side voltage detection circuit; a second end of the second resistor is electrically connected with a third grounding end of the high-side voltage detection circuit;

the positive voltage detection circuit further includes: a third resistor and a fourth resistor, wherein the third resistor and the fourth resistor are connected in series,

the first end of the third resistor is electrically connected with the second detection end of the positive voltage detection circuit; the second end of the third resistor and the first end of the fourth resistor are electrically connected with the second output end of the positive voltage detection circuit; and the second end of the fourth resistor is electrically connected with the second grounding end of the positive voltage detection circuit.

4. The fault diagnosis circuit for switching elements according to claim 1, wherein any one of said low-side voltage detection circuits further comprises: a fifth resistor, a sixth resistor and a first diode,

the fifth resistor is connected in series with the first diode, and a first end of the fifth resistor, which is connected in series with the first diode, is electrically connected with a low-side detection end of the low-side voltage detection circuit; a second end of the fifth resistor, which is connected with the first diode in series, and a first end of the sixth resistor are electrically connected with a first output end of the low-side voltage detection circuit; the second end of the sixth resistor is electrically connected with the voltage input end of the low-side voltage detection circuit;

the conducting direction of the first diode is that the second end of the fifth resistor connected with the first diode in series points to the first end of the fifth resistor connected with the first diode in series.

5. The fault diagnosis circuit for switching elements according to claim 2, characterized in that said control and diagnosis circuit comprises: an analog-to-digital converter, a communication line and a processor,

wherein the analog-to-digital converter is electrically connected to the at least one first signal input, the second signal input, and the at least one third signal input; the analog-to-digital converter is electrically connected with the processor through the communication line; the processor is electrically connected with the at least one first signal output end and the at least one second signal output end; the processor is used for controlling the at least one first signal output end to output a closing signal and an opening signal, and judging whether the at least one low-side switching element has a fault or not according to a digital signal converted by the analog-to-digital converter from a signal of the first output end of the at least one low-side voltage detection circuit; and controlling the at least one second signal output end to output a closing signal and an opening signal, and judging whether the at least one high-side switching element has a fault according to a signal of the second output end of the positive voltage detection circuit and a digital signal converted by the analog-to-digital converter from a signal of the third output end of the at least one high-side voltage detection circuit.

6. The fault diagnosis circuit for switching elements according to claim 1, wherein a voltage of the voltage output terminal of the second power supply is lower than a voltage of the positive pole of the direct current power supply.

7. An electronic device, comprising: a direct current power supply, at least one low-side switching element and a fault diagnosis circuit for a switching element as claimed in any one of claims 1 to 6.

8. The electronic device of claim 7, further comprising: a plurality of high-side switching elements; the high-side switch element and the low-side switch element are relays, the direct-current power supply is a battery, the electronic equipment comprises an electric automobile, and the number of the low-side switch elements is multiple.

9. A fault diagnosis method for a fault diagnosis circuit for a switching element according to any one of claims 1 to 6, comprising:

the control and diagnosis circuit controls the first signal output end to output a closing signal;

if the signal of the first output end of the corresponding low-side voltage detection circuit is not in the first preset threshold range, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is in an open fault;

if the signal of the first output end of the corresponding low-side voltage detection circuit is within a first preset threshold range, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is normally closed;

the control and diagnosis circuit controls the first signal output end to output a disconnection signal;

if the signal of the first output end of the corresponding low-side voltage detection circuit is not in the range of a first preset threshold value, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is normally disconnected;

and if the signal of the first output end of the corresponding low-side voltage detection circuit is within a first preset threshold range, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is in an adhesion fault.

10. The fault diagnosis method according to claim 9, wherein when the switching element further includes: when at least one high-side switching element is used, the fault diagnosis method further includes:

the control and diagnosis circuit controls the second signal output end to output a closing signal;

if the difference value between the signal of the second output end of the positive voltage detection circuit and the signal of the third output end of the corresponding high-side voltage detection circuit is smaller than a second preset threshold value, the control and diagnosis circuit determines that the high-side switching element corresponding to the high-side voltage detection circuit is normally closed;

if the difference value between the signal of the second output end of the positive voltage detection circuit and the signal of the third output end of the corresponding high-side voltage detection circuit is greater than or equal to a second preset threshold value, the control and diagnosis circuit determines that the high-side switching element corresponding to the high-side voltage detection circuit is in an open fault;

the control and diagnosis circuit controls the second signal output end to output a disconnection signal;

if the difference value between the signal of the second output end of the positive voltage detection circuit and the signal of the third output end of the corresponding high-side voltage detection circuit is greater than or equal to a second preset threshold value, the control and diagnosis circuit determines that the high-side switching element corresponding to the high-side voltage detection circuit is normally disconnected;

and if the difference value between the signal of the second output end of the positive voltage detection circuit and the signal of the third output end of the corresponding high-side voltage detection circuit is smaller than a second preset threshold value, the control and diagnosis circuit determines that the high-side switch element corresponding to the high-side voltage detection circuit is in adhesion fault.

Technical Field

The present invention relates to the field of circuit technologies, and in particular, to a fault diagnosis circuit for a switching element, a method thereof, and an electronic device.

Background

The relay is used as an energy control switch of the electric automobile, and is safe in use of the whole automobile. Therefore, the relay needs to be diagnosed regularly to ensure the relay can operate correctly during discharging and charging. With the accelerated development of the intellectualization and the electromotion of the electric automobile, more and more branches are controlled by the relays, and the state of each relay can be effectively diagnosed.

