Patent Number: 8,797,014

Title: DC-DC converter including circuit to detect switching frequency of switching supply

Abstract: A DC-DC converter to convert an input voltage into a predetermined voltage includes a first switching device to provide energy for an inductor; a second switching device to discharge the energy from the inductor to an output terminal; an error amplifier to amplify an error voltage between a first reference voltage and a monitoring voltage obtained by dividing an output voltage output from the output terminal; a set signal generation circuit including a first comparator into which a second reference voltage and an output of the error amplifier are input; a reset signal generation circuit; a control circuit into which an output from the set signal generation circuit and an output from the reset signal generation circuit are input; and a detection circuit to detect a switching frequency of an electric power supply, wherein a characteristic of the first comparator is changed according to the switching frequency.

Inventors: Michishita; Yuusuke (Osaka, JP), Shimizu; Shinya (Hyogo, JP)

Assignee: Ricoh Company, Ltd.

International Classification: G05F 1/565 (20060101); G05F 1/575 (20060101)

Expiration Date: 8/05/12018