TI UC2544

UC1543 UC1544
UC2543 UC2544
UC3543 UC3544
Power Supply Supervisory Circuit
FEATURES
•
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)
BLOCK DIAGRAM
DESCRIPTION
The monolithic integrated circuits contain 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 undervoltage (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
minimum time duration of fault before triggering. All functions contain open collector outputs which 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 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 UC1544/2544/3544 devices have the added versatility of completely uncommitted inputs to the voltage sensing comparators so that levels less than 2.5V may
be monitored by dividing down the internal reference voltage. The current sense
circuit may be used with external compensation as a linear amplifier or as a highgain 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.
Note: For each terminal, first number refers to 1543 series, second to 1544 series.
* On 1543 series, this function is internally connected to VREF.
4/97
UC1543 UC1544
UC2543 UC2544
UC3543 UC3544
ABSOLUTE MAXIMUM RATINGS
Input Supply Voltage, VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40V
Sense Inputs, Voltage Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to VIN
SCR Trigger Current (Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -600mA
Indicator Output Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40V
Indicator Output Sink Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50mA
Power Dissipation (Package Limitation). . . . . . . . . . . . . . . . . . . . . . . 1000mW
Operating Temperature Range
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 limiting 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.
CONNECTION DIAGRAMS
DIL-16, SOIC-16 (TOP VIEW)
J or N, DW Package
PLCC-20, LCC-20
(TOP VIEW)
Q or L Package
UC 1543
UC 2543
UC 3543
DIL-18, SOIC-18 (TOP VIEW)
J or N, DW Package
PLCC-20, LCC-20
(TOP VIEW)
Q or L Package
PACKAGE PIN FUNCTION
FUNCTION
PIN
N/C
SCR Trigger
Remote Activate
Reset
O.V. Indicate
N/C
O.V. Delay
O.V. Input
N/C
N/C
U.V. Input
U.V. Delay
U.V. Indicate
C.L. INV. Input
C.L. N.I. Input
Offset/Comp
C.L. Output
Ground
VREF
VIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
2
UC 1544
UC 2544
UC 3544
PACKAGE PIN FUNCTION
FUNCTION
PIN
N/C
SCR Trigger
Remote Activate
Reset
O.V. Indicate
N/C
O.V. Delay
O.V. N.I. Input
O.V. INV. Input
U.V. N.I. Input
U.V. INV. Input
U.V. Delay
U.V. Indicate
C.L. INV. Input
C.L. N.I. Input
Offset/Comp
C.L. Output
Ground
VREF
VIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
UC1543 UC1544
UC2543 UC2544
UC3543 UC3544
ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TA = -55°C to +125°C for the
UC1543 and UC1544; -25°C to +85°C for the UC2543 and UC2544; and 0°C to +70°C for the UC3543 and UC3544. Electrical
tests are performed with VIN = 10V and 2kΩ pull-up resistors on all indicator outputs. All electrical specifications for the UC1544,
UC2544, and UC3544 devices are tested with the inverting over-voltage input and the non-inverting under-voltage input externally
connected to the 2.5V reference. TA = TJ.
PARAMETER
Input Voltage Range
Supply Current
Reference Section
Output Voltage
Output Voltage
Line Regulation
Load Regulation
Short Circuit Current
Temperature Stability
SCR Trigger Section
Peak Output Current
Peak Output Voltage
Output Off Voltage
Remote Activate Current
Remote Activate Voltage
Reset Current
Reset Voltage
Output Current Rise Time
Prop. Delay from R/A
Prop. Delay from O/V input
Comparator Section
Input Threshold (Input
voltage rising on O.V. and
falling on U.V.)
