Control unit for vehicle

• US 9,328,711 B2
• Filed: 10/23/2012
• Issued: 05/03/2016
• Est. Priority Date: 10/31/2011
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Uchida, Tetsuya
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): Dhillon, Jagdeep
• Application Number:
  US13/658,271
• Publication Number:
  US 20130106174A1
• Time in Patent Office: 1,288 Days
• Field of Search: 307/9.1, 307/10.7, 307/65, 307/66, 307/10.1, 320/15, 320/30, 320/43, 320/12, 320/14, 320/19, 322/99, 169/61
• US Class Current: 1/1
• CPC Class Codes: F02N 11/0814 comprising means for controlling automatic idle-start-stop
• CPC Class Codes: F02N 11/0866 comprising several power sources, e.g. battery and capacitor or two batteries
• CPC Class Codes: F02N 11/108 for diagnosis of the starter or its components
• CPC Class Codes: G01R 31/007 using microprocessors or computers
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/46 Accumulators structurally combined with charging apparatus circuits for charging H02J7/00
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

In a control unit for a vehicle, a redundancy circuit includes a main power source line, a back-up power source line, and a diode. The back-up power source line performs a voltage compensation operation when a voltage of the main power source line is lower than a predetermined voltage. The back-up power source line is turned on when a predetermined period of time has elapsed after the main power source line is turned on. The back-up power source line is turned off when a predetermined period of time has elapsed after the main power source line is turned off. The diode is disposed on the back-up power source line. The fault detector detects an open fault of the diode when a voltage of a cathode of the diode is lower than a predetermined threshold within the predetermined period of time after the main power source line is turned off.

Claims

1. A control unit for a vehicle, comprising:

a redundancy circuit including;

a main power source line being supplied with electric power from a battery of the vehicle;

a back-up power source line performing a voltage compensation operation when a voltage of the main power source line is lower than a predetermined voltage, the back-up power source line being turned on when a predetermined period of time has elapsed after the main power source line is turned on, and the back-up power source line being turned off when a predetermined period of time has elapsed after the main power source line is turned off; and

a diode being disposed on the back-up power source line; and

a fault detector monitoring a voltage of an anode of the diode and a voltage of a cathode of the diode; and

an energy reserve capacitor supplying electric power to the fault detector until the predetermined period of time elapses after the main power source line is turned off, wherein;

the fault detector detects an open fault of the diode when the voltage of the cathode of the diode is lower than a predetermined threshold within the predetermined period of time after the main power source line is turned off, and

the predetermined threshold is less than or equal to a value that is obtained by subtracting a voltage drop of the diode in a forward direction from the voltage of the anode of the diode, and is larger than the voltage drop of the diode in the forward direction.

2. The control unit according to claim 1, wherein

the fault detector stores a detection result in a nonvolatile memory when the open fault of the diode is detected, and reads out the detection result from the nonvolatile memory next time the main power source line is turned on.

3. The control unit according to claim 1, wherein

the back-up power source line is supplied with the electric power from the battery.

4. The control unit according to claim 1, wherein

the back-up power source line is supplied with electric power from a power source different from the battery.