Dc/dc converter
AssigneeSiemens Aktiengesellschaft
InventorLorand Cesnak
Life of this patent
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Abstract
A DC/DC converter has an active energy store, such as an inductance, which can be periodically charged and discharged by one or more semiconductor switches, such as transistors. To avoid voltage overshoot, an RCD element is provided for at least one semiconductor switch, wherein a capacitor and a diode of the RCD element are connected in series, and a resistor of the RCD element can be connected either in parallel with the diode or disconnected from the diode by a switch. The diode of the RCD element is arranged so as to be blocking in the conducting direction of the semiconductor switch.
Claims15
1-9. (canceled)
A DC/DC converter, comprising
- an active energy store having an inductance,
- a first semiconductor switch configured to periodically charge the active energy store, and
- a second semiconductor switch configured to periodically discharge the active energy store,
- with at least one of the first and second semiconductor switches having an RCD element to prevent voltage overshoots for the at least one semiconductor switch, said RCD element comprising a capacitor and a diode connected in series and a resistor, and furthermore a switch having a first switching position connecting the resistor in parallel with the diode and a second switching position disconnecting the resistor from the diode, wherein the diode is arranged so as to be blocking when the semiconductor switch is conducting.
A method for operating a DC/DC converter having an active energy store in form of an inductance, a first controllable semiconductor switch constructed as a buck converter transistor configured to periodically charge the active energy store and a second controllable semiconductor switch constructed as a step-up converter transistor configured to periodically discharge the active energy store, with at least one of the first and second semiconductor switches having an RCD element to prevent voltage overshoots for the at least one semiconductor switch, said RCD element comprising a capacitor and a diode connected in series and a resistor, and furthermore a switch having a first switching position connecting the resistor in parallel with the diode and a second switching position disconnecting the resistor from the diode, wherein the diode is arranged so as to be blocking when the semiconductor switch is conducting, the method comprising:
- for operation as a buck converter, switching only the buck converter transistor on,
- connecting the resistor in the RCD element, that is connected in parallel to the buck converter transistor, in parallel with the capacitor of the step-up converter transistor, and
- selectively connecting the resistor, that is connected in parallel with the step-up converter transistor, in parallel with the diode in the RCD element of the buck converter transistor or disconnecting the resistor from the diode.
A method for operating a DC/DC converter having an active energy store in form of an inductance, a first controllable semiconductor switch constructed as a buck converter transistor configured to periodically charge the active energy store and a second controllable semiconductor switch constructed as a step-up converter transistor configured to periodically discharge the active energy store, with at least one of the first and second semiconductor switches having an RCD element to prevent voltage overshoots for the at least one semiconductor switch, said RCD element comprising a capacitor and a diode connected in series and a resistor, and furthermore a switch having a first switching position connecting the resistor in parallel with the diode and a second switching position disconnecting the resistor from the diode, wherein the diode is arranged so as to be blocking when the semiconductor switch is conducting, the method comprising:
- for operation as a step-up converter, switching only the step-up converter transistor on,
- connecting the resistor in the ROD element, that is connected in parallel to the step-up converter transistor, in parallel with the capacitor of the buck converter transistor, and
- selectively connecting the resistor, that is connected in parallel with the buck converter transistor, in parallel with the diode in the RCD element of the step-up converter transistor or disconnecting the resistor from the diode.
Dependencies are inferred from the claim text.