| 摘要 |
A power adapter includes a processing circuit converting mains power to another alternating current (AC) power or a direct current (DC) power, a first output outputting the converted AC or DC power, a sense resistor connected between the processing circuit and the first output for sampling current flowing through the first output and converting the sampled current to a sampled voltage, an amplifying circuit connected to the sense resistor for amplifying the sampled voltage, and a metallic oxide semiconductor field effect transistor (MOSFET). A gate of the MOSFET is connected to the amplifying circuit. A drain of the MOSFET is connected to the first output through a first resistor and grounded through a second resistor. A source of the MOSFET is grounded. A node between the first and second resistors is connected to the processing circuit. The amplifying circuit makes the MOSFET work in a variable resistance region. |
