Delta Electronics, Inc.

Chaoqun Sun

Hongjian Gan

Alpha J Zhang

Jianping Ying

Zhongwei Ke

Huijie Xue

A time delay synchronous control scheme for a power supply, which has multiple outputs and tight output regulations, is provided. The switching mode power supply includes (1) a front-end DC/DC converter with current mode output, which can be a LLC Series Resonant converter (SRC) or a flyback converter; (2) one or several post buck converters directly cascaded from the output capacitor of the front-end DC/DC converter; (3) a new scheme of time delay synchronous control used to make the post buck synchronize and modulate from the front-end LLC-SRC or flyback converter. The proposed time delay synchronous control circuit can eliminate the conventional input filter of the post buck converters, as well as reduce the ripple current on the output capacitor of the front-end DC/DC converter, as a result of which, a high efficiency for the overall architecture can be obtained.

Time delay control scheme for a power supply with multiple outputs

An LLC series resonant converter and a driving method for the synchronous rectification power switches thereof are provided. The LLC series resonant converter includes a bridge circuit, a resonant network, a transformer, a rectification circuit, and a frequency adjustment controller. The bridge circuit includes at least one pair of power switches. The power switches drive the resonant network. The rectification circuit includes at least one pair of synchronous rectification power switches. The synchronous rectification power switches and the power switches have a mapping relation between them. The frequency adjustment controller provides driving signals to the synchronous rectification power switches in response to the operating frequency of the LLC series resonant converter and the series resonant frequency of the resonant network, to implement synchronous rectification in the LLC series resonant converter.

LLC series resonant converter and the driving method for the synchronous rectification power switches thereof

A constant voltage reset circuit used in a forward converter for the holdup time requirement or the wide input voltage range is disclosed. In one embodiment, the constant voltage reset circuit comprises a reset capacitor, a parallel-coupled switch, and a diode coupled in series with the reset capacitor which is configured to cooperate therewith to reset an energy from the transformer. The forward converter employing the reset circuit or the method achieves a higher efficiency with a larger turn ratio and without the 50% limitation of maximum duty cycle.

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Taoyuan Hsien, Taiwan

Chaoqun Sun