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some ways to discuss some ac to dc methods.

Question asked by alanhan on Jan 9, 2013
Latest reply on Jan 16, 2013 by MMA

I am a chip designer. I have some questions about the isopower icoupler.

Now I want to use a simple device to convert the 220Vac to a low DC (1~3V current is around 10mA). The efficiency demand is not very high, more than 10% is OK.  I want to design this power supply to a chip.


First idea is to use a linear capacitor to get the 2V AC, two capacitors, 120nF and 12uF, and then, I use a 1Kohm parallel to 12uF, then the load's output voltage is

around 2V ac. Since the caps do not consume a lot of energy, I think the efficiency will more than 10%. But I dont see peope mention this, and never see someone

use this. I am not an expert for this. 120nF and 12uF, for these two capacitors, I want to build them on pcb board by myself. I mean, double side metal on the board,

it can be seen as a cap, right.   Above all, I am not sure this will work or not.


Second idea, is about the isoower icoupler.My idea is to use a transformer to convert a 220V ac to a fairly low voltage (2V~12v), and then I will use a nm process chip to design the low voltage ac to the low voltage dc I really need. So I am searching alot.  I am very interested in the microtransformer design.   The isolation voltage is very high, and I like that. Do you think I can use it to convert the 220Ac line to a low voltage ac? I know the main line frequency is very low. So I am not sure if it is working.

There are many converters in the world. But I just need to design a converter from wall main line to a low dc voltage that can power supply my nm single chip. The efficiency is not very important, >10% is enough. Also, not big, better to be a chip I can design.

So what do you think about it.