Switch circuit, control method thereof and device

The invention discloses a switch circuit, a control method thereof and a device. The switch circuit is used for a switch module of a direct-current converting circuit, a load of the direct-current converting circuit is parallelly connected with a supporting capacitor C2, the switch module comprises a positive-electrode side switch element Q1 and a negative-electrode side switch element Q2 which are serially connected, the switch circuit comprises a capacitor C1, an inductance L1, a switch element Q3, a one-way conducting element D1 and an inductance L2, the capacitor C1 and the inductance L1 are serially connected between a joint of the positive-electrode side switch element Q1 and the negative-electrode side switch element Q2 and the load, the switch element Q3, the one-way conducting element D1 and the inductance L2 are parallelly connected with the capacitor C1 and sequentially connected, and current can flow in the inductance L2 from the switch element Q3 by the one-way conducting element D1. 本发明公开了种开关电路、