User's Guide
SLUU273 – February 2009
bq27541EVM Single-Cell Impedance Track™ Technology
Evaluation Module
This evaluation module (EVM) is a complete evaluation system for the bq27541. The EVM includes one
bq27541 circuit module, a current sense resistor, one thermistor, an EV2300 personal computer (PC)
interface board for gas gauge interface, a PC USB cable, and Windows™-based PC software. The circuit
module includes one bq27541 integrated circuit (IC), and all other onboard components necessary to
monitor and predict capacity. The circuit module connects directly across the cell in a battery. With the
EV2300 interface board and software, the user can read the bq27541 data registers, program the chipset
for different pack configurations, log cycling data for further evaluation, and evaluate the overall
functionality of the bq27541 solution under different charge and discharge conditions.
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Contents
Features ....................................................................................................................... 2
bq27541-Based Circuit Module ............................................................................................ 2
bq27541 Circuit Module Schematic ....................................................................................... 3
Circuit Module Physical Layouts and Bill of Materials .................................................................. 3
EVM Hardware and Software Setup ...................................................................................... 8
Troubleshooting Unexpected Dialog Boxes .............................................................................. 8
Hardware Connection ....................................................................................................... 8
Operation .................................................................................................................... 10
Calibrate Screen ............................................................................................................ 13
I2C Pro Screen ............................................................................................................. 15
bqEasy™ Software ......................................................................................................... 16
Send HDQ Screen ......................................................................................................... 20
Related Documentation From Texas Instruments ..................................................................... 21
List of Figures
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bq27541EVM-001 Layout, Silk Screen ................................................................................... 3
Top Assembly ................................................................................................................ 4
Top Layer ..................................................................................................................... 4
Bottom Layer ................................................................................................................. 5
Schematic ..................................................................................................................... 7
bq27541 Circuit Module Connection to Cell and System Load/Charger ............................................. 9
DataRAM Screen ........................................................................................................... 10
Data Flash Screen ......................................................................................................... 11
Calibration Screen.......................................................................................................... 14
I2C Pro Screen ............................................................................................................. 15
bqEasy™ Flowchart........................................................................................................ 17
Load and Switch ............................................................................................................ 19
bqEasy Welcome Screen ................................................................................................. 20
Send HDQ Screen ......................................................................................................... 21
List of Tables
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2
3
4
Ordering Information ........................................................................................................
Bill of Materials ...............................................................................................................
Performance Specification Summary .....................................................................................
Circuit Module to EV2300 Connections – I2C ...........................................................................
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1
Features
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5
Circuit Module to EV2300 Connections – HDQ.......................................................................... 9
1
Features
•
•
•
•
1.1
Kit Contents
•
•
•
•
1.2
Complete evaluation system for the bq27541 gas gauge with Impedance Track™ Technology
Populated circuit module for quick setup
PC software and interface board for easy evaluation
Software that allows data logging for system analysis
bq27541 circuit module
EV2300 (specifically labeled as only to be used with bq27541 EVMs) PC interface board
USB connection cable to interface board
Set of support documentation
Ordering Information
Table 1. Ordering Information
2
EVM PART NUMBER
CHEMISTRY
CONFIGURATION
CAPACITY
bq27541EVM-001
Li-ion
1 cell
Any
bq27541-Based Circuit Module
The bq27541-based circuit module is a complete and compact example solution of a bq27541 circuit for
battery management. The circuit module incorporates a bq27541 battery gas gauge IC, and all other
components necessary to accurately predict the capacity of a 1-series Li-Ion cell.
2.1
Circuit Module Connections
Contacts on the circuit module provide the following connections:
• Direct connection to the cells: CELL+ and CELL• To the serial communications ports (SDA, SCL) or HDQ
• The system load and charger connect across PACK+ and PACK-
Single-Cell Solution Impedance Track, Impedance Track, bqEasy are trademarks of Texas Instruments.
Windows is a trademark of Microsoft Corporation.
