Patent ID: 7480163

Claim:
A semiconductor device for use in a synchronous-rectification-type power supply device that drives gates of a rectification MOSFET and a commutation MOSFET by a control circuit, one of main terminals of the rectification MOSFET being connected to a positive potential side of a direct-current input power source, an other of the main terminals of the rectification MOSFET being connected to one of terminals of a choke coil and one of main terminals of the commutation MOSFET, an other of the main terminals of the commutation MOSFET being connected to a negative potential side of the direct-current input power source, one of terminals of an output capacitor being connected to an other of the terminals of the choke coil, an other of the terminals of the output capacitor being connected to the other of the main terminals of the commutation MOSFET, one of terminals supplying power to the semiconductor device as a load being connected to the other of the terminals of the choke coil, and an other of the terminals supplying power to the semiconductor device as the load being connected to the other of the main terminals of the commutation MOSFET, and the semiconductor device having integrated thereon the rectification MOSFET, the commutation MOSFET, and a driving semiconductor element that drives these two MOSFETs, wherein the rectification MOSFET and the commutation MOSFET are laminated via a conductive member, the conductive member is electrically connected to the one of the terminals of the choke coil, and output terminals are placed on a same plane.