5962-8869701VA [TI]
四路电源和线路监视器 | J | 18 | -55 to 125;
| 型号： | 5962-8869701VA |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | 四路电源和线路监视器 | J | 18 | -55 to 125 控制器 监视器 微控制器 微控制器和处理器 外围集成电路 uCs集成电路 uPs集成电路 |
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UC1903
UC2903
UC3903
Quad Supply and Line Monitor
FEATURES
DESCRIPTION
•
•
•
•
Inputs for Monitoring up to Four
Separate Supply Voltage Levels
The UC1903 family of quad supply and line monitor integrated circuits will re-
spond to under- and over-voltage conditions on up to four continuously moni-
tored voltage levels. An internal op-amp inverter allows at least one of these
levels to be negative. A separate line/switcher sense input is available to pro-
vide early warning of line or other power source failures.
Internal Inverter for Sensing a
Negative Supply Voltage
Line/Switch Sense Input for Early
Power Source Failure Warning
The fault window adjustment circuit on these devices provides easy program-
ming of under- and over-voltage thresholds. The thresholds, centered around
a precision 2.5V reference, have an input hysteresis that scales with the win-
dow width for precise, glitch-free operation. A reference output pin allows the
sense input fault windows to be scaled independently using simple resistive
dividers.
Programmable Under- and
Over-Voltage Fault Thresholds
with Proportional Hysteresis
•
•
A Precision 2.5V Reference
The three open collector outputs on these devices will sink in excess of 30mA
of load current when active. The under- and over-voltage outputs respond af-
ter separate, user defined, delays to respective fault conditions. The third out-
put is active during any fault condition including under- and over-voltage,
line/switcher faults, and input supply under-voltage. The off state of this out-
put indicates a "power OK" situation.
General Purpose Op-Amp for
Auxiliary Use
•
•
•
Three High Current, >30mA,
Open-Collector Outputs Indicate
Over-Voltage, Under-Voltage
and Power OK Conditions
An additional, uncommitted, general purpose op-amp is also included. This
op-amp, capable of sourcing 20mA of output current, can be used for a num-
ber of auxiliary functions including the sensing and amplification of a feed-
back error signal when the 2.5V output is used as a system reference.
Input Supply Under-Voltage
Sensing and Start-Latch
Eliminate Erroneous Fault Alerts
During Start-Up
In addition, these ICs are equipped with a start-latch to prevent erroneous un-
der-voltage indications during start-up. These parts operate over an 8V to
40V input supply range and require a typical stand-by current of only 7mA.
8-40V Supply Operation with
7mA Stand-By Current
BLOCK DIAGRAM
Note: Pin numbers refer to J, N and DW packages.
4/97
UC1903
UC2903
UC3903
ABSOLUTE MAXIMUM RATINGS (Note 1)
Supply Voltage (+VIN). . . . . . . . . . . . . . . . . . . . . . . . . . . . . +40V
Open Collector Output Voltages. . . . . . . . . . . . . . . . . . . . . +40V
Open Collector Output Currents. . . . . . . . . . . . . . . . . . . . 50mA
Sense 1-4 Input Voltages . . . . . . . . . . . . . . . . . . . -0.3V to +20V
Line/Switcher Sense Input Voltage . . . . . . . . . . . -0.3V to +40V
Op-Amp and Inverter Input Voltages . . . . . . . . . . -0.3V to +40V
Op-Amp and Inverter Output Currents . . . . . . . . . . . . . . -40mA
Window Adjust Voltage. . . . . . . . . . . . . . . . . . . . . 0.0V to +10V
Delay Pin Voltages . . . . . . . . . . . . . . . . . . . . . . . . . 0.0V to +5V
Reference Output Current . . . . . . . . . . . . . . . . . . . . . . . -40mA
Power Dissipation at TA = 25°C (Note 1) . . . . . . . . . . . 1000mW
Power Dissipation at TC = 25°C (Note 1) . . . . . . . . . . . 2000mW
Operating Junction Temperature . . . . . . . . . . . -55°C to +150°C
Storage Temperature . . . . . . . . . . . . . . . . . . . . -65°C to +150°C
Lead Temperature (Soldering, 10 Seconds) . . . . . . . . . . 300°C
Note 1: Voltages are referenced to ground (Pin 3). Currents
are positive into, negative out of, the specified terminals.
