BQ27541-V200_17 Datasheet, PDF (7/46 Pages) Texas Instruments – Single Cell Li-Ion Battery Fuel Gauge for Battery Pack Integration

Not Recommended for New Designs
bq27541-V200
www.ti.com
SLUSA11B – FEBRUARY 2010 – REVISED SEPTEMBER 2013
I²C-COMPATIBLE INTERFACE TIMING CHARACTERISTICS
T_A = –40°C to 85°C, C_REG = 0.47μF, 2.45 V < V_REGIN = V_BAT < 5.5 V; typical values at T_A = 25°C and V_REGIN = V_BAT = 3.6 V
(unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN TYP MAX UNIT
t_r
t_f
t_w(H)
t_w(L)
t_su(STA)
t_d(STA)
t_su(DAT)
t_h(DAT)
t_su(STOP)
t_BUF
f_SCL
SCL/SDA rise time
SCL/SDA fall time
SCL pulse width (high)
SCL pulse width (low)
Setup for repeated start
Start to first falling edge of SCL
Data setup time
Data hold time
Setup time for stop
Bus free time between stop and start
Clock frequency
600
1.3
600
600
1000
0
600
66
300 ns
300 ns
ns
μs
ns
ns
ns
ns
ns
μs
400 kHz
t_SU(STA)
t_w(H)
t_w(L)
t_f
t_r
t_(BUF)
SCL
SDA
t_d(STA)
t_f
t_r
t_h(DAT)
t_su(DAT)
t_su(STOP)
REPEATED
START
STOP
START
Figure 2. I²C-Compatible Interface Timing Diagrams
GENERAL DESCRIPTION
The bq27541 accurately predicts the battery capacity and other operational characteristics of a single Li-based
rechargeable cell. It can be interrogated by a system processor to provide cell information, such as state-of-
charge (SOC), time-to-empty (TTE) and time-to-full (TTF).
Information is accessed through a series of commands, called Standard Commands. Further capabilities are
provided by the additional Extended Commands set. Both sets of commands, indicated by the general format
Command( ), are used to read and write information contained within the bq27541 control and status registers,
as well as its data flash locations. Commands are sent from system to gauge using the bq27541’s serial
communications engine, and can be executed during application development, pack manufacture, or end-
equipment operation.
Cell information is stored in the bq27541 in non-volatile flash memory. Many of these data flash locations are
accessible during application development. They cannot, generally, be accessed directly during end-equipment
operation. Access to these locations is achieved by either use of the bq27541’s companion evaluation software,
through individual commands, or through a sequence of data-flash-access commands. To access a desired data
flash location, the correct data flash subclass and offset must be known.
The bq27541 provides 96 bytes of user-programmable data flash memory, partitioned into three (3) 32-byte
blocks: Manufacturer Info Block A, Manufacturer Info Block B, and Manufacturer Info Block C. This data
space is accessed through a data flash interface. For specifics on accessing the data flash, see section
Manufacturer Information Blocks. The key to the bq27541’s high-accuracy gas gauging prediction is Texas
Instrument’s proprietary Impedance Track™ algorithm. This algorithm uses cell measurements, characteristics,
and properties to create state-of-charge predictions that can achieve less than 1% error across a wide variety of
operating conditions and over the lifetime of the battery.
Copyright © 2010–2013, Texas Instruments Incorporated
Product Folder Links: bq27541-V200
Submit Documentation Feedback
7