[sdiy] PSU ramblings

René Schmitz uzs159 at uni-bonn.de
Fri Jun 28 20:21:27 CEST 2002

Hi all,

recently I bought some nice PSUs, that I plan to use to power my modular. 

The unit has +/- 18V @300mA and separate floating +25V @500mA output. 
The +18 and +25 are done with an LM317, the -18 with a 79G.

Well I need to bring the +-18V down to +-15. So if I have to use a 
regulator anyway, I think its a good idea to provide separate regulators 
for each module.

My idea would be to use a 723 (maybe a 4195 instead) as a reference and 
derrive the individual outputs with opamps and pass transistors. Most of the
modules draw very little current maybe some 20-50mA, so BC5xx would not 
be out of the question, right? The more power hungry modules could be powered 
from +/-12.5V derrived from the 25V.

So while I'm at it I think it would also be good to regulate the ground also. 
I.e. makeing a "dustbin" for each module. Could maybe also be an opamp with an 
extra class AB output stage. 

Anybody ever done that? Would that be worth the effort for all modules, or rather 
only the oscillators?


uzs159 at uni-bonn.de


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