LM31T question

[anthony]

i've put together a 60V unregulated power supply
and would like to add a small voltage regulator circuit to provide
24Vdc to two small cooling fans (0.070A each).

i wired it in, but my last 317T (R.I.P.), didnt like 60V input. it worked
for a little while

tech sheet says 40V max input.

best way of getting 35V-40V from my power supply to my regulator circuit
without affecting the 60V output? (don't mind if it drops a volt or two)

-anthony

[anthony]

ps. would also like to add an LED as a power indicator for the subcircuit.. where's the best place to put this in the basic 317 wiring?

thanks again
-anthony

[CNCgr]

There's LM317HV, a 60V version

[anthony]

'gr,thanks. i'll see if i can't find one.

failing that, any easy way to make the 317 work? some diodes and/or duct tape?
(its already in and soldered and hot-to-the-touch and everything

-anthony

[Al_The_Man]

You could use a power pass transistor like the applications sheets show, but if you are going to add too much you may as well get the HV version, also the T03 package offers a bit better ability to Heatsink better.
Al.

[H500]

Since the fan load is constant, why not just just use some power resistors?

[TinkerDJ]

Another option is to build a transformer or modify one to get from 60 to 24 or 30 volts. Then use a lm317 to regulate the output.