Texas Instruments UC3544N, UC3544J, UC3544DWTR, UC3544DW, UC3543J Datasheet

Power Supply Supervisory Circuit

•

Includes Over-voltage,
Under-voltage, And Current
Sensing Circuits

•

Internal 1% Accurate
Reference

•

Programmable Time Delays

•

SCR “Crowbar” Drive Of
300mA

•

Remote Activation Capability

•

Optional Over-voltage Latch

•

Uncommitted Comparator
Inputs For Low Voltage
Sensing (UC1544 Series
Only)

The monolithic integrated circuits contain all the functions necessar y to monitor
and control the output of a sophisticated power supply sy stem. Over-voltage (O.V.)
sensing with provision to t rigger an exter nal SCR “crowbar” shutdown; an under­voltage (U.V.) circuit which can be us ed 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 include d in this IC, together with an independent, accurate reference
generator.

Both over- and under- voltage sensing circuits can be externally programmed for
minimum time dura tion of fault before trigg eri ng. All functions contain open collec­tor outputs wh ich can be used independently or wire-or’ed together, and although
the SCR trigger is directly connected only to the over-voltage sensing circuit, it
may be optionall y ac t ivated 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 UC1544/254 4/3544 devices have the ad ded versatility of completely uncom­mitted inputs to the voltage sensing com parators so that levels less than 2.5V may
be monitored by dividing down the internal reference voltage. The current sense
circuit may be us ed with exter nal co mpen sation as a linear amplifier or as a high­gain comparator. Although nominally s et 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 generat or circuit is internall y trimmed to el iminate 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.

BLOCK DIAGRAM

Note: For each terminal, firs t n um be r refers to 1543 series, se co nd to 15 44 series.

* On 1543 series, this function is internally connected to V

REF.

UC1543 UC1544
UC2543 UC2544
UC3543 UC3544

DESCRIPTIONFEATURES

4/97

ABSOLUTE MAXIMUM RATINGS

Input Supply Voltage, VIN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40V

Sense Inputs, Voltage Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to V

IN

SCR Trigger Current (Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -600mA

Indicator Output Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40V

Indicator Output Sink C u rrent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50mA

Power Dissipation (Package Limitation). . . . . . . . . . . . . . . . . . . . . . . 1000mW

Operating Temp era tu r e Ran ge

UC1543, UC1544 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55°C to +125°C

UC2543, UC2544 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -25°C to +85°C

UC3543, UC3544 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°C

Storage Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . -65°C to +150°C

Note 1: At higher input voltages, a dissipation limiti ng resistor, RG, is required.
Note 2: Currents are positive-into, negative-out of the specified terminal. Con­sult Packaging section of Databook for thermal limitations and considerations
of package.

UC1543 UC1544
UC2543 UC2544
UC3543 UC3544

CONNECTION DIAGRAMS

DIL-16, SOIC-16 (TOP VIEW)
J or N, DW Package

UC 1543
UC 2543
UC 3543

DIL-18, SOIC-18 (T OP VIEW)
J or N, DW Package

UC 1544
UC 2544
UC 3544

PACKAGE PIN FUNCTION

FUNCTION PIN

N/C 1
SCR Trigger 2
Remote Activate 3
Reset 4
O.V. Indicate 5
N/C 6
O.V. Delay 7
O.V. Input 8
N/C 9
N/C 10
U.V. Input 11
U.V. Delay 12
U.V. Indicate 13
C.L. INV. Input 14
C.L. N.I. Input 15
Offset/Comp 16
C.L. Output 17
Ground 18
V

REF

19

V

IN

20

PLCC-20, LCC-20
(TOP VIEW)
Q or L Package

PACKAGE PIN FUNCTION

FUNCTION PIN

N/C 1
SCR Trigger 2
Remote Activate 3
Reset 4
O.V. Indicate 5
N/C 6
O.V. Delay 7
O.V. N.I. Input 8
O.V. INV. Input 9
U.V. N.I. Input 10
U.V. INV. Input 11
U.V. Delay 12
U.V. Indicate 13
C.L. INV. Input 14
C.L. N.I. Input 15
Offset/Comp 16
C.L. Output 17
Ground 18
V

REF

19

V

IN

20

PLCC-20, LCC-20
(TOP VIEW)
Q or L Package

2