Patent ID: 6545513
Filing Date: 2003-04-08
Classification: H03K

Abstract:
An electric load drive apparatus comprising:a switching element provided in an electric power supply path extending from a direct-current power source to an electric load; a detecting resistor, connected in series with said switching element, for detecting a voltage value representing a load current flowing across said electric load via said switching element; a saturation state detecting section for outputting a current saturation signal during a term an upper limit current flows across said electric load, said upper limit current being a maximum current flowable via said switching element in an open/close controllable range of said switching element; a signal generating section for producing a trapezoidal wave signal whose voltage value starts changing in accordance with increase of said load current when a drive start command signal is entered, stops changing in response to the output of said current saturation signal generated from said saturation state detecting section, and then starts changing in accordance with decrease of said load current when a drive stop command signal is entered, and a current control section for comparing said trapezoidal wave signal produced from said signal generating section with said voltage value detected by said detecting resistor and then controlling said switching element based on said trapezoidal wave signal in such a manner a trapezoidal wave current flows across said electric load.