Rohm Co., Ltd.

Nobukazu Tsukiji

Kazuhiro Murakami

Masashi Nagasato

Tadashi Akaho

A high-side variable current source and a high-side transistor are provided in series between a supply power terminal of a control circuit and a gate of a switching transistor. A low-side variable current source and a low-side transistor are provided in series between the gate of the switching transistor and a ground terminal. A slew rate controller controls the current value of at least one of the high-side and low-side variable current sources according to the state of a setting terminal. A switching power supply device has a plurality of output transistors connected in parallel with one another and a controller that generates control signals turning on and off the output transistors at a predetermined frequency so as to generate a desired output voltage from an input voltage and supply the output voltage to a load. The controller determines which output transistor to drive according to the magnitude of the load.

Switching regulator control circuit, switching regulator, electronic appliance, switching power supply device, and television receiver

A switching transistor is arranged between a switching (SW) terminal and the ground terminal. An error amplifier amplifies the difference between the feedback voltage Vthat corresponds to the output voltage Vwith a predetermined reference voltage Vso as to generate an error voltage V. A pulse modulator generates a pulse signal Shaving a duty ratio that is adjusted according to the error voltage V. A driver drives a switching transistor according to the pulse signal S. An overvoltage detection circuit generates an overvoltage protection (OVP) signal which is asserted when the voltage at the switching (SW) terminal becomes higher than a predetermined threshold voltage. When the OVP signal is asserted, a control circuit performs a predetermined protection operation.

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Kyoto, Japan

Nobukazu Tsukiji