UC1904N [TI]
UC1904N;
| 型号： | UC1904N |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | UC1904N |
| 文件： | 总6页 (文件大小：306K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
UC1904
UC2904
UC3904
Precision Quad Supply and Line Monitor
FEATURES
DESCRIPTION
•
Inputs for Monitoring Up to Four
Supply Voltages
The UC1904 Quad Supply Monitor will respond to under- and over-volt-
age conditions on up to four continuously monitored voltage levels. Four
independent positive voltages can be monitored or, alternatively, two of
the sense inputs are preset to monitor -5V and -12V supplies. The de-
vice also monitors Over-Current and Line Sense inputs, both with preci-
sion input thresholds.
•
Two Inputs Preset for -5V and -12V
Monitoring, or Programmable
Positive Levels
•
•
Precision 2.5V Reference
Four open collector outputs on the UC1904 give the following re-
sponses: 1. The OV/OC output is a latched over-voltage, or over-current
response. 2. A Power Good signal responds low with any fault detection
– on power-up a programmable delay is used to hold this output low for
a system Power On Reset signal. 3. The PWRW output responds only to
a Line Sense input, for early warning of power failures. 4. The last open
collector, the ON/OFF output, generates a delayed supply OFF control
signal in response to an OFF input command, under-voltage condition,
or line fault detection.
Separate Inputs for Over-Current and
Line Fault Sensing
•
•
•
•
•
Adjustable Under- to Over-Voltage
Fault Windows
Latched Over-Voltage and
Over-Current Output
Power Good and Power Warning
Outputs
The OV-UV fault window is adjustable with a programming input. The
thresholds are centered around the precision 2.5V reference, with a
scaled hysteresis for precise, glitch free operation. In the positive mode
of operation, the fault windows at each of the sense inputs can be inde-
pendently scaled using external resistors and the 2.5V reference output.
An Auto Restart function couples with the under-voltage and line sens-
ing circuits to allow controlled power supply start-up and shutdown.
Auto Restart Function with ON/OFF
Control, and Programmable Delay
Programmable Pwr On Reset Delay
This device will operate over a supply range of 4.75V to 18V. The device
is available in a DIP, SOIC, or PLCC outline. This device is ESD pro-
tected on all pins.
BLOCK DIAGRAM
Note: Pin Numbers refer to J, N, and DW Packages.
4/97
UC1904
UC2904
UC3904
ABSOLUTE MAXIMUM RATINGS (Note 1)
Input Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20V
Sense Inputs, S1 And S2, Other Analog And Logic Inputs
Maximum Forced Voltage . . . . . . . . . . . . . . . . . . -0.3V to 10V
Note 1: Unless otherwise indicated, voltages are reference to
ground and currents are positive into, negative out of, the speci-
fied terminals.
±
Maximum Forced Current . . . . . . . . . . . . . . . . . . . . . . 10mA
Sense Input S3, (-12V Sense Input)
Maximum Forced Voltage . . . . . . . . . . . . . . . . . . -18V to 10V
Maximum Forced Current . . . . . . . . . . . . . . . . . . . . . . 10mA
Sense Input S4, (-5V Sense Input)
CONNECTION DIAGRAMS
PLCC-20 (TOP VIEW)
±
PACKAGE PIN FUNCTION
Q PACKAGE
FUNCTION
2.5V
PIN
1
Maximum Forced Voltage . . . . . . . . . . . . . . . . . . -10V to 10V
±
Maximum Forced Current . . . . . . . . . . . . . . . . . . . . . . 10mA
Open Collector Outputs
POR DLY
N.C.
2
Maximum Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20V
Maximum Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50mA
Reference Output Current . . . . . . . . . . . . . . . Internally Limited
Operating Junction Temperature . . . . . . . . . . . -55°C to +150°C
Storage Temperature . . . . . . . . . . . . . . . . . . . . -65°C to +150°C
3
S1
4
S2
5
S3
6
S4
7
DIL-18, SOIC-18 (TOP VIEW)
J or N PACKAGE, DW PACKAGE
N.C.
8
LS Input
OC Input
PWRW Out
PG Out
OV/OC Out
VIN
9
10
11
12
13
14
15
16
17
18
19
20
ON/OFF Out
OFF DLY
ON/OFF Input
ARST Input
WADJ
Gnd
Unless otherwise stated, these specifications hold for TA = 0 to 70°C for the
ELECTRICAL CHARACTERISTICS:
UC3904, -40 to +85°C for the UC2904, and -55 to +125°C for the UC1904, +VIN =
15V, WADJ = 0.5V, Sense Inputs 1-4, OC and LS Inputs = 2.5V. The ON/OFF Input
and the ARST Input = 0V.
