Vicor 4kW MegaPAC AC-DC Switchers - Manual (Page 21)

UG:107 vicorpower.com Applications Engineering: 800 927.9474 Page 21
Interface Connections (Cont.)
Auxiliary Vcc +5V/0.3A (J10-16, 17)
The Vcc on J10-16, 17 is an auxiliary 5 V regulated power source (see Figure 8 and
Connector Pin Identification of page 18). It is +5 Vdc +/–5% with respect to Signal
Ground and can supply 300 mA maximum. It is short-circuit-proof, but if shorted all
outputs will shut down through the Enable/Disable circuitry. The Auxiliary Vcc typically
powers user circuitry or is 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, a J10 Signal Ground must also be connected to the J3-1 Signal Ground pin
of the ConverterPAC.
Power Good (J3-3)
The optional Power Good signal on J3-3 is referenced to Signal Ground on J3-1, and
indicates the status of the output voltage. This signal is asserted a TTL "1" when the
output voltage is above 95% of nominal. It is a TTL "0" when the output voltage is below
85% of nominal.
If the Trim option is also used, the Power Good trip points DO NOT track with the
trimmed voltage. It is possible to trim the output below the fixed setpoints of the Power
Good circuit and cause a negative Power Good signal.
Figure 8.
Auxiliary Vcc
Figure 9.
Power Good and Vcc
78M05
Auxiliary Vcc 16, 17
0.1 µF
Signal Ground
J10
1, 2, 12, 15
+5V/300 mA
Signal Ground
2
Vcc In
4
J3
10K
2.49K
2N2222
2.49K
1
Power Good
3
Power Good Inverted
ConverterPAC