CN115951190A - MOSFET detection circuit and detection method - Google Patents

MOSFET detection circuit and detection method Download PDF

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Publication number
CN115951190A
CN115951190A CN202211736556.8A CN202211736556A CN115951190A CN 115951190 A CN115951190 A CN 115951190A CN 202211736556 A CN202211736556 A CN 202211736556A CN 115951190 A CN115951190 A CN 115951190A
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mosfet
sampling circuit
voltage sampling
loop switch
voltage
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陈凯
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Hubei Eve Power Co Ltd
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Hubei Eve Power Co Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

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  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Measurement Of Current Or Voltage (AREA)

Abstract

The invention discloses a MOSFET detection circuit and a detection method, which comprises the following steps: initializing a BMS control chip, wherein the BMS control chip sends out an instruction to turn off all switches included in the MOSFET switch array; and acquiring the voltages of the input end voltage sampling circuit, the output end voltage sampling circuit and the first voltage sampling circuit through a BMS control chip, and comparing the voltage values. According to the invention, through the combination of each charging and discharging loop switch in the MOSFET switch array and the comparison by acquiring the difference value of each voltage sampling circuit, compared with the MOSFET diagnosis scheme in the prior art, the normal close and normal open diagnosis functions of the MOSFET serving as the charging and discharging loop switch can be completed without adding any additional electronic component; through adopting including MOSFET as charging, discharge circuit switch, because MOSFET self conduction characteristic for the compatibility of this scheme is strong, is applicable to and can uses MOSFET as the charging, discharge circuit switch scheme of battery system.

