Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!att!cbnewsc!levy
From: levy@cbnewsc.ATT.COM (Daniel R. Levy)
Newsgroups: comp.sys.att
Subject: Re: ups for 3b1
Summary: square wave won't hurt, it's peak value that matters
Keywords: ups 3b1 squarewave
Message-ID: <14697@cbnewsc.ATT.COM>
Date: 28 Mar 90 09:28:34 GMT
References: <3005@umbc3.UMBC.EDU>
Organization: AT&T Bell Laboratories, Skokie IL
Lines: 16

In article <3005@umbc3.UMBC.EDU>, motteler@umbc3.UMBC.EDU (Howard E. Motteler) writes:
> 
> Does anyone know how the 3b1 power supply holds up when fed the square
> wave output typical of most UPS's?  I know this causes a problem for
> some switching power supplies.

The 3B1 power supply input is a voltage doubler / brute force capacitive filter
circuit.  The switching circuit doesn't see but a few volts of ripple.
The peak to peak value of the input waveform is what matters; so long as the
p-p value of the UPS output approximates that of a 120v (RMS) AC sinewave
(i.e., about 320v p-p) it ought to work OK.
-- 
Daniel R. Levy                     >>> God: just say "yes" <<<
AT&T Bell Laboratories     UNIX(R) mail:  att!ttbcad!levy, att!cbnewsc!levy
5555 West Touhy Avenue     Any opinions expressed in the message above are
Skokie, Illinois  60077    mine, and not necessarily AT&T's.