MIKE ROSS wrote in a message to Greg Mayman:

 MR> "Greg Mayman" bravely wrote to "William
Kitchen" (30 Oct 03 
 MR> 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.

Any of you guys have a pointer to a data sheet on 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.

 MR> Thanks all for the comments. I will sometimes tend to think some IC
 MR> is common then blindly assume someone else knows of it. Another
 MR> happy IC is the TL431 voltage reference.

Is that the three-legged critter that comes in a TO92-type package?

 MR> It is often seen in supply circuits because it has built-in gain. 
 MR> In fact in one app-note it is shown driving 400mW into a speaker 
 MR> from a phono input. To make a simple switching supply, just add a 
 MR> pass transistor, an inductor, and a scant few more parts. 

Hmm.

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