The simplistic Salas low voltage shunt regulator

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RollE2k

Member
Joined 2007
Don't need a SMD pcb anymore, i made a (really) compact design board 4mm wider than original pcb and two regulators per PCB, including psu common mode choke. Although i have removed sensing output, maybe i keep it like this or use smaller output connectors.
This will be perfect for my low current (100-120mA) demands.



Thanks alot (once again) Salas for a great design.
 
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canvas

Member
Joined 2003
spicetree.no-ip.com
The 1.2R could be very compact. Here is my result.

salas12rf.jpg



salas12rb.jpg



As you can see, the heat sinks occupy many of the space. I chose larger ones to sustain up to 600ma current draw in total (12vin/5vout). At 600ma, the heat sinks are "very" hot, but it's been running for weeks without problem. BTW, the red WIMAs are 4.7uf MKS2.
 
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canvas

Member
Joined 2003
spicetree.no-ip.com
Hi Salas,

Yes, it includes 4 HFA08TB60 and filter caps. The output cap is OSCON 47uf/16v, and it's stable under my scope. By the way, the zobel network is very important. At first, I put an OSCON 4.7uf there, but after I replaced it with 4.7uf WIMA MKS2, the sound has dramatic improvement. With limited space, it seems the WIMA MKS2 (MKS4 maybe?) is my only choice.
 
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RollE2k

Member
Joined 2007
Salas:
Since my SSLV boards above will feed high capactance load (~220uF), i'll need to put a ~1R resistor in series before the load, but i started wondering. Wouldn't this in my case be best to skip the Sense-output, and just put the shunt-load in parallel directly on the board, then maybe series ~0,5R on the output wires. Why i'm asking is because i could use to smaller output terminals (2,54mm spacing) rather than the big 5,08mm ones i like to get sensing. But i would still need to put a series resistor at the load then, right? And this makes me think it would be better put the shunt directly connected on the board...
 
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RollE2k

Member
Joined 2007
I haven't ordered the PCB's yet, which is why i ask. I'm thinking about skipping the Sense-output due to that maybe won't work with the capacitance, and also in the compact design, i get a little bit "better" layout without the extra pcb-lanes for sensing. So why i asked now is because i wonder which version of the PCB i should order, with or without sensing.
 
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RollE2k

Member
Joined 2007
The reason is actually to fit them inside my case, i have room for two boards in the case that is approx SSLV-size. Unfortunately i need four regulators, which is why i need more compact design. And they will have approx 20cm wiring to the load. Also current will be low, approx 110-120mA total, and the load will draw approx 72-73mA
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
RollE2k said:
Salas, do you think it would matter much with the 20cm wires? Since in my circuit it almost would be "good" to have resistance in between, wouldn't this just be pretty much it?
Click to expand...

20cm without sense degrades resolution. Its not only the mOhm its the inductance too. Keep them minimal in length and thick if in two wire mode. Twisted pair also for narrow loop area.
 
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marcus1

Member
Joined 2004
C301, C302... cap question

I'm building a reg with 8V output with mosphet. If my dc input will be around 15V to 18V dc, do I need the caps rated at 50-63v (as per the BiB manual quote below?)

"C102,202,302,104,204,304 4,7uF-10uF/63V MKT radial
C101,201,301 220uF/50-63V. C103,203,303 47uF/50-63V.
C105,205 4700uF/63V pitch 10mm snap-in up to 200mA. 10000uF/63V 10mm snap-in ''hot-rod''"

Will caps rated at 25V be OK in my case?

Thanks
 
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