This reference design is a compact, high efficiency, fast transient, universal input, 12-V DC, 200-W nominal output, AC/DC power supply (PSU) targeted for desktop PCs and gaming adapters. The TIDA-01557 circuit consists of a front-end transition-mode (TrM) power factor correction (PFC) circuit based on the UCC28056, followed by an LLC stage for isolated DC/DC conversion based on UCC256301. For high efficiency needs, synchronous rectification is done using the UCC24612-2 synchronous rectifier controller and low RDS (on) MOSFETs CSD18511. This design does not need additional auxiliary power supply for meeting no-load and light-load specifications. The design can be used as an AC/DC power supply in applications that demand efficient power conversion and fast transient response.