3

rise

2/3

50

10

C1

t

sec

VIN

´

´

=

final

initial

inrush

load

load

VOUT

– VOUT

dv

I

C

C

dt

Vout Slew Rate

´

´

=

=

Q1

R1

VGS

VIN

V

R1

12.5 k

= -

´

+

Ω

ESD

ESD

ESD

Logic &

Control

TPS27082L

(4)

(6)

(5)

(2, 3)

RS=12.5kΩ

C1

VOUT

VIN

R1/C1

ON/OFF

R1

GND

(1)

ESD

Q1

Q2

TPS27082L

www.ti.com

SLVSBR5 – DECEMBER 2012

APPLICATION INFORMATION

The TPS27082L IC is a high side load switch that integrates a Power PFET and its control circuit in a tiny TSOT-

23 package. TPS27082L supports up to 8V supply input and up to 3A of load current. The TPS27082L can be

used in a variety of applications. Figure 1 shows a general application of TPS27082L to control capacitive load

inrush current.

Figure 1. Typical Application Diagram

Configuring Q1 ON resistance

(1)

e.g. R1= 125k

NOTE

It is recommended to keep R1

≥ 125 kΩ. Higher value resistor R1 reduces ON-state

quiescent current, increases turn-OFF delay, while reducing ON/OFF negative going

Configuring Turn-ON slew rate

Switching a large capacitive load CL instantaneously results in a load inrush current given by the following

equation:

(2)

An uncontrolled fast rising ON/OFF logic input may result in a high slew rate (dv/dt)at the output thus leading to a

higher load inrush current. To control the inrush current connect a capacitor C1 as shown in the Figure 1. Use

the following approximate empirical equation to configure the TPS27082L slew rate to a specific value.

(3)

from 10% to 90% of VIN voltage.

Copyright © 2012, Texas Instruments Incorporated

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