I'm starting to think about my next project where I want to power an AVR MCU and some LEDs efficiently from the 120V AC mains. I'm hoping to get above 90% efficiency.
I could use a transformer to get the line voltage down to something in the 10V-20V range, but transformers are big, heavy, expensive. Is there a way to pre-regulate the AC line voltage with high efficiency and with no transformer? I only need about 50mA.
Thanks for all inputs.