There's a bunch of topics around this but i haven't found something that fits my requirements. I'd imagine this is a fairly common thing though so any pointers would be appreciated
Basically i want to design a circuit that can use mains power anywhere (85-265v AC) and power a simple system with max power consumption of around 100mA.
- 85-265v AC input
- 3.3v +-5% DC output
- 10-100mA current
- Size as small as possible
- ~10mV ripple
- Cheap (less than ~$10)
This is for a networked device and will be totally enclosed (no buttons etc) so i don't think it has to be isolated although it of course wouldn't hurt.
I've looked at existing PCB mount PSUs but the price is a bit too high. Also they can be fairly big (mostly tall) and provide much more current than i really need.
A simple solution with
AC -> Transformer -> Diode bridge -> Voltage regulator would probably work but the transformer size becomes very big. Also i'm unclear how this will work with the universal voltage range.
Basically i probably want something similar to the 3rd solution here: https://electronics.stackexchange.com/a/41944/6809
The components from Power Integrations seem to be what i should be looking at but i'm slightly unsure where to start. Also very few of the examples give 3.3v out and usually at a much higher wattage than i need (= i'm thinking i can make something smaller/cheaper as i only need .1 Amp)