MCU

Radio

SOC

LCD

Display + Driver

Control Subsystem

Acceleration

Sensor

Electronic

Compass

Temperature

Sensor

ADC

GND

TPS82740

L

V

IN

2.2 V ... 5.5 V

ENABLE

DC/DC Converter

VOUT

VSEL3

SW

VIN

CTRL

VSEL1

LOAD

VSEL2

EN

GND

VSEL1

VSEL2

VSEL3

Main Supply

Switched Supply

TPS82740A, TPS82740B

SLVSCE3A – JUNE 2014 – REVISED JUNE 2014

www.ti.com

11 Application and Implementation

11.1 Application Information

The device is designed to operate from an input voltage supply range between 2.2V and 5.5V with a maximum

output current of 200mA. Once the input voltage comes close to the output voltage, the DC/DC converter stops

switching and enters 100% duty cycle operation. The integrated slew rate controlled load switch can distribute

the selected output voltage to a temporarily used sub-system. The TPS82740 module operates in PWM mode for

medium and high load conditions and in power save mode at light load currents.

At high load currents, the converter operates in quasi fixed frequency PWM mode operation. The switching

frequency is up to 1.7MHz with a controlled frequency variation depending on the input voltage. If the load

current decreases, the converter seamlessly enters Power Save Mode by varying the switching frequency

linearly to maintain high efficiency over the full load current range. At very light load conditions the device

generates a single switching pulse to ramp up the inductor current and recharge the output capacitor, followed by

a sleep period where most of the internal circuits are shutdown to achieve 360nA quiescent current consumption.

11.2 Typical Application

Example of Implementation in a SOC Based System

11.2.1 Design Requirements

TPS82740 is a complete step-down converter module including all passive components (inductor, input and

output capacitor). For most applications no additional input / output capacitors are required. Use the following

typical application design procedure to select additional external components in case further performance

improvement of the module is desired.

11.2.2 Detailed Design Procedure

11.2.2.1 Input Capacitor Selection

For most applications, the integrated input capacitor at the VIN pin is sufficient.

18

Submit Documentation Feedback

Copyright © 2014, Texas Instruments Incorporated