Failure diagnosis circuit and failure diagnosis method

Patent metadata

Field	Value
Publication number	US-10352990-B2
Application number	US-201615578351-A
Country	US
Kind code	B2
Filing date	Apr 6, 2016
Priority date	Jul 7, 2015
Publication date	Jul 16, 2019
Grant date	Jul 16, 2019

Abstract

A failure diagnosis circuit configured to diagnose an open-circuit failure in a reverse connection protection transistor includes a power supply unit having a switching transistor electrically connected to a power source and the reverse connection protection transistor and is brought into an on state or an off state in response to a control signal, and in which power is supplied from the power source to the reverse connection protection transistor when the switching transistor is in the on state; a power supply control unit that controls power supply to the reverse connection protection transistor and stop of the power supply by outputting the control signal to the switching transistor; and a diagnosis unit that diagnoses an open-circuit failure in the reverse connection protection transistor on the basis of an output state of the control signal and a detection result of voltage between the switching transistor and the reverse connection protection transistor.

First claim

The invention claimed is:

1. A failure diagnosis circuit configured to diagnose an open-circuit failure in a reverse connection protection transistor that prevents flow of current in a direction opposite to a direction in a normal state in the case of a reverse connection state, the failure diagnosis circuit comprising:
a power supply which includes a switching transistor that is electrically connected to a power source and the reverse connection protection transistor and is brought into an on state or an off state in response to a control signal applied to a control terminal, and in which power is supplied from the power source to the reverse connection protection transistor when the switching transistor is in the on state;
a power supply controller that controls power supply to the reverse connection protection transistor and stop of the power supply by outputting the control signal to the switching transistor; and
a diagnosis microcontroller, which includes a processor, that diagnoses an open-circuit failure in the reverse connection protection transistor on the basis of an output state of the control signal and a detection result of voltage between the switching transistor and the reverse connection protection transistor.

2. The failure diagnosis circuit according to claim 1 ,
wherein the diagnosis microcontroller diagnoses an open-circuit failure in the reverse connection protection transistor on the basis of a change in the voltage after power supply to the reverse connection protection transistor is stopped.

3. The failure diagnosis circuit according to claim 2 ,
wherein the diagnosis microcontroller makes a diagnosis that an open-circuit failure has occurred in the reverse connection protection transistor in the case where a fall in the voltage is not detected after power supply to the reverse connection protection transistor is stopped.

4. The failure diagnosis circuit according to claim 2 ,
wherein the diagnosis microcontroller refrains from making a diagnosis that an open-circuit failure has occurred in the reverse connection protection transistor in the case where a fall in the voltage is detected after power supply to the reverse connection protection transistor is stopped.

5. The failure diagnosis circuit according to claim 1 , further comprising:
the reverse connection protection transistor.

6. A failure diagnosis method in a failure diagnosis circuit configured to diagnose an open-circuit failure in a reverse connection protection transistor that prevents flow of current in a direction opposite to a direction in a normal state in the case of a reverse connection state,
the failure diagnosis circuit including a switching transistor that is electrically connected to a power source and the reverse connection protection transistor and is brought into an on state or an off state in response to a control signal applied to a control terminal,
the failure diagnosis method comprising:
controlling power supply to the reverse connection protection transistor and stop of the power supply by outputting the control signal to the switching transistor; and
diagnosing, by a microcontroller that includes a processor, an open-circuit failure in the reverse connection protection transistor on the basis of an output state of the control signal and a detection result of voltage between the switching transistor and the reverse connection protection transistor.

Assignees

• Tokai Rika Co Ltd

Inventors

• Miyazaki Shinichi
• Suzuki Tatsuya

Classifications

• H02H7/205

  for controlled semi-conductors which are not included in a specific circuit arrangement · CPC title

• H02H7/00

  Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions · CPC title

• H02H11/003

  using a field effect transistor as protecting element in one of the supply lines · CPC title

• H02P7/00

  Arrangements for regulating or controlling the speed or torque of electric DC motors · CPC title

• G01R31/02

  Physics · mapped topic