Design Support

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This application note describes an approach to design feedback loop compensation for an LLC resonant half-bridge power converter. The approach described here is based on the measured Bode plots of the modulator generated by a network analyzer. Frequency domain poles and zeros in the feedback loop compensation can be analytically determined, then fine-tuned with a bench test. This measurement is necessary as part of feedback loop design because a practical small-signal model is not available for LLC resonant converters. This document uses the Texas Instruments' UCC25600 as the frequency controller.