8 Sep
2007
8 Sep
'07
10:02 p.m.
On a BA123 power supply, each regulator has three
non-power pins - LTC, POK and DCOK. Am I correct to
assume these are TTL level outputs? What is the
I'm pretty sure they're open-collector outputs. They can be pulled low by
the PSU, but are pulled high by a resistor on the bus terminator (maybe
the CPU in Q-bus systems?)
computer expecting to get from these three lines if
everything is OK?
POK = Power OK, and is pulled low by the PSU if the AC input to the
regulator fails
DCOK is pulled low if the DC output of the regulator is too low.
In normal operation, both these signals are high
LTC = Line Time Clock, and is a regular square wave. What I can't
remember is if the frequency is the same as mains (50/60Hz) or twice it
(100/120Hz).
-tony