Zero-Pole

AMP.

Integrator

Error Amp.

PFM Comparator

PWM

Comp.

VREF

Control

Stage

Gate Driver

Anti

Shoot-Through

Current

Limit Comparator

Current

Limit Comparator

VREF

FB

SW

EN

AVIN

Softstart

VOUT RAMP

CONTROL

Thermal

Shutdown

Reference

0.6V VREF

Undervoltage

Lockout 1.8V

Limit

High Side

Limit

Low Side

Sawtooth

Generator

FB

AGND

PVIN

PGND

3MHz

Clock

R

Discharge

MODE

TLV62065

www.ti.com

SLVSAC4B – NOVEMBER 2010 – REVISED DECEMBER 2015

7 Detailed Description

7.1 Overview

The TLV62065 step-down converter operates with typically 3-MHz fixed frequency pulse width modulation

(PWM) at moderate to heavy load currents. At light load currents the converter can automatically enter power-

save mode and operates then in pulse frequency modulation (PFM) mode.

During PWM operation, the converter use a unique fast response voltage mode controller scheme with input

voltage feed-forward to achieve good line and load regulation allowing the use of small ceramic input and output

capacitors. At the beginning of each clock cycle initiated by the clock signal, the high-side MOSFET switch is

turned on. The current flows now from the input capacitor through the high-side MOSFET switch through the

inductor to the output capacitor and load. During this phase, the current ramps up until the PWM comparator trips

and the control logic will turn off the switch. The current limit comparator will also turn off the switch in case the

current limit of the high-side MOSFET switch is exceeded. After a dead time preventing shoot through current,

the low-side MOSFET rectifier is turned on and the inductor current ramps down. The current flows now from the

inductor to the output capacitor and to the load. It returns back to the inductor through the low-side MOSFET

rectifier.

The next cycle will be initiated by the clock signal again turning off the low-side MOSFET rectifier and turning on

the high-side MOSFET switch.

7.2 Functional Block Diagram

Copyright © 2010–2015, Texas Instruments Incorporated

Submit Documentation Feedback

7

Product Folder Links: TLV62065