BQ25708 datasheet(19/77 Pages) TI2

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bq25708

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SLUSCU2 – NOVEMBER 2017

Product Folder Links: bq25708

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8 Detailed Description

8.1 Overview

The bq25708 is a buck boost NVDC (narrow voltage DC) charge controller for multi-chemistry portable

applications such as notebook, detachable, ultrabook, tablet and other mobile devices with rechargeable

batteries. It provides seamless transition between converter operation modes (buck, boost, or buck boost), fast

transient response, and high light load efficiency.

The bq25708 supports wide range of power sources, including USB PD ports, legacy USB ports, traditional

ACDC adapters, etc. It takes input voltage from 3.5 V to 24 V, and charges battery of 1-4 series.

The bq25708 features Dynamic Power Management (DPM) to limit the input power and avoid AC adapter

overloading. During battery charging, as the system power increases, the charging current will reduce to maintain

total input current below adapter rating. If system power demand temporarily exceeds adapter rating, the

bq25708 supports NVDC architecture to allow battery discharge energy to supplement system power. For details,

refer to System Voltage Regulation section.

In order to be compliant with an Intel IMVP8 compliant system, the bq25708 includes PSYS function to monitor

the total platform power from adapter and battery. Besides PSYS, it provides both an independent input current

buffer (IADPT) and a battery current buffer (IBAT) with highly accurate current sense amplifiers. If the platform

power exceeds the available power from adapter and battery, a PROCHOT signal is asserted to CPU so that the

CPU optimizes its performance to the power available to the system.

The bq25708 controls input current, charge current and charge voltage registers with high resolution, high

accuracy regulation limits. It also sets the PROCHOT timing and threshold profile to meet system requirements.

BQ25708 Folha de dados(PDF) 19 Page - Texas Instruments