Datasheet

1 Introduction

1.1 Background

1.2 Performance Specification Summary

User's Guide

SLUU200A – July 2004 – Revised December 2007

Using the bq241xx (bqSWITCHER™)

This user's guide describes the bq241xxEVM ( bqSWITCHER™) Evaluation Module. The Evaluation

Module provides a convenient method for evaluating the performance of a charge management solution

for portable applications using the bq241xx product family. A complete designed and tested charger is

presented. The charger is designed to deliver up to 2.0 A of continuous output current. The charger is

programmed from the factor to deliver 1.33 A of charging current. Follow the instructions in this user's

guide that pertain to the specific bq241xxEVM (one-, two- or three-cell) to be evaluated. See the

bqSWITCHER data sheet (SLUS606 ) prior to evaluation for detailed information on the bqSWITCHER

device.

The bqSWITCHER series are highly integrated Li-Ion and Li-Pol switch-mode charge management

devices targeted at a wide range of portable applications. The bqSWITCHER series offer integrated

synchronous PWM Controller and PowerFETs, high-accuracy current and voltage regulation, charge

conditioning, charge status, and charge termination, in a small thermally enhanced QFN package. The

system-controlled version provides additional input for full charge management under system control.

The bqSWITCHER charges the battery in three phases: conditioning, constant current, and constant

voltage. Charge is terminated based on user-selectable minimum current level. A programmable charge

timer provides a backup safety for charge termination. The bqSWITCHER automatically restarts the

charge if the battery voltage falls below an internal threshold. The bqSWITCHER automatically enters

sleep mode when V

supply is removed.

This section summarizes the performance specifications of the EVM. Table 1 gives the EVM performance

specifications. The TS pin has been disabled, for easier charging evaluation, by fixing its voltage to a set

value. See the EVM schematic (Figure 1 ) and data sheet (SLUS606 ) for information on how to change

R10 and R11 values to use with an external thermistor

bqSWITCHER is a trademark of Texas Instruments.

SLUU200A – July 2004 – Revised December 2007 Using the bq241xx (bqSWITCHER™) 5

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