Fujitsu Semiconductor Limited

Naoki Nagase

Koichi Inatomi

A control circuit for a DC-DC converter includes a controller configured to control, based on a feedback voltage, a first switch provided between an inductor and a reference potential and a second switch provided between a coupling node of the first switch and the inductor and an output terminal, a third switch provided between the second switch and the output terminal and turned off when an overcurrent flows in a coupling path between the second switch and the output terminal, and a selector configured to select a voltage of a first position which is located on a side of the second switch in the coupling path as the feedback voltage when the third switch is turned off, or a voltage of a second position which is located on a side of the output terminal in the coupling path as the feedback voltage when the third switch is turned on.

Control circuit for DC-DC converter, control method for DC-DC converter, and electronic device

To provide a control circuit of a step-down DC-DC converter, a step-down DC-DC converter and a control method thereof which can prevent overshoot and production of a through current flowing to a main switching transistor and a synchronous rectifier transistor by adopting a simple circuit configuration. The control circuit of the step-down DC-DC converter in which a main switching transistor Mis constituted of a NMOS transistor has a MOS transistor Mconnected between a gate of the main switching transistor Mand a ground potential and is operable to become conductive in response to an OFF command from the main switching transistor M

Growing community of inventors

Kasugai, Japan

Naoki Nagase