The simplistic Salas low voltage shunt regulator

[merlin el mago]

Sorry my ignorance: what's the diffeence between the doted line and the straight line?

[Salas]

Phase and amplitude.

[RCruz]

Originally Posted by Salas

These are the sim curves for 1.2R and Reflektor (the two versions that fair better in that respect). A 1.1 reg was measured by a member on AP station up to 100kHz once and followed well, fairing a bit better than the sim actually. So the sims should be trustworthy enough.

Here is V1.1 sim:

[merlin el mago]

Originally Posted by Salas

Phase and amplitude.

Thanks for teachering me

[vandenberg]

the schematic is a bit the same .
because the current through the second transistor is regulated it is very easy to use .

schematic[URL="http://kkkaudio.nl"].

see shuntregulator 1

[gentlevoice]

These are the sim curves for 1.2R and Reflektor (the two versions that fair better in that respect).

Hi Salas,

& thanks for posting the simulation curves

It makes me think that combining the shunts with a capacitor with superb high frequency performance (e.g. low impedance) might be feasible, however, I noticed in another post that there were some reservations about using high capacity capacitors on the output... Can I ask you if this this is so or may I combine e.g. the reflector with high value low impedance capacitors?

And then another question pops up and that is if one of those who built these shunts have tried to submit the shunt to a square wave load so as to see how it fares with dynamic loads?

Thanks again for replying Salas - best wishes from Denmark

Jesper

[Salas]

The large output capacitor is going to restrict the open loop bandwidth and change the phase. Less OLG bandwidth means specific application purposes and less integrated total noise. Also means a slower regulator. It can possibly lead to redesign of sorts if it will make it oscillate. For the Reflektor use the STP type output Mosfet for best HF. You should try combining for yourself, haven't experimented with large output cap and Reflektor. Square wave load test has been done with 1.0 once.

[orelli]

About diodes bridge. I read somewhere that capacitor snubber across diode is useful with standard diodes, but not with FRED type .In BiB board there are not holes to parallel capacitors to diodes; it's for the same reason? What do you think about this issue?

[Salas]

In Bib there are pads for small or TO-220 diodes depending on what you need/want to use. They can can double as parallel capacitors places those left unpopulated. Although not optimally short length.

[Salas]

Its a measurement thing. Got to see there is actual EMI from the diodes, then see what caps or other diodes like soft recovery/avalance mode etc. solve it on the oscilloscope.