Disclosure of Invention

The embodiment of the invention provides a fault diagnosis circuit for a switching element, a method and electronic equipment thereof, which are used for realizing fault diagnosis of the switching element such as a relay.

In a first aspect, an embodiment of the present invention provides a fault diagnosis circuit for a switching element, where the switching element includes:

at least one low-side switching element, a first end of any one of the low-side switching elements being electrically connected to a negative pole of the direct current power supply;

the failure diagnosis circuit includes:

a second power supply comprising: the first grounding end of the second power supply is electrically connected with the negative pole of the direct current power supply;

at least one low side voltage detection circuit, with at least one low side switching element one-to-one correspondence, arbitrary low side voltage detection circuit includes: the voltage input end of the low-side voltage detection circuit is electrically connected with the voltage output end of the second power supply; the low-side detection end of any one low-side voltage detection circuit is electrically connected with the second end of the corresponding low-side switching element;

control and diagnostic circuitry comprising: at least one first signal input and at least one first signal output; at least one first signal input end corresponds to at least one low-side switch element one to one, and any first signal input end is electrically connected with the control end of the corresponding low-side switch element; the at least one first signal output end corresponds to the at least one low-side voltage detection circuit one by one, and any first signal output end is electrically connected with the first output end of the corresponding low-side voltage detection circuit; the control and diagnosis circuit is used for controlling the at least one first signal output end to output a closing signal and an opening signal and judging whether the at least one low-side switching element has faults or not according to the signal of the first output end of the at least one low-side voltage detection circuit.

Further, the switching element further includes: at least one high-side switching element, wherein the first end of any high-side switching element is electrically connected with the positive electrode of the direct-current power supply;

the failure diagnosis circuit further includes: a positive voltage detection circuit and at least one high side voltage detection circuit,

the positive voltage detection circuit includes: the second detection end, the second grounding end and the second output end; the second detection end of the positive voltage detection circuit is electrically connected with the first end of the at least one high-side switching element, and the second grounding end of the positive voltage detection circuit is electrically connected with the first grounding end of the second power supply;

at least one high side voltage detection circuit corresponds to at least one high side switching element one-to-one, and any high side voltage detection circuit includes: a high side detection terminal, a third ground terminal and a third output terminal; a third grounding end of the high-side voltage detection circuit is electrically connected with a first grounding end of the second power supply, and a high-side detection end of any high-side voltage detection circuit is electrically connected with a second end of the corresponding high-side switching element;

the control and diagnostic circuitry further comprises: a second signal input, at least one third signal input, and at least one second signal output; the second signal input end is electrically connected with the second output end of the positive voltage detection circuit, at least one third signal input end corresponds to at least one high-side switch element one by one, and any third signal input end is electrically connected with the control end of the corresponding high-side switch element; the at least one second signal output end corresponds to the at least one high-side voltage detection circuit one by one, and any second signal output end is electrically connected with a third output end of the corresponding high-side voltage detection circuit; and the control and diagnosis circuit is used for controlling the at least one second signal output end to output a closing signal and an opening signal, and judging whether the at least one high-side switching element has a fault or not according to the difference value of the signal of the second output end of the positive voltage detection circuit and the signal of the third output end of the at least one high-side voltage detection circuit.

Further, any one of the high-side voltage detection circuits further includes: a first resistance and a second resistance, wherein the first resistance and the second resistance are connected,

the first end of the first resistor is electrically connected with the high-side detection end of the high-side voltage detection circuit; the second end of the first resistor and the first end of the second resistor are electrically connected with the third output end of the high-side voltage detection circuit; the second end of the second resistor is electrically connected with a third grounding end of the high-side voltage detection circuit;

the positive voltage detection circuit further includes: a third resistor and a fourth resistor, wherein the third resistor and the fourth resistor are connected in series,

the first end of the third resistor is electrically connected with the second detection end of the positive voltage detection circuit; the second end of the third resistor and the first end of the fourth resistor are electrically connected with the second output end of the positive voltage detection circuit; and the second end of the fourth resistor is electrically connected with the second grounding end of the positive voltage detection circuit.

Further, any one of the low-side voltage detection circuits further includes: a fifth resistor, a sixth resistor and a first diode,

the first end of the fifth resistor, which is connected with the first diode in series, is electrically connected with the low-side detection end of the low-side voltage detection circuit; the second end of the fifth resistor, which is connected with the first diode in series, and the first end of the sixth resistor are electrically connected with the first output end of the low-side voltage detection circuit; the second end of the sixth resistor is electrically connected with the voltage input end of the low-side voltage detection circuit;

the conducting direction of the first diode is that the second end of the fifth resistor connected with the first diode in series points to the first end of the fifth resistor connected with the first diode in series.

Further, the control and diagnostic circuitry includes: an analog-to-digital converter, a communication line and a processor,

the analog-to-digital converter is electrically connected with at least one first signal input end, at least one second signal input end and at least one third signal input end; the analog-to-digital converter is electrically connected with the processor through a communication line; the processor is electrically connected with the at least one first signal output end and the at least one second signal output end; the processor is used for controlling the at least one first signal output end to output a closing signal and an opening signal, and judging whether the at least one low-side switching element has a fault or not according to a digital signal converted by the analog-to-digital converter from a signal of the first output end of the at least one low-side voltage detection circuit; and controlling at least one second signal output end to output a closing signal and an opening signal, and judging whether at least one high-side switching element has a fault or not according to a digital signal converted by an analog-to-digital converter from a signal of the second output end of the positive voltage detection circuit and a signal of the third output end of at least one high-side voltage detection circuit.

