Texas Instruments UCC3913N, UCC3913DTR, UCC3913D, UCC2913D, UCC2913N Datasheet

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UCC1913 UCC2913 UCC3913

DESCRIPTION

The UCC1913 family of negative voltage circuit breakers provides complete power management, hot swap, and fault handling capability. The IC is referenced to the negative input voltage and is driven through an external resistor connected to ground, which is essentially a current drive as opposed to the traditional voltage drive. The on-board 10V shunt regulator protects the IC from excess voltage and serves as a reference for programming the maximum allowable output sourcing current during a fault. All control and housekeeping functions are integrated, and externally programmable. These include the fault current level, maximum output sourcing current, maximum fault time, soft start time, and average power limiting. In the event of a constant fault, the internal timer will limit the on-time from less than 0.1% to a maximum of 3%. The duty cycle modulates depending on the current into the PL pin, which is a function of the voltage across the FET, and will limit average power dissipation in the FET. The fault level is fixed at 50mV across the current sense amplifier to minimize total dropout. The fault current level is set with an external current sense resistor. The maximum allowable sourcing current is programmed with a voltage divider from VDD to generate a fixed voltage on the IMAX pin. The current level, when the output appears as a current source, is equal to V

IMAX/RSENSE

.If desired, a controlled current startup can be programmed with a capacitor on the IMAX pin.

When the output current is below the fault level, the output device is switched on. When the output current exceeds the fault level, but is less than the maximum sourcing level programmed by the IMAX pin, the output remains switched on, and the fault timer starts charging CT. Once CT charges to 2.5V, the output device is turned off and performs a retry some time later. When the output current reaches the maximum sourcing current level, the output appears as a current source, limiting the output current to the set value defined by IMAX.

Other features of the UCC1913 family include undervoltage lockout, and 8-pin small outline (SOIC) and Dual-In-Line (DIL) packages.

Negative Voltage Hot Swap Power Manager

FEATURES

• Precision Fault Threshold

• Programmable Average Power

Limiting

• Programmable Linear Current Control

• Programmable

• Overcurrent Limit

• Programmable Fault Time

• Fault Output Indication

• Shutdown Control

• Undervoltage Lockout

• 8-Pin SOIC

SLUS274 - JANUARY 1999

LINEAR CURRENT AMPLIFIER

7OUT

IMAX

50Ω

6 SENSE

5 VSS

4CT

ON-TIME

CONTROL

VDD

UVLO

5.0V REF

LOGIC

SUPPLY

9.5V SHUNT REGULATOR

20µA

1= UNDERVOLTAGE

SOURCE

ONLY

SD/FLT

0.2V

OVERCURRENT COMPARATOR

DISABLE

5.0V

OVERLOAD COMPARATOR

50mV

BLOCK DIAGRAM

UDG-99001

UCC1913 UCC2913 UCC3913

ABSOLUTE MAXIMUM RATINGS

VCC

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50mA

SHUTDOWN Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10mA

PL Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10mA

IMAX Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VCC

Storage Temperature . . . . . . . . . . . . . . . . . . . –65°C to +150°C

Junction Temperature. . . . . . . . . . . . . . . . . . . –55°C to +150°C

Lead Temperature (Soldering, 10 sec.). . . . . . . . . . . . . +300°C

All voltages are with respect to VSS (The most negative voltage). All currents are positive into, negative out of the specified terminal. Consult Packaging Section of Databook for thermal limitations and considerations of packages.

ELECTRICAL CHARACTERISTICS: Unless otherwise stated these specifications apply for T

= –55°C to +125°C for

UCC1913; –40°C to +85°C for UCC2913; 0°C to +70°C for UCC3913; I

VDD

= 2mA, CT = 4.7pF, TA= T

PARAMETER TEST CONDITIONS MIN TYP MAX UNITS

VDD Section

IDD 1.0 2.0 mA Regulator Voltage I

SOURCE

= 2mA to 10mA 8.5 9.5 10.5 V

UVLO Off Voltage 678V

Fault Timing Section

Overcurrent Threshold T

= 25°C 47.5 50 53 mV

Over Operating Temperature 46 50 53.5 mV Overcurrent Input Bias 50 500 nA CT Charge Current VCT= 1.0V, IPL= 0 –50 –36 –22 µA