Input Hysteresis
Input Bias Current
Delay Saturation
Delay High Level
Delay Charging Current
Indicate Saturation
Indicate Leakage
Propagation Delay
Current Limit Section
Input Voltage Range
Input Bias Current
Input Offset Voltage
CMRR
AVOL
Output Saturation
Output Leakage
Small Signal Bandwidth
Propagation Delay
UC1543/UC1544
UC2543/UC2544
MIN
TYP
MAX
4.5
40
4.7
40
7
10
15
MIN
4.5
4.7
TJ = 25°C
Over Temperature Range
VIN = 5 to 30V
IREF = 0 to 10mA
VREF = 0
2.48
2.45
2.52
2.55
5
10
-40
2.45
2.40
VIN = 5V, RG = 0, VO = 0
VIN = 15V, IO = -100mA
VIN = 40V
R/A Pin = Gnd
R/A Pin Open
Reset = Gnd, R/A = Gnd
Reset open, R/A = Gnd
RL = 50Ω, TJ = 25°C, CD = 0
RL = 50Ω, TJ = 25°C, CD = 0
RL = 50Ω, TJ = 25°C, CD = 0
-100
12
-300
13
0
-0.4
2
-0.4
2
400
300
500
-600
-100
12
TJ = 25°C
Over Temperature Range
2.45
2.40
2.50
2.55
2.60
TEST CONDITIONS
TJ = 25°C to TMAX
TMIN to TMAX
VIN = 40V, Output Open, TJ = 25°C
TMIN ≤ TJ ≤ TMAX
-10
Sense Input = 0V
VO = 0
IL = 10mA
VIND = 40V
Input Over Drive = 200mV, TJ = 25°C, CD = 0
Input Over Drive = 200mV, TJ = 25°C, CD = 1µF
-200
2.50
1
1
-20
50
25
-0.3
0.2
6
-250
0.2
.01
400
10
0
Offset Pin Open, VCM = 0
Offset Pin Open, VCM = 0
10kΩ from Offset Pin to Gnd
0 ≤ VCM ≤ 12V, VIN = 15V
Offset Pin Open, VCM = 0V,
RL = 10k to 15kΩ, ∆VOUT = 1 to 6V
IL = 10mA
VIND = 40V
AV = 0dB, TJ = 25°C
VOVERDRIVE = 100mV, TJ = 25°C
3
80
60
72
-0.3
0
100
70
80
0.2
.01
5
200
UC3543/UC3544
7
-12
0.1
-0.8
6
-0.8
6
-1.0
0.5
7
-300
0.5
1.0
VIN -3V
-1.0
10
120
0.5
1.0
TYP
2.40
2.35
-200
2.50
V
V
mA
mA
2.55
2.60
5
10
-40
V
V
mV
mV
mA
ppm/°C
-300
13
0
-0.4
2
-0.4
2
400
300
500
-600
mA
V
V
mA
V
mA
V
mA/µs
ns
ns
2.50
2.60
2.65
1
1
-20
50
25
-0.3
0.2
6
-250
0.2
.01
400
10
0
80
60
72
MAX
40
40
10
15
UNITS
-0.3
0
100
70
80
0.2
.01
5
200
0.1
-0.8
6
-0.8
6
-1.0
0.5
7
-300
0.5
1.0
V
V
mV
µA
V
V
µA
V
µA
ns
ms
VIN -3V
-1.0
10
120
V
µA
mV
mV
dB
dB
0.5
1.0
V
µA
MHz
ns
UC1543 UC1544
UC2543 UC2544
UC3543 UC3544
SCR Trigger Power Limiting
Comparator Input Hysteresis
Activation Delay vs Capacitor Value
Current Limit Input Threshold
Current Limit Amplifier Gain
Current Limit Amplifier Frequency Response
Note: RT is connected from Offset Pin to Gnd. Values of
RT below 5.0k may cause Amplifier Cutoff at -55°C.
4
UC1543 UC1544
UC2543 UC2544
UC3543 UC3544
APPLICATIONS (Pin numbers given for UC1543 series devices)
Typical Application
The values for the external components are determined
as follows:
1000
Current limit input threshold, VTH =
R1
CS is determined by the current loop dynamics
VTH VO  R 2 
+
Peak current to load, IP ≅
RSC RSC  R2 + R 3 


VTH
Short Circuit Current, ISC =
RSC
2.5 (R4 + R5 + R6)
Low output voltage limit, VO (Low) =
R5 + R6
2.5 (R4 + R5 + R6)
High output voltage limit, VO (High) =
R6
Voltage sensing delay, tD = 10,000Cd
VIN − 5
SCR trigger power limiting resistor, RG >
0.2
Sensing Multiple Supply Voltages
Input Line Monitor
Overcurrent Shutdown
UNITRODE CORPORATION
7 CONTINENTAL BLVD. • MERRIMACK, NH 03054
TEL. (603) 424-2410 • FAX 603-424-3460
5
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