A power semiconductor device is a semiconductor device used as a switch or rectifier in power electronics (for example in a switched-mode power supply). Such a device is also called a power device or, when used in an integrated circuit, a power IC.
A power semiconductor device is usually used in "commutation mode" (i.e., it is either on or off), and therefore has a design optimized for such usage; it should usually not be used in linear operation. Linear power circuits are widespread as voltage regulators, audio amplifiers, and radio frequency amplifiers.
Power semiconductors are found in systems delivering as little as a few tens of milliwatts for a headphone amplifier, up to around a gigawatt in a high-voltage direct current transmission line.
