Title:
FAULT DIAGNOSING CIRCUIT FOR CONTROLLER
Document Type and Number:
Japanese Patent JPH03271904
Kind Code:
A
Abstract:
PURPOSE:To surely diagnose fault of a power transistor TR even in the case of the use of this TR in an active area by detecting the potential at the connection point between the power TR and an inductance load by a voltage detecting circuit including a Zener diode. CONSTITUTION:A voltage detecting circuit A including a Zener diode D2 having the zener voltage which is cut off at the time of using a power TR 1 in an active area and is supplied at the time of turning off the power TR is provided at a connection point X between an inductance load 1 and the power TR 1. A fault decision means 2 which decides fault based on the output from the voltage detecting means A is provided. Consequently, the Zener diode D2 is not made conductive at the time of controlling the power TR 1 to turn off it because the voltage at the connection point X is not dropped to the ground level but is lower than the Zener voltage, and the voltage detecting circuit A detects the ground level, and the fault decision means decides that the power TR is normal. Thus, fault of the power TR 1 is surely diagnosed though the power TR 1 is used in the active area.
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Inventors:
TAKAHASHI MANABU
ITO SATORU
ITO SATORU
Application Number:
JP7249490A
Publication Date:
December 03, 1991
Filing Date:
March 22, 1990
Export Citation:
Assignee:
NIPPON DENSO CO
International Classes:
G01R31/00; F02D41/22; F02D45/00; G01M15/00; G01M15/04; G01M17/007; G05B23/02; (IPC1-7): F02D41/22; F02D45/00; G01M15/00; G01R31/00; G05B23/02
Attorney, Agent or Firm:
Takashi Okabe (1 outside)