My take on a discrete shunt voltage regulator

[Salas]

The vintage meter is way cool. Nice compact board too.

[ikoflexer]

Originally Posted by stormsonic

and 2N2819 (on PCB) => 2N3819

yes, indeed, fixed now.

Originally Posted by salas

The vintage meter is way cool. Nice compact board too.

Thanks! Oh, the Avometer is very dear to me, a gift from a old professor. I use it all the time

[Bertel]

Gentlemen,

may I allow to introduce myself to this thread

I have been in discussion with ikoflexer to specify two regulators for 12v output, one at 500mA current limit, the other at 200mA. I cannot praise ikoflexer enough for his knowledge, willingness to share and help, and patience! Thank you so much!

I have just sourced the parts and will soon start building the prototypes. Will be pleased to report :-)

Best,
Robert

@ikoflexer: I was intending to start out point-to-point, but would your new PCB also be a possibility for me?

[ikoflexer]

Hi Robert,
Welcome to the thread.

Regarding the pcb, it's passed the "reality" test, but it may be a little while before it's ready for prime time. It's up to you.

I'll see if I get the time to try a 12V prototype soon, to help you with choosing R9 and R11.

[Bertel]

Hi Relu,

hmm, in post#1 you had said that

Low output impedance at high frequencies depends a lot on the actual implementation and board layout

Would you say (I know it can just be an estimate based on your experience) that point-to-point is substantially worse in this respect?

That's very kind of you that you want to support me with a 12V prototype! I have started out with R11 implemented as a trimmer, let's see where this gets me.

Many thanks
Robert

[ikoflexer]

Originally Posted by Bertel

Hi Relu,

hmm, in post#1 you had said that
Would you say (I know it can just be an estimate based on your experience) that point-to-point is substantially worse in this respect?

I intended to make a pcb for those people who:
* have no time to pay much attention to layout, parts connections, etc.
* are beginners and want to get as close as possible to plug and play
* like to include something that looks neat in some other project


Point-to-point can be just as good IMHO, but let's face it, not everybody likes it.

That's very kind of you that you want to support me with a 12V prototype! I have started out with R11 implemented as a trimmer, let's see where this gets me.

No worries.

I just tried R9 = R11 = 8K2 and got 11.4V out. This should give you a value to start from.

[ikoflexer]

Quanghao asked for a high voltage regulator. He's a brave man.

I've built a similar version but not exactly this one below. These days I don't have a lot of time to be on the forum, so, Quanghao, if you don't really understand how to get this working, it might be better not to go for it.

NOTE: R2 might not have exactly this value of 10R. You need to adjust R2 for the desired current!!!

EDIT: each pair of zeners can be replaced with a resistor, of about 100k.

[stormsonic]

Board assembled
Modification for 5V output of Version 5c

R9 = R11 = 5K6

R2 = 2K2 trimmer (to set shunt current)
All LEDs are not equal (different Vf) and all 2SK170 are not equal (different Idss), without trimmer R7 and R2 need some tweaking and experimenting for desired results. With trimmer is much easier

R10 = depends on particular J201. Smaller value = bigger current through voltage reference. 750R or 1K or 1K2 will be OK My current is set to 200uA.

Initial impression: subtle improvement (better mids & highs) compared to Simplistic Salas V1 (without Q7 mod). More details, music flows more easy. Just initial impression, not final decision.
C1 = 4.7uF EPCOS MKT, C2 = 4.7uF EPCOS MKT (at output, not at load).

[ikoflexer]

I'm curious how you modified it for 5V. Did you use a logic level shunt mosfet? (I hope you did.)

[stormsonic]

yes, good point.
IRFBC40 is on the edge here, Vgs is bellow treshold. For 5.5V output or more is OK, lower is possible only, when properly heated But only low shunt currents

I have CEB703AL from old MSI6163 computer motherboard and some old 2SJ306 to experiment. Still working on this issue, to find easy available, cheap logic level N-channel MOSFET with high transconductance.