Description

MOSFET detection circuit and detection method
Technical Field
The invention relates to the technical field of electronic circuits, in particular to a MOSFET detection circuit and a detection method.
Background
In the use process of the battery system, the problems of energy consumption and safety are considered, and a switch element of a charge-discharge loop is required to close and open the charge-discharge loop.
Most of battery system all are the relay scheme of chooseing for use at present, and general lithium electricity energy storage is equipped with the electric system, sets up between direct current bus and load, including lithium electricity group battery, battery management unit BMS, each relay, pre-charge resistance, prevent anti-component, constitute the pre-charge return circuit through relay and pre-charge resistance earlier, and the main positive charge-discharge return circuit of constituteing again, main burden charge-discharge return circuit and other discharge return circuits are born to the relay.
At present, MOSFET is less used as a main loop switch, the MOSFET scheme has great advantages in cost, noise and volume, and any additional electronic component is required to be added to realize the diagnosis function in the existing MOSFET scheme; in the prior art, a general MOSFET detection circuit and a fault diagnosis method include a plurality of sets of parallel current conduction paths, each current conduction path includes two sets of MOSFET modules, and a current detection resistor is installed between the two sets of MOSFET modules; most of the circuits of the MOSFET can be detected only by depending on a current detection device, and a perfect diagnosis strategy for normally open and normally closed faults of MOSFET switches of a multi-path parallel loop is not provided.
Disclosure of Invention
The invention aims to solve the problem that most of the existing battery systems are selected relay schemes; in the scheme of the prior art, most of circuits can be detected by relying on a current detection device, and the MOSFET detection circuit and the detection method are provided.
In order to achieve the above object, the present invention provides the following technical solutions:
a MOSFET detection circuit comprises a power supply module, a BMS control chip and a MOSFET switch array;
parallel branches are arranged in the MOSFET switch array, and each parallel branch comprises a discharge loop switch and a charge loop switch which are sequentially connected in series; the discharging loop switch is connected with the positive electrode of the power supply module, and the charging loop switch is connected with the negative electrode of the power supply module; the discharging loop switch and the charging loop switch comprise diodes and MOSFETs, and the MOSFETs are connected with the BMS control chip;
a first voltage sampling circuit is arranged between the discharge loop switch and the discharge loop switch, and the first voltage sampling circuit is connected with the BMS control chip and used for the BMS control chip to collect voltage;
the input of MOSFET switch array is equipped with input voltage sampling circuit, the output of MOSFET switch array is equipped with output voltage sampling circuit, input voltage sampling circuit and output voltage sampling circuit all are connected with BMS control chip, supply BMS control chip to gather voltage.
As a preferable aspect of the present invention, the diode includes a first diode or a second diode, and the MOSFET includes a first MOSFET or a second MOSFET;
the positive electrode of the power supply module is electrically connected with the D electrode of a first MOSFET included in the discharge loop switch, and the G electrode of the first MOSFET is electrically connected with the BMS control chip;
the S pole of the first MOSFET is electrically connected with the D pole of a second MOSFET included in the charging loop switch, the G pole of the second MOSFET is electrically connected with the BMS control chip, and the S pole of the second MOSFET is connected with the output end of the MOSFET switch array;
the cathode of the first diode is electrically connected with the D pole of the first MOSFET, and the anode of the first diode is electrically connected with the S pole of the first MOSFET;
the cathode of the second diode is electrically connected with the S pole of the second MOSFET, and the anode of the second diode is electrically connected with the D pole of the second MOSFET.
As a preferable aspect of the present invention, the MOSFET is an N-channel depletion MOSFET.
As a preferred embodiment of the present invention, the diode is TVS for preventing a reverse discharge.
In a preferred embodiment of the present invention, the turn-on voltage drop of the TVS is 0.7V.
As the preferred scheme of the invention, the BMS control chip is an MCU.
As a preferable scheme of the present invention, the power supply module is a rechargeable battery.
In a preferred embodiment of the present invention, the maximum charging voltage of the rechargeable battery is 48V.
The invention also discloses a MOSFET detection method, which is based on the MOSFET detection circuit and comprises the following detection steps:
initializing a BMS control chip, wherein the BMS control chip sends out an instruction to turn off all switches included in the MOSFET switch array;
acquiring voltages of the input end voltage sampling circuit, the output end voltage sampling circuit and the first voltage sampling circuit through a BMS control chip, and comparing voltage values;
if the voltage value obtained by subtracting the voltage value of the first voltage sampling circuit from the voltage value of the input end voltage sampling circuit is smaller than a set threshold value, a normally closed fault exists in the discharge loop switch; if no fault exists, the next step is carried out, and if the fault exists, the flow is ended;
closing a charging loop switch, wherein if the voltage value obtained by subtracting the first voltage sampling circuit from the input end voltage sampling circuit is greater than a set threshold value, the charging loop switch has a normally open fault; if no normally open fault exists, the next step is carried out, and if the normally open fault exists, the flow is ended;
