This reference design was designed for the 3 Phase E-meter application. It uses the UCC28600 quasi-resonant flyback controller to generate three 3KV isolated output rails from an extremely wide input source from 110VAC to 420VAC. The 3 output rails have independent protections to improve system reliability. The synchronous buck converter TPS560430 was used on the 12V 0.7A rail to generate a 0.1% output ripple voltage for post modules. The board size is 100mm(L)*50mm(W)*20mm(H).