Research and Design of Active Clamp Forward Converter

For the problems in the hard-switching mode of the traditional forward converter, such as high switching loss and large voltage/current spikes, the low-side active clamp topology was selected as the research object in this paper. The ZVS (Zero-Voltage Switching) conditions of the primary and auxiliary switches were emphasized by studying the operation modes of the active-clamped forward converter in one cycle. Synchronous rectification technology was adopted to reduce the loss, and UCC2897 was used as the main control chip of the output circuit to make the converter more flexible. Finally, the theoretical analysis and parameter design was verified from a 120W prototype.