The present invention provides a protection circuit. The protection circuit includes an output stage circuit and a feedback unit that generates a first current. Under a first condition that the first current is one of currents larger than and equal to a rated current and the first condition remains for a first period, the feedback unit controls the output stage circuit to restrict the first current. Under a second condition that the first current is one of currents larger than and equal to a restriction current and the second condition remains for a second period, the feedback unit controls the output stage circuit to terminate the first current.