"Greg Mayman" bravely wrote to "William Kitchen" (30
Oct 03  09:39:00)
 --- on the heady topic of "POWER SUPPLY"

 -=> William Kitchen said to Roy J. Tellason
 -=> about "POWER SUPPLY" on 10-26-03  19:48.....

 MR>> The TL494 is hard to kill.
 RJT> What is that chip,  anyway?  Something application-specific?

 WK> It's a PWM controller chip. It's an off-the-shelf TI part, though not
 WK> overly  common. Most larger part suppliers will have it.

 GM> IIRC it's been around for at least 15 years, maybe 20, and used
 GM> in almost every chopper power supply for all that time.

Thanks all for the comments. I will sometimes tend to think some IC is
common then blindly assume someone else knows of it. Another happy IC is
the TL431 voltage reference. It is often seen in supply circuits because
it has built-in gain. In fact in one app-note it is shown driving 400mW
into a speaker from a phono input. To make a simple switching supply,
just add a pass transistor, an inductor, and a scant few more parts.

 Mike
 ****

... A fail-safe circuit will destroy others.
--- Blue Wave/DOS v2.30