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bq27541 Circuit Module Schematic
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2.2
Pin Descriptions
PIN NAME
3
DESCRIPTION
PACK+
Pack positive terminal
PACK-
Pack negative terminal
CELL+
Cell positive terminal
CELL-
Cell negative terminal
SDA
I2C communication data line
SCL
I2C communication clock line
HDQ
Single wire communication line
bq27541 Circuit Module Schematic
This section contains schematic information.
3.1
Schematic
The schematic follows the bill of materials in this user's guide.
4
Circuit Module Physical Layouts and Bill of Materials
This section contains the printed-circuit board (PCB) layout, bill of materials, and assembly drawings for
the bq27541 circuit module.
4.1
Board Layout
This section shows the PCB layers (Figure 1 through Figure 4), and assembly drawing for the bq27541
module.
Figure 1. bq27541EVM-001 Layout, Silk Screen
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Figure 2. Top Assembly
Figure 3. Top Layer
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Circuit Module Physical Layouts and Bill of Materials
Figure 4. Bottom Layer
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Circuit Module Physical Layouts and Bill of Materials
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Bill of Materials and Schematic
Table 2. Bill of Materials
Count
6
Ref Des
Description
Size
MFG
Part No.
7
C1, C2, C4, C5,
C7, C11, C12
Capacitor, Ceramic, 0.1uF, 10V, X5R
402
Murata
GRM155R61A104KA01D
2
C3, C6
Capacitor, Ceramic, 0.47uF, 6.3V, X5R
402
Murata
GRM155R60J474KE19D
3
C8, C9, C10
Capacitor, Ceramic, 150pF, 50V, NPO, 5%
402
Murata
GRM1555C1H151JA01D
2
J1, J2
Terminal Block, 2-pin, 6-A, 3.5mm
0.27 x 0.25 inch
OST
ED1514
2
J3, J4
Header, Friction Lock Ass'y, 4-pin Right Angle, 0.400 x 0.500
Molex
22-05-3041
2
J5, J6
Header, Male 2-pin, 100mil spacing, (36-pin
strip)
0.100 inch x 2
Sullins
PTC36SAAN
1
R1
Resistor, Chip, 0.01-Ohms, 0.25W, 1%
1206
Vishay
WSL1206R0100FEA
2
R14, R15
Resistor, Chip, 10k-Ohms, 1/16W, 5%
402
Std
Std
5
R3, R4, R11,
R12, R13
Resistor, Chip, 100-Ohms, 1/16W, 5%
402
Std
Std
3
R5, R6, R7
Resistor, Chip, 300-Ohms, 1/16W, 5%
402
Std
Std
3
R8, R9, R10
Resistor, Chip, 1M-Ohms, 1/16W, 5%
402
Std
Std
1
RT1
Thermistor, 10K ohms
0.095 X 0.150
inch
Semitec
NTC103AT
9
TP1, TP2, TP3,
TP4, TP5, TP6,
TP7, TP8, SE
Test Point, Black, Thru Hole Color Keyed
0.100 x 0.100
inch
Keystone
5001
1
U1
IC, Single-Cell Impedance Track Gas Gauge
QFN12
TI
BQ27541DRZ
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Circuit Module Physical Layouts and Bill of Materials
Figure 5. Schematic
4.3
bq27541 Circuit Module Performance Specification Summary
This section summarizes the performance specifications of the bq27541 circuit module.
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Table 3. Performance Specification Summary
Specification
5
Min
Typ
Max
Units
Input voltage Pack+ to Pack–
2.7
3.6
4.3
V
Input voltage CELL+ to CELL-
2.7
3.6
4.3
Charge and discharge current
0
1
2
A
EVM Hardware and Software Setup
This section describes how to install the bq27541EVM-001 PC software, and how to connect the different
components of the EVM.
5.1
System Requirements
The bq27541EVSW software requires Windows™ 2000 or Windows XP. Drivers for Windows 98SE are
provided, but Microsoft no longer supports Windows 98; Windows 98 may have issues with USB driver
support. The EV2300 USB drivers have been tested for Windows 98SE, but no assurance is made for
problem-free operation with specific system configurations.
