Patent ID: 8884309

Claim:
An AC switch comprising: a first compound semiconductor MOSFET and a second compound semiconductor MOSFET whose sources are connected with each other, the first compound semiconductor MOSFET including a current detection portion for detecting a conduction current, the current detection portion being included within a device structure of the first compound semiconductor MOSFET, the first compound semiconductor MOSFET and the second compound semiconductor MOSFET being planar MOSFETs or trench gate MOSFETs, the first compound semiconductor MOSFET having a first body diode with an anode and a cathode respectively connected to a source and a drain of the first compound semiconductor MOSFET, the second compound semiconductor MOSFET having a second body diode with an anode and a cathode respectively connected to a source and a drain of the second compound semiconductor MOSFET; a first output terminal connected to the drain of the first compound semiconductor MOSFET; a second output terminal connected to the drain of the second compound semiconductor MOSFET; a first metal pattern electrically connected to the source of the first compound semiconductor MOSFET; and a second metal pattern separated from the first metal pattern and electrically connected to the current detection portion and the source of the first compound semiconductor MOSFET, wherein a withstand voltage between the first output terminal and the second output terminal in an off state is not less than 400 V, and wherein a resistance between the first output terminal and the second output terminal in an on state is not more than 20 mΩ.