Transformerless Power Suppply

**ERIK** · - 7th March 2006, 01:55

Thanks Mel, I have finally got some 275V X2 caps and some VDR's (I had to buy 100 of them but thats OK). So I'll sort out a PCB (well marked, and well housed) and let you know how it goes...

**sayzer** · - 2nd August 2006, 19:08

Hi Melanie,

Going back to this post,

Would that be too much to ask for your complete fan controller schematic?
and, if possible, for the code also?

I am having a similar inquiry and would like to see your approach.
Or if there is anyone else who had a similar design.

Regards

**Melanie** · - 3rd August 2006, 10:43

Hi Sayzer

This product is still in volume production (about 1000/month), and I'm treading on thin ice just posting the PCB view (a couple of posts above) and some snippets out of the PSU schematic - the remainder if you're clever you can figure from most of the components in use and eliminating those I've already revealed... a licence for the complete Software and Schematics would cost... I envisage around $5K.

Melanie

**sayzer** · - 3rd August 2006, 15:10

May be, I can support that thin ice, so it will not crack.

Since you already have it in production, I may need not to work on it;

This is of course if you are able to sell it to other customers. Are you?

Should I PM to you?

**Melanie** · - 3rd August 2006, 15:34

Sure, continue this by email, as I can then send you the product Datasheet so you can see if it fits your requirements.

**sayzer** · - 11th August 2006, 12:29

Upon the discussion with Melanie, attached is the capacitor value table for the current (mA) that your circuit draws.

Table is quite simple to figure out.

Table is for 110V@60Hz and 220V@50Hz.

Example: If your circuit draws 12mA, and your power line is 110V 60Hz, then, you use 0.289uF (290nF) for C2 in the circuit that Melanie posted here.

Of course you will have to adjust D2 and VDR accordingly.

If this table is any help to anyone!

Regards

**Melanie** · - 11th August 2006, 12:44

Nice table, but if you limited the Capacitor values to those dozen or so X2 values available (eg 10n, 22n, 47n, 100n, 220n etc, etc), you'll be able to pick the one closest to your current requirement. No point in having a 290n value when you can't buy one, and putting heaps in parallel negates the advantages (cost, size and weight) of a transformerless design to start with.