Texas Instruments BQ25887, User Manual

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Introduction
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2 SLUUC12 – February 2019
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Copyright © 2019, Texas Instruments Incorporated
BQ25887 QFN boost-mode battery charger with cell balancing evaluation
module
Advance Information
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Microsoft, Windows are registered trademarks of Microsoft Corporation.
All other trademarks are the property of their respective owners.
1 Introduction
As industry improvements continue to make portable electronics more powerful, their power requirements
increase. Using two series Li-Ion polymer cells is one way to achieve this power increase. Charging these
8.4-V battery packs from a legacy 5-V USB port requires a boost charger. The BQ25887 is a highly-
integrated 2-A boosting, 1.5-MHz switch-mode battery charge management device for a 2s Li-Ion and Li-
polymer battery. BQ25887 integrates cell balancing solution which is essential in applications with two
series connected individual discrete battery cells.
1.1 EVM Features
The BQ25887 QFN evaluation module (EVM) is a complete charger module for evaluating the I
2
C-
controlled, 2s battery NVDC charger in the QFN package. Key features of this EVM include:
• Easily evaluate the high-efficiency 2-A, 1.5-MHz integrated field-effect-transistor (FET), switch-mode
boost charger in the QFN package
• Use of an onboard USB input adapter for connecting to a USB source and either using the PSEL pin
header to set the default input current limit
• Use the EV2400 interface to program parameters for charge operation as well as monitor voltages and
current with an integrated analog-to-digital converter (ADC)
• Cell balancing feature with resistor programmable current setting
• Onboard test points, sense resistors, and jumpers facilitate measurement of high-efficiency- and high-
accuracy voltage and current regulation
See the device data sheet ( Table 1 ) for detailed features and operation of the integrated circuit (IC).
Table 1. Device Data Sheets
Device Data Sheet EVM Label Variant
BQ25887 SLUSDE7 BQ25887EVM-001 001
This EVM does not include the EV2400 interface board. To evaluate the EVM, order an EV2400 interface
board separately.
1.2 I/O Descriptions
Table 2 lists the jumper connections available on this EVM.
Table 2. EVM Connections
Jack Description
J1(2)–VBUS Connection for positive terminal of charger power source
J1(1)–GND Connection for negative terminal (ground terminal) of charger power source
J3(1)–PMID PMID pin connection
J3(2)–GND Ground
J4(1)–BAT+ Connection for battery pack positive node to BAT pin
J4(2)-TOP-
/BOT+
Connection for the mid connection point of the top and bottom cell (BQ25887only. Do
not use for BQ25883 or BQ25886)
J5(1)–GND Connection to battery pack negative node = EVM ground
J5(2)–TS Connection for the NTC thermistor
J6 I
2
C 4-pin connector for EV2400
J7 Input mini-USB port
lists the EVM jumper connections.