Switching power supply device and a semiconductor integrated circuit

摘要

In a switching power source which controls a current which flows in an inductor through a switching element which performs a switching operation in response to a PWM signal, and forms an output voltage by a capacitor which is provided in series in the inductor, a booster circuit which is constituted of a bootstrap capacity and a MOSFET is provided between an output node of the switching element and a predetermined voltage terminal. The boosted voltage is used as an operational voltage of a driving circuit of the switching element, another source/drain region and a substrate gate are connected with each other, and a junction diode between one source/drain region and the substrate gate is inversely directed with respect to the boosted voltage which is formed by the bootstrap capacity.

主权项

1. A regulator comprising:
an inductor having a first end and a second end; an output capacitor coupled to the second end of the inductor; a boost capacitor; and a semiconductor device comprising:
an input voltage terminal;an output terminal coupled to the first end of the inductor;a ground potential terminal;a power terminal;a first terminal coupled to the output terminal via the boost capacitor;a first MOSFET having a source-drain path coupled between the input voltage terminal and the output terminal and a gate;a second MOSFET having a source-drain path coupled between the output terminal and the ground potential terminal and a gate;a control circuit coupled to the power terminal, coupled to provide a first control signal to the gate of the first MOSFET and coupled to provide a second control signal to the gate of the second MOSFET; anda P-channel switch MOSFET having a source-drain path coupled between the power terminal and the first terminal, a source thereof being coupled to a back gate thereof and to the first terminal, and a drain thereof being coupled to the power terminal.