The simplistic Salas low voltage shunt regulator

[Salas]

I would start with V1.1 Mosfet output symmetrical VCC+ VCC-, set at 100mA fed from existing bridge and 2200uF filter caps for the 5532s in the analogue output. There are many chips with 3.3V needs. I would substitute the A+3.3 and D+3.3 regulated feeds for V1.1 BJT with 10.000uF electrolytic filter cap. You should measure the current at A,D, feeds and set CCS accordingly. See in the SSLV1.1 build thread for guide, other builder's examples etc.

 

[merlin el mago]

SSLV1.1 BJT output option, 1000uF PANASONIC FC Vref cap for clock. 220uF for ADC.

I will change my Vref Pana FC 220uF 63V for 1000uF 63V😉

 

[ferynov]

Thankyou Salas, i will try to implement your advices...

 

[merlin el mago]

With V1.2R can I get +1.2V Vout or have I to change something?

Tx 9VAC 1A
R1 0R5 0.26V across = current 528mA
R12 500R trimmer
Dummy load 15R
Vout 7.54V fixed can't go high or low with trimmer

 

[merlin el mago]

With V1.2R can I get +1.2V Vout or have I to change something?

Tx 9VAC 1A
R1 0R5 0.26V across = current 528mA
R12 500R trimmer
Dummy load 15R
Vout 7.54V fixed can't go high or low with trimmer

I'm sorry answered my question in other post: "voltage too low for V1.2R", so I have to do Disco's reg

 

[AndrewT]

A follower after a LED must end up pretty close to 1.2Vdc

 

[merlin el mago]

Could you post the schematic?

 

[merlin el mago]

Disco's reg Vout 1.2V 360mA performing very very good instead Trident 1.2V in BII, the only thing that I find to being absent is the LED😉

 

[Salas]

It had a D45H8 for output originally (#1616). What did you use there and what is its Vbe voltage for your current settings if you measure voltage between base and emitter?

 

[Joshua_G]

Disco's reg Vout 1.2V 360mA performing very very good instead Trident 1.2V in BII

What is "Disco's reg"?

Edit:
Oops, sorry, I found it.

 

[Joshua_G]

What is "Disco's reg"?

Oops, sorry, I found it.

 

[Salas]

It was one rather basic variation for small voltage margins that I designed for powering DHT heaters on a request by Dutch member Disco. See the post number I mentioned. It has been shown on the #26 preamp thread too on the actual preamp along with double mono original SHV with BJT Vref. Its sometime back.

 

[Joshua_G]

Thanks, Salas, I've seen it in an earlier post in this thread.
I guess that asking if DHT filaments really need Shunt Regulator is for another thread…

 

[merlin el mago]

It had a D45H8 for output originally (#1616). What did you use there and what is its Vbe voltage for your current settings if you measure voltage between base and emitter?

Yes I use a D45H8 as output mosfet the Vbe loaded is 0.645 VDC & without load 0.652 VDC

 

[Salas]

OK.

 

[merlin el mago]

Wich range of Vbe is the optimum? there is other values to check?

 

[Salas]

I just wanted to see if it was enough to run its Jfet because we used the original for 1-1.5A heaters. Runs OK for you too.

 

[AndrewT]

Vbe of all BJT devices is dependant on device current (Ic, Ie) and on device temperature (Tj)

 

[merlin el mago]

Thank you guys.

 

[merlin el mago]

For my Disco's version of SSlvSR 1.2V Vout I matched some D45H8 (high value hfe 193), IRF9540 (high value VGS 2.97V), BC550C (high value hfe 715) & BC560C (high value hfe 619). I have lower values or have I to use these?