5.2
Software Installation
Find the latest software version in the bq27541 tool folder on power.ti.com. Make a search by Part
Number for bq27541 to access the tool folder. Use the following steps to install the bq27541EVSW
software:
1. Ensure that the EV2300 is not connected to the PC through a USB cable before starting this
procedure.
2. Browse for the Supported Software link within the bq27541 TI Web site product folder to find the
downloadable evaluation software installation files.
3. Open the software file that was downloaded from the TI Web site.
4. Follow the instructions on screen until the software installation is completed.
5. Before starting the evaluation software, connect the EV2300 to the computer using the USB cable.
6. Wait until the system prompt “new hardware found” appears. Choose “select location manually”, and
use the “browse” button to point to subdirectory TIUSBWin2K-XP-1.
7. Answer “continue” to the warning that drivers are not certified with Microsoft™.
8. After installation finishes, another system prompt "new hardware found" appears. Repeat steps 6 and
7, but specify the directory as TIUSBWin2K-XP-2.
9. Answer "continue" to the warning that drivers are not certified with Microsoft. Driver installation is now
finished.
6
Troubleshooting Unexpected Dialog Boxes
The user that is downloading the files must be logged in as the administrator. The driver is not signed, so
the administrator must allow installation of unsigned drivers in the operating system policy.
7
Hardware Connection
The bq27541EVM-001 comprises three hardware components: the bq27541 circuit module, the EV2300
PC interface board, and the PC.
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Hardware Connection
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7.1
Connecting the bq27541 Circuit Module to a Battery Cell
Figure 6 shows how to connect the bq27541 circuit module to the cell and system load/charger.
Figure 6. bq27541 Circuit Module Connection to Cell and System Load/Charger
7.2
PC Interface Connection
The bq27541 can be configured as an HDQ communication device or left in default as an I2C device.
Once the bq27541 is configured for HDQ communication, it cannot be reverted to I2C mode. Refer to
chapter 12 of this document for information on configuring the bq27541 to HDQ mode.
The following steps configure the hardware for interfacing to the PC:
1. Connect the bq27541-based pack to the EV2300 using wire leads as shown in Table 4.
Table 4. Circuit Module to EV2300 Connections – I2C
bq27541-Based Battery (I2C mode)
EV2300 (I2C port)
SDA
SDA
SCL
SCL
PACK-
GND
Table 5. Circuit Module to EV2300 Connections – HDQ
bq27541-Based Battery (HDQ mode)
EV2300 (HDQ port)
HDQ
HDQ
PACK-
GND
2. Connect the PC USB cable to the EV2300 and the PC USB port.
The bq27541EVM-001 is now set up for operation.
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Operation
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Operation
This section details the operation of the bq27541 EVSW software.
8.1
Starting the Program
Run bq27541 EVSW from the Start | Programs | Texas Instruments | bq Evaluation Software menu
sequence. The DataRAM screen (Figure 7) appears. Data begins to appear once the (single
time scan) button is clicked, or when the check box is checked. To disable the scan
feature, deselect .
The continuous scanning period can be set via the | Options | and | Set Scan Interval | menu selections.
The range for this interval is 0 ms to 65,535 ms. Only items that are selected for scanning are scanned
within this period.
The bq27541 EVSW provides a logging function which logs the values that were last scanned by the
EVSW. To enable this function, select the Start Logging button, which causes the Keep Scanning button
to be selected. When logging is Stopped, the keep scanning button is still selected and has to be manually
unchecked.
The logging intervals are specified under the | Options | menu with the maximum value of 65,535 ms. The
Log interval cannot be smaller than scan interval because this results in the same value being logged at
least twice.
Figure 7. DataRAM Screen
This screen (Figure 7) shows the DataRAM data set. Additional Flags/Status Bits data can be viewed at
the bottom of the DataRAM screen.
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Operation
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Dragging the splitter bar (line that separates the Flags/Static Bits data from SBS values) changes the
height of the Flags/Static Bits data display. Selecting | View |, then | Auto Arrange | returns the splitter bar
to its original location.
