Patent ID: 8576581

Claim:
A circuit for controlling a current in an electrical control member or a voltage across terminals of said electrical control member, said circuit comprising: a bridge provided with four terminals and comprising four control switches; a first power source for said bridge; and means of controlling at least two of said four switches by pulse width modulation, wherein said power source is connected between a first terminal and a second terminal of said bridge, wherein said electrical control member is connected between a third terminal and a fourth terminal of said bridge, wherein the first switch is connected between said first terminal and said third terminal of said bridge, wherein the second switch is connected between said first terminal and said fourth terminal of said bridge, wherein the third switch is connected between said third terminal and said second terminal of said bridge, wherein the fourth switch is connected between said fourth terminal and said second terminal of said bridge, and wherein the circuit for controlling the current or the voltage comprises: a first state in which said first and fourth switches are closed and said second and third switches are open, a second state in which said second and third switches are closed and said first and fourth switches are open, and at least one of the following two states: a third state in which said third and fourth switches are closed and said first and second switches are open, and a fourth state in which said first and second switches are closed and said third and fourth switches are open; wherein said means of controlling the at least two switches by pulse width modulation authorizes: a transition from said first state to at least one of said third or fourth states, a transition from said second state to at least one of said third or fourth states, a transition from at least one of said third or fourth states to said first state, and a transition from at least one of said third or fourth states to said second state, and a first negative alternation phase comprising: transitions from said first state to said third state and transitions from said third state to said first state, said first and third switches forming a first amplitude leg, switching at a chopping frequency, and second and fourth transistors forming a second sign leg, wherein the second and fourth transistors are respectively closed and open; and a second positive alternation phase comprising: transitions from said second state to said fourth state and transitions from said fourth state to said second state, said first and third switches switching at said chopping frequency and said second and fourth switches being respectively open and closed, wherein the switching of said second and fourth switches of said sign leg ensures a transition between said negative and positive alternations at a frequency below said chopping frequency.