The PMP3799 reference design provides an adjustible 20V output at 4A from a standard 48V telecom input with greater than 93% efficiency. This design uses the UCC2897A active clamp controller along with an ISO721 digital isolator and TPS28225 to drive synchronous rectifiers. The output voltage can be adjusted from 16V to 24V by changing a single resistor value. The circuit is built in an industry standard quarter-brick footprint.