8.2
Setting Programmable bq27541 Options
The bq27541 data flash comes configured per the default settings detailed in the bq27541 data sheet
(SLUS861). Ensure that the settings are correctly changed to match the pack and application for the
bq27541 solution being evaluated.
IMPORTANT: The correct setting of these options is essential to get the best performance.
The settings can be configured using the Data Flash screen (Figure 8).
Figure 8. Data Flash Screen
To read all the data from the bq27541 data flash, click on menu option | Data Flash | Read All |.
To write to a data flash location, click on the desired location, enter the data and press , which
writes the entire tab of flash data, or select menu option | Data Flash | Write All |. The data flash must be
read before any writes are performed to avoid any incorrect data being written to the device.
The | File | Special Export | menu options allows the data flash to be exported, but it configures the
exported data flash to a learned state ready for mass production use.
The data flash configuration can be saved to a file by selecting | File | Export | and entering a file name. A
data flash file can also be retrieved in this way, imported, and written to the bq27541 using the | Write All |
button.
The module calibration data is also held in the bq27541 data flash.
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The bq27541 allows for an automatic data flash export function, similar to the DataRAM logging function.
This feature, when selected via | Options | Auto Export |, exports Data Flash to a sequential series of files
named as FilenameNNNNN.gg where N = a decimal number from 0 to 9.
The AutoExport interval is set under the | Options menu | with a minimum value of 15 s. The AutoExport
filename is also set under the | Options menu |.
When a check is next to | AutoExport |, the AutoExport is in progress. The same menu selection is used to
turn on/off AutoExport.
If the data flash screen is blank, then the bq27541 that is being used may not be supported by the
bqEVSW version that is being used. An upgrade may be required.
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Calibrate Screen
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9
Calibrate Screen
To ensure proper calibration, proceed in the order that follows. These steps may or may not be required,
depending on the type of calibration being performed.
9.1
To Calibrate the bq27541
Select the types of calibration to be performed (see Figure 9).
Enter the measured values for the types selected.
If Voltage Calibration is selected, then ensure that cell count is 1.
If Temperature Calibration is selected, then select the sensor that is to be calibrated.
Press the Calibrate Part button.
9.2
CC Offset Calibration
This performs the internal calibration of the coulomb counter input offset.
9.3
Board Offset Calibration
This performs the offset calibration for the current offset of the board.
It is expected that no current is flowing through the sense resistor while performing this calibration step.
Remove load/external voltage and short Pack- to Batt-.
Press the CC Board Offset Calibration button.
9.4
Voltage Calibration
Remove the load applied between Pack+ and Pack-.
Ensure that voltage is stable before performing voltage calibration. Measure the voltage across Pack+ and
Pack-. Type the voltage value in mV into Enter Actual Voltage .
Press the Calibrate Part as indicated below button to calibrate.
9.5
Temperature Calibration
Measure the temperature for PACK. Type the temperature value into Enter Actual Temperature. Select if
the temperature sensor to calibrate is the internal or the external.
Press the Calibrate Part as indicated below button.
9.6
Pack Current Calibration
Connect a load to LOAD– and LOAD+ that draws approximately 1 A, or connect a current source to
LOAD– and Pack-. Measure the current and type value into Enter Actual Current using (-) for current in
discharge direction.
Press the Calibrate Part as indicated below button.
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Figure 9. Calibration Screen
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I2C Pro Screen
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10
I2C Pro Screen
10.1 I2C Communication
The set of read/write operations over I2C are not specific to any gas gauge. These are provided as
general-purpose communication tools (Figure 10).
Figure 10. I2C Pro Screen
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bqEasy™ Software
11
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bqEasy™ Software
11.1 Introduction
Texas Instruments fuel gauges, employing the Impedance Track™ algorithm, offer an unmatched array of
features and benefits. Sometimes, however, the wide range of configuration settings can make it seem a
bit challenging to get started with the evaluation process. In addition, determining the correct chemistry
model and producing the 'golden image' file can be time consuming. The bqEASY™ program is designed
to greatly simplify the process of configuring, calibrating, selecting chemistry, and performing learning
cycles through the step-by-step use of a wizard program.
