The simplistic Salas low voltage shunt regulator

[Salas]

Using a BJT output it takes 27R not 270R base stopper as in the Mosfet option gate stopper. That could choke base current if missed in the instructions. Just a guess.

 

[Salas]

I am using IRF9610 and MJE15030.

Ooops, that's an NPN for sure, or a typo? Positive rail uses 15031 PNP.

 

[studiostevus]

Ooops, that's an NPN for sure, or a typo? Positive rail uses 15031 PNP.

That's a typo yes

 

[studiostevus]

Using a BJT output it takes 27R not 270R base stopper as in the Mosfet option gate stopper. That could choke base current if missed in the instructions. Just a guess.

I missed that! I am using 270R!

 

[agussug]

I missed that! I am using 270R!

So, problem solved?

Regards 🙂

 

[studiostevus]

Haven't had chance to try yet... 47R is the closest I have have in my box...

 

[studiostevus]

No luck... I replaced the 270R with 2*47R in parallel.... still the same error.

 

[Salas]

A photo of the layout and parts side could help us spot something.

 

[studiostevus]

this is the layout... i doubt photo's will help (smd).

note that some of the cap positions are not used (as you advised last week).


Also note that I am using only 2SK170's (no 2SK117's) and BC547

 

[studiostevus]

maybe this is easier

 

[Salas]

Saved it, will look into it a bit later. Thanks.

 

[studiostevus]

Note that one leg of the bc547 is connected to the gnd plane for s0

 

[Salas]

What you use for output? MKT+1R or Muse + jumper in place of 1R? I see both.

 

[Salas]

What is that 100R in series with an output node?

 

[studiostevus]

What you use for output? MKT+1R or Muse + jumper in place of 1R? I see both.

Output = MKT (wima 3.3uf) + 1R
BIB C101 = Muse 220uF

 

[studiostevus]

What is that 100R in series with an output node?

eeehm

 

[Salas]

Maybe that one drops your Vo when you load up the reg?

 

[Salas]

Output = MKT (wima 3.3uf) + 1R
BIB C101 = Muse 220uF

So the upper Muse on your board the one near the MKT is a missing option in the actual build? Then it would be OK.

 

[studiostevus]

yes that's correct (for a tda1541a)

And, if you don't mind, I will sit in a corner being ashamed of myself now for a bit....

The 100R was a remnant from an earlier regulator I replaced with the your reg... without it, everything seems a-ok...

 

[studiostevus]

By the way, what is the impact of using a higher base/gate stopper on a BJT (270R) ?