Further, the voltage of the voltage output terminal of the second power supply is lower than the voltage of the positive pole of the direct current power supply.

In a second aspect, an embodiment of the present invention further provides an electronic device, including: the invention provides a direct current power supply, at least one low-side switching element and a fault diagnosis circuit for the switching element.

Further, the electronic device further includes: a plurality of high-side switching elements; the high-side switching element and the low-side switching element are relays, the direct-current power supply is a battery, the electronic equipment comprises an electric automobile, and the number of the low-side switching elements is multiple.

In a third aspect, an embodiment of the present invention further provides a fault diagnosis method for a fault diagnosis circuit of a switching element, where the fault diagnosis method is provided in any embodiment of the present invention, and includes:

the control and diagnosis circuit controls the first signal output end to output a closing signal;

if the signal of the first output end of the corresponding low-side voltage detection circuit is not in the first preset threshold range, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is in an open fault;

if the signal of the first output end of the corresponding low-side voltage detection circuit is within a first preset threshold range, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is normally closed;

the control and diagnosis circuit controls the first signal output end to output a disconnection signal;

if the signal of the first output end of the corresponding low-side voltage detection circuit is not in the first preset threshold range, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is normally disconnected;

and if the signal of the first output end of the corresponding low-side voltage detection circuit is within the first preset threshold range, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is in adhesion fault.

Further, when the switching element further includes: the fault diagnosis method further includes, when at least one high-side switching element is present:

the control and diagnosis circuit controls the second signal output end to output a closing signal;

if the difference value between the signal of the second output end of the positive voltage detection circuit and the signal of the third output end of the corresponding high-side voltage detection circuit is smaller than a second preset threshold value, the control and diagnosis circuit determines that the high-side switch element corresponding to the high-side voltage detection circuit is normally closed;

if the difference value between the signal of the second output end of the positive voltage detection circuit and the signal of the third output end of the corresponding high-side voltage detection circuit is greater than or equal to a second preset threshold value, the control and diagnosis circuit determines that the high-side switching element corresponding to the high-side voltage detection circuit is in an open fault;

the control and diagnosis circuit controls the second signal output end to output a disconnection signal;

if the difference value between the signal of the second output end of the positive voltage detection circuit and the signal of the third output end of the corresponding high-side voltage detection circuit is larger than or equal to a second preset threshold value, the control and diagnosis circuit determines that the high-side switching element corresponding to the high-side voltage detection circuit is normally disconnected;

and if the difference value between the signal of the second output end of the positive voltage detection circuit and the signal of the third output end of the corresponding high-side voltage detection circuit is smaller than a second preset threshold value, the control and diagnosis circuit determines that the high-side switch element corresponding to the high-side voltage detection circuit is in adhesion fault.

The technical scheme fault diagnosis circuit of the embodiment of the invention comprises: the system comprises a second power supply, at least one low-side voltage detection circuit and a control and diagnosis circuit, wherein a first grounding end of the second power supply is electrically connected with a negative electrode of a direct-current power supply; the at least one low-side voltage detection circuit corresponds to the at least one low-side switching element one by one, and the voltage input end of the low-side voltage detection circuit is electrically connected with the voltage output end of the second power supply; the low-side detection end of any one low-side voltage detection circuit is electrically connected with the second end of the corresponding low-side switching element; at least one first signal input end of the control and diagnosis circuit corresponds to at least one low-side switching element one to one, and any first signal input end is electrically connected with the control end of the corresponding low-side switching element; at least one first signal output end of the control and diagnosis circuit is in one-to-one correspondence with at least one low-side voltage detection circuit, and any first signal output end is electrically connected with the first output end of the corresponding low-side voltage detection circuit; the control and diagnosis circuit is used for controlling the at least one first signal output end to output a closing signal and an opening signal, judging whether the at least one low-side switching element has a fault or not according to the signal of the first output end of the at least one low-side voltage detection circuit, and realizing fault diagnosis of the switching element.

Drawings

Fig. 1 is a schematic structural diagram of a fault diagnosis circuit for a switching element according to an embodiment of the present invention;

fig. 2 is a schematic diagram of an application scenario of a fault diagnosis circuit for a switching element according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a fault diagnosis circuit for a switching element according to another embodiment of the present invention;

fig. 4 is a schematic view of an application scenario of a fault diagnosis circuit for a switching element according to another embodiment of the present invention;

fig. 5 is a schematic structural diagram of a high-side voltage detection circuit according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of another low-side voltage detection circuit according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a low-side voltage detection circuit according to an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of another low-side voltage detection circuit according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of a control and diagnostic circuit according to an embodiment of the present invention;

fig. 10 is a flowchart of a fault diagnosis method for a switching element according to an embodiment of the present invention;

fig. 11 is a flowchart of a fault diagnosis method for a switching element according to another embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

The embodiment of the invention provides a fault diagnosis circuit for a switching element. Fig. 1 is a schematic structural diagram of a fault diagnosis circuit for a switching element according to an embodiment of the present invention. The switching element includes: at least one low-side switching element 11, and a first terminal N1 of any one of the low-side switching elements 11 is electrically connected to the negative pole V-of the DC power supply 2. The failure diagnosis circuit 3 includes: a second power supply 31, control and diagnostic circuitry 32 and at least one low side voltage detection circuit 33.

