02/99
FEATURES
Integrated 0.15
Power MOSFET
7V to 15V Operation
Digital Programmable Current Limit
from 0A to 3A
Programmable ON Time
Programmable Start Delay
Fixed 2% Duty Cycle
Thermal Shutdown
Fault Output Indicator
Maximum Output Current can be set
to 1A above the Programmed Fault
Level or to a full 4A
Power SOIC and TSSOP, Low
Thermal Resistance Packaging
DESCRIPTION
The UCC39151 Programmable Hot Swap Power Manager provides com-
plete power management, hot swap capability, and circuit breaker func-
tions. The only external component required to operate the device, other
than power supply bypassing, is the fault timing capacitor, C
T
. All control
and housekeeping functions are integrated, and externally programmable.
These include the fault current level, maximum output sourcing current,
maximum fault time, and startup delay. In the event of a constant fault, the
Internal fixed 2% duty cycle ratio limits average output power.
The internal 4 bit DAC allows programming of the fault level current from
0A to 3A with 0.25A resolution. The IMAX control pin sets the maximum
sourcing current to 1A above the trip level or to a full 4A of output current
for fast output capacitor charging.
When the output current is below the fault level, the output MOSFET is
switched ON with a nominal ON resistance of 0.15
. When the output cur-
rent exceeds the fault level, but is less than the maximum sourcing level,
the output remains switched ON, but the fault timer starts, charging CT.
Once CT charges to a preset threshold, the switch is turned OFF, and re-
mains OFF for 50 times the programmed fault time. When the output cur-
rent reaches the maximum sourcing level, the MOSFET transitions from a
switch to a constant current source.
(continued)
BLOCK DIAGRAM
UCC39151
15V Programmable Hot Swap Power Manager
UDG-94136-3
Note: Pin numbers refer to DIL-16 and SOIC-16 packages.
2
UCC39151
ABSOLUTE MAXIMUM RATINGS
VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +15.5 Volts
VOUT
VIN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.3V
FAULT Sink Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50mA
FAULT Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 to 8V
Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . Self Limiting
TTL Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 to V
IN
Storage Temperature . . . . . . . . . . . . . . . . . . . 65 C to +150 C
Junction Temperature . . . . . . . . . . . . . . . . . . . 55 C to +150 C
Lead Temperature (Soldering, 10 sec.) . . . . . . . . . . . . . +300 C
Currents are positive into, negative out of the specified termi-
nal. Consult Packaging Section of Databook for thermal limita-
tions and considerations of packages.
FAULT
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
VOUT
VOUT
GND*
GND*
CT
IMAX
B0
SHTDWN
VIN
VIN
GND*
EGND*
B3
B2
B1
CONNECTION DIAGRAMS
*Pin 5 serves as lowest impedance to the electrical ground;
Pins 4, 12, and 13 serve as heat sink/ground. These pins
should be connected to large etch areas to help dissipate heat.
For N Package, pins 4, 12, and 13 are N/C.
DESCRIPTION (cont.)
The UCC39151 can be put into sleep mode, drawing
only 20mA of supply current. Other features include an
open drain Fault Output Indicator, Thermal Shutdown,
Undervoltage Lockout, 7V to 15V operation, and low
thermal resistance SOIC and TSSOP Power Packages.
B3
N/C
N/C
GND*
GND*
FAULT
VIN
EGND*
GND*
GND*
VIN
N/C
GND*
SHTDWN
GND*
B2
GND*
GND*
CT
12
11
10
9
8
7
6
5
4
3
2
1
13
14
15
16
17
18
19
20
21
22
23
24
IMAX
VOUT
VOUT
B1
B0
*Pin 9 serves as lowest impedance to the electrical ground;
other GND pins serve as heat sink/ground. These pins should
be connected to large etch areas to help dissipate heat.
