A high-step-down digital controlled isolated DC-DC converter with a wide input/output operation range is popular in industrial applications. This paper presents a high-step-down isolated DC-DC converter with accurate output regulation ability in a wide operation range. The active clamp circuit and full-bridge ZVS synchronous rectification are implemented for efficiency concerns. The planar magnetic technique is employed to reduce the volume and maintain parameter consistency. Meanwhile, combining the high resolutions of DSP I/O configurations, a simple effective control approach for the accurate output voltage regulation is found. A 180-420V wide input voltage range and 28V/10A output isolated DC-DC converter prototype is built and tested to verify the effectiveness of the converter.

High-step-down,wide operation range,synchronous rectification,isolated DC-DC converter