The second power supply 31 includes: the voltage output terminal Out1 and the first ground terminal GND1, the first ground terminal GND1 of the second power supply 31 is electrically connected to the first terminal N1 of the at least one low-side switching element 11 (i.e., the first ground terminal GND1 of the second power supply 31 is electrically connected to the negative electrode V-of the dc power supply 2). At least one low-side voltage detection circuit 33 corresponds to at least one low-side switching element 11 one-to-one, and any one of the low-side voltage detection circuits 33 includes: a low-side detection end Det1, a voltage input end In1 and a first output end Out2, wherein the voltage input end In1 of the low-side voltage detection circuit 33 is electrically connected with the voltage output end Out1 of the second power supply 31; the low side detection terminal Det1 of any one of the low side voltage detection circuits 33 is electrically connected to the second terminal N2 of the corresponding low side switching element 11, so as to detect the voltage at the second terminal N2 of the low side switching element 11. The control and diagnostic circuitry 32 includes: at least one first signal input Si1 and at least one first signal output So 1; at least one first signal input end Si1 is in one-to-one correspondence with at least one low-side switching element 11, and any one first signal input end Si1 is electrically connected with the control end Ctr1 of the corresponding low-side switching element 11; at least one first signal output end So1 is in one-to-one correspondence with at least one low-side voltage detection circuit 33, and any first signal output end So1 is electrically connected with the first output end Out2 of the corresponding low-side voltage detection circuit 33; the control and diagnosis circuit 32 is used for controlling the at least one first signal output terminal So1 to output a closing signal and an opening signal, and judging whether the at least one low-side switching element 11 is in fault or not according to the signal of the first output terminal Out2 of the at least one low-side voltage detection circuit 33.

Wherein, optionally, the dc power supply 2 may be a battery. The second power source 31 may be an isolated dc power source, and the second power source 31 is electrically isolated from the dc power source 2. The negative pole V-of the dc power supply 2 may serve as a reference ground for the second power supply 31. Fig. 1 shows an exemplary case of two low-side switching elements 11. Optionally, the low-side switching element 11 is a relay. Fig. 2 is a schematic view of an application scenario of a fault diagnosis circuit for switching elements according to an embodiment of the present invention, where a dc power supply 2 may supply power to at least one load 4, the loads 4 correspond to low-side switching elements 11 one to one, a first end of each of the loads 4 is electrically connected to an anode V + of the dc power supply 2, a second end of each of the loads 4 is electrically connected to a second end N2 of the corresponding low-side switching element 11, and whether the dc power supply 2 supplies power to the load 4 is controlled by controlling the on and off of the low-side switching element 11. Optionally, a charger is connected between the positive electrode V + of the dc power supply 2 and the second end N2 of one of the low-side switching elements 11, and the charger is controlled to charge the dc power supply 2 or not by controlling the on and off of the low-side switching element. Optionally, the voltage at the voltage output terminal Out1 of the second power supply 31 is lower than the voltage at the positive electrode V + of the dc power supply 2, so that power consumption can be reduced compared with a case where the dc power supply 2 is used as a power supply of the low-side voltage detection circuit.

For example, the low-side voltage detection circuit 33 may include a seventh resistor, wherein a first terminal of the seventh resistor and the low-side detection terminal Det1 are electrically connected to the first output terminal Out2, and a second terminal of the seventh resistor is electrically connected to the voltage input terminal In 1. The diagnostic process of one of the low-side switching elements 11 is described as an example: the control and diagnostic circuit 32 may control the first signal output So1 corresponding to the low-side switching element 11 to output a close signal; under normal conditions, the low-side switching element 11 will be closed, so that the voltage detected by the corresponding low-side detection terminal Det1 is zero voltage, so that the signal of the first output terminal Out2 of the low-side voltage detection circuit 33 is within a first preset threshold range, wherein, for example, the first preset threshold range may be set to include zero voltage, and the first preset threshold range is smaller than the voltage of the voltage output terminal Out1 of the second power supply 31, the control and diagnosis circuit 32 will determine that the low-side switching element 33 corresponding to the low-side voltage detection circuit 33 can be normally closed; in the case of an open fault, the low-side switching element 11 cannot be normally closed, i.e., remains open, so that the voltage detected by the corresponding low-side detection terminal Det1 is greater than zero voltage and approaches the voltage of the voltage output terminal Out1 of the second power supply 31, so that the signal of the first output terminal Out2 of the low-side voltage detection circuit 33 is not within the first preset threshold range, and then the control and diagnosis circuit 32 determines that the low-side switching element 33 corresponding to the low-side voltage detection circuit 33 is in an open fault. The control and diagnostic circuit 33 can control the first signal output So1 corresponding to the low-side switching element 11 to output a disconnection signal; under normal conditions, the low-side switching element 11 will be turned off, so that the voltage detected by the corresponding low-side detection terminal Det1 is greater than zero voltage and approaches the voltage of the voltage output terminal Out1 of the second power supply 31, so that the signal of the first output terminal Out2 of the low-side voltage detection circuit 33 is not within the first preset threshold range, and then the control and diagnosis circuit 32 will determine that the low-side switching element 33 corresponding to the low-side voltage detection circuit 33 can be normally turned off; in the event of an adhesion fault, the low-side switching element 11 cannot be normally opened, i.e., remains closed, so that the voltage detected by the corresponding low-side detection terminal Det1 is zero voltage, and the signal of the first output terminal Out2 of the low-side voltage detection circuit 33 is within the first preset threshold range, then the control and diagnostic circuit 32 determines that the low-side switching element 33 corresponding to the low-side voltage detection circuit 33 is an adhesion fault. Alternatively, the control and diagnosis circuit 32 may control all the first signal output terminals So1 to output the close signals at the same time, and the control and diagnosis circuit 32 may control all the first signal output terminals So1 to output the open signals at the same time, So as to detect all the low-side switching elements 11 in parallel, and to increase the diagnosis speed. The failure diagnosis circuit 3 can realize rapid failure diagnosis of the low-side switching element 11.