Consult Packaging Section of Databook for thermal
limitations and considerations of package.
CONNECTION DIAGRAMS
PLCC-20, LCC-20
(TOP VIEW)
Q, L Package
PACKAGE PIN FUNCTION
FUNCTION PIN
+VIN
1
2
3
4
5
6
7
VREF (2.5V)
GROUND
GROUND
WINDOW ADJUST
N/C
SENSE 4 INVERT
INPUT
DIL-18, SOIC-18 (TOP VIEW)
J or N, DW Package
SENSE 4
8
SENSE 3
9
SENSE 2
10
11
12
13
14
15
16
17
SENSE 1
OV DELAY
OV FAULT
UV FAULT
UV DELAY
POWER OK
LINE/SWITCHER
SENSE
G.P. OP-AMP OUT
G.P. OP-AMP N.I.
G.P. OP-AMP INV.
18
19
20
Unless otherwise stated, these specifications apply for TA = –55°C to +125°C for the
UC1903; –40°C to +85°C for the UC2903; and 0°C to +70°C for the UC3903; +VIN =
15V; Sense Inputs (Pins 6–9 and Pin 15) = 2.5V; VPIN 4 = 1.0V, TA = TJ.
ELECTRICAL CHARACTERISTICS:
PARAMETERS
Supply
TEST CONDITIONS
UC1903 / UC2903
UC3903
TYP
UNITS
MIN
TYP
MAX
MIN
MAX
Input Supply Current
No Faults
7
9
7
11
18
mA
mA
V
UV, OV and Line Fault
Fault Outputs Enabled
10
7.0
15
7.5
10
7.0
Supply Under Voltage
Threshold (VSUV)
6.0
5.5
8.0
Minimum Supply to Enable
Power OK Output
3.0
2.5
4.0
3.0
2.5
4.0
V
Reference
Output Voltage (VREF)
TJ = 25°C
2.485
2.465
2.515 2.470
2.530
2.535
15
V
Over Temperature
IL = 0 to 10mA
+VIN = 8 to 40V
TJ = 25°C
2.535 2.465
V
Load Regulation
Line Regulation
1
1
10
4
1
1
mV
mV
mA
8
Short Circuit Current
Fault Thresholds (Note 4)
OV Threshold Adj.
40
40
Offset from VREF as a function of VPIN 4
Input = Low to High, 0.5V ≤ VPIN 4 ≤ 2.5V
.230
.25
.270
.230
.25
.270
V/V
V/V
UV Threshold Adj.
Offset from VREF as a function of VPIN 4
-.270
-.25
-.230 -.270
-.25
-.230
Input = High to Low, 0.5V ≤ VPIN 4 ≤ 2.5V
2
UC1903
UC2903
UC3903
Unless otherwise stated, these specifications apply for TA = –55°C to +125°C for the
UC1903; –40°C to +85°C for the UC2903; and 0°C to +70°C for the UC3903; +VIN =
15V; Sense Inputs (Pins 6–9 and Pin 15) = 2.5V; VPIN 4 = 1.0V, TA = TJ.
ELECTRICAL CHARACTERISTICS:
PARAMETERS
TEST CONDITIONS
UC1903/UC2903
UC3903
TYP
UNITS
MIN
TYP
MAX
MIN
MAX
Fault Thresholds (cont.)
OV & UV Threshold Hyst.