The bqEasy™ software runs inside the current EV software when it is executed by clicking the bqEasy™
button in the left column of buttons below the Calibrate button in the EV software.
11.2 Program Navigation and Flowchart
The sequence of operation of bqEASY™ can be understood by reviewing the basic flowchart in Figure 11.
Using the program is simple – just start a new project, and follow the steps sequentially from 1A to 5C.
You can use the Next button, or click on the top tabs and left subsection labels to move to any desired
page. Some operations must be completed in sequence due to data dependencies, or to implement the
proper flow. Therefore, it is recommended that the prescribed sequence be followed, at least at first.
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(1A) Open Project
(4B) Display available chemistry files
(1B) Write default .DFI file to
gauge (or keep existing image)
(4A) Is the cell
chemistry
identifiable
from the list?
(2A~2H) Configure gauge from
wizard questions
(4C) Do chemistry selection cycle
to log elapsed time, voltage,
temperature and current
(3A~3F) Calibrate gauge
Yes
(3F) Read/save configured flash
from gauge to .DFI binary file
(4A) Are the
cell based on
standard Li-Ion
chemistry?
No
(4C) Write previously saved
configured .DFI file to gauge
(4C) Programmatically select best
chemistry match
No
(4C) Write selected chemistry
model to gauge
Yes
(4C) Read/save configured flash
from gauge to .DFI binary file
(5A) Enable Impedance Track
algorithm
(5A~5B) Perform learning cycles
(5C) Write previously saved .DFI
binary file to the gauge to insure
no cycling corruption
(5C) Write Ra Table, Qmax, Cycle
Count and Update Status to gauge
(5C) Reset Gauge
(5C) Read flash, save golden .DFI
file
Figure 11. bqEasy™ Flowchart
11.3 Simplified Configuration Procedures
These simplified configuration procedures can be used to quickly set up the parameters without navigating
through the entire user interface.
1. Simple configuration of the gas gauge with default or custom data:
a. Open the current EV software and click the bqEasy button in the left column of buttons below the
"Calibrate" button in the EV software.
b. Click the "2. Configure" tab at the top row of bqEASY tabs. (Note: You can skip the 1st tab)
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c. Answer all questions or leave defaults for all of tab "2", but be sure to click the ok button at the
bottom of each tab "2" page to ensure that a Completion checkmark appears for each page.
d. On page 2H, when you click the "OK" button, the software asks you to write to the data flash
memory. Click "Yes" for OK to write to the data flash.
2. Simple installation of the Chemistry data using bqEASY if the chemistry is a known chemistry available
in the bqEASY software:
a. Open the current EV software and click the bqEasy button in the left column of buttons below the
"Calibrate" button in the EV software.
b. Click the "4. Chemistry" tab at the top row of bqEASY tabs. (Note: You can skip all tabs prior to
this.)
c. Either select "Use Default Chemistry", or click "Enable Chemistry Selection" and select the correct
chemistry from the list.
d. If you cannot find the proper chemistry, check the device EVM tool folder on the TI Web site for
any new bqChemistry file updates. These are updated more frequently than the EV software; so,
between EV software updates, TI creates a self-extracting installer and posts it in the EVM tool
folder for the part being used. Install these updates if they are in the folder.
The software now configures all data flash locations on your gas gauge module that deal with chemistry
functions. No other data flash locations are modified.
11.4 Files
bqEASY uses four types of files to configure a fuel gauge.
1. .ENCR – These are default data-flash definition files found in the \bq_Evaluation_Software folder. The
ENCR file is basically a copy of the entire data flash from a fresh gas gauge prior to any data-flash
updates either by the user or the gas gauge. They are unique for each version of each TI fuel gauge
product. If you are working with a new version fuel gauge and an older version of bqEASY, the correct
file may not be present. This requires a new version of the EV software with bqEASY. Navigate to the
TI Web site in the EVM tool folder for the device being used, and download the latest version, or
contact TI. For bqEASY, the ENCR files act mainly as a dictionary to look up the address for a given
data-flash location. For bqEVSW, they define screen parameters including address, display formulas,
and data type. An error message appears if the correct .ENCR file cannot be found.
