Patent ID: 7477082

Claim:
An H-bridge drive circuit for driving a load with a first power supply and a second power supply that is lower in voltage than the first power supply, the H-bridge drive circuit comprising: first and second transistors connected in series between the first and second power supplies, with the first transistor being connected to the first power supply and the second transistor being connected to the second power supply; third and fourth transistors connected in series between the first and second power supplies, with the third transistor being connectable to the first power supply, the fourth transistor being connectable to the second power supply, and the load being connectable to a node between the first and the second transistors and a node between the third and the fourth transistors; and a control circuit for switching the activation and inactivation of the first to fourth transistors in accordance with the following sequence, activating the fourth transistor and then activating the first transistor, inactivating the first transistor, when the gate of the first transistor has a low voltage, inactivating the fourth transistor, activating the second transistor before the gate of the fourth transistor has a low voltage, and activating the third transistor when the gate of the second transistor has a high voltage and the gate of the fourth transistor has a low voltage, thereby causing an output voltage at the node between the third and fourth transistors to drive the load.