PARAMETER
Input Supply
TEST CONDITIONS
MIN
TYP
MAX UNITS
VIN Supply Current
VIN UVLO Threshold
UVLO Threshold Hysteresis
Minimum VIN to Enable PG Out
Reference
VIN = 15V
3.2
4.5
50
4.5
mA
V
Low to High
4.75
mV
V
0.8
1.5
Output Voltage(VREF)
TJ = 25°C
2.475
2.47
2.5
2.525
2.53
2.535
6
V
V
Over Temperature, UC3904
Over Temperature, UC2904 & UC1904
IOUT = 0 to 4mA
2.465
V
Load Regulation
Line Regulation
mV
mV
mA
VIN = 4.75 to 18V
5
Short Circuit Current
VREF = 0V
17
OV UV Window, LS Input, OC Input, ARST Input, and ON/OFF Input Thresholds
Over-Voltage Thresholds
S1, S2
WADJ = 0.25V, Offset from VREF, Input L to H
WADJ = 0.5V, Offset from VREF, Input L to H
WADJ = 1V, Offset from VREF, Input L to H
WADJ = 0.25V, Offset from VREF, Input L to H
WADJ = 0.5V, Offset from VREF, Input L to H
WADJ = 1V, Offset from VREF, Input L to H
110
230
460
110
230
460
125
250
500
125
250
500
140
270
540
145
280
550
mV
mV
mV
mV
mV
mV
Over-Voltage Thresholds
S3, S4 Positive Mode
2
UC1904
UC2904
UC3904
Unless otherwise stated, these specifications hold for TA = 0 to 70°C for the UC3904, -40 to
+85°C for the UC2904, and -55 to +125°C for the UC1904, +VIN = 15V, WADJ = 0.5V, Sense
Inputs 1-4, OC and LS Inputs = 2.5V. The ON/OFF Input and the ARST Input = 0V.
ELECTRICAL
CHARACTERISTICS (cont):
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNITS
OV UV Window, LS Input, OC Input, ARST Input, and ON/OFF Input Thresholds (cont.)
Under-Voltage Thresholds
S1, S2
WADJ = 0.25V, Offset from VREF, Input H to L
WADJ = 0.5V, Offset from VREF, Input H to L
WADJ = 1V, Offset from VREF, Input H to L
WADJ = 0.25V, Offset from VREF, Input H to L
WADJ = 0.5V, Offset from VREF, Input H to L
WADJ = 1V, Offset from VREF, Input H to L
-140
-270
-540
-150
-285
-555
30
-125
-250
-500
-125
-250
-500
50
-110
-230
-460
-110
-230
-460
70
mV
mV
mV
mV
mV
mV
mV/V
V
Under-Voltage Thresholds
S3, S4 Positive Mode
OV and UV Threshold Hysteresis As a Function of WADJ
S3 Negative Mode Thresholds
Over-Voltage, WADJ = 0.5V, Input H to L
-13.52 -13.2 -12.88
-11.06 -10.8 -10.54
Under-Voltage, WADJ = 0.5V, Input L to H
Hysteresis, WADJ = 0.5V
Over-Voltage, WADJ = 0.5V, Input H to L
Under-Voltage, WADJ = 0.5V, Input L to H
Hysteresis, WADJ = 0.5V
0.25V < WADJ <1.0V
V
80
-5.63
-4.61
30
120
-5.5
-4.5
50
160
-5.37
-4.39
70
mV
V
S4 Negative Mode Thresholds
V
mV
µA/V
V
WADJ Input Bias Current
LS Threshold
-5
5
Input = H to L
1.96
65
2
2.04
125
2.1
Threshold hysteresis
Input = H to L
100
2
mV
V
OC Threshold
1.9
Threshold hysteresis
Input = L to H
50
100
2.5
150
2.75
mV
V
ARST Input Threshold
ON/OFF Input Threshold
2.25
Input = H to L
0.56 0.625 0.69
V
Input high level
1.74
1.35
2.4
V
Input low level
0.6
V
Sense and Logic Input Bias Currents
Sense 1-4, Positive Mode
Input = 2.8V
250
800
nA
nA
µA
µA
nA
nA
nA
Input = 2.2V
Input = -12V
Input = -5V
Input = 2.2V
Input = 2.5V
Input = 0.5
-1000 -250
Sense 3 Negative Mode
Sense 4 Negative Mode
Line, and OC Inputs
ON/OFF Input
-700
-700
-500
-500
300
-300
-300
1000
600
150
ARST Input
-2000 -700
0.2
Open Collector Outputs (OV/OC Out, PG Out, PWRW Out, ON/OFF Out)
Saturation Voltage
Leakage current
POR Delay
IOUT = 10mA
VOUT = 20V
0.4
5
V
µA
Delay
160
120
10
250
9
350 ms/µF
Internal Pullup Current
Threshold Low to High
OFF Delay
µA
2.25
V
Delay
185
12
250 ms/µF
Internal Pullup current
Threshold Low to High
OV Fault Delay
Delay
µA
2.25
V
20
50
µs
3
UC1904
UC2904
UC3904
PIN FUNCTIONAL DESCRIPTION
2.5V: This is the output of the precision 2.5V reference.
