Article View: sci.electronics
Article #742Re: want help with power supply
From: Bob Myers
Date: Thu, 06 Jul 1989 18:05
Date: Thu, 06 Jul 1989 18:05
51 lines
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2785 bytes
>ac hot ac
"line"
>acc ac common
"common"
>gnd earth ground
yep - "safety" or "green wire" ground
>pf ????
This is probably a logic output - "power fail" - indicating to
the equipment being powered that the supply has detected the loss
of the AC line and will be shutting itself down VERY soon (say
about 1-10 msec from the assertion of this signal - actual time
depends on how long the caps can keep the supply going, but around
1-10 msec is typical.)
>on/off ???? This is NOT a switch, just a bind post
Probably a logic input - a "remote" on/off, permitting the supply
to be shut down/turned on via a TTL line. If the supply does not
function when this pin is left unconnected, try grounding it.
(You may wish to trace it out first, to verify that it runs to
an appropriate-looking input.)
>+s1 ??
>-s1 ???
The "s" inputs are most likely for remote sensing of the output
voltages; +/- s1 would correspond to output 1, and so forth.
Remote sensing is used in many supplies so that the voltage being
regulated is actually that across the load, and not that at the
output terminals of the supply. This eliminates potential (pardon
the pun) problems caused by voltage drops in the wires between the
supply and the load. Simply hook these terminals up across the
load, so that the voltage to be regulated appears across the
terminals in the proper polarity. Heavy wire is not required for
this, as the current drawn by the sense terminals will be very
small.
Not all of the outputs will necessarily have remote sensing
capabilities; this is typically used only on those outputs which
are expected to have a fairly heavy load. Outputs without
sensing are either regulated separately, with the voltage being
monitored at the supply terminals, or (and more typically) use
some simple linear regulation and actually track the main output
to some degree, as this is the only output which is actually
monitored by the regulation circuitry.
Hope this helps.
Bob M.
Technical Details
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hpfcdc!hpfcdj!myers From: myers@hpfcdj.HP.COM (Bob Myers) Newsgroups: sci.electronics Subject: Re: want help with power supply Message-ID: <11170022@hpfcdj.HP.COM> Date: 6 Jul 89 18:05:43 GMT References: <113785@sun.Eng.Sun.COM> Organization: Hewlett Packard -- Fort Collins, CO Lines: 51