EPR-9 - 5 W, universal input, dual output, isolated power supply

This document describes the specifications, schematic and BOM, transformer design, test data, waveforms and EMI scans of a low-cost dual output (5 VDC, 12 VDC) isolation converter for home appliance applications. The device must operate at ambient temperatures up to 85 °C and withstand input voltage surges up to 2 kV (configuration "1") or 6 kV (configuration "2"). The unit is also designed to meet industry safety and EMI standards. Low-cost transformers (no shielded windings and flux bands) and low-cost input filters (no common-mode chokes) meet EMI standards. Depending on the geographic region where the white goods are manufactured, there are different input voltage surge withstand requirements. The power supply designer must choose the level of protection, voltage level, and number of surges that the equipment must withstand. For applications where the ambient temperature is elevated and full power is required, a heat sink (included in the kit) must be soldered to the board in the slot next to U1. The board comes with a kit that includes a copper heat sink (Figure 5.2) and input voltage surge protection components (R7, R8, RV1) for 6 kV (configuration "2") protection. For applications requiring 5 VDC and 24 VDC, Appendix A contains the schematic, BOM, and transformer spreadsheet.