Patent ID: 7432719

Claim:
An abnormality monitoring apparatus in a load drive circuit which includes a converter for performing at least one of an operation for increasing a voltage and an operation for decreasing a voltage, and a battery connected to an input side of the converter, the converter supplying electric power to a load, the abnormality monitoring apparatus comprising: first detecting means for detecting a voltage value of the battery; second detecting means for detecting a voltage value on an output side of the converter; battery voltage estimating means for calculating an estimated voltage value of the battery; calculating means for calculating at least one of the difference value between the voltage value detected by the first detecting means and the estimated voltage value, and the difference value between the voltage value detected by the second detecting means and the estimated voltage value; and monitoring means for monitoring at least one of an abnormality of the first detecting means and an abnormality of the second detecting means based on each of the difference values and a predetermined threshold value.