This design is auxiliary power supply with 5-V/1-A and 5-V/1-A dual output. The line and load regulation of the power supply is designed to be within 1% using the secondary side regulator: UCC28742. The system's reliability is improved through input UVLO and output OVP: OCP: SCP. The four point's load (25%: 50%:75%: 100%) average efficiency is above 81%.