Changing a switching state of a switching half-bridge

A method for changing a switching state of a switching half-bridge having two field-effect transistors and a supplementary circuit arranged upstream of a gate terminal of a first of the two field-effect transistors and formed of a first circuit branch having a damping resistor and an inductor connected in series with the damping resistor and a second circuit branch having a series resistor and an auxiliary switch connected in series with the series resistor, with the first circuit branch and the second circuit branch being connected in parallel, the method comprising:

• switching from a first switching state, wherein a gate terminal of the first of the two field-effect transistors adapts a gate-source voltage corresponding to a switch-on level, and a second of the two field-effect transistors adapts a gate-source voltage corresponding to a first switch-off level, to a second switching state, wherein the gate-source voltage of the first of the two field-effect transistors adapts the first switch-off level, and the gate-source voltage of the second of the two field-effect transistors adapts the switch-on level,
• while the auxiliary switch is open, changing a control voltage of the first of the two field-effect transistors from the switch-on level to the first switch-off level;
• said changing of the control voltage causing the first circuit branch to temporarily change the gate-source voltage of the first of the two field-effect transistors from the switch-on level to a second switch-off level having a magnitude that is greater than a magnitude of a first switch-off level,
• changing the gate-source voltage of the second of the two field-effect transistors from the first switch-off level to the switch-on level;
• and
• changing the gate-source voltage of the first of the two field-effect transistors from the second switch-off level to the first switch-off level.

A switching arrangement for changing a switching state of a switching half-bridge comprising two field-effect transistors, the switching arrangement comprising:

• for each of the two field-effect transistors, a respective gate driver associated with the respective field-effect transistor and driving the respective field-effect transistor with a control voltage,
• for each of the two field-effect transistors, a supplementary circuit arranged between a gate terminal of the respective field-effect transistor and the respective gate driver, the supplementary circuit formed of a first circuit branch having a damping resistor and an inductor connected in series with the damping resistor and a second circuit branch having a series resistor and an auxiliary switch connected in series with the series resistor, said first circuit branch and second circuit branch connected in parallel,
• the respective gate driver in combination with the supplementary circuit switching the half-bridge from a first switching state, wherein the gate terminal of the first of the two field-effect transistors adapts a gate-source voltage corresponding to a switch-on level and the gate terminal of the second of the two field-effect transistors adapts a gate-source voltage corresponding to a first switch-off level, to a second switching state, wherein the gate-source voltage of the first of the two field-effect transistors adapts the first switch-off level, and the gate-source voltage of the second of the two field-effect transistors adapts the switch-on level,
• wherein, when the auxiliary switch is open, the respective control voltage of the first of the two field-effect transistors changes from the switch-on level to the first switch-off level;
• said change in the control voltage causing the first circuit branch to temporarily change the gate-source voltage of the first of the two field-effect transistors from the switch-on level to a second switch-off level having a magnitude that is greater than a magnitude of a first switch-off level,
• wherein the respective control voltage of the second of the two field-effect transistors then changes the gate-source voltage of the second of the two field-effect transistors from the first switch-off level to the switch-on level;
• and
• wherein the gate-source voltage of the first of the two field-effect transistors then changes from the second switch-off level to the first switch-off level.

A power converter comprising a switching half-bridge which has two field-effect transistors and a switching arrangement for changing a switching state of a switching half-bridge, the switching arrangement comprising:

• for each of the two field-effect transistors, a gate driver associated with the respective field-effect transistor and driving the respective field-effect transistor with a control voltage,
• for each of the two field-effect transistors, a supplementary circuit arranged between a gate terminal of the respective field-effect transistor and the gate driver, the supplementary circuit formed of a first circuit branch having a damping resistor and an inductor connected hi series with the damping resistor and a second circuit branch having a series resistor and an auxiliary switch connected in series with the series resistor, said first circuit branch and second circuit branch connected in parallel,
• the gate driver in combination with the supplementary circuit switching the half-bridge from a first switching state, wherein the gate terminal of the first of the two field-effect transistors adapts a gate-source voltage corresponding to a switch-on level and the gate terminal of the second of the two field-effect transistors adapts a gate-source voltage corresponding to a first switch-off level, to a second switching state, wherein the gate-source voltage of the first of the two field-effect transistors adapts the first switch-off level, and the gate-source voltage of the second of the two field-effect transistors adapts the switch-on level,
• wherein, when the auxiliary switch is open, the respective control voltage of the first of the two field-effect transistors changes from the switch-on level to the first switch-off level;
• said change in the control voltage causing the first circuit branch to temporarily change the gate-source voltage of the first of the two field-effect transistors from the switch-on level to a second switch-off level having a magnitude that is greater than a magnitude of a first switch-off level,
• wherein the respective control voltage of the second of the two field-effect transistors then changes the gate-source voltage of the second of the two field-effect transistors from the first switch-off level to the switch-on level;
• and
• wherein the gate-source voltage of the first of the two field-effect transistors then changes from the second switch-off level to the first switch-off level.