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on, it causes J3-6 ( Preset-On-Power ) to be low thus, if used, can initialize or delay a customer's system operation.
AC Dropout Buffer Circuit
This circuit couples, inverts and isolates the DROPOUT signal (received from the A2 Control Board) of status output
terminal J3-19 (DROPOUT ). The dropout signal indicates loss of primary power, momentary AC dropout, or "brownout"
conditions where the AC line voltage drops below approximately 70% normal. The following paragraph provides a brief
description of the AC Dropout Buffer circuit. Refer to the Schematic Diagram
The AC Dropout Buffer Circuit receives a DROPOUT signal from the A2 Control Board. This causes the bias voltage
supplied to the Dropout Buffer U14A to be pulled down through diode CR4 thus, turning U14A off. This in turn will cause
opto-isolator U3 to turn off. Since external pull up resistors are used, terminal J3-19 (DROPOUT) will go high and remain
high until the dropout signal from the A2 Control Board is removed.
Multiple Supply System Shutdown
When using more than one 002 Option equipped power supply in a system, it may be desirable to implement a system
shutdown. In this configuration, an OVP trip or remote shutdown of a single unit will cause all of the supplies to shut down
Figure A-9. System Shutdown using Controller Power Supply
Figure A-9 shows one method of system shutdown. The advantages of this method are that one common is used for all
status and control lines (useful for controller-operated systems), and the capability of system reset. As shown in Figure A-9,
one supply's EOVERVOLTAG line is connected to the next supply's TRIPREMOTE line, and so on in a continuous
chain.
Note +5V REG/POWER SUPPLY common from Supply 1 can be used instead of the bias voltage from the
controller. However, because of current limits of the + 5V REG, no more than four units can be
connected together in this configuration. To prevent ground loops, do not parallel connect + 5V REG
from more than one supply.
The note on page 91 tells how to determine if a shutdown was initiated through the remote trip line or by a supply's OVP. This
allows the controller to determine which supply initiated the shutdown. Following a multiple supply shutdown, each unit can
be reset individually or all the REMOTE RESET lines can be tied together for a system reset.