if the voltage value of the output end voltage sampling circuit subtracted from the voltage value of the first voltage sampling circuit is smaller than a first set threshold value, or the voltage value of the output end voltage sampling circuit subtracted from the voltage value of the first voltage sampling circuit is larger than a second set threshold value, a normally-closed fault exists in a discharge loop switch; if no normally closed fault exists, the next step is carried out, and if the normally closed fault exists, the flow is ended; wherein the second set threshold is greater than the first set threshold;
sequentially closing the charging loop switch, sequentially subtracting the voltage value of the input end voltage sampling circuit from the voltage value of the first voltage sampling circuit between the closed charging loop switch and the discharging loop switch, and if the difference value is greater than a set threshold value, judging that the charging loop switch has a normally open fault;
and completing the diagnosis of the charging loop switch and the discharging loop switch in the MOSFET switch array.
As the preferred scheme of the invention, the BMS control chip is an MCU.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention compares the difference values of all voltage sampling circuits by the combination of all charge and discharge loop switches in the MOSFET switch array and by the acquisition of the difference values of all voltage sampling circuits; compared with the MOSFET diagnosis scheme in the prior art, the diagnosis function of normally closing and normally opening by using the MOSFET as a charging and discharging loop switch can be completed without adding any additional electronic component;
2. the invention adopts the MOSFET as the charge and discharge loop switch, and the compatibility of the scheme is strong due to the self-conduction characteristic of the MOSFET, thereby being suitable for the scheme of using the MOSFET as the charge and discharge loop switch of the battery system.
Drawings
FIG. 1 is a flow chart of the operation of a MOSFET detection method of the present invention;
FIG. 2 is a schematic diagram of a MOSFET detection circuit of the present invention;
fig. 3 is a schematic diagram of a MOSFET detection circuit applied to an electric vehicle according to the present invention.
Detailed Description
The present invention will be described in further detail with reference to test examples and specific embodiments. It should be understood that the scope of the above-described subject matter of the present invention is not limited to the following examples, and any technique realized based on the contents of the present invention is within the scope of the present invention.
Example 1
Referring to fig. 2, a MOSFET detection circuit includes a power supply module, a BMS control chip, and a MOSFET switch array;
the MOSFET switch array is provided with 3 parallel branches, and each of the 3 parallel branches comprises 1 discharging loop switch and 1 charging loop switch which are sequentially connected in series; the discharging loop switch is connected with the positive electrode of the power supply module, and the charging loop switch is connected with the negative electrode of the power supply module; the discharging loop switch and the charging loop switch comprise diodes and MOSFETs, and the MOSFETs are connected with the BMS control chip;
a first voltage sampling circuit is arranged between the discharge loop switch and the discharge loop switch, and the first voltage sampling circuit is connected with the BMS control chip and used for the BMS control chip to collect voltage;
the input of MOSFET switch array is equipped with input voltage sampling circuit, the output of MOSFET switch array is equipped with output voltage sampling circuit, input voltage sampling circuit and output voltage sampling circuit all are connected with BMS control chip, supply BMS control chip to collect the voltage.
Example 2
Referring to fig. 2, this embodiment is further upgraded and optimized based on embodiment 1, that is, the diode includes a first diode or a second diode, and the MOSFET includes a first MOSFET or a second MOSFET;
the positive electrode of the power supply module is electrically connected with the D electrode of a first MOSFET included in the discharge loop switch, and the G electrode of the first MOSFET is electrically connected with the BMS control chip;
the S pole of the first MOSFET is electrically connected with the D pole of a second MOSFET included in the charging loop switch, the G pole of the second MOSFET is electrically connected with the BMS control chip, and the S pole of the second MOSFET is connected with the output end of the MOSFET switch array;
the cathode of the first diode is electrically connected with the D pole of the first MOSFET, and the anode of the first diode is electrically connected with the S pole of the first MOSFET;
the cathode of the second diode is electrically connected with the S pole of the second MOSFET, and the anode of the second diode is electrically connected with the D pole of the second MOSFET.
The MOSFET is an N-channel depletion type MOSFET.
The diode is a TVS for preventing reverse discharge.
The turn-on voltage drop of the TVS is 0.7V.
The BMS control chip is an MCU.
The power supply module is a rechargeable battery.
The maximum charging voltage of the rechargeable battery is 48V.
Example 3
Referring to fig. 1 to 2 together, the present embodiment provides a MOSFET detection circuit, which includes a power supply module, a BMS control chip, and a MOSFET switch array;
2 parallel branches are arranged in the MOSFET switch array, and each of the 2 parallel branches comprises 1 discharging loop switch and 1 charging loop switch which are sequentially connected in series; the discharging loop switch is connected with the positive electrode of the power supply module, and the charging loop switch is connected with the negative electrode of the power supply module; the discharging loop switch and the charging loop switch comprise diodes and MOSFETs, and the MOSFETs are connected with the BMS control chip;
