Specifications

12
1-800-927-9474
20-15
DC MegaPAC Interface Connections (cont)
Input Power OK (J10-18)
This is an active high TTL compatible signal on pin J10-18, and provides a status indication of
the DC input power. It is capable of sinking 20 mA maximum. This signal switches to a TTL
“1” when Vin voltage is within specification. See Table 1, page 20-16 for specifications.
Input Power Fail (J10-19)
The Input Power Fail signal on pin J10-19 is the inverse of the Input Power OK signal on J10-18,
and goes to a TTL “0” when the input DC power is OK. It is capable of sinking 20 mA maximum.
Analog Temperature (J10-4)
This signal on J10-4, referenced to Signal Ground, provides an analog DC voltage output
between 0V and 10V that represents the air temperature of 0˚C to 100˚C, respectively, inside the
power supply. The inlet air temperature is monitored close to the fan.
Overtemperature Warning (J10-3)
J10-3 is a signal that asserts a TTL level “1” if the air temperature exceeds the following factory
set levels. The warning trip point is 65˚C to 76˚C typically and the recovery point is 1˚C lower
than the actual trip point.
Overtemperature Shutdown
If the inlet ambient air temperature exceeds the following factory set levels, then the outputs are
disabled. The shutdown trip point is 70˚C to 81˚C typically and the recovery point is 10˚C lower
than the actual trip point.
Gate In/Gate Out (J10-13,25)
The Gate In and Gate Out signals are used for paralleling DC MegaPACs for power expansion.
The Gate Out signal, J10-25, of the driver DC MegaPAC should be connected to the Gate In,
J10-13, of the Booster DC MegaPAC; J10 signal ground of the driver DC MegaPAC also needs
to be connected to J10 signal ground of the booster DC MegaPAC.
The driver DC MegaPAC (ModuPAC, slot #8) generates the Gate Out signal and sends it to the
booster DC MegaPAC (ModuPAC, slot #1). Vicor’s zero-current-switching Booster technology
provides for accurate, dynamic power sharing within arrays, without the need for trimming,
module “matching” or external components.
Auxiliary Vcc +5V/0.3A (J10-16,17)
The Vcc on J10-16, 17 is an auxiliary 5V regulated power source. It is +5Vdc +/–5% with
respect to Signal Ground, and can supply 300 mA maximum. It is short circuit protected, but if
shorted all outputs will shut down through the Enable/Disable circuitry.
The Auxiliary Vcc can be used with the Power Good circuitry to provide a pull-up reference for
the outputs of the DC Power Good circuit on a ConverterPAC. If used for this purpose, then the
Signal Ground on J10-1, 2, 12 or 15 must also be connected to the J3-4 Signal Ground pin of the
ConverterPAC.
1
J10
16
18
Auxiliary Vcc (+5V/0.3A)
TTL "1": DC Input Power is OK
Input Power OK
Input Power Fail
Signal Ground
TTL "0": DC Input Power is OK
19
DC MegaPAC
2.49K
2.49K
10K
Figure 21.
Input Power OK,
Input Power Fail
MegaPAC™ Family AC-DC, DC-DC Switchers