The technical scheme fault diagnosis circuit of the embodiment comprises: the system comprises a second power supply, at least one low-side voltage detection circuit and a control and diagnosis circuit, wherein a first grounding end of the second power supply is electrically connected with a negative electrode of a direct-current power supply; the at least one low-side voltage detection circuit corresponds to the at least one low-side switching element one by one, and the voltage input end of the low-side voltage detection circuit is electrically connected with the voltage output end of the second power supply; the low-side detection end of any one low-side voltage detection circuit is electrically connected with the second end of the corresponding low-side switching element; at least one first signal input end of the control and diagnosis circuit corresponds to at least one low-side switching element one to one, and any first signal input end is electrically connected with the control end of the corresponding low-side switching element; at least one first signal output end of the control and diagnosis circuit is in one-to-one correspondence with at least one low-side voltage detection circuit, and any first signal output end is electrically connected with the first output end of the corresponding low-side voltage detection circuit; the control and diagnosis circuit is used for controlling the at least one first signal output end to output a closing signal and an opening signal, judging whether the at least one low-side switching element has a fault or not according to the signal of the first output end of the at least one low-side voltage detection circuit, and realizing fault diagnosis of the switching element.

Fig. 3 is a schematic structural diagram of another fault diagnosis circuit for a switching element according to an embodiment of the present invention. Fig. 4 is a schematic view of an application scenario of a fault diagnosis circuit for a switching element according to another embodiment of the present invention. On the basis of the above embodiment, the switching element further includes: at least one high-side switching element 12, and a first terminal N3 of any one of the high-side switching elements 12 is electrically connected to the positive electrode V + of the dc power supply 2. The failure diagnosis circuit 3 further includes: a positive voltage detection circuit 34 and at least one high side voltage detection circuit 35.

The positive voltage detection circuit 34 includes: a second detection terminal Det2, a second ground terminal GND2, and a second output terminal Out 3; the second detection terminal Det2 of the positive voltage detection circuit 34 is electrically connected to the first terminal N3 of the at least one high-side switching element 12 (i.e., the second detection terminal Det2 of the positive voltage detection circuit 34 is electrically connected to the positive electrode V + of the dc power supply 2), so as to detect the voltage of the positive electrode V + of the dc power supply 2. The second ground GND2 of the positive voltage detection circuit 34 is electrically connected to the first ground GND1 of the second power supply 31 (i.e., the second ground GND2 of the positive voltage detection circuit 34 is electrically connected to the negative electrode V-of the dc power supply 2). At least one high-side voltage detection circuit 34 corresponds to at least one high-side switching element 12 one-to-one, and any one of the high-side voltage detection circuits 34 includes: a high-side detection terminal Det3, a third ground terminal GND3 and a third output terminal Out 4; the third ground GND3 of the high-side voltage detection circuit 34 is electrically connected to the first ground GND1 of the second power supply 31 (i.e., the third ground GND3 of the high-side voltage detection circuit 34 is electrically connected to the negative electrode V-of the dc power supply 2), and the high-side detection terminal Det3 of any high-side voltage detection circuit 35 is electrically connected to the corresponding second terminal N4 of the high-side switching element 12, so as to detect the voltage of the second terminal N4 of the high-side switching element 12.

The control and diagnostic circuitry 32 also includes: a second signal input terminal Si2, at least one third signal input terminal Si3 and at least one second signal output terminal So 2; the second signal input end Si2 is electrically connected with the second output end Out3 of the positive voltage detection circuit 34, at least one third signal input end Si3 is in one-to-one correspondence with at least one high-side switching element 12, and any third signal input end Si3 is electrically connected with the control end Ctr2 of the corresponding high-side switching element 12; the at least one second signal output terminal So2 is in one-to-one correspondence with the at least one high-side voltage detection circuit 35, and any one second signal output terminal So2 is electrically connected with the third output terminal Out4 of the corresponding high-side voltage detection circuit 35; the control and diagnosis circuit 32 is configured to control the at least one second signal output So2 to output a close signal and an open signal, and determine whether the at least one high-side switching element 12 is faulty according to a difference between a signal at the second output Out3 of the positive voltage detection circuit 34 and a signal at the third output Out4 of the at least one high-side voltage detection circuit 35.

Optionally, the number of the high-side switching elements 12 is equal to that of the low-side switching elements 11. Optionally, the high-side switching element 12 is a relay. The high-side voltage detection circuit 35 and the reference ground of the second power supply 31 are both the negative pole V-of the dc power supply 2.