the fault latch is reset by the ON/OFF Input, or a UVLO
condition on the device.
ARST Input: This input, with a 4:1 hysteretic threshold,
is used to sequence a power system through the Auto
ReStarT cycle. A delayed representation of a supply out-
put voltage is used at this pin to provide adequate startup
time for the power system, and a minimum power-off pe-
riod.
POR DLY: This pin is used, with an external capacitor, to
program a Power-On-Reset delay. This delay is reset
whenever there is a UV condition at one of the S1-S4 in-
puts, and then triggered upon the clearing of the UV con-
dition. When reset, the voltage across the capacitor is
quickly discharged to near zero volts, and the PG Out pin
goes active low. Once triggered the capacitor is charged
by a 9µA current source. The PG Out pin remains active
low until the delay capacitor voltage reaches a 2.1V
threshold.
Gnd: Reference point for the internal reference and all
thresholds, as well as the return for the remainder of the
device.
LS Input: The Line Sense input is used to monitor a volt-
age that varies with the input line voltage to a system.
The input is compared to a precision 2.0V level and is
used to activate the PWRW and PG outputs, as well as
triggering the Auto Restart sequence.
PG Out: During any fault, under-voltage, or UVLO condi-
tion this output is low. A Power Good indication (output
off) is given when all supply conditions are within defined
operating limits. During power-up the PG signal is de-
layed by a programmable Power On Reset delay. During
UVLO the output is active low as long as the input sup-
ply, VIN, is above approximately 1.0V.
OC Input: The Over-Current input can be used to re-
spond to an inverted over-current signal. A low level sig-
nal at this input latches in a fault indication at the OV/OC
output.
PWRW Out: When a low line condition is sensed by the
LS Input this output goes low. This output is disabled
(off) during a UVLO condition.
OFF DLY: This pin functions similarly to the POR DLY
pin to delay the turn-on of the ON/OFF output transistor.
The charging current and upper threshold are 12µA and
2.1V.
S1-S4: These are the sense inputs for OV and UV moni-
toring of external voltages. All four inputs can be used to
sense positive voltages with a simple divider to scale the
voltage level to the 2.5V centered window. The S3 and
S4 inputs can also be used to sense -12V and -5V sup-
plies respectively with no external components. This is
done with internal precision resistor dividers and two
source only op-amps that are disabled when the pins are
used in the positive mode.
ON/OFF Input: With a high level at this input the
ON/OFF Out pin is activated after a user-programmable
delay. A high level also activates the PG Out pin, and re-
sets the OV/OC fault latch.
On/Off Out: This output is an open collector output that
is activated by the ON/OFF Input, or the Auto Restart cir-
cuitry. Saturation voltage on this and all the open collec-
tor outputs is rated at 10mA of current.
VIN: Input supply for the UC1904. The device is opera-
tional with 4.75V to 18V on this pin.
OV/OC Out: In response to either an Over-Voltage or
Over-Current situation this output is latched active low.
There is nominal 20µs delay in the OV path to the fault
latch, providing rejection to transient overshooting on the
monitored voltages. The low condition is cleared when
WADJ: The WADJ input is used to program the OV and
UV window thresholds. The OV-UV window is centered
around the 2.5V reference and is nominally 20% per
volt on the WADJ input pin.
±
4
UC1904
UC2904
UC3904
Note: Pin Numbers refer to J, N, and DW Packages.
UNITRODE CORPORATION
7 CONTINENTAL BLVD. • MERRIMACK, NH 03054
TEL. (603) 424-2410 • FAX (603) 424-3460
5
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