Placid-BP Bipolar Shunt Regulated Power Supply

[Russ White]

Originally Posted by tailspn

Also, what does CFP stand for? Constant something I'm sure.

Thanks again,
Tom

I Think you have the general idea.

CFP stands for complementary feedback pair.

The shunt reg has two main components(per side). The Constant current source, and the shunt. The shunt in this case is a CFP which is driven by an opamp. The whole thing is in a feedback loop and adjustable for both current and output voltage.

A CFP is basically a way to create a high current gain similar to a Darlington Pair.

2-3W per power device could easily be handled with 2" HS.

You could even do more than that if you use a larger heat sink. Once you reach a certain point a series reg would be a more sensible choice.

Cheers!
Russ

[Russ White]

Originally Posted by eclectic2k

How do you think this would work with IVY or Ballsie? If I understand correctly how you've configured it, Placid should be a good upgrade to your LCBPS for most applications...?

I'm planning to order an Opus ASAP, along with an IVY as a balanced buffer and SE converter. A Placid would be a great touch. (even if I need to wait a bit for it)

Thanks!

Sure it would be a great choice for most of our designs. Including Ballsie Lite, Ventus, Ivy, Ivy II, Mesh, Buffalo32S.

It should provide better load regulation and line regulation than a LCBPS. It also has a very low noise voltage reference (2 green LEDSs with 1K/100uf filter) and as long as a low noise high PSRR opamp is used you will achieve excellent results.

Cheers!
Russ

[Russ White]

Hey folks here is the schematic and 100% scale PDF for those planning case space etc.

The cct is not very complicated, but very effective.

Cheers!
Russ

[Russ White]

For those who are wondering, yes Placid(non-BP) is simply just the positive half the cct.

Cheers!
Russ

[eclectic2k]

Originally Posted by Russ White

Hey folks here is the schematic and 100% scale PDF for those planning case space etc.

The cct is not very complicated, but very effective.

Cheers!
Russ

Thanks!

To confirm that my system/printer did not scale it (I unchecked those options) The board is ~ 3" x 3.5"?

I think I can fit that in. I'll leave a little extra room around the LCBPS

[eclectic2k]

Originally Posted by BrianDonegan

The Placid (kit) uses FJP5200/FJP1943 devices (80W, 230V, 15A). The only other limiting part are the caps, but they are >=50V. I think you should be fine.

Any idea yet what is the ETA for the kits? (no hurry, just curious)

Thanks!

[Javin5]

Hi Russ

Have you thought about separating the grounds of the two circuits? You would need a 4-pin phoenix connector (instead of a 3-pin) at the output. Having the circuits separated from each other would make the supply more universal, as it could also be used as dual supplies. Even if used as a bipolar supply, it may be preferable to join the grounds at the load, not at the source. May help in avoiding ground loops.

Kurt

[Russ White]

It's Bipolar, meaning they are supposed to share GND. It designed to work as such, both voltage references have to share the same 0V point.

Its a single supply with three voltages V+/0V/V- not two supplies.

Now having said all that, if you like you can use two (non-bipolar) placid in series and achieve what you want.

Cheers!
Russ

[BrianDonegan]

Originally Posted by eclectic2k

Any idea yet what is the ETA for the kits? (no hurry, just curious)

Thanks!

The bipolar kits are almost ready (another couple days). The other kits should be ready a few days later.

[Russ White]

Originally Posted by eclectic2k

Thanks!

To confirm that my system/printer did not scale it (I unchecked those options) The board is ~ 3" x 3.5"?

I think I can fit that in. I'll leave a little extra room around the LCBPS

The placid BP is 3" x 3.5"

The Placid is 2.85" x 2.35". I tried to make it as compact as practical thus the odd size.

Cheers!
Russ