Vicor 4kW MegaPAC AC-DC Switchers - Manual (Page 22)

UG:107 vicorpower.com Applications Engineering: 800 927.9474 Page 22
Interface Connections (Cont.)
Power Good Inverted (J3-2)
This is the inverse of the Power Good signal and is referenced to Signal Ground on J3-1.
Signal Ground (J3-1)
Signal Ground on J3-1 is an isolated secondary ground reference for J3 status signals. It
is used to provide a reference point for the Power Good circuitry and is not the same as
Earth Ground on input power connector J1.
Vcc In (J3-4)
The Vcc In on J3-4 is an input that requires +5V either from the J10 Auxiliary Vcc, or
from another source. Input current to this pin is limited by an internal resistor to 3
mA. If the J10 Auxiliary Vcc is connected to Vcc In on J3-4, then at least one J10 Signal
Ground must be connected to Signal Ground on J3-1.
+Sense/ –Sense (J2-2 and J2-3)
The +Sense on J2-2 should be connected to the +Power Out, and the –Sense on J2-3 to
the –Power Out terminal. Do not reverse or leave the Sense pins open. Sense pins can
be terminated locally at the output of the power supply, in which case the power supply
will provide regulation at the output terminals. The voltage appearing at the load may
drop slightly due to voltage drop in the power cables. If it is necessary to compensate
for voltage drop along the output power cables, this termination should be made close
to the output load. Compensation of up to 0.5V (0.25 V per lead) can be obtained. Use
twisted pair 22-24 AWG wire for this purpose.
Reminder: Only units with Autosense will automatically operate in Local Sense
mode if no sense connections are made. It will operate in remote sense mode if
remote sense connections are made. Units without Autosense MUST have sense
connections (Local or Remote) terminated to their respective output for the unit to
operate properly.
Figure 10.
Sense Leads
(Remote Sense)
Load
(Local Sense)
+P +Out
J2-2 +Sense
J2-3 -Sense
-P -Out
Use 22-24 AWG
Twisted Pair Wires