Zen -> Cen -> Sen, evolution of a minimalistic IV Converter

[needsp]

Hi RollE2K

IMO (if I'm wrong, I'm sure Patrick will correct me) common mode noise on the mains is our enemy here. The regulators you propose, and those Nic used, are guard against differential noise only. Common mode noise will sail straight through them and develop as a voltage selectively across the IV resistors in SEN.

Mains transformers with non overlaid primary and secondary windings- such as R cores- will help, but perhaps not enough?

Nic- congratulations on the F5X!

Best

Paul

[bcarso]

Originally Posted by needsp

Hi RollE2K

IMO (if I'm wrong, I'm sure Patrick will correct me) common mode noise on the mains is our enemy here. The regulators you propose, and those Nic used, are guard against differential noise only. Common mode noise will sail straight through them and develop as a voltage selectively across the IV resistors in SEN.

Mains transformers with non overlaid primary and secondary windings- such as R cores- will help, but perhaps not enough?

Nic- congratulations on the F5X!

Best

Paul

I believe you are correct. In fact most of these circuits are relatively insensitive to differential noise, and the cascoded ones even less sensitive. Common mode is tough. A given very-high-quality common-mode choke is effective over a given frequency range. A cascade of them with different coverages may be adequate. It depends on your mains and environment. But by the time you've gotten it all to work adequately, the inconvenience of batteries may start to look like a relatively minor concern.

[NicMac]

Originally Posted by bcarso

But by the time you've gotten it all to work adequately, the inconvenience of batteries may start to look like a relatively minor concern.

Yes - and apparently this is learned the best way by personal experience.

[EUVL]

Or just take Patrick's word.

But I am glad that you didn't, and learned "the hard way".
You'll then never forget.


Patrick

[RollE2k]

Thanks alot for the answer guys.. So choke-filtering seems to be the first thing to try then.
NicMac: did you use any kind of common mode choke, or did you just use plain linear or a shunt-regulator for it?

[NicMac]

Originally Posted by RollE2k

Thanks alot for the answer guys.. So choke-filtering seems to be the first thing to try then.

If anything batteries would be the first to try

Originally Posted by RollE2k

NicMac: did you use any kind of common mode choke, or did you just use plain linear or a shunt-regulator for it?

Yes - there were in fact common mode chokes in the regs I tried.

[bcarso]

Somewhere in this thread there are some suggestions for common-mode chokes --- I don't have time to sift through and find them right now. I obtained some but didn't get round to trying them. However the choice(s) will depend a lot on your particular EM environment.

[EUVL]

> Somewhere in this thread there are some suggestions for common-mode chokes

Floating PSU schematics by Joachim.


Patrick

[massimo]

Originally Posted by bcarso

Somewhere in this thread there are some suggestions for common-mode chokes

IIRC Telema CAF 0,6-100 (easily available in Germany) or Panasonic PLK1273-ND (digikey p/n)

[RollE2k]

Brand probably doesn't matter, i was looking at some other branded 100mH Common mode chokes, 350mA.
Also, today i have made an order for a custom made R-core with outer shield, plus shielding between primary/secondary. 4x 0-18v secondaries with extra insulation between each winding. To this i will probably build the regs above i think. But this will certainly be a while before i'm finished, since i lack alot of other things before. Will order the DAC itself first next month.