a first voltage sampling circuit is arranged between the discharge loop switch and the discharge loop switch, and the first voltage sampling circuit is connected with the BMS control chip and used for the BMS control chip to collect voltage;
the input of MOSFET switch array is equipped with input voltage sampling circuit, the output of MOSFET switch array is equipped with output voltage sampling circuit, input voltage sampling circuit and output voltage sampling circuit all are connected with BMS control chip, supply BMS control chip to gather voltage.
The diode comprises a first diode or a second diode, and the MOSFET comprises a first MOSFET or a second MOSFET;
the positive electrode of the power supply module is electrically connected with the D electrode of a first MOSFET included in the discharge loop switch, and the G electrode of the first MOSFET is electrically connected with the BMS control chip;
the S pole of the first MOSFET is electrically connected with the D pole of a second MOSFET included in the charging loop switch, the G pole of the second MOSFET is electrically connected with the BMS control chip, and the S pole of the second MOSFET is connected with the output end of the MOSFET switch array;
the cathode of the first diode is electrically connected with the D electrode of the first MOSFET, and the anode of the first diode is electrically connected with the S electrode of the first MOSFET;
the cathode of the second diode is electrically connected with the S pole of the second MOSFET, and the anode of the second diode is electrically connected with the D pole of the second MOSFET.
The MOSFET is an N-channel depletion type MOSFET.
The diode is a TVS for preventing reverse discharge.
The turn-on voltage drop of the TVS is 0.7V.
The BMS control chip is an MCU.
The power supply module is a rechargeable battery.
The maximum charging voltage of the rechargeable battery is 48V.
The embodiment also provides a MOSFET detection method, which is based on the above MOSFET detection circuit, and includes the following detection steps:
initializing a BMS control chip, wherein the BMS control chip sends out an instruction to turn off all switches included in the MOSFET switch array;
acquiring voltages of the input end voltage sampling circuit, the output end voltage sampling circuit and the first voltage sampling circuit through a BMS control chip, and comparing voltage values;
if the voltage value of the first voltage sampling circuit subtracted from the voltage value of the input end voltage sampling circuit is smaller than a set threshold value of 3V, the corresponding discharge loop switch is judged to be in a normally-closed fault state; if no fault exists, the next step is carried out, and if the fault exists, the flow is ended;
closing a charging loop switch, and if the voltage value obtained by subtracting the first voltage sampling circuit from the input end voltage sampling circuit is greater than a set threshold value of 3V, which indicates that the voltage difference between the voltage at the input end voltage sampling circuit and the voltage at the voltage difference value of the first voltage sampling circuit is greater, judging that the corresponding charging loop switch is in a normally open fault; if no normally open fault exists, the next step is carried out, and if the normally open fault exists, the flow is ended;
if the voltage value of the output end voltage sampling circuit subtracted from the voltage value of the first voltage sampling circuit is smaller than a first set threshold value, the first set threshold value is the conduction voltage drop of the TVS, namely the voltage flows to the output end voltage sampling circuit through a TVS diode of the charging loop switch, and then the corresponding discharging loop switch has a normally-closed fault; or the voltage value obtained by subtracting the voltage value of the output end voltage sampling circuit from the voltage value of the first voltage sampling circuit is greater than a second set threshold value of 0.3V, which indicates that the voltage at the first voltage sampling circuit flows to the output end voltage sampling circuit through the MOSFET in the charging circuit switch, and then the corresponding discharging circuit switch has a normally closed fault; if no normally closed fault exists, the next step is carried out, and if the normally closed fault exists, the flow is ended; wherein the second set threshold is greater than the first set threshold;
sequentially closing the charging loop switches, sequentially subtracting the voltage value of the input end voltage sampling circuit from the voltage value of a first voltage sampling circuit between the closed charging loop switch and the discharging loop switch, judging whether the subtracted difference value is greater than the conduction voltage drop of the TVS by 0.7V, and if the subtracted difference value is greater than the threshold value by 0.7V, indicating that the voltage at the first voltage sampling circuit flows to the input end voltage sampling circuit through a TVS diode in the charging loop switch, and enabling the corresponding charging loop switch to have a normally open fault;
and completing the diagnosis of the charging loop switch and the discharging loop switch in the MOSFET switch array.
Example 4
Referring to fig. 1 and fig. 3 together, the present embodiment provides a MOSFET detection circuit for practical applications, which includes a battery, a BMS control chip, a MOSFET switch array, a DCDC converter, and a motor;
2 parallel branches are arranged in the MOSFET switch array, and each of the 2 parallel branches comprises 1 discharging loop switch and 1 charging loop switch which are sequentially connected in series; the positive electrode of the battery is connected with the input end of the MOSFET switch array, the discharge loop switch is connected with the input end of the MOSFET switch array, the charge loop switch is connected with the output end of the MOSFET switch array, the output end of the MOSFET switch array is respectively connected with one end of the DCDC converter and one end of the motor, and the other end of the DCDC converter and the other end of the motor are respectively connected with the negative electrode of the battery; the discharging loop switch and the charging loop switch comprise diodes and MOSFETs, and the MOSFETs are connected with the BMS control chip;
