Power device for rectifier

A power device for a rectifier includes a first terminal and a second terminal for connecting an external circuit, and a circuit system located between the first terminal and the second terminal. The circuit system is electrically connected to the first terminal and the second terminal. The circuit system includes a pre-molded chip and a control device. The pre-molded chip includes a transistor and a first encapsulant for encapsulating the transistor, wherein the transistor has a first electrode, a second electrode, and a third electrode. The first terminal, the second terminal and the control device are respectively electrically connected to the first electrode, the second electrode and the third electrode of the transistor.