Overload Condition, V

SENSE

– V

IMAX

= 300mV –1.7 –1.2 –0.7 mA CT Discharge Current VCT= 1.0V, IPL= 0 0.6 1 1.5 µA CT Fault Threshold 2.2 2.4 2.6 V CT Reset Threshold 0.32 0.5 0.62 V Output Duty Cycle Fault Condition, IPL= 0 1.7 2.7 3.7 %

Output Section

Output High Voltage I

OUT

= 0A 8.5 10 V

OUT

= –1mA 6 8 V

Outut Low Voltage I

OUT

= 0A; V

SENSE

– V

IMAX

= 100mV 0 0.01 V

OUT

= 2mA; V

SENSE

– V

IMAX

= 100mV 0.2 0.6 V

Linear Amplifier Section

Sense Control Voltage IMAX = 100mV 85 100 115 mV

IMAX = 400mV 370 400 430 mV

Input Bias 50 500 nA

Shutdown/Fault Section

Shutdown Threshold 1.4 1.7 2.0 V Input Current Shutdown = 5V 15 25 45 µA Fault Output High 6 7.5 9 V Fault Output Low 0 0.01 V Delay to Output (Note 1) 150 300 ns

SENSE

OUT

VSS

IMAX

SD/FLT

VDD

CONNECTION DIAGRAMS

DIL-8, SOIC-8 (Top View) N or J, D Package

UCC1913 UCC2913 UCC3913

ELECTRICAL CHARACTERISTICS:

Unless otherwise stated these specifications apply for TA= –55°C to +125°C for

UCC1913; –40°C to +85°C for UCC2913; 0°C to +70°C for UCC3913; I

VDD

= 2mA, CT = 4.7pF, TA= T

PARAMETER TEST CONDITIONS MIN TYP MAX UNITS

Power Limiting Section

SENSE

Regulator Voltage IPL= 64 A 4.35 4.85 5.35 V

Duty Cycle Control IPL= 64µA 0.6 1.2 1.7 %

= 1mA 0.045 0.1 0.17 %

Overload Section

Delay to Output (Note 1) 300 500 ns Output Sink Current V

SENSE

= V

IMAX

= 300mV 40 100 mA

Threshold Relative to IMAX 140 200 260 mV

Note 1: Guaranteed by design. Not 100% tested in production.

CT: A capacitor is connected to this pin in order to set the maximum fault time. The maximum fault time must be more than the time to charge external load capacitance. The maximum fault time is defined as:

()

FAULT

•2

where

IAI

CH PL

=+36µ

and I

is the current into the power limit pin. Once the fault time is reached the output will shutdown for a time given by:

TCT

=• •2 106 IMAX: This pin programs the maximum allowable sour-

cing current. Since VDD is a regulated voltage, a voltage divider can be derived from VDD to generate the program level for the IMAX pin. The current level at which the output appears as a current source is equal to the voltage on the IMAX pin over the current sense resistor. If desired, a controlled current startup can be programmed with a capacitor on the imax pin, and a programmed start delay can be achieved by driving the shutdown with an open collector/drain device into an RC network.

OUT: Output drive to the MOSFET pass element. PL: This feature ensures that the average MOSFET

power dissipation is controlled. A resistor is connected

from this pin to the drain of the NMOS pass element. When the voltage across the NMOS exceeds 5V, current will flow into the PL pin which adds to the fault timer charge current, reducing the duty cycle from the 3% level. When I

>>36µA then the average MOSFET

power dissipation is given by:

PIMAX R

FET avg PL

()

=•••

−

110

SENSE: Input voltage from the current sense resistor. When there is greater than 50mV across this pin with respect to VSS, then a fault is sensed, and CT starts to charge.

SD/FLT: This pin provides fault output indication and shutdown control. Interface into and out of this pin is usually performed through level shift transistors. When 20µA is sourced into this pin, shutdown drives high causing the output to disable the NMOS pass device. When opened, and under a non-fault condition, the SD/FLT pin will pull to a low state. When a fault is detected by the fault timer, or undervoltage lockout, this pin will drive to a high state, indicating the output FET is off.

VDD: Current driven with a resistor to a voltage at least 10V more positive than VSS. Typically a resistor is connected to ground. The 10V shunt regulator clamps VDD at 10V above the VSS pin, and is also used as an output reference to program the maximum allowable sourcing current.

VSS: Ground reference for the IC and the most negative voltage available.

PIN DESCRIPTIONS

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