0.5V ≤ VPIN 4 ≤ 2.5V
10
20
30
10
20
30
mV/V
%/V
OV & UV Threshold Supply +VIN = 8V to 40V
Sensitivity
.002
.01
.002
.02
Adjust Pin (Pin 4)
Input Bias Current
0.5V ≤ VPIN 4 ≤ 2.5V
±1
±10
±1
±12
µA/V
Line Sense Threshold
Line Sense Threshold Hyst.
Sense Inputs
Input = High to Low
1.94
125
2.0
2.06
225
1.9
2.0
2.1
V
175
100
175
250
mV
Sense 1-4
Input Bias Current
Input = 2.8V (Note 2)
Input = 2.2 (Note 2)
Input = 2.3V (Note 2)
1
-1
1
3
-3
3
1
-1
1
6
-6
6
µA
µA
µA
Line Sense Input
Bias Current
OV and UV Fault Delay
Charging Current
Threshold Voltage
Threshold Hysteresis
Delay
60
1.8
250
30
60
1.8
250
30
µA
V
Delay Pin = Low to High
TJ = 25°C
mV
Ratio of Threshold Voltage to Charging
Current
20
30
50
20
30
50
ms/µF
Fault Outputs (OV, UV, & Power 0K)
Maximum Current
Saturation Voltage
Leakage Current
Sense 4 Inverter (Note 3)
Input Offset Voltage
Input Bias Current
Open Loop Gain
PSRR
VOUT = 2V
70
.25
3
70
.25
3
mA
V
IOUT = 12mA
VOUT = 40 V
.40
25
.40
25
µA
2
.1
8
2
2
.1
10
4
mV
µA
65
65
80
100
1
65
65
80
100
1
dB
+VIN = 8 to 40 V
TJ = 25°C
dB
Unity Gain Frequency
Slew Rate
MHz
V/µs
mA
.4
.4
Short Circuit Current
G.P. Op-Amp (Note 3)
Input Offset Voltage
Input Bias Voltage
Input Offset Current
Open Loop Gain
CMRR
40
40
1
.1
5
2
1
.1
8
4
mV
µA
.01
120
100
100
1
.5
.01
120
100
100
1
1.0
µA
65
65
65
65
65
65
dB
VCM = 0 to +VIN = 2.0V
+VIN = 8 to 40V
dB
PSRR
dB
Unity Gain Frequency
Slew Rate
MHz
V/µs
mA
.4
.4
Short Circuit Current
TJ = 25°C
40
40
Note 2: These currents represent maximum input bias currents required as the sense inputs cross appropriate thresholds.
Note 3: When either the G.P. OP-Amp, or the Sense 4 Inverter, are configured for sensing a negative supply voltage, the divider
resistance at the inverting input should be chosen such that the nominal divider current is ≤ 1.4mA. With the divider current
at or below this level possible latching of the circuit is avoided. Proper operation for currents at or below 1.4mA is 100%
tested in production.
Note 4: Reference to pin numbers in this specification pertain to 18 pin DIL N and J packages and 18 pin SOIC DW package.
3
UC1903
UC2903
UC3903
Typical 2.5V Reference
Temperature Characteristic
Typical Fault Delay
Temperature Characteristic (CDELAY ≥ 270pF)
OPERATION AND APPLICATION INFORMATION
Figure 1. The UC1903 fault window circuitry generates OV and UV thresholds centered around the 2.5V reference.
Window magnitude and threshold hysteresis are proportional to the window adjust input voltage at Pin 4.
4
UC1903
UC2903
UC3903
OPERATION AND APPLICATION INFORMATION
Setting a Fault Window
hysteresis at the sense inputs which is always 8% of the
window magnitude. This is shown graphically in Figure 2.
The fault thresholds on the UC1903 are generated by cre-
ating positive and negative offsets, equal in magnitude,
that are referenced to the chip’s 2.5V reference. The re-
sulting fault window is centered around 2.5V and has a
magnitude equal to that of the applied offsets. Simplified
schematics of the fault window and reference circuits are
shown in Figure 1 (see previous page). The magnitude of
the offsets is determined by the voltage applied at the
window adjust pin, Pin 4. A bias cancellation circuit keeps
the input current required at Pin 4 low, allowing the use of
a simple resistive divider off the reference to set the ad-
just pin voltage.
