regulated supply +- 28V -20A

[sss]

hello guys
i made a power amp using opa549 chips , bridged stereo
now the chips max voltage is -+ 30V my traffo makes more , so i need to regulate it , now i need 20amp and i dont know what device(s) to use , any help will be appriciated

 

[AndrewT]

Hi,
can you alter the transformer? Remove turns to reduce it's output.
How about adding a capacitance multplier? You can adjust the output voltage by varying the dropper resistors feeding the base of the pass transistor. Some contributors don't like this as a solution.

 

[sss]

nah ...
i'll stick to a regulated supply , i just dont know what device will give me 20A , maybe i'll make a regulator from scratch , with power transistors and an op amp

 

[Danko]

how much is the regulatoed puffered voltage on your powersupply?

 

[sss]

i need +-30V regulated @20A

 

[Danko]

and how much voltage does your trafo make?

 

[sss]

i got many m one makes -+35V and one makes -+42V after rectifier (DC)

 

[venki]

try this ckt it is easy. The emitter of the transistor forms the output. You can use the same for negative supply also. hope this helps

Venki.

 

[AndrewT]

Hi,
if you want the reg to survive a short you will need to put at least 600watts of (maybe 1000w after temp derating) of output Trs in parallel and enormous heatsinks or use fold back current limiting or a slow blow fuse <= to max output current.