Abstract: A power conversion circuit for an uninterruptible power system, including an inductor, a first capacitor, a second capacitor, a first switch, a second switch, a third switch, a first diode, a second diode, and a third diode body, is provided. A terminal of the second switch is electrically coupled to the inductor through the first switch, and another terminal of the second switch is electrically coupled to a neutral wire and the third switch. An anode and a cathode of the first diode are electrically coupled to the first switch and a positive DC bus, respectively. A cathode and an anode of the second diode are electrically coupled to the first switch and the third switch, respectively. A cathode and an anode of the third diode are electrically coupled to the third switch and a negative DC bus, respectively. In addition, an uninterruptible power system using the same is provided.

Abstract: A process for forming a T-gate with enhanced mechanical strength and a reduced gate length for high electron mobility transistors is provided. The process includes the steps of forming a stem portion cavity with rounded top edges to enhance the mechanical strength, creating an insoluble diffused feature shrinking layer to reduce the gate length, carrying out a thermal flow process to further reduce the gate length, and forming a head portion cavity with negative side wall slopes to facilitate lift-off of gate metal layers.