Patent ID: 7336046

Claim:
Apparatus for controlling a drive signal to be supplied from a drive device to a load apparatus along an electric path connecting the drive device and the load apparatus, the drive device comprising: load control means for receiving a PWM (pulse width modulation) signal so that the drive signal is PWM-controlled on the PWM signal; detecting means for detecting information about a short circuit in the electric path; and notification means for notifying the information about the short circuit detected by the short circuit detecting means; the control device comprising: producing means for producing the PWM signal to be supplied to the drive device; inquiry means for inquiring of the notification means about the information about the short circuit at predetermined inquiry intervals; first determining means for determining whether or not the detecting means detects the short circuit based on the information about the short circuit notified from the notification means in response to the inquiry of the inquiry means; and second determining means for determining how the short circuit occurs, on the basis of history information in the information about the short circuit notified from the notification means when the first determining means determines that the detecting means detects the short circuit.