Anden Co., Ltd.

Takeshi Hattori

Nobutomo Takagi

Fukuo Ishikawa

Shigekazu Sugimoto

Kazunori Ozawa

An electric current detection circuit for detecting an electric current flowing to a load includes a voltage generation circuit, a plurality of comparators, and a reference voltage shift circuit. The voltage generation circuit includes a plurality of resistors coupled in series and generates different voltages by dividing a reference voltage with the resistors. The comparators determine a current level of the electric current flowing to the load using the voltages generated by the voltage generation circuit as threshold values. The reference voltage shift circuit shifts the reference voltage. The electric current flowing to the load is detected based on the current level determined by the plurality of comparators before shifting the reference voltage and the current level determined by the plurality of comparators after shifting the reference voltage.

Electric current detection circuit

A switch device controls a voltage applied to a load element according to an electric power supply from a power source. A driver circuit controls activation and deactivation of the switch device. A circuit portion sets a duty ratio and output the duty ratio to the driver circuit for causing the driver circuit to activate the switch device according to the duty ratio to control a voltage applied to the load element. The circuit portion sets the duty ratio according to a duty ratio characteristic curve. In the duty ratio characteristic curve, the duty ratio decreases gradually with increase in a voltage of the power source, and decrease in the duty ratio with increase in the voltage of the power source becomes small gradually.

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Okazaki, Japan

Takeshi Hattori