Patent ID: 8169803

Claim:
A power transistor chip, which is adaptable to an AC/DC voltage converter, comprising: a first pin; a second pin; a third pin; a fourth pin; a fifth pin; a power transistor acting as a power switch of said AC/DC voltage converter and having a first source/drain, a second source/drain and a power transistor gate, wherein said first source/drain couples with said first pin, said second source/drain couple with said second pin and said power transistor gate couple with said third pin; and a junction field effect transistor acting as a start-up circuit of said AC/DC voltage converter and having a third source/drain, a fourth source/drain and a junction field effect transistor gate, wherein said third source/drain couples with said first pin, said fourth source/drain couples with said fourth pin and said junction field effect transistor gate couples with said fifth pin.