Patent ID: 7768290

Claim:
A circuit for detecting electric current, comprising: a MOSFET having a gate terminal, a source terminal, and a drain terminal, the source terminal and the drain terminal being connected in series in a loop through which an electric current flows; a bias circuit, configured to generate a bias voltage at a gate terminal of the MOSFET to make the MOSFET to operate in the linear region, wherein the bias circuit comprises a first bias resistor connected between a voltage source terminal of a power supply and the gate terminal of the MOSFET, and a second bias resistor connected between the gate terminal of the MOSFET and a common circuit ground, the first bias resistor and the second bias resistor generating the bias voltage at the gate terminal of the MOSFET from the voltage source terminal of the power supply and the common circuit ground to make the MOSFET to operate in the linear region; a voltage detection circuit, connected to the source terminal and the drain 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.