GND

control logic

UVLO

PG control

power

control

error

amplifier

gate

drive

HS lim

LS lim

SW

VIN

PG

comp

comp

+

_

timer t , t

ON

OFF

DCS - Control

TM

direct control &

compensation

comparator

ramp

EN

SS/TR

VOS

FB

EN

Soft

start

Thermal

Shutdown

VSEL

FB2

Copyright © 2016, Texas Instruments Incorporated

8

TPS62135, TPS621351

SLVSBH3A – JUNE 2016 – REVISED SEPTEMBER 2016

www.ti.com

Product Folder Links: TPS62135 TPS621351

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Copyright © 2016, Texas Instruments Incorporated

9 Detailed Description

9.1 Overview

The TPS62135 synchronous switched mode power converters are based on DCS-Control™ (Direct Control with

Seamless Transition into Power Save Mode), an advanced regulation topology, that combines the advantages of

hysteretic, voltage mode and current mode control. This control loop takes information about output voltage

changes and feeds it directly to a fast comparator stage. It sets the switching frequency, which is constant for

steady state operating conditions, and provides immediate response to dynamic load changes. To get accurate

DC load regulation, a voltage feedback loop is used. The internally compensated regulation network achieves

fast and stable operation with small external components and low ESR capacitors.

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

conditions and a Power Save Mode at light loads. During PWM, it operates at its nominal switching frequency in

continuous conduction mode. This frequency is typically about 2.5 MHz with a controlled frequency variation

depending on the input voltage. If the load current decreases, the converter enters Power Save Mode to sustain

high efficiency down to very light loads. In Power Save Mode the switching frequency decreases 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. An internal current limit

supports nominal output currents of up to 3.5 A. The TPS62135x family offers both excellent DC voltage and

superior load transient regulation, combined with very low output voltage ripple, minimizing interference with RF

circuits.

9.2 Functional Block Diagram

The discharge switch on the VOS pin is only available in the TPS62135.