The diagnostic procedure of one of the high-side switching elements 12 is described as an example: the voltage detected by the second detection terminal Det2 of the positive voltage detection circuit 34 is the voltage of the positive electrode V + of the dc power supply 2, and the control and diagnosis circuit 32 can control the second signal output terminal So2 corresponding to the high-side switching element 12 to output a close signal; under normal conditions, the high-side switching element 12 is closed, so that the voltage detected by the corresponding high-side detection terminal Det3 is equal to the voltage of the positive electrode V + of the dc power supply 2, the difference between the signal of the second output terminal Out3 of the positive electrode voltage detection circuit 34 and the signal of the third output terminal Out4 of the high-side voltage detection circuit 35 is close to zero voltage and is smaller than a second preset threshold, where the second preset threshold may be larger than zero voltage and smaller than the voltage of the positive electrode V + of the dc power supply 2, and the control and diagnosis circuit 32 determines that the high-side switching element 12 corresponding to the high-side voltage detection circuit 35 is normally closed; in the case of an open fault, the high-side switching element 12 cannot be normally closed, that is, remains open, so that the voltage detected by the corresponding high-side detection terminal Det3 is much lower than the voltage of the positive electrode V + of the dc power supply 2 and approaches zero voltage, the difference between the signal of the second output terminal Out3 of the positive voltage detection circuit 34 and the signal of the third output terminal Out4 of the high-side voltage detection circuit 35 is greater than or equal to a second preset threshold, and the control and diagnosis circuit 32 determines that the high-side switching element 12 corresponding to the high-side voltage detection circuit 35 is in an open fault. The control and diagnostic circuit 32 may control the second signal output So2 corresponding to the high-side switching element 12 to output a turn-off signal; under normal conditions, the high-side switching element 12 is turned off, so that the voltage detected by the corresponding high-side detection terminal Det3 is far less than the voltage of the positive electrode V + of the dc power supply 2 and approaches zero voltage, the difference between the signal of the second output terminal Out3 of the positive electrode voltage detection circuit 34 and the signal of the third output terminal Out4 of the high-side voltage detection circuit 35 is greater than or equal to a second preset threshold, and the control and diagnosis circuit 32 determines that the high-side switching element 12 corresponding to the high-side voltage detection circuit 35 is normally turned off; in the case of an adhesion fault, the high-side switching element 12 cannot be normally opened, that is, is kept closed, so that the voltage detected by the corresponding high-side detection terminal Det1 is equal to the voltage of the positive electrode V + of the dc power supply 2, the difference between the signal of the second output terminal Out3 of the positive electrode voltage detection circuit 34 and the signal of the third output terminal Out4 of the high-side voltage detection circuit 35 is close to zero voltage and is smaller than a second preset threshold, and the control and diagnosis circuit 32 determines that the high-side switching element 12 corresponding to the high-side voltage detection circuit 35 is an adhesion fault. The failure diagnosis circuit can perform failure diagnosis of the high-side switching element 12.

The embodiment of the invention provides a fault diagnosis circuit for a switching element. Fig. 5 is a schematic structural diagram of a high-side voltage detection circuit according to an embodiment of the present invention. On the basis of the above embodiment, any of the high-side voltage detection circuits 35 further includes: a first resistor R1 and a second resistor R2.

Wherein, the first end of the first resistor R1 is electrically connected to the high-side detection end Det3 of the high-side voltage detection circuit 35; the second end of the first resistor R1 and the first end of the second resistor R2 are electrically connected to the third output terminal Out4 of the high-side voltage detection circuit 35; a second end of the second resistor R2 is electrically connected to a third ground GND3 of the high-side voltage detection circuit 35. The first resistor R1 and the second resistor R2 are connected in series to divide voltage, and the proportion of the first resistor R1 and the second resistor R2 can be set according to requirements.

Optionally, on the basis of the foregoing embodiment, with reference to fig. 5, each high-side voltage detection circuit 35 further includes: the first capacitor C1 is connected in parallel with the second resistor R2. The first capacitor C1 acts as a filter.

The embodiment of the invention provides a fault diagnosis circuit for a switching element. Fig. 6 is a schematic structural diagram of another low-side voltage detection circuit according to an embodiment of the present invention. On the basis of the above embodiment, the positive voltage detection circuit 34 further includes: a third resistor R3 and a fourth resistor R4.

A first end of the third resistor R3 is electrically connected to the second detection end Det2 of the positive voltage detection circuit 34; the second end of the third resistor R3 and the first end of the fourth resistor R4 are electrically connected to the second output terminal Out3 of the positive voltage detection circuit 34; a second terminal of the fourth resistor R4 is electrically connected to the second ground GND2 of the positive voltage detection circuit 34. The third resistor R3 and the fourth resistor R4 are connected in series to divide voltage, and the proportion of the third resistor R3 and the fourth resistor R4 can be set according to requirements.

Optionally, on the basis of the foregoing embodiment, with continuing reference to fig. 6, the positive voltage detection circuit 34 further includes: and the second capacitor C2 is connected with the fourth resistor R4 in parallel. The second capacitor C2 acts as a filter.

The embodiment of the invention provides a fault diagnosis circuit for a switching element. Fig. 7 is a schematic structural diagram of a low-side voltage detection circuit according to an embodiment of the present invention. On the basis of the above embodiment, any one of the low-side voltage detection circuits 33 further includes: a fifth resistor R5, a sixth resistor R6, and a first diode D1.

The fifth resistor R5 is connected in series with the first diode D1, and the first end of the fifth resistor R5 connected in series with the first diode D1 is electrically connected to the low-side detection end Det1 of the low-side voltage detection circuit 33; a second end of the fifth resistor R5 connected in series with the first diode D1 and a first end of the sixth resistor R6 are electrically connected to the first output end Out2 of the low-side voltage detection circuit 33; a second end of the sixth resistor R6 is electrically connected to a voltage input end In1 of the low-side voltage detection circuit 33; the conducting direction of the first diode D1 is from the second end of the fifth resistor R5 connected in series with the first diode D1 to the first end of the fifth resistor R5 connected in series with the first diode D1.

