To detect abnormality with high accuracy in a voltage supply device for detecting the abnormality by monitoring a voltage supplied to a load side from a regulator.
After a power is turned on (S1), a control part reads an execution threshold value stored in an EEPROM (S2), stores the execution threshold value in a RAM, and sets it as a threshold value Vd (S3). When the control part detects a voltage Vdet input to an A/D port (YES at S4), the control part detects a peripheral temperature by use of a temperature sensor (S5), and corrects the voltage Vdet based on the detected temperature (S6). The control part determines whether or not the voltage Vdet after the correction is normal to the threshold value Vd (S7). When it is not normal, the control part outputs a power off signal from a power on/off port to disable a regulator (S8). The regulator is disabled, so that power supply to the load wherein the abnormality occurs is stopped.
Katsumi Taguchi
Shinichi Mizuta