SG1543_1 Datasheet, PDF (1/6 Pages) Microsemi Corporation – POWER SUPPLY OUTPUT SUPERVISORY CIRCUIT

SG1543/SG2543/SG3543
POWER SUPPLY OUTPUT SUPERVISORY CIRCUIT
DESCRIPTION
This monolithic integrated circuit contains all the functions necessary to monitor and
control the output of a sophisticated power supply system. Over-voltage (O.V.) sensing
with provision to trigger an external SCR “crowbar” shutdown; an under-voltage (U.V.)
circuit which can be used to monitor either the output or to sample the input line voltage;
and a third op amp/comparator usable for current sensing (C.L.) are all included in this
IC, together with an independent, accurate reference generator.
Both over and under-voltage sensing circuits can be externally programmed for mini-
mum time duration of fault before triggering. All functions contain open collector outputs
which can be used independently or wire-ORed together; and although the SCR trigger
is directly connected only to the over-voltage sensing circuit, it may be optionally
activated by any of the other outputs, or from an external signal. The O.V. circuit also
includes an optional latch and external reset capability.
The current sense circuit may be used with external compensation as a linear amplifier
or as a high gain comparator. Although nominally set for zero input offset, a fixed
threshold may be added with an external resistor. Instead of current limiting, this circuit
may also be used as an additional voltage monitor.
The reference generator circuit is internally trimmed to eliminate the need for external
potentiometers and the entire circuit may be powered directly from either the output being
monitored or from a separate bias voltage.
FEATURES
• Over-voltage, under-voltage, and
current sensing circuits all
included
• Reference voltage trimmed to 1%
accuracy
• SCR "Crowbar" drive of 300mA
• Programmable time delays
• Open-collector outputs and
remote activation capability
• Total standby current less than
10mA
HIGH RELIABILITY FEATURES
- SG1543
♦ Available to MIL-STD-883 and
DESC SMD
♦ LMI level "S" processing avail-
able
BLOCK DIAGRAM
Rev 1.1a 3.19.2005
Copyright © 1994
Microsemi Inc.
1
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