Vicor PFC MegaPAC-HPEL Power Factor Corrected AC-DC Switchers - Manual (Page 18)

UG:119 vicorpower.com Applications Engineering: 800 927.9474 Page 18
Figure 7.
AC OK Power Fail
Auxiliary Vcc +5V/0.3A (J10-9)
The Vcc on J10-9 is an auxiliary 5 V regulated power source (see Figure 8 and Connector
Pin Identification on Page 16). 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, the
Signal Ground on J10-10 must also be connected to the J3-1 Signal Ground pin of the
ConverterPAC.
Power Good (J2-3/P2-3)
The optional Power Good signal on J2-3/P2-3 is referenced to Signal Ground on
J2-1/P2-1, 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.
10K
Signal Ground
AC Power OK 11
+5V
10
J10
2.49K
PN2222
Figure 8.
Auxiliary Vcc
78M05
Auxiliary Vcc 9
0.1 µF
Signal Ground
J10
10
+5V/300 mA
Figure 9.
Power Good and Vcc
Signal Ground
2
Vcc In
4
J2/P2
10K
2.49K
2N2222
2.49K
1
Power Good
3
Power Good Inverted