Murata Manufacturing Co., Ltd.

Sanyo Electric Co., Ltd.

Semiconductor Components Industries, LLC

Masahiro Maruki

Iwao Fukushi

Takashi Noma

Shuhei Kawai

A switching-control circuit to control switching of a transistor whose input electrode is applied with an input voltage, and turn off the transistor, when an output current from the transistor is greater than a reference current, includes: a reference-voltage-generating circuit to generate such a first-reference voltage that the reference current is reduced with reduction in an output voltage; a comparing circuit to compare a voltage corresponding to the output current with the first-reference voltage; and a driving circuit to turn on/off the transistor based on a feedback voltage corresponding to the output voltage and a second reference voltage corresponding to a target level so that the output voltage reaches the target level, when the comparing circuit determines that the output current is smaller than the reference current, and turn off the transistor when the comparing circuit determines that the output current is greater than the reference current.

Switching control circuit

A switching control circuit comprises: an error amplifying circuit configured to output an error voltage obtained by amplifying an error between a feedback voltage corresponding to an output voltage and a lower voltage selected out of a first reference voltage increasing with time passage and a second reference voltage used as a reference for a target level; a comparison circuit configured to output a comparison signal obtained by comparing the feedback voltage with the error voltage output from the error amplifying circuit; and a drive circuit configured to output first and second control signals for controlling first and second transistors, respectively, in order to turn the output voltage to the target level by complementarily turning on and off the first and second transistors, after the error voltage exceeds the feedback voltage, based on the comparison signal output from the comparison circuit.

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Oizumi-machi, Japan

Masahiro Maruki