ꢀ
ꢁ
ꢂ
ꢃ
ꢄ
ꢅ
SLUS502 – SEPTEMBER 2001
ꢆ ꢇꢆ ꢈꢉ ꢊ ꢋꢌ ꢍꢎꢏ ꢐ ꢑ ꢎꢆ ꢑ ꢎꢒꢑ ꢓ ꢍꢈ
ꢔꢉ ꢕ ꢒꢆꢓ ꢖ ꢍꢐ ꢗ ꢐ ꢗꢓ ꢀ ꢁꢂ ꢘ ꢙ ꢅꢅ
The bq2081 uses an integrating converter with
continuous sampling for the measurement of
battery charge and discharge currents. Optimized
for coloumb counting in portable applications, the
FEATURES
D
D
D
Provides Accurate Measurement of Available
Charge in Li-Ion and Li-Polymer Batteries
Supports the Smart Battery Specification
(SBS) V1.1
self-calibrating integrating converter has
a
resolution better than 3-nVh and an offset
measurement error of less than 1-µV (typical). For
voltage, temperature, and current reporting, the
bq2081 uses a 15-bit A-to-D converter. In
conjunction with the bq29311, the onboard ADC
also monitors individual cell voltages in a battery
pack and allows the bq2081 to generate the
control signals necessary to implement the
required safety protection for Li-Ion and
Li-Polymer battery chemistries.
Works With the TI bq29311 Protection IC to
Provide Complete Pack Electronics for
10.8-V or 14.4-V Battery Packs with Few
External Components
D
D
D
Based on a Powerful Low-Power RISC CPU
Core With High-Performance Peripherals
Integrated FLASH Memory Eliminates the
Need for External Configuration EEPROM
Measures Charge Flow Using a High
Resolution 15–Bit Integrating Converter
– Better Than 3-nVh of Resolution
– Self-Calibrating
The bq2081 supports the smart battery data
(SBData) commands and charge control
functions. It communicates data using the System
Management Bus (SMBus) 2-wire protocol or the
1-wire HDQ16 protocol. The data available
includes the battery’s remaining capacity,
temperature, voltage, current, and remaining
run-time predictions. The bq2081 provides LED
drivers and a push button input to depict remaining
battery capacity from full to empty in 20% or 25%
increments with a 4 or 5 segment display.
– Offset Error Less Than 1-µV
D
Uses 15-Bit Delta Sigma Converter for
Accurate Voltage, Temperature, and Current
Measurements
D
D
D
Programmable Cell Modeling for Maximum
Battery Fuel Gauge Accuracy
Drives 4- or 5-Segment LED Display for
Remaining Capacity Indication
The bq2081 contains 512 bytes of internal FLASH
EPROM, whith store configuration information.
The information includes nominal capacity and
voltage, self–discharge rate, rate compensation
factors, and other programmable cell–modeling
factors used to accurately adjust remaining
capacity for use–conditions based on time, rate,
and temperature. The bq2081 also automatically
calibrates or learns the true battery capacity in the
course of a discharge cycle from programmable
near full to near empty levels.
38–pin TSSOP (DBT)
DESCRIPTION
The bq2081 SBS Compliant gas gauge IC for
battery pack or in-system installation maintains an
accurate record of available charge in Li-Ion or
Li-Polymer batteries. The bq2081 monitors
capacity and other critical parameters of the
battery pack and reports the information to the
The bq29311 protection IC provides power to the
bq2081 from a 3 or 4 series Li-Ion cell stack,
eliminating the need for an external regulator
circuit.
system host controller over
a
serial
communication bus. It is designed to work with the
bq29311 protection IC to maximize functionality
and safety and minimize component count and
cost in smart battery circuits.
ꢋ
ꢕ
ꢉ
ꢚ
ꢒ
ꢈ
ꢐ
ꢋ
ꢕ
ꢓ
ꢛ
ꢍ
ꢓ
ꢖ
ꢜ
ꢝ
ꢞ
ꢟ
ꢠ
ꢡ
ꢢ
ꢣ
ꢜ
ꢟ
ꢝ
ꢤ
ꢟ
ꢝ
ꢤ
ꢥ
ꢠ
ꢝ
ꢦ
ꢧ
ꢠ
ꢟ
ꢨ
ꢩ
ꢨꢥ ꢦ ꢜ ꢬꢝ ꢧꢪ ꢢ ꢦ ꢥ ꢟꢞ ꢨꢥ ꢫ ꢥ ꢭꢟ ꢧꢡꢥ ꢝꢣꢮ ꢈ ꢪꢢ ꢠꢢ ꢤꢣ ꢥꢠ ꢜꢦ ꢣꢜ ꢤ ꢨꢢ ꢣꢢ ꢢꢝ ꢨ ꢟꢣ ꢪꢥꢠ
ꢤ
ꢣ
ꢦ
ꢜ
ꢝ
ꢣ
ꢪ
ꢥ
ꢞ
ꢟ
ꢠ
ꢡ
ꢢ
ꢣ
ꢜ
ꢫ
ꢥ
ꢟ
ꢠ
Copyright 2001, Texas Instruments Incorporated
ꢦ
ꢧ
ꢥ
ꢤ
ꢜ
ꢞ
ꢜ
ꢤ
ꢢ
ꢣ
ꢜ
ꢟ
ꢝ
ꢦ
ꢢ
ꢠ
ꢥ
ꢨ
ꢥ
ꢦ
ꢜ
ꢬ
ꢝ
ꢬ
ꢟ
ꢢ
ꢭ
ꢦ
ꢮ
ꢐ
ꢥ
ꢯ
ꢢ
ꢦ
ꢍ
ꢝ
ꢦ
ꢣ
ꢠ
ꢩ
ꢡ
ꢥ
ꢝ
ꢤ ꢪꢢ ꢝ ꢬꢥ ꢟꢠ ꢨꢜ ꢦ ꢤ ꢟꢝ ꢣꢜ ꢝꢩꢥ ꢣ ꢪꢥ ꢦ ꢥ ꢧꢠ ꢟꢨ ꢩꢤꢣ ꢦ ꢰ ꢜꢣꢪ ꢟꢩꢣ ꢝꢟꢣ ꢜꢤꢥ ꢮ
ꢣ
ꢦ
ꢠ
ꢥ
ꢦ
ꢥ
ꢠ
ꢫ
ꢥ
ꢦ
ꢣ
ꢪ
ꢥ
ꢠ
ꢜ
ꢬ
ꢪ
ꢣ
ꢣ
ꢟ
1
www.ti.com