Many electrical devices such as cell phones, personal digital assistants (PDAs), laptops, etc., utilize power to operate. Because power is generally delivered through a wall socket as high-voltage alternating current (AC), a device, typically referred to as a power converter, can be utilized to transform the high-voltage AC input to a well-regulated direct current (DC) output through an energy transfer element. Switched-mode power converters are commonly used to improve efficiency and size and reduce component count in many of today's electronics. A switched-mode power converter may use a power switch that switches between a closed position (ON state) and an open position (OFF state) to transfer energy from an input to an output of the power converter. Typically, power switches are high-voltage devices required to withstand voltages substantially greater than the AC input voltage.
One type of high-voltage field effect transistor (FET) used in switched-mode power converters is the HFET, also referred to as a high-electron mobility transistor (HEMT). HFETs may be used as switches in switching devices for high-voltage power electronics, such as power converters. In certain applications, HFETs based on wide-bandgap semiconductors may be useful because the higher bandgap may improve performance at elevated temperatures. Examples of wide-bandgap semiconductors used in high-voltage HFETs include materials such as silicon carbide (SiC), gallium nitride (GaN), and diamond, although other materials may be used as well.
USPTO Backgrounds
USPTO Backgrounds