the MOSFET switch array further comprises 1 pre-charging parallel branch, the pre-charging parallel branch is connected with 2 parallel branches in parallel, the pre-charging parallel circuit comprises a pre-charging switch and a pre-charging resistor which are sequentially connected in series, the pre-charging switch is connected with the input end of the MOSFET switch array, the pre-charging resistor is connected with the output end of the MOSFET switch array, the pre-charging switch comprises a diode and an MOSFET, and the MOSFET of the pre-charging switch is connected with the BMS control chip;
a first voltage sampling circuit is arranged between the discharge loop switch and the discharge loop switch, and the first voltage sampling circuit is connected with the BMS control chip and used for the BMS control chip to collect voltage;
the input of MOSFET switch array is equipped with input voltage sampling circuit, the output of MOSFET switch array is equipped with output voltage sampling circuit, input voltage sampling circuit and output voltage sampling circuit all are connected with BMS control chip, supply BMS control chip to collect the voltage.
The diode comprises a first diode or a second diode, and the MOSFET comprises a first MOSFET or a second MOSFET;
the positive electrode of the battery is electrically connected with the D electrode of a first MOSFET (metal-oxide-semiconductor field effect transistor) which is included in the discharge loop switch and the pre-charging switch, and the G electrode of the first MOSFET is electrically connected with a BMS (battery management system) control chip;
the S pole of a first MOSFET in the pre-charging switch is connected with the pre-charging resistor;
the S pole of a first MOSFET in the discharge loop switch is electrically connected with the D pole of a second MOSFET included in the charge loop switch, the G pole of the second MOSFET is electrically connected with a BMS control chip, and the S pole of the second MOSFET is connected with the output end of the MOSFET switch array;
the cathode of the first diode is electrically connected with the D pole of the first MOSFET, and the anode of the first diode is electrically connected with the S pole of the first MOSFET;
the cathode of the second diode is electrically connected with the S pole of the second MOSFET, and the anode of the second diode is electrically connected with the D pole of the second MOSFET.
The MOSFET is an N-channel depletion type MOSFET.
The diode is TVS for preventing reverse discharge.
And the conduction voltage drop of the TVS is 0.7V.
The BMS control chip is an MCU.
The power supply module is a rechargeable battery.
The maximum charging voltage of the rechargeable battery is 48V.
The embodiment further provides a MOSFET detection method, which is based on the above MOSFET detection circuit and includes the following detection steps:
initializing a BMS control chip, wherein the BMS control chip sends out an instruction to turn off all switches included in the MOSFET switch array;
acquiring voltages of the input end voltage sampling circuit, the output end voltage sampling circuit and the first voltage sampling circuit through a BMS control chip, and comparing voltage values;
if the voltage value obtained by subtracting the voltage value of the first voltage sampling circuit from the voltage value of the input end voltage sampling circuit is smaller than a set threshold value of 3V, judging that a corresponding discharge loop switch is in a normally-closed fault; if there is no fault, the next step is carried out, if there is fault, the flow is ended
Closing a charging loop switch, and if the voltage value obtained by subtracting the first voltage sampling circuit from the input end voltage sampling circuit is greater than a set threshold value of 3V, which indicates that the voltage difference between the voltage at the input end voltage sampling circuit and the voltage at the voltage difference value of the first voltage sampling circuit is greater, judging that the corresponding charging loop switch is in a normally open fault; if no normally open fault exists, the next step is carried out, and if the normally open fault exists, the flow is ended;
if the voltage value of the output end voltage sampling circuit subtracted from the voltage value of the first voltage sampling circuit is smaller than a first set threshold value, the first set threshold value is the conduction voltage drop of the TVS, namely the voltage flows to the output end voltage sampling circuit through a TVS diode of the charging loop switch, and then the corresponding discharging loop switch has a normally-closed fault; or the voltage value of the output end voltage sampling circuit subtracted from the voltage value of the first voltage sampling circuit is greater than a second set threshold value of 0.3V, which indicates that the voltage at the first voltage sampling circuit flows to the output end voltage sampling circuit through the MOSFET in the charging circuit switch, and then the corresponding discharging circuit switch has a normally closed fault; if no normally closed fault exists, the next step is carried out, and if the normally closed fault exists, the flow is ended; wherein the second set threshold is greater than the first set threshold;
sequentially closing the charging loop switches, sequentially subtracting the voltage value of the input end voltage sampling circuit from the voltage value of a first voltage sampling circuit between the closed charging loop switch and the discharging loop switch, judging whether the subtracted difference value is greater than the conduction voltage drop of the TVS by 0.7V, and if the subtracted difference value is greater than the threshold value by 0.7V, indicating that the voltage at the first voltage sampling circuit flows to the input end voltage sampling circuit through a TVS diode in the charging loop switch, and enabling the corresponding charging loop switch to have a normally open fault;
and completing the diagnosis of the charging loop switch and the discharging loop switch in the MOSFET switch array.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (10)

