Soft-switched power converters
AssigneeDelta Electronics, Inc.
InventorsMilan M. Jovanovic, Yungtaek Jang, Yu-ming Chang, Kung-Hui Fang
Life of this patent
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Abstract
A soft-switched boost converter includes an active snubber to provide soft switching of all semiconductor components. Specifically, the current (“turn-off current”) in the rectifier is switched off at a controlled rate, the main switch is closed under zero-voltage switching (ZVS) condition, and the auxiliary switch in the active snubber is opened under zero-current switching (ZCS) condition. As a result, switching losses are reduced with beneficial effects on conversion efficiency and EMC performance.
Claims52
A power converter having an input terminal and an output terminal, the input terminal being coupled to a power source, the power converter comprising:
- a storage inductor coupled to the input terminal;
- a first switch operating to charge and discharge the storage inductor;
- an active snubber including a second switch, coupled to a reference voltage that is substantially constant over a switching cycle of the first and second switches;
- a rectifier operatively coupled to the storage inductor, the active snubber and the output terminal to transfer energy from the storage inductor to the output terminal;
- and
- a control circuit that provides control signals to control the operations of the first and second switches over the switching cycle, such that the second switch closes to cause a current in the rectifier to be diverted from the rectifier to the active snubber, so as to allow the first switch to close at a substantially zero voltage condition and, in turn, to allow the second switch to open at substantially zero current condition.
A method for power regulation in a power converter having an input terminal and an output terminal, the input terminal being coupled to a power source, the method comprising:
- providing a storage inductor coupled to the input terminal;
- coupling a first switch to charge and discharge the storage inductor;
- providing an active snubber including a second switch, the active snubber being coupled to a reference voltage that is substantially constant over a switching cycle of the first and second switches;
- coupling a rectifier to the storage inductor, the active snubber and the output terminal, so as to transfer energy from the storage inductor to the output terminal;
- and
- controlling the operations of the first and second switches over the switching cycle, such that the second switch closes to cause a current in the rectifier to be diverted from the rectifier to the active snubber, so as to allow the first switch to close at a substantially zero voltage condition and, in turn, to allow the second switch to open at substantially zero current condition.
Dependencies are inferred from the claim text.