Patent ID: 7772924

Claim:
An H-bridge controller for controlling a common-mode voltage and/or current of an H-bridge circuit, comprising: a section for receiving a signal indicating at least one of a common-mode voltage or common-mode current of the H-bridge circuit; and a section for generating control signals which determine switching of the H-bridge circuit so as to control at least one of the common-mode voltage or common-mode current of the H-bridge circuit; wherein the signal is a digital signal having one of a plurality of voltage levels, the one voltage level being selected based on a modulated input signal, each of the plurality of voltage levels being assigned to a corresponding one of a plurality of logic states; wherein the H-bridge circuit includes a plurality of states of operation, each of the plurality of states of operation being associated with a corresponding one of the plurality of logic states; wherein one of the plurality of states of operation includes two variations; wherein the section for generating control signals generates control signals which control the H-bridge circuit to operate in one of the two variations; wherein the one of the two variations is determined based on the received signal so as to reduce variations in at least one of an average of the common-mode voltage of the H-bridge circuit or an average of the common-mode current of the H-bridge circuit; wherein each of the first state of operation, the second state of operation, the first variation of the third state of operation and the second variation of the third state of operation are associated with a logic state; wherein the control signals control the H-bridge circuit to operate in the state of operation associated with the logic state assigned to the voltage level of the received digital signal; and wherein the H-bridge controller further comprises: a section for checking the voltage and/or current level of the received digital signal; a section for assigning a logic state to the voltage and/or current level of the received digital signal; a section for controlling the H-bridge circuit in the state of operation associated with the logic state if the logic state is associated with a state of operation having no variations; and a section for controlling the H-bridge circuit in one of a plurality of variations of a state of operation associated with the logic state that reduces variations in at least one of the average common-mode voltage or the average common-mode current of the H-bridge circuit if the logic state is associated with a state of operation having a plurality of variations.