DIL-16, SOIC-16 (Top View)
N, DP Package
PWP-24 (Top View)
TSSOP Package
ELECTRICAL CHARACTERISTICS
Unless otherwise stated, these specifications apply for T
A
= 0C to 70C for the
UCC39151, VIN = 12V, IMAX = 0.4V, SHTDWN = 2.4V, T
A
= T
J
.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Supply Section
Voltage Input Range
7.0
15.0
V
Supply Current
1.0
2.0
mA
Sleep Mode Current
SHTDWN = 0.2V, No load
100
150
A
Output Leakage
SHTDWN = 0.2V
20
mA
Output Section
Voltage Drop
I
OUT
= 1A (10V to 12V)
0.15
0.3
V
I
OUT
= 2A (10V to 12V)
0.3
0.6
V
I
OUT
= 3A (10V to 12V)
0.45
0.9
V
I
OUT
= 1A, VIN = 7V and 15V
0.2
0.4
V
I
OUT
= 2A, VIN = 7V and 15V
0.4
0.8
V
I
OUT
= 3A, VIN = 7V, 12V Max.
0.6
1.2
V
3
UCC39151
ELECTRICAL CHARACTERISTICS
Unless otherwise stated, these specifications apply for T
A
= 0C to 70C for the
UCC39151, VIN = 12V, IMAX = 0.4V, SHTDWN = 2.4V, T
A
= T
J
.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Output Section (continued)
Initial Startup Time
(Note 2)
100
s
Short Circuit Response
(Note 2)
100
ns
DAC Section
Trip Current
Code = 0000-0011 (Device Off)
Code = 0100
0.07
0.25
0.45
A
Code = 0101
0.32
0.50
0.7
A
Code = 0110
0.50
0.75
0.98
A
Code = 0111
0.75
1.00
1.3
A
Code = 1000
1.0
1.25
1.6
A
Code = 1001
1.25
1.50
1.85
A
Code = 1010
1.5
1.75
2.15
A
Code = 1011
1.70
2.00
2.4
A
Code = 1100
1.90
2.25
2.7
A
Code = 1101
2.1
2.50
2.95
A
Code = 1110
2.30
2.75
3.25
A
Code = 1111
2.50
3.0
3.5
A
Max Output Current Over Trip (Current Source
Mode)
Code = 0100 to 1111, I
MAX
= 0V
0.35
1.0
1.65
A
Max Output Current (Current Source Mode)
Code = 0100 to 1111, I
MAX
= 2.4V
3.0
4.0
5.2
A
Fault Output Section
CT Charge Current
V
CT
= 1.0V
83
62
47
A
CT Discharge Current
V
CT
= 1.0V
0.8
1.2
1.8
A
Output Duty Cycle
V
OUT
= 0V
1.0
1.9
3.3
%
CT Fault Threshold
1.2
1.5
1.7
V
CT Reset Threshold
0.4
0.5
0.6
V
Shutdown Section
Shutdown Threshold
1.1
1.5
1.9
V
Shutdown Hysteresis
150
mV
Input Current
100
500
nA
Open Drain Output Section
High Level Output Current
FAULT = 5V
250
A
Low Level Output Voltage
I
OUT
= 5mA
0.2
0.8
V
TTL Input DC Characteristics Section
TTL Input Voltage High
2.0
V
TTL Input Voltage Low
0.8
V
TTL Input High Current
V
IH
= 2.4V
3
10
A
TTL Input Low Current
V
IL
= 0.4V
1
A
Note 1: All voltages are with respect to Ground. Current is positive into and negative out of the specified terminal.
Note 2: Guaranteed by design. Not 100% tested in production.
4
UCC39151
PIN DESCRIPTIONS
B0, B1, B2, B3: These pins provide digital input to the
DAC, which sets the fault current threshold. They can be
used to provide a digital soft-start and adaptive current
limiting.
