Vicor PFC MegaPAC-HPEL Power Factor Corrected AC-DC Switchers - Manual (Page 19)

UG:119 vicorpower.com Applications Engineering: 800 927.9474 Page 19
Power Good Inverted (J2-2/P2-2)
This is the inverse of the Power Good signal and is referenced to Signal Ground
on J2-1/P2-1.
Signal Ground (J1-1/P2-1)
Signal Ground on J2-1/P2-1 is an isolated secondary ground reference for J2/P2 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 J9.
Vcc In (J2-4/P2-4)
The Vcc In on J2-4/P2-4 is an input that requires +5 V 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 J2-4/P2-4, then the J10 Signal
Ground must be connected to Signal Ground on J2-1/P2-1.
+Sense/ –Sense - J2-6 and J2-7 (See Pages 11 and 12 for information on Autosense)
The +Sense on J2-7 should be connected to the +Power Out, and the –Sense on J2-7 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 0.5 V (0.25 V per lead) can be obtained. Use
twisted pair 22-24 AWG wire for this purpose.
For DualQPACs, the +Sense pins are available on connectors designated as J2A-2 and
J2B-2 for outputs A and B, respectively. –Sense pins are on J1A-3 and J1B-3, respectively.
These pins are also duplicated on the power connectors J1A and J1B.
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. Further, NEVER disconnect the +Out and
-Out load wires while the supply is operating as disconnecting
WILL cause damage to the power supply.
Figure 10.
Sense Leads
(Remote Sense)
Load
(Local Sense)
+P +Out
P2-7 +Sense
P2-6 -Sense
-P -Out
Use 22-24 AWG
Twisted Pair Wires