The first diode D1 plays a role in preventing reverse connection of high voltage, and prevents reverse flow of current. Fig. 7 exemplarily shows that the cathode of the first diode D1 is electrically connected to the low-side detection terminal Det1 of the low-side voltage detection circuit 33, and the anode of the first diode D1 is electrically connected to the first terminal of the sixth resistor R6 and the first output terminal Out2 of the low-side voltage detection circuit 33 via the fifth resistor R5. When the low-side switching element 11 is closed, and the corresponding low-side detection end Det1 of the low-side voltage detection circuit 33 is equal to zero voltage, the first diode D1 is turned on, at this time, the fifth resistor R5 and the sixth resistor R6 are connected in series to divide voltage, the proportion of the fifth resistor R5 and the sixth resistor R6 can be set as required, and at this time, the voltage of the first output end Out2 of the low-side voltage detection circuit 33 is within a first preset threshold range; when the low-side switching element 11 is turned off, the first diode D1 is turned off, and the corresponding low-side detection terminal Det1 of the low-side voltage detection circuit 33 is equal to the voltage of the voltage output terminal Out1 of the second power supply 31, at this time, the voltage of the first output terminal Out2 of the low-side voltage detection circuit 33 is not within the first preset threshold range. The first diode should be rated at a voltage greater than the maximum voltage across the dc power supply, and 2 identical diodes may be connected in series if necessary to increase reliability.

Fig. 8 is a schematic structural diagram of another low-side voltage detection circuit according to an embodiment of the present invention. On the basis of the above embodiment, the low side detection terminal Det1 of the low side voltage detection circuit 33 is electrically connected to the cathode of the first diode D1 through the fifth resistor R5; an anode of the first diode D1 and a first end of the sixth resistor R6 are electrically connected to the first output terminal Out2 of the low-side voltage detection circuit 33. The operation of the solution of fig. 7 is similar to that of the solution of fig. 8, and is not described here again.

Optionally, on the basis of the foregoing embodiment, with continuing reference to fig. 7 or fig. 8, any low-side voltage detection circuit 33 further includes: a fourth ground GND4, a seventh resistor R7 and a third capacitor C3. The second end of the fifth resistor R5 connected in series with the first diode D1 and the first end of the sixth resistor R6 are electrically connected with the first end of the seventh resistor R7; a second end of the seventh resistor R7 and a first end of the third capacitor C3 are electrically connected to the first output terminal Out2 of the low-side voltage detection circuit 33; the second terminal of the third capacitor C3 is electrically connected to the fourth ground GND4, and the fourth ground GND4 is electrically connected to the first ground GND 1. The reference grounds of the high-side voltage detection circuit 35 and the low-side voltage detection circuit 33 are both negative V-of the DC power supply 2. The seventh resistor R7 functions as a current limiter. The third capacitor C3 acts as a filter.

The embodiment of the invention provides a fault diagnosis circuit for a switching element. Fig. 9 is a schematic structural diagram of a control and diagnostic circuit according to an embodiment of the present invention. On the basis of the above embodiment, the control and diagnostic circuit 32 includes: an analog-to-digital converter 321, a communication line 322, and a processor 323.

Wherein the analog-to-digital converter 321 is electrically connected to at least one first signal input Si1, a second signal input Si2, and at least one third signal input Si 3; the analog-to-digital converter 321 is electrically coupled to the processor 323 via communication line 322; the processor 323 is electrically connected to at least one first signal output So1 and at least one second signal output So 2.

The processor 323 is configured to control the at least one first signal output So1 to output a close signal and an open signal, and determine whether the at least one low-side switching element 11 fails according to a digital signal converted by the analog-to-digital converter 321 from a signal at the first output Out2 of the at least one low-side voltage detection circuit 33; and controlling at least one second signal output terminal So2 to output a closing signal and an opening signal, and judging whether at least one high-side switching element 12 has a fault according to a digital signal converted by the analog-to-digital converter 321 from the signal of the second output terminal Out3 of the positive voltage detection circuit 34 and the signal of the third output terminal Out4 of the at least one high-side voltage detection circuit 35.

The communication line 322 may be an isolated communication line, such as an SPI (Serial Peripheral Interface) bus or an IIC (Inter-Integrated Circuit) bus. The processor 323 may include an MCU (micro controller Unit) or ARM (advanced RISC machines) processor. Optionally, the analog-to-digital converter 321 includes a first analog-to-digital conversion unit electrically connected to the at least one first signal input terminal Si1, and a second analog-to-digital conversion unit electrically connected to the second signal input terminal Si2 and the at least one third signal input terminal Si 3. If the communication bus is the SPI communication bus, a first analog-to-digital conversion unit and a second analog-to-digital conversion unit are chip-selected through 2 different Chip Selection (CS) pins; if the bus is the IIC bus, the first analog-to-digital conversion unit and the second analog-to-digital conversion unit are addressed through level combination, and then data communication is carried out according to different addresses.

The embodiment of the invention provides electronic equipment. With continued reference to fig. 1, the electronic device includes: a direct current power supply, at least one low-side switching element 11 and a fault diagnosis circuit 3 for the switching element provided by any embodiment of the present invention.

The electronic device provided in the embodiment of the present invention includes the fault diagnosis circuit for the switching element in the above embodiment, and therefore, the electronic device provided in the embodiment of the present invention also has the beneficial effects described in the above embodiment, and details are not described herein again.

Optionally, on the basis of the foregoing embodiment, with continued reference to fig. 2, the electronic device further includes: at least one high-side switching element 12. Optionally, the electronic device comprises an electric vehicle.