CT: A capacitor connected to ground sets the maximum
fault time. The maximum fault time must be more than
the time required to charge the external capacitance in
one cycle. The maximum fault time is defined as:
T
C
FAULT
T
=
16 1 10
3
.
.
Once the fault time is reached the output will shutdown
for a time given by:
T
C
SD
T
=
833 10
3
,
this equates to a 1.9% duty cycle.
FAULT: Open drain output, which pulls low upon any
fault or interrupt condition, Fault, or Thermal Shutdown.
IMAX: When this pin is set to a logic low, the maximum
sourcing current will always be 1A above the pro-
grammed fault level. When set to a logic high, the maxi-
mum sourcing current will be a constant 4A for
applications which require fast charging of load capaci-
tance.
SHTDWN: When this pin is brought to a logic low, the IC
is put into a sleep mode drawing typically less than
100
A of I
CC
(with V
OUT
unloaded). The input threshold
is hysteretic, allowing the user to program a startup delay
with an external RC circuit.
VIN: Input voltage to the UCC39151. The recommended
voltage range is 7V to 15V. Both VIN pins should be con-
nected together and connected to power source.
VOUT: Output voltage from the UCC39151. Both VOUT
pins should be connected together and connected to the
load. When switched:
(
)
V
V
I
OUT
IN
OUT
-
0 15
.
VOUT must not exceed VIN by more than 0.3V.
SHTDWN
14
15
10
1
2
16
11
VOUT
CT
+5V
VIN
FAULT
B0
GND
R
L
C
IN
LED
5
13
12
4
GND
GND
GND
C
OUT
C
SD
R
SD
V
IN
S6
6
7
8
9
V
IN
S4
S3
S2
S5
B1
B2
B3
IMAX
S1
C
T
R1
3
VIN
V
IN
HEATSINK GROUND PINS
UCC39151
DIP SWITCH
APPLICATIONS INFORMATION
Figure 1. Evaluation circuit.
UDG-98176
5
UCC39151
APPLICATION INFORMATION (cont.)
Figure 2. Load current, timing capacitor voltage, and output voltage of the UCC39151 under fault conditions.
Estimating Maximum Load Capacitance
For hot swap applications, the rate at which the total
output capacitance can be charged depends on the
maximum output current available and the nature of the
load. For a constant-current, current-limited application,
the output will come up if the load asks for less than the
maximum available short-circuit current.
To guarantee recovery of a duty-cycle from a short-
circuited load condition, there is a maximum total output
capacitance which can be charged for a given unit ON
time (Fault time). The design value of ON or Fault time
can be adjusted by changing the timing capacitor C
T
.
For worst-case constant-current load of value just less
than the trip limit; C
OUT(max)
can be estimated from:
(
)
C
I
I
C
V
OUT
MAX
LOAD
T
OUT
(max)
.
-
16 1 10
3
Where V
OUT
is the output voltage.
For a resistive load of value R
I
, the value of C
OUT(max)
can be estimated from:
C
C
R
n
V
I
R
OUT
T
L
OUT
MAX
L
(max)
.
-
16 1 10
1
1
3
Long C
T
times must consider the maximum tempera-
ture. Thermal shutdown protection may be the limiting
Fault time.
UDG-94138
UNITRODE CORPORATION
7 CONTINENTAL BLVD ( MERRIMACK, NH 03054
TEL (603) 424-2410 ( FAX (603) 424-3460
Although the UCC39151 is designed to provide system
protection for all fault conditions, all integrated circuits
can ultimately fail short. For this reason, if the
UCC39151 is intended for use in safety critical applica-
tions where UL or some other safety rating is required, a
redundant safety device such as a fuse should be placed
in series with the device. The UCC39151 will prevent the
fuse from blowing for virtually all fault conditions, in-
creasing system reliability and reducing maintenance
cost, in addition to providing the hot swap benefits of the
device.
SAFETY RECOMMENDATIONS
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Copyright
1999, Texas Instruments Incorporated
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