A circuit for detecting electric current is provided. The circuit includes a MOSFET having a gate terminal, a source terminal, and a drain terminal, the drain terminal and the source terminal are connected in series in a loop through which an electric current flows. The circuit also includes a bias circuit, configured to generate a bias voltage at a gate terminal of the MOSFET to make the MOSFET operate in the linear region, and a voltage detection circuit, connected to the drain terminal and the source terminal of the MOSFET to detect a voltage difference between the drain terminal and the source terminal of the MOSFET, the voltage difference being used as a detection signal in the circuit for detecting the electric current.