TI UCC39151

UCC39151
15V Programmable Hot Swap Power Manager
FEATURES
DESCRIPTION
• Integrated 0.15Ω Power MOSFET
The UCC39151 Programmable Hot Swap Power Manager provides complete power management, hot swap capability, and circuit breaker functions. The only external component required to operate the device, other
than power supply bypassing, is the fault timing capacitor, CT. 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.
• 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
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 0.15Ω. When the output current 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 remains OFF for 50 times the programmed fault time. When the output current reaches the maximum sourcing level, the MOSFET transitions from a
switch to a constant current source.
BLOCK DIAGRAM
Note: Pin numbers refer to DIL-16 and SOIC-16 packages.
02/99
(continued)
UDG-94136-3
UCC39151
ABSOLUTE MAXIMUM RATINGS
DESCRIPTION (cont.)
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 VIN
Storage Temperature . . . . . . . . . . . . . . . . . . . 65 C to +150 C
Junction Temperature . . . . . . . . . . . . . . . . . . . 55 C to +150 C
Lead Temperature (Soldering, 10 sec.) . . . . . . . . . . . . . +300 C
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.
Currents are positive into, negative out of the specified terminal. Consult Packaging Section of Databook for thermal limitations and considerations of packages.
CONNECTION DIAGRAMS
DIL-16, SOIC-16 (Top View)
N, DP Package
SHTDWN
1
PWP-24 (Top View)
TSSOP Package
16
FAULT
VIN
2
15
VOUT
VIN
3
14
VOUT
GND*
4
13
GND*
EGND*
5
12
GND*
B3
6
11
CT
B2
7
10
IMAX
B1
8
9
SHTDWN
1
24
FAULT
VIN
2
23
VOUT
B0
*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.
VIN
3
22
VOUT
N/C
4
21
N/C
GND*
5
20
GND*
GND*
6
19
GND*
GND*
7
18
GND*
GND*
8
17
GND*
EGND*
9
16
N/C
B3
10
15
CT
B2
11
14
IMAX
B1
12
13
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.
ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for TA = 0°C to 70°C for the
UCC39151, VIN = 12V, IMAX = 0.4V, SHTDWN = 2.4V, TA = TJ.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNITS
Supply Section
Voltage Input Range
7.0
Supply Current
Sleep Mode Current
SHTDWN = 0.2V, No load
Output Leakage
SHTDWN = 0.2V
15.0
V
1.0
2.0
mA
100
150
µA
20
mA
Output Section
Voltage Drop
IOUT = 1A (10V to 12V)
0.15
0.3
V
IOUT = 2A (10V to 12V)
0.3
0.6
V
IOUT = 3A (10V to 12V)
0.45
0.9
V
IOUT = 1A, VIN = 7V and 15V
0.2
0.4
V
IOUT = 2A, VIN = 7V and 15V
0.4
0.8
V
IOUT = 3A, VIN = 7V, 12V Max.
0.6
1.2
V
2
UCC39151
ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for TA = 0°C to 70°C for the
UCC39151, VIN = 12V, IMAX = 0.4V, SHTDWN = 2.4V, TA = TJ.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNITS
Output Section (continued)
Initial Startup Time
(Note 2)
100
µs
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
Code = 0110
0.50
0.50
0.7
A
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, IMAX = 0V
0.35
1.0
1.65
A
Max Output Current (Current Source Mode)
Code = 0100 to 1111, IMAX = 2.4V
3.0
4.0
5.2
A
Fault Output Section
CT Charge Current
VCT = 1.0V
83
–62
47
µA
CT Discharge Current
VCT = 1.0V
0.8
1.2
1.8
µA
Output Duty Cycle
VOUT = 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
1.1
1.5
1.9
V
Shutdown Section
Shutdown Threshold
Shutdown Hysteresis
150
Input Current
100
mV
500
nA
250
µA
0.8
V
0.8
V
Open Drain Output Section
High Level Output Current
FAULT = 5V
Low Level Output Voltage
IOUT = 5mA
0.2
TTL Input DC Characteristics Section
TTL Input Voltage High
2.0
V
TTL Input Voltage Low
TTL Input High Current
VIH = 2.4V
TTL Input Low Current
VIL = 0.4V
3
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.
3
10
µA
1
µA
UCC39151
PIN DESCRIPTIONS
IMAX: When this pin is set to a logic low, the maximum
sourcing current will always be 1A above the programmed fault level. When set to a logic high, the maximum sourcing current will be a constant 4A for
applications which require fast charging of load capacitance.
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:
SHTDWN: When this pin is brought to a logic low, the IC
is put into a sleep mode drawing typically less than
100µA of ICC (with VOUT unloaded). The input threshold
is hysteretic, allowing the user to program a startup delay
with an external RC circuit.
TFAULT = 16 .1 • 10 3 • CT .
Once the fault time is reached the output will shutdown
for a time given by:
VIN: Input voltage to the UCC39151. The recommended
voltage range is 7V to 15V. Both VIN pins should be connected together and connected to power source.
TSD = 833 • 10 3 • CT ,
this equates to a 1.9% duty cycle.
VOUT: Output voltage from the UCC39151. Both VOUT
pins should be connected together and connected to the
load. When switched:
FAULT: Open drain output, which pulls low upon any
fault or interrupt condition, Fault, or Thermal Shutdown.
VOUT ≈ VIN − (0 .15 Ω • IOUT
)
VOUT must not exceed VIN by more than 0.3V.
APPLICATIONS INFORMATION
HEATSINK GROUND PINS
VIN
+5V
2
VIN
3
VIN
4
12
13
5
GND
GND
GND
GND
VOUT
14
CIN
RL
15
R1
COUT
UCC39151
RSD
LED
16
FAULT
SHTDWN
VIN
1
S6
CSD
11
CT
CT
B0
B1
B2
B3
IMAX
9
8
7
6
10
VIN
S1
S2
S3
S4
S5
DIP SWITCH
UDG-98176
Figure 1. Evaluation circuit.
4
UCC39151
APPLICATION INFORMATION (cont.)
UDG-94138
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.
Where VOUT is the output voltage.
For a resistive load of value RI, the value of COUT(max)
can be estimated from:
To guarantee recovery of a duty-cycle from a shortcircuited 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 CT.
COUT (max)
For worst-case constant-current load of value just less
than the trip limit; COUT(max) can be estimated from:
COUT (max) ≈ (IMAX




16 .1 • 10 3 • CT

≈



1
 RL • n 
VOUT

1 −
I


MAX • R L










Long CT times must consider the maximum temperature. Thermal shutdown protection may be the limiting
Fault time.
16 .1 • 10 3 • CT 

− ILOAD ) • 
VOUT


Figure 2. Load current, timing capacitor voltage, and output voltage of the UCC39151 under fault conditions.
SAFETY RECOMMENDATIONS
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 applications 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, increasing system reliability and reducing maintenance
cost, in addition to providing the hot swap benefits of the
device.
UNITRODE CORPORATION
7 CONTINENTAL BLVD ( MERRIMACK, NH 03054
TEL (603) 424-2410 ( FAX (603) 424-3460
5
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