Fault Windows Can Be Scaled Independently
In many applications, it may be desirable to monitor vari-
ous supply voltages, or voltage levels, with varying fault
windows. Using the reference output and external resis-
tive dividers this is easily accomplished with the UC1903.
Figures 3 and 4 illustrate how the fault window at any
sense input can be scaled independently of the remaining
inputs.
The adjust voltage at Pin 4 is internally applied across R4,
and an 8k resistor. The resulting current is mirrored four
times to generate current sources IOA, IOB, IOC, and IOD,
all equal in magnitude. When all four of the sense inputs
are inside the fault window, a no-fault condition, Q4 and
Q5 are turned on. In combination with D1 and D2 this pre-
vents LOB and LOD from affecting the fault thresholds. In
this case, the OV and UV thresholds are equal to VREF +
IOA(R5 + R6) and VREF - IOC(R7 + R8) respectively. The
fault window can be expressed as:
Fault window for the Sense Input,
in percent, is:
R3 + R1R2/(R1 + R2)
±10 (VADJ) •
for:
,
R3
R2
VS (NOM) •
= 2.5V
R1 + R2
VADJ
4
(1)
2.5V ±
.
Figure 3. Using the reference output and a resistive divider, a
sense input with an independently wider fault window can be
generated.
In terms of a sensed nominal voltage level, VS, the win-
dow as a percent variation is:
(2)
VS ± ( 10 VADJ) %.
When a sense input moves outside the fault window given
in equation(1), the appropriate hysteresis control signal
turns off Q4 or Q5. For the under-voltage case, Q5 is dis-
abled and current source IOB flows through D2. The net
current through R7 becomes zero as IOB cancels IOC, giv-
ing an 8% reduction in the UV threshold offset. The over-
voltage case is the same, with Q4 turning off, allowing IOD
to cancel the current flow, IOA, through R6. The result is a
Fault window for the sense input, in percent, is:
R2
±10 (VADJ) •
R1 + R2
Figure 4. The general purpose op-amp on the UC1903 can be
used to create a sense input with an independently tighter fault
window.
Figure 4 demonstrates one of many auxiliary functions
that the uncommitted op-amp on the UC1903 can be
used for. Alternatively, this op-amp can be used to buffer
high impedance points, perform logic functions, or for
sensing and amplification. For example, the G.P. op-amp,
combined with the 2.5V reference, can be used to pro-
duce and buffer an optically coupled feedback signal in
isolated supplies with primary side control. The output
stage of this op-amp is detailed in Figure 5. The NPN
emitter follower provides high source current capability.
≥20mA while the substrate device, Q3, provides good
transient sinking capability.
Figure 2. The fault window and threshold hysteresis scale as a
function of the voltage applied at Pin 4, the window adjust pin.
5
UC1903
UC2903
UC3903
OPERATION AND APPLICATION INFORMATION (continued)
SENSE input goes from above to below 2.0V. The line
sense comparator has approximately 175mV of hystere-
sis requiring the line/switcher input to reach 2.175V be-
fore the POWER OK output device can be turned off,
allowing a no-fault indication. In Figure 7 an example
showing the use of the LINE/SWITCHER SENSE input
for early switcher-fault detection is detailed. A sample sig-
nal is taken from the output of the power transformer, rec-
tified and filtered, and used at the line/switcher input. By
adjusting the R2C time constant with respect to the
switching frequency of the supply and the hold up time of
the output capacitor, switcher faults can be detected be-
fore supply outputs are significantly affected.
Figure 5. The G.P. op-amp on the UC1903 has a high source
current (≥20mA) capability and enhanced transient sinking capa-
bility through substrate device Q3.
