The simplistic Salas low voltage shunt regulator

[Salas]

Thanks for the good words. What do you mean climbs very slowly? What kind of voltage climb value?

 

[RCruz]

It climbs from zero to 28v in 5 minutes when connected to the riaa amp. (The led starts very dim and grows stronger within minutes.)

It climbs much faster when connected with a dummy load on the bench.

 

[Salas]

There is something wrong going on initially. There should always be 4mA available to charge the filter capacitor. Can 2000uF be overkill to start up? Here is an alternative routing by the way.

 

[RCruz]

Thank you Salas

Your routing looks awesome.... I will try it soon. (Can I use BC327 ?)

 

[Salas]

Of course 327 also. Its a consult with CRT the routing. I give guidelines he does the art, back n' forth, till I say OK and he likes too.

 

[RCruz]

CRT ?

 

[Salas]

My friend the Eagle man. Member.

 

[RCruz]

I should have know better... sorry Eagle man.

 

[klewis]

Salas,

I have run simulations comparing Reflektor and V1.2. The V1.2 is at 60v out the Reflektor is at 10v out. The first image is the Reflecktor, the second the V1.2, the third is the AC analysis V(005) is the Reflektor, V(outpos1) is V1.2. Are my results correct (relatively speaking) ?

Thanks

Ken

 

[RCruz]

What are the solid lines ?

What are the dotted lines ?

 

[Salas]

Ken:

Let me see...yes. That is how it sims with 300mA CCS, 34Vin, 24Vout, C1 0.47uF as I had it last saved on file. They look alike, don't they?

 

[RCruz]

Solid... dotted ?

 

[Salas]

What are the solid lines ?

What are the dotted lines ?

They are output impedance traces versus frequency. Dotted is their phase. You can read the one I posted before in dB, also in Ohm as such (~7mOhm flat portion):

 

[RCruz]

 

[klewis]

They are output impedance traces versus frequency. Dotted is their phase. You can read the one I posted before in dB, also in Ohm as such (~7mOhm flat portion):

Salas, I know I've probably asked this before, so, forgive my poor memory... How do you get the impedance analysis? Which simulation CDM are you using? I understand how to make the formula in the graph output...
Ken

 

[Salas]

Do your Vout slash 1A, then run again, then click to the left of analysis window on the vertical axis numbers, will give you linear option also. There you enter Ohm margins.

 

[RCruz]

A correction is in order. My previous info was based on a friend´s measurements that is using my build.

I remade the measurements in real time and to reach 28Vout I need 10 minutes but with a different behaviour:
1st minute, Vout climbs steadily from 0 to 29Vout
9 minutes, Vout decreases slowly from 29 to 28 Vout

 

[Salas]

It charging the 2000uF with 4mA then, and the transistors TC behavior. Must have no special start up issue.

 

[RCruz]

No issues

 

[RCruz]

Happy New Year Ricardo, just curious all Salas shunt regs sounds good with more current

P.S. Pics will welcome.

Happy New year for you too Merlin.

Yes... a little more current does wonders sometimes