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All   >>  Energy Efficiency   >>   Power Supplies   >>   Questions
 

Simple, complete Low cost isolated 100Vac to 260Vac input and 3V or 3.3V 250mA+ output design? I have a couple of engineer friends I know and we are all having issues getting a really low cost simple isolated supply. Why cant we get 240Vac to 3.3V/3V isolated designs for a few dollars? Do you have design references you can link that would be USD$5 tp USD$8 or so for complete BOM? we feel like this should be very simple with loads of references and already complete designs for engineers to just plug in, obviously people want to power processors from mains power so it should be a simply task right?

The universal AC input converter circuit is a simple flyback regulator utilizing the monolithic NCP1012 controller with internal Mosfet to provide an isolated 12 volts at 300 mA output.

Magnetic design need to be adjusted according your specification e.g 3.3V output voltage at 0.825 W.

The NCP785A is a high−performance linear regulator, offering a very wide operating input voltage range of up to 450 V DC, with an output current of up to 10 mA.

It is an ideal choice for high input voltage applications such as industrial and home automation, smart metering, home appliances. However, it is linear not isolated power supply, but price competitive.
Answered by:
ON Semiconductor
2015-01-12 14:26:14.669