Datasheet

0.7 V

t - TIME

1.4 V

2.4 V

2.0 V

1.0 V

WAIT

VDD

VREG

BP5

UVLO_CEx

TRKx

VOUT

PGOOD

TPS40140

SLUS660H –SEPTEMBER 2005–REVISED JUNE 2013

www.ti.com

5 APPLICATION INFORMATION

5.1 FUNCTIONAL DESCRIPTION

The TPS40140 operates with a programmable fixed switching frequency. It is a current feedback controller

with forced phase current balancing. When compared to voltage mode control, the current feedback

controller results in a simplified feedback network and reduced input line sensitivity. Phase current is

sensed by using either the DCR (direct current resistance) of the filter inductors or current sense resistors

installed in series with the output. See the section on INDUCTOR DCR CURRENT SENSE. The current

signal is then amplified and superimposed on the amplified voltage error signal to provide current mode

PWM control.

Other features include programmable input undervoltage lockout (UVLO), differential input amplifier for

precise output regulation, user programmable operation frequency, programmable pulse-by-pulse

overcurrent protection, output under-voltage shutdown and re-start, capacitor to set soft-start time and

power good indicators.

5.2 DATA SHEET ORGANIZATION

The Application Information section is partitioned to facilitate applying the TPS40140 in various modes and

configurations. The first sections describe functions that are used in all configurations. The following

sections are specific to the configuration ( i.e., single controller, multiple controllers, master and slave).

5.3 TYPICAL START UP SEQUENCE

Figure 5-1 shows a typical start up with the VDD applied to the controller and then the UVLO-CEx being

enabled. Shut down occurs when the VDD is removed.

Figure 5-1. Typical Start-Up and Shut-Down Sequence

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