TIDUET3 February 2021
This compact, high-efficiency reference design with a 48-V DC, 500-W output targeting 5G telecom power and industrial AC/DC power supplies. The circuit consists of a front-end continuous conduction mode (CCM) power factor correction (PFC) circuit based on the UCC28180 device, followed by a robust LLC stage for an isolated DC/DC converter based on the UCC256403. For high-efficiency needs, the UCC24624 handles synchronous rectification. This design uses an auxiliary power supply flyback with the UCC28911, which has an internal high-voltage MOSFET. This design enables 94.5% peak efficiency and allows the system to work without forced cooling. The whole system has low THD, with 30% load at < 12%, 50% load at < 8%, 100% load at < 5.5%, and good load transient performance.