Terminal capacitors represent the new bottleneck for converter miniaturization. To reduce their size, an optimum clocking scheme must be used to preserve multi-resonant operation. This paper demonstrates a closed-loop control method that can achieve multi-resonant operation allowing an optimum operating point to be tracked dynamically. The hardware prototype achieves zero current switching operation while demonstrating over 70% reduction in terminal capacitor volume for only a 0.2% decrease in full load efficiency. The controller also achieves up to 44% reduction in power loss compared with the conventional open-loop control without ZCS autotuning.