Sensing a Negative Voltage Level
The UC1903 has a dedicated inverter coupled to the
sense 4 input. With this inverter, a negative voltage level
can be sensed as shown in Figure 6. The output of the in-
Figure 7. The line/switcher sense input can be used for an
early line or switcher fault indication.
verter is an unbiased emitter follower. By tying the invert- OV and UV Comparators Maintain Accurate
ing input, Pin 5, high the output emitter follower will be Thresholds
reverse biased, leaving the sense 4 input in a high imped- The structure of the OV and UV comparators, shown in
ance state. In this manner, the sense 4 input can be used, Figure 8 results in accurate fault thresholds even in the
as the remaining sense inputs would be, for sensing posi- case where multiple sense inputs cross a fault threshold
tive voltage levels.
simultaneously. Unused sense inputs can be tied either to
the 2.5V reference, or to another, utilized, sense input.
The four under- and over-voltage sense inputs on the
UC1903 are clamped as detailed on the Sense 1 input in
Figure 8. The series 2k resistor, R1, and zener diode Z1,
prevent extreme under- and over-voltage conditions from
inverting the outputs of the fault comparators. A parasitic
diode, D1, is present at the inputs as well. Under normal
operation it is advisable to insure that voltage levels at all
of the sense inputs stay above -0.3V. The same type of
input protection exists at the line sense input, Pin 15, ex-
cept a 5k series resistor is used.
Note: A similar scheme w/the G.P. op-amp will allow a sec-
ond negative supply to be monitored.
The fault delay circuitry on the UC1903 is also shown in
Figure 8. In the case of an over-voltage condition at one
of the sense inputs Q20 is turned off, allowing the internal
60µA current source to charge the user-selected delay
capacitor. When the capacitor voltage reaches 1.8V, the
OV and POWER OK outputs become active low. When
the fault condition goes away Q20 is turned back on, rap-
idly discharging the delay capacitor. Operation of the un-
der-voltage delay is, with appropriate substitutions, the
same.
Figure 6. Inverting the sense 4 input for monitoring a negative
supply is accommodated with the dedicated inverter.
Using The Line/Switcher Sense Output
The line switcher sense input to the UC1903 can be used
for early detection of line, switcher, or other power source,
failures. Internally referenced to 2.0V, the line sense com-
parator will cause the POWER OK output to indicate a
fault (active low) condition when the LINE/SWITCHER
6
UC1903
UC2903
UC3903
OPERATION AND APPLICATION INFORMATION (continued)
Figure 8. The OV and UV comparators on the UC1903 trigger respective fault delay circuits when one or more of the sense inputs
move outside the fault window. Input clamps insure proper operation under extreme fault conditions. Terminating the UV delay ca-
pacitor to VREF assures correct logic at power up.
Start Latch and Supply Under-Voltage Sense Allow
Predictable Power-Up
The supply under-voltage sense and start-latch circuitry
on the UC1903 prevents fault indications during start-up
or low input supply (+VIN) conditions. When the input sup-
ply voltage is below the supply under-voltage threshold
the OV and UV fault outputs are disabled and the
POWER OK output is active low. The POWER OK output
will remain active until the input supply drops below ap-
proximately 3.0V. With +VIN below this level, all of the
open collector outputs will be off.
When the input supply is low, the under-voltage sense cir-
cuitry resets the start-latch. With the start-latch reset, the
UV fault output will remain disabled until the input supply
rises to its normal operating level (8-40V), and all of the
sense inputs are above the under-voltage threshold. This
allows slow starting, or supply sequencing, without an ar-
tificial under-voltage fault indication. Once the latch is set,
the UV fault output will respond if any of the sense inputs
drop below the under-voltage threshold.
UNITRODE CORPORATION
7 CONTINENTAL BLVD. • MERRIMACK, NH 03054
TEL. (603) 424-2410 • FAX (603) 424-3460
7
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