将有源钳位添加到同步反向电源的优势

Flyback converters are a popular choice in applications that require an isolated power supply to deliver low to medium output power. When efficiency is a primary concern, you can replace the flyback output diode with a MOSFET, resulting in what is commonly referred to as a synchronous flyback converter. POE (power-over-Ethernet) applications are prime candidates for synchronous flyback supplies. Presently, the input power for POE supplies is limited to 12.95W. Maximizing the efficiency of the power supply allows the system to deliver more power to the load. You can gain further improvements to the converter’s efficiency by using an active-clamp controller to reduce the snubber and shoot-through losses.

Active-clamp forward converters have been an increasingly popular choice in higher power applications. Yet few power-supply designers are aware that they can also employ an active clamp in flyback converters. To investigate the benefits of the active-clamp control in a flyback topology, we designed, built, and tested two power supplies.