Patent ID: 7245163

Claim:
A semiconductor device controller comprising: an input signal processing circuit for carrying out signal processing of a pulse signal input as a current supply instruction from the outside on the basis of a circuit time constant to generate and output a control signal; a current supply control unit for controlling a conduction state of a semiconductor device connected to a load in series in response to the control signal to supply current to the load; a current detecting unit for detecting current flowing in the load; an overcurrent judging unit for comparing the current detected by the current detecting unit with an overcurrent judgment value to carry out an overcurrent judgment; a current limiting unit for limiting current to be supplied to the load through the semiconductor device by the current supply control unit when the overcurrent judgment is carried out by the overcurrent judging unit; a current level judging unit for comparing one or more switching judgment values set to be smaller than the overcurrent judgment value with the current detected by the current detecting unit to carry out a current level judgment; a time constant changing unit for changing the circuit time constant of the input signal processing circuit in accordance with a judgment result by the current level judging unit; and a judgment result holding unit for holding the judgment result of the current level judging unit for only a predetermined time.