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Scalable PSU/regulator GB

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This came out of the active filter board group buy - with nearly 500 boards sold, what are we going to use to power them? I started a design here, and Jens is tweaking it.

The basic concept is a "universal" positive and negative supply capable of several hundred mA output with:

discrete rectifiers - either 1n4007 types or TO-220 high speed

CRC filter

Discrete regulator with plenty of heat sinking available.

Rather than use the ubiquitous three pin devices, the board will use discrete components to allow using this board for higher voltages as well as the 12-15 used for op amps.

A low noise precision voltage reference will be used.

We're not looking to duplicate an extreme regulator like the Didden/Jung Super Regulators. We are expecting a reasonably quiet, stable regulator suitable for audio.

Since we now have Jens' design services, what would you like to see incorporated in a multi purpose regulator board? We'd like to keep it within the free Eagle size limit of 80 x 100 mm.
 
idea 2

The space for the electrolitics is rather small.I would like to use bigger caps than the ones used (i guess 12-15mm).
You could combine the space for the rectifier diodes.You either want to use standard or TO220 devices.This way you could reserve more space for the electrolitics.
Also wider tracks for the higher current parts.

I very nice layout though.

Kees.
 
Finally a 3D model of the board.

\Jens
 

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Wow, and it's not even Friday!

Comments -

The pass devices are not at the edges of the board, but the heat sink provided should enable these boards to handle an amp or more, correct?

Any way to make a spot for LM4040 or similar instead of zeners? - maybe they could share a common pad.

We lost the TO-220 rectifiers. An extra pad at one end of the diodes would allow that without taking up more board space. I know your feelings about them, but the board might have more universal acceptance with them

The bigger main filter caps are good.

Would you explain the purpose of the extra resistor in the tail of the LTP?

Thanks
 
Bob,Thats exactly what i meant about the space for the diodes.If you provide extra pads for the TO220 devices within the space of the diodes you don't lose extra space and still can use both.
The same goes for the LM4040.One extra pad within the space for the zener will do.You just cut the third leg of the lm4040.

As for the heatsinks, for the purpose it is intended the size should be big enough provided you choose the right transformer.

Say 3 to 5 Volts drop across the output device and a current of 200 to 300 mA max. will give you 1.5 Watt dissipation.The SK104 has a coefficient of 11K/W So at room temperature it should not get hotter then 36-40 K.

Kees.

Jens, what is the diameter of the Buffer caps?
 
kro5998 said:
Here's another one.

Has anybody thought about a relais for shorting the outputs during startup/shutdown?
I've heard that these filters will make the strangest noises when shutting down.

A delayed - on and fast - off would be nice.

Kees.

Probably ought to be a separate board, since it will have signal on it. I've been thinking along those lines and that accepts a 12V trigger - I'll work up something tomorrow.
 
kro5998 said:
...what is the diameter of the Buffer caps?

The main filter caps (C4,5,23,24) are 17mm, the output caps (C10,18) are 10.5mm

Heat sinks are not needed for many applications. The WIKI will show parts kits and heat sinks separately.

I'm thinking the parts kit will include:

standard resistors (Xicon or Panasonic)
Panasonic FC electrolytics (values TBD)
polyester caps
MPSA42/92
MJE15031/32
1N4007
1N5239

Comments on parts selection?
 
I added some a few extra parts to bring to the output impedance with a factor of 10 to about 25mOhm (@DC)

PSRR looks ok and stability is not an issue....

Work to come:
Update/evaluate voltage ref to TL431.
Look at snobbers... Carlos are you listening??
Change Terminals to something smarter
Build ratsnest to test circuit and different caps (I might make room for some SMT ceramics)

Updated the schmatics to latest version.

\Jens
 

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JensRasmussen said:
Update/evaluate voltage ref to TL431.
Look at snobbers... Carlos are you listening??
Why don't have LM431+LM385 pinout. If you have that you can use almost any reference in TO92 package. LM329 will fit without any hassle. Look at my JSR-06 PSU for inspiration.

If you have room why don't you add SOT23 transistors also. There are many good SOT23 devices out there.

It might also be an idea to have an extra LP-filter for the reference but this has also to do how much the noise is from the regulator itself.

C13, C15 why? Don't you loose feedback in high frequences?

Have you noticed that you have equally many parts as in a super regulator but it is still a discrete regulator.

Snobber what is that? :bigeyes:
 
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