Salas SSLV1.3 UltraBiB shunt regulator

[Salas]

I don’t really understand what it is, where is it located?

He means Q1

 

[NikNet]

I bought them here:
https://www.pcbway.com/project

it turns out the board designer made a mistake

 

[Salas]

The multimeter shows my set value. When I connect the load, the LED just blinks and that’s it. What could it be?

Replaced irf530, does not help

Also see that you have set high enough current limit for the load current demand you try to power.

 

[Salas]

it turns out the board designer made a mistake

Too bad. Get some good official ones.

 

[NikNet]

Also see that you have set high enough current limit for the load current demand you try to power.

via R1?

 

[Salas]

Yes

 

[Salas]

And use bigger sinks next time. Those you got are really small for a shunt regulator even if you manage to fix the mistake.

 

[NikNet]

I mean, radiators for transistors?
I hope the board developer did everything right. (he wrote that he tested it)
I hope I made a mistake somewhere

 

[Salas]

Yes radiators for M1 M2 MOSFETs.

 

[NikNet]

I replaced Q2, M1, M2 and everything worked...
only M1 gets very hot) radiators are probably needed more

Although all the soldered transistors seem to be working

 

[NikNet]

I didn’t understand with “R1”, I just couldn’t find the resistors (
I bought 3.3 ohm resistors, will they suit my requirements?
I put a table in Excel and took the information on mA from the datasheet.

 

[Salas]

Whatever total mA load add 100mA more for headroom (mAFinal). Then calculate R1=600mV/mAFinal.

 

[NikNet]

Whatever total mA load add 100mA more for headroom (mAFinal). Then calculate R1=600mV/mAFinal.

3.3 ohm, suitable for -5V and +5V?
The minus shows 2.5 ohms. Plus, shows 3.3 ohms in the table.

Can I put 3.3 also for the minus? Instead of 2.5? How critical is a difference of 0.08 ohm?

 

[Salas]

Yes 600mV/178mAFinal is 3.37Ω for the plus. 600mV/238mAFinal is 2.52Ω for the minus.
No don't put 3.3Ω in the minus also. You will lose 60% current headroom if you will do that.

 

[Salas]

Can I put 3.3 also for the minus? Instead of 2.5? How critical is a difference of 0.08 ohm?

Its 0.8Ω actually

 

[NikNet]

Its 0.8Ω actually

Yes, I accidentally added an extra zero.

I had to buy an additional 0.75ohm
to reduce 3.3 ohms.
How important is the quality of resistors?
And what resistors require quality?

 

[Salas]

All will work but 100ppm class for R1 is good if you can. Mox or even better metal film. Power rating is not high because only 600mV on the resistor. 1W-2W for your current levels.

 

[NikNet]

For R1 (All the rest are ordinary)
VISHAY Sfernice 3W, Carbon Film Resistor, Ceramic Composition

 

[NikNet]

Salas, thank you very much! I hope all be fine

 

[juliobozek]

Nice construction!

Did you design the DAC? Could you share the design?

Thanks!!!

Thanks! This is a heavily modified DDDAC so I redesigned some stuff. I can send you the design in the conversations area.

ps: I also designed the pcb and case (if drilling the case can be called designing).