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Re: gEDA-user: OT: help needed; asymmetric load after rectifier seems to disrupt its working.



Yeap, it should be a very low power power supply. Vx is not important Vcc and Vss are. Vin can be anything from 15Khz to 28Khz so a transformer is not the most desired option. I have designed two SMPS for Vcc and Vss but there load to the rectifier are not the same, with the described result.
I will try the options suggested in this list today.
Robert.

On 17/06/11 04:13, gene glick wrote:
On 06/16/2011 02:30 PM, myken wrote:
Hello all,

I would appreciate some expert advice.

Are you trying to make a low current power supply?

I agree with DJ - the unequal loading on + and - cycle will average to something other than zero (unequal capacitors, unequal diodes, etc) If Vx must always be average zero - you'll need to do something else.

If you can handle a little voltage drop, don't care what happens to Vx, and don't mind adding a few parts, make a cheapo regulator with a zener and BJT? (Or maybe use TL31 instead of zener)

What about a small transformer, one winding on primary, center tapped on secondary. Add a diode and a cap for each leg - and there you go!

Anyway, there's lots of ways to do this. If regulated output is what you want, a little more work is required.


gene




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