UVLO

EN

Gate Driver

Anti

Shoot-Through

Current

Limit Comparator

Limit

High Side

PMOS

NMOS

V

TH_UVLO

VIN

UVLO

Comp

Softstart

Control

Logic

VOUT

V

FB

Main

Comparator

Direct Control

& Compensation

Error

amplifier

Min. On

Min. OFF

VIN

VOUT

Timer

DCS

Control

Current

Limit Comparator

Limit

Low Side

Power Stage

UVLO

Slew Rate

Control

VOUT

Discharge

Load Switch

EN

UVLO

CTRL

LOAD

Internal

feedback

divider

network

(typ. 50M )

W

Ultra Low Power

Reference V

= 1.2V

REF

V

TH_100

VIN

Auto 100% Mode

Comp

100%

Mode

V

Discharge

OUT

V

FB

UVLO

EN

CTRL

VOUT

V

REF

L

ENABLE

VSEL1

VSEL2

VSEL3

VIN

GND

TPS82740A, TPS82740B

www.ti.com

SLVSCE3A – JUNE 2014 – REVISED JUNE 2014

10 Detailed Description

10.1 Overview

The TPS82740 is the first fully integrated step down converter module with an ultra low quiescent current

consumption (360nA typ.) while maintaining a regulated output voltage and featuring TI's DCS-Control™

topology. The device extends high efficiency operation to output currents down to a few micro amperes.

10.2 Functional Block Diagram

10.3 Feature Description

10.3.1 DCS-Control™

TI's DCS-Control™ (Direct Control with Seamless Transition into Power Save Mode) is an advanced regulation

topology, which combines the advantages of hysteretic and voltage mode control. Characteristics of DCS-

Control™ are excellent AC load regulation and transient response, low output ripple voltage and a seamless

transition between PFM and PWM mode operation. DCS-Control™ includes an AC loop which senses the output

voltage (VOUT pin) and directly feeds the information to a fast comparator stage. This comparator sets the

switching frequency, which is constant for steady state operating conditions, and provides immediate response to

dynamic load changes. In order to achieve accurate DC load regulation, a voltage feedback loop is used.

The DCS-Control™ topology supports PWM (Pulse Width Modulation) mode for medium and high load

conditions and Power Save Mode at light loads. During PWM mode, it operates in continuous conduction. The

switching frequency goes 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 to maintain high efficiency down

to very light loads. In Power Save Mode, the switching frequency varies nearly linearly with the load current.

Since DCS-Control™ supports both operation modes within one single building block, the transition from PWM to

Power Save Mode is seamless without effects on the output voltage. The TPS82740 offers both excellent DC

Copyright © 2014, Texas Instruments Incorporated

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