Patent ID: 6625046
Filing Date: 2003-09-23
Classification: B23K,H02M,Y02B,Y02P

Abstract:
A method of providing power from a power supply including a first power switch, a second power switch, a first snubber switch, a second snubber switch, a first dc bus, a second dc bus, a first power capacitor, a second power capacitor, a first snubber diode, a second snubber diode, a first snubber capacitor, a second snubber capacitor, a first anti-parallel power diode, a second anti-parallel power diode, and a transformer, comprising:turning on the first power switch and the first snubber switch, and allowing current to flow through the first power switch, the first dc bus, the first power capacitor, and in a first direction through the transformer; turning the first power switch off and allowing current to flow through the first snubber switch, the second snubber diode, the first snubber capacitor, and through the transformer in the first direction, while the first power switch is turning off, to provide a slow voltage transition off; allowing current to flow through the second anti-parallel power diode, the second DC bus, the second power capacitor, and through the transformer in the first direction, while the first power switch is continuing to turn off, to continue providing a slow voltage transition off; turning off the first snubber switch; turning on the second power switch and the second snubber switch after the first power switch is off, and allowing current to flow through the second power switch, the transformer in a second direction, the second power capacitor, and the second dc bus; turning the second power switch off and allowing current to flow through the second snubber switch, the first snubber diode, the transformer in the second direction, and the second snubber capacitor, while the second power switch is turning off, to provide a slow voltage transition off; allowing current to flow through the first anti-parallel power diode, the transformer in the second direction, and the first power capacitor, while the second power switch is turning off, to provide a slow voltage transition off; turning off the second snubber switch; and repeating these steps.