Patent ID: 9705488
Date: 2017-07-11
CPC Classifications: H01L,H03K

Claim:
1. A semiconductor device comprising: a semiconductor substrate; a first-conductivity-type vertical MOSFET; a first-conductivity-type horizontal MOSFET; a circuit that controls the first-conductivity-type vertical MOSFET and the first-conductivity-type horizontal MOSFET; and a second-conductivity-type horizontal MOSFET, wherein the first-conductivity-type vertical MOSFET, the first-conductivity-type horizontal MOSFET, and the circuit are formed on the semiconductor substrate, a drain of the first-conductivity-type vertical MOSFET is connected to a power supply terminal, a source of the first-conductivity-type horizontal MOSFET is connected to a ground terminal, a source of the first-conductivity-type vertical MOSFET and a drain of the first-conductivity-type horizontal MOSFET are connected to an output terminal to form a synchronous rectification circuit, the second-conductivity-type horizontal MOSFET is connected in parallel to the first-conductivity-type horizontal MOSFET between the output terminal and the ground terminal, a drain of the second-conductivity-type horizontal MOSFET is connected to the source of the first-conductivity-type horizontal MOSFET, a back gate of the second-conductivity-type horizontal MOSFET has a potential that is different from a potential of the source of the first-conductivity-type horizontal MOSFET, a gate of the second-conductivity-type horizontal MOSFET is connected to the drain of the first-conductivity-type horizontal MOSFET, and a gate of the second-conductivity-type horizontal MOSFET is connected to a source of the second-conductivity-type horizontal MOSFET.