Datasheet

Features

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1 Features

• Complete evaluation system for the bq20z655 and bq34z651 SBS 1.1-compliant advanced gas gauges

with Impedance Track™ technology and bq29412 independent overvoltage protection IC

• Populated circuit module for quick setup

• Software that allows data logging for system analysis

1.1 Kit Contents

• bq20z655/bq29412 and bq34z651/bq29412 circuit module

• Set of support documentation

1.2 Ordering Information

Table 1. Ordering Information

EVM Part Number Chemistry Configuration Capacity

bq34z651EVM Li-Ion 2-series, 3-series, or 4-series cell Any

bq20z655EVM Li-Ion 2-series, 3-series, or 4-series cell Any

2 bq20z655-Based and bq34z651-Based Circuit Module

The bq20z655/bq29412 and bq34z651/bq29412-based circuit module is a complete and compact example

solution of a bq20z655 and bq34z651 circuit for battery management and protection of Li-Ion or

Li-Polymer packs. The circuit module incorporates a bq20z655 and bq34z651 battery monitor IC, bq29412

independent overvoltage protection IC, and all other components necessary to accurately predict the

capacity of 2-series, 3-series, or 4-series cells.

2.1 Circuit Module Connections

Contacts on the circuit module provide the following connections:

• Direct connection to the cells: 1N (BAT–), 1P, 2P, 3P, 4P (BAT+)

• To the serial communications port (SMBC, SMBD)

• To the system load and charger connect across PACK+ and PACK–

• To the system-present pin (SYS PRES)

• To the LED/LCD interface (LED(1:5), common) (LCD option only on the bq20z655)

• To charge enable input (CE) (bq20z655 option only)

• To the heater control port (HEATER CNTRL) (bq34z651 option only)

2.2 Pin Descriptions

Pin Name Description

1N –ve connection of first (bottom) cell

1P +ve connection of first (bottom) cell

2P +ve connection of second cell

3P +ve connection of third cell

4P +ve connection of fourth (top) cell

CE Charge enable overrides firmware control when high

COMMON Output/open drain: LCD common connection

HEATER CNTRL (X3) Drain connection to n-channel FET

LED1 Output/open drain: LED 1 current sink. LCD segment 1

LED2 Output/open drain: LED 2 current sink. LCD segment 2

LED3 Output/open drain: LED 3 current sink. LCD segment 3

bq20z655EVM and bq34z651EVM SBS 1.1 Impedance Track SLUU697– November 2011

Technology-Enabled Evaluation Module

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