Control

Logic

BAT

USB

DC_IN

VOUT

CAP

EN

GND

LOUT

Ref

- +

LDO

TPS22933

www.ti.com

SLVSB34A – OCTOBER 2011 – REVISED JUNE 2015

8 Detailed Description

8.1 Overview

The TPS22933 is a triple-input power multiplexer with auto-input selection and a low dropout linear regulator.

The device contains three P-channel MOSFETs that can operate over an input voltage range of 2.5 V to 12 V.

The TPS22933 automatically selects the highest voltage level (from BAT, USB, and DC_IN) and enables that

input to source the LDO. LOUT is an always-on output from the LDO, but VOUT can be switched on and off

using the EN pin.

8.2 Functional Block Diagram

8.3 Feature Description

8.3.1 ON and OFF Control

The EN pin controls the state of the VOUT switch and VOUT pulldown switch. EN has no control over LOUT.

Asserting EN enables the VOUT switch and disables the Quick Output Discharge (QOD) switch. Deasserting EN

disables the VOUT switch and enables the QOD switch. EN is active high and has a low threshold, making it

capable of interfacing with low voltage signals. The EN pin is compatible with standard GPIO Logic threshold and

can be used with any microcontroller with 1.2-V, 1.8-V, 2.5-V or 3.3-V GPIOs.

8.3.2 Power Changeover

The TPS22933 LDO is powered by the highest level input. When input voltages change, the TPS22933 may

change which input powers the LDO. During initial power up, the input that reaches the highest value first will

power the LDO. Once that decision is made, changing between input sources is based on VCO. When an input

source becomes VCO over the input currently supplying power to the LDO, changeover will occur and the new,

higher input will power the LDO.

Copyright © 2011–2015, Texas Instruments Incorporated

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Product Folder Links: TPS22933