The embodiment of the invention provides a fault diagnosis method for a switching element. Fig. 10 is a flowchart of a fault diagnosis method for a switching element according to an embodiment of the present invention. The fault diagnosis method provided by the embodiment of the invention is realized based on the fault diagnosis circuit for the switching element provided by any embodiment of the invention. The fault diagnosis method comprises the following steps:

step 110, the control and diagnostic circuitry controls the first signal output to output a close signal.

Optionally, the control and diagnosis circuit 32 may control all the first signal output terminals So1 to output the close signal one by one or simultaneously.

And step 120, if the signal of the first output end of the corresponding low-side voltage detection circuit is not within the first preset threshold range, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is in an open fault.

Step 130, if the signal of the first output end of the corresponding low-side voltage detection circuit is within the first preset threshold range, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is normally closed.

Step 140, the control and diagnostic circuitry controls the first signal output to output a disconnect signal.

Optionally, the control and diagnosis circuit 32 may control all the first signal output terminals So1 to output the open signal one by one or simultaneously.

Step 150, if the signal of the first output terminal of the corresponding low-side voltage detection circuit is not within the first preset threshold range, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is normally turned off.

And step 160, if the signal of the first output end of the corresponding low-side voltage detection circuit is within the first preset threshold range, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is in adhesion fault.

It should be noted that if the number of the low-side switching elements is plural, the first signal output terminals So1 corresponding to all the low-side switching elements 11 may be controlled to output the on signal or the off signal as needed, and for example, a part of the first signal output terminals So1 may be controlled to output the on signal, and at the same time, the rest of the first signal output terminals So1 may be controlled to output the off signal. Steps 110 to 130 may be performed after steps 140 to 160.

The fault diagnosis method provided by the embodiment of the present invention is implemented based on the fault diagnosis circuit for the switching element provided by any embodiment of the present invention, and therefore, the fault diagnosis method provided by the embodiment of the present invention also has the beneficial effects described in the above embodiments, and details are not described here.

Fig. 11 is a flowchart of a fault diagnosis method for a switching element according to another embodiment of the present invention. On the basis of the above embodiment, when the switching element further includes: the fault diagnosis method comprises the following steps when at least one high-side switching element is used:

step 210, the control and diagnostic circuitry controls the first signal output to output a close signal.

Step 220, if the signal of the first output end of the corresponding low-side voltage detection circuit is not within the first preset threshold range, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is in an open fault.

Step 230, if the signal of the first output terminal of the corresponding low-side voltage detection circuit is within the first preset threshold range, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is normally closed.

Step 240, the control and diagnostic circuitry controls the first signal output to output a disconnect signal.

Step 250, if the signal of the first output end of the corresponding low-side voltage detection circuit is not within the first preset threshold range, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is normally turned off.

And step 260, if the signal of the first output end of the corresponding low-side voltage detection circuit is within the first preset threshold range, the control and diagnosis circuit determines that the low-side switching element corresponding to the low-side voltage detection circuit is in an adhesion fault.

Step 270, the control and diagnostic circuitry controls the second signal output to output a close signal.

Optionally, the control and diagnosis circuit 32 may control the second signal output So2 to output the off signal one by one or simultaneously.

And step 280, if the difference value between the signal of the second output end of the positive voltage detection circuit and the signal of the third output end of the corresponding high-side voltage detection circuit is smaller than a second preset threshold value, the control and diagnosis circuit determines that the high-side switching element corresponding to the high-side voltage detection circuit is normally closed.

And step 290, if the difference value between the signal of the second output end of the positive voltage detection circuit and the signal of the third output end of the corresponding high-side voltage detection circuit is greater than or equal to a second preset threshold value, the control and diagnosis circuit determines that the high-side switching element corresponding to the high-side voltage detection circuit is in an open fault state.

Step 300, the control and diagnosis circuit controls the second signal output end to output a disconnection signal.

Optionally, the control and diagnosis circuit 32 may control the second signal output So2 to output the off signal one by one or simultaneously.

And 310, if the difference value between the signal of the second output end of the positive voltage detection circuit and the signal of the third output end of the corresponding high-side voltage detection circuit is greater than or equal to a second preset threshold value, the control and diagnosis circuit determines that the high-side switching element corresponding to the high-side voltage detection circuit is normally disconnected.

And step 320, if the difference value between the signal of the second output end of the positive voltage detection circuit and the signal of the third output end of the corresponding high-side voltage detection circuit is smaller than a second preset threshold value, the control and diagnosis circuit determines that the high-side switch element corresponding to the high-side voltage detection circuit is in adhesion fault.

Wherein, steps 210 to 260 may be performed after steps 270 to 320. Steps 270 to 290 may be performed after steps 300 to 320.

It should be noted that if the number of the high-side switching elements is plural, the second signal output terminals So2 corresponding to all the high-side switching elements 12 may be controlled to output the on signal or the off signal as needed, and for example, a part of the second signal output terminals So2 may be controlled to output the on signal, and at the same time, the other part of the second signal output terminals So2 may be controlled to output the off signal.

The embodiment of the invention not only can effectively diagnose the multi-branch relay, but also only needs 1 path of isolation power supply and digital isolation communication by referring to the same detection reference ground, thereby improving the reliability and safety of the battery management system of the electric automobile, having fewer devices and small volume, and obviously reducing the relay diagnosis cost of the battery management system. Meanwhile, the parallel diagnosis of the multi-path relays can be realized, and the detection speed is greatly improved.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.