Diigital power controllers of various sizes and shapes were in evidence at APEC, including this reference design from Microchip. This 750-W ac/dc power supply implements a semi-bridgeless PFC topology followed by a peak current controlled zero-voltage switching full-bridge converter with digital slope compensation to get high conversion efficiencies. It can be firmware updated (including the compensator algorithm) while it runs. It is implemented using two processors called dsPIC33EP “GS” that control the power conversion as well as all system management functions. The converter is designed to step down an input dc voltage of 400 V to an output dc voltage of 12 V. The reference design also implements peak current control, using a software-based slope compensation algorithm, which eliminates the use of external analog components for slope compensation.