control logic

Soft

start

Thermal

Shtdwn

UVLO

PG control

power

control

error

amplifier

gate

drive

HS lim

LS lim

VIN

PG

PGND

AGND

comp

comp

+

_

DCS - Control

TM

direct control

&

compensation

comparator

ramp

SW

EN

*

VOS

FB

Copyright © 2016, Texas Instruments Incorporated

7

TPS62170-Q1, TPS62171-Q1, TPS62172-Q1

www.ti.com

SLVSCK7A – DECEMBER 2014 – REVISED SEPTEMBER 2016

Product Folder Links: TPS62170-Q1 TPS62171-Q1 TPS62172-Q1

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Copyright © 2014–2016, Texas Instruments Incorporated

7 Detailed Description

7.1 Overview

The TPS6217x-Q1 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 including an AC loop directly associated to the output

voltage. 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.

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 2.25 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

from PWM to Power Save Mode is seamless without effects on the output voltage.

7.2 Functional Block Diagram

* This pin is connected to a pull down resistor internally (see Feature Description section).