1. A MOSFET detection circuit is characterized by comprising a power supply module, a BMS control chip and a MOSFET switch array;
parallel branches are arranged in the MOSFET switch array, and each parallel branch comprises a discharge loop switch and a charge loop switch which are sequentially connected in series; the discharging loop switch is connected with the positive electrode of the power supply module, and the charging loop switch is connected with the negative electrode of the power supply module; the discharging loop switch and the charging loop switch comprise diodes and MOSFETs, and the MOSFETs are connected with the BMS control chip;
a first voltage sampling circuit is arranged between the discharge loop switch and the discharge loop switch, and the first voltage sampling circuit is connected with the BMS control chip and used for the BMS control chip to collect voltage;
the input of MOSFET switch array is equipped with input voltage sampling circuit, the output of MOSFET switch array is equipped with output voltage sampling circuit, input voltage sampling circuit and output voltage sampling circuit all are connected with BMS control chip, supply BMS control chip to gather voltage.
2. The MOSFET detection circuit of claim 1, wherein the diode comprises a first diode or a second diode, and the MOSFET comprises a first MOSFET or a second MOSFET;
the positive electrode of the power supply module is electrically connected with the D electrode of a first MOSFET (metal oxide semiconductor field effect transistor) included in the discharge loop switch, and the G electrode of the first MOSFET is electrically connected with a BMS (battery management system) control chip;
the S pole of the first MOSFET is electrically connected with the D pole of a second MOSFET included in the charging loop switch, the G pole of the second MOSFET is electrically connected with the BMS control chip, and the S pole of the second MOSFET is connected with the output end of the MOSFET switch array;
the cathode of the first diode is electrically connected with the D pole of the first MOSFET, and the anode of the first diode is electrically connected with the S pole of the first MOSFET;
the cathode of the second diode is electrically connected with the S pole of the second MOSFET, and the anode of the second diode is electrically connected with the D pole of the second MOSFET.
3. The MOSFET detection circuit of claim 2, wherein the MOSFET is an N-channel depletion mode MOSFET.
4. A MOSFET detection circuit as claimed in any of claims 1 to 3, wherein the diode is a TVS for preventing reverse discharge.
5. The MOSFET detection circuit of claim 4, wherein the turn-on voltage drop of the TVS is 0.7V.
6. The MOSFET detection circuit of claim 1, wherein the BMS control chip is an MCU.
7. The MOSFET detection circuit of claim 1, wherein the power supply module is a rechargeable battery.
8. The MOSFET detection circuit of claim 7, wherein the rechargeable battery voltage maximum charging voltage is 48V.
9. A MOSFET detection method, characterized in that the method is based on a MOSFET detection circuit according to any of claims 1-8, comprising the following detection steps:
initializing a BMS control chip, wherein the BMS control chip sends out an instruction to turn off all switches included in the MOSFET switch array;
acquiring voltages of the input end voltage sampling circuit, the output end voltage sampling circuit and the first voltage sampling circuit through a BMS control chip, and comparing voltage values;
if the voltage value of the first voltage sampling circuit subtracted from the voltage value of the input end voltage sampling circuit is smaller than a set threshold value, a normally-closed fault exists in a discharge loop switch; if no fault exists, the next step is carried out, and if the fault exists, the flow is ended;
closing a charging loop switch, wherein if the voltage value obtained by subtracting the first voltage sampling circuit from the input end voltage sampling circuit is greater than a set threshold value, a normally open fault exists in the charging loop switch; if no normally open fault exists, the next step is carried out, and if the normally open fault exists, the flow is ended;
if the voltage value of the output end voltage sampling circuit subtracted from the voltage value of the first voltage sampling circuit is smaller than a first set threshold value, or the voltage value of the output end voltage sampling circuit subtracted from the voltage value of the first voltage sampling circuit is larger than a second set threshold value, a normally-closed fault exists in a discharge loop switch; if no normally closed fault exists, the next step is carried out, and if the normally closed fault exists, the flow is ended; wherein the second set threshold is greater than the first set threshold;
sequentially closing the charging loop switch, sequentially subtracting the voltage value of the input end voltage sampling circuit from the voltage value of a first voltage sampling circuit between the closed charging loop switch and the discharging loop switch, and if the difference value is greater than a set threshold value, determining that the charging loop switch has a normally open fault;
and completing the diagnosis of the charging loop switch and the discharging loop switch in the MOSFET switch array.
10. The method of claim 9, wherein the BMS control chip is a MCU.
CN202211736556.8A 2022-12-30 2022-12-30 MOSFET detection circuit and detection method Pending CN115951190A (en)

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Application Number Priority Date Filing Date Title
CN202211736556.8A CN115951190A (en) 2022-12-30 2022-12-30 MOSFET detection circuit and detection method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211736556.8A CN115951190A (en) 2022-12-30 2022-12-30 MOSFET detection circuit and detection method

Publications (1)

Publication Number Publication Date
CN115951190A true CN115951190A (en) 2023-04-11

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