This compact, high efficiency reference design with a 48-V DC, 500-W output targets 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, 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 iTHD, with 30% load at <12%, 50% load at <8%, 100% load at <5.5% and good load transient performance.
Features
- Peak efficiency of 94.5% at 230-V AC and 94% across 30%~100% load
- CCM PFC and half-bridge LLC based (UCC28180 and UCC256403)
- Low iTHD: 30% load at <12%, 50% load at <8%, 100% load at <5.5%
- Good load transient performance at less than 1% regulation
- Meets ±1% accuracy for input power meter across whole load range
- Passive cooling with sealed metal case