Patent ID: 8441825

Claim:
An H-bridge circuit, comprising: an AC power source having a first and a second terminals; an H-bridge comprising: a first and a second bridge arms, each of which has a first and a second terminals and a middle point, wherein the first terminal of the first bridge arm connects the first terminal of the second bridge arm, the second terminal of the first bridge arm connects the second terminal of the second bridge arm, and the middle point of the first bridge arm and the middle point of the second bridge arm connect the first and the second terminals of the AC power source respectively; and a bidirectional switch connected between the two middle points; a bootstrap circuit comprising a bootstrap capacitor and providing a bootstrap voltage; a driving circuit receiving the bootstrap voltage and driving the bidirectional switch; and an energy compensation circuit coupled to the H-bridge, the bootstrap circuit and the driving circuit, and comprising a first, a second and a third terminals, wherein the first and the second terminals are coupled to the AC power source, and the second and the third terminals connect to the bootstrap capacitor to provide a compensation energy to the bootstrap capacitor.