2. .CHEM (Chemistry Files) – These are read-only files found in the
..\bq_Evaluation_Software\Plugins\Chemistry folder of the application. When a new Li-ion battery
chemistry is developed, a new Impedance Track™ model is required to define the chemical model.
During automated chemistry selection, each of these files is scanned in order to select the best match
with the recorded data. If you are working with a newly developed chemistry, it is possible that an
acceptable match may not be found. If this is the case, check for updated bqEasy software or
bqChemistry files on the TI Web site in the EVM tool folder for the part being used.
3. .DFI (Data-Flash Image Files) – These are binary images of the fuel gauge data-flash with modified
values based on the application. Because of the binary format, it is quick and easy to transfer them to
and from a gauge. Each fuel gauge model and firmware version has a unique read-only .DFI which is
found in the ..\bq_Evaluation_Software\Plugins\Device_Defaults folder of the application. During the
bqEASY process, intermediate versions of .DFI files are recorded with current updated data in order to
prevent the possibility of corruption. Then, the final output of bqEASY is also a .DFI file which is the
'golden image' that will be programmed into each production unit. This output file is placed in the
..\bq_Evaluation _Software\Plugins\Projects folder.
4. .EZY (bqEASY Project Files) – These are read-write text files which record header information
regarding a project, answers to the wizard questions, and status regarding the stage of completion (the
red checkmarks). They are kept in the ..\bq_Evaluation _Software\Plugins\Projects folder.
11.5 Completion Checkmarks
As the wizard questions and tasks are completed, completion checkmarks appear in two places – along
the task list on the left and on the category tabs on top. A checkmark on a top tab only appears after all
tasks in the category have been completed. Completion marks are saved in the .EZY project text file.
When a completed or partially completed project file is opened, the user is given the chance to erase the
checkmarks.
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11.6 Device Detection
BqEASY is designed to work with a fuel gauge present and already communicating with the bqEVSW
evaluation software through the EV2300 USB interface. When the evaluation software is started, it reads
the device type and displays it on the upper title block. This information is used by bqEASY to select the
correct default data-flash image (.DFI) and data-flash configuration file (.ENCR) for this particular device.
To ensure that the device has not changed, bqEASY also checks the device type when the bqEASY
button is pressed. If the correct files are not found, first check the TI Web site in the EVM tool folder for
the part being used, and download the latest version of EV software with bqEASY support. If that does not
help, then contact Texas Instruments.
1. Setup
As the wizard questions and tasks are completed, completion checkmarks appear in two places –
along the task list on the left and on the category tabs on top. A checkmark on a top tab only appears
after all tasks in the category have been completed. Completion marks are saved in the .EZY project
text file. When a completed or partially completed project file is opened, the user is given the chance to
erase the checkmarks.
2. Configure
A series of eight screens is used to collect information about the battery pack application to enable
automatic configuration of the most critical data-flash parameters.
3. Calibrate
If you proceed with either automatic chemistry selection or 'golden' unit learning cycles, the Impedance
Track™ fuel gauge must be accurately calibrated. The bqEASY screens simply ask the user to use the
calibration screen of the bqEVSW for this purpose.
4. Chemistry
The chemistry choices presented in section 4B are based on files in the \Chemistry folder of the
bqEASY application. The latest files are available for downloading from the TI Web site. Automation of
the chemistry-selection cycle is made possible using a simple load and switch as depicted in
Figure 12. The VOUT pin of the EV2300 may require a 1-MΩ pulldown resistor to ensure that switch is
turned off when signaled to do so. The switch can be implemented with either a low VGS-threshold
FET or a small relay such as the OMICRON G6RN-1 with a 5-VDC coil. Multiple 2N7000 FETs can be
paralleled if nothing else is available. The load can be either a power resistor or an electronic load set
to a discharge rate of C/5. Hint: Follow the instructions exactly, or errors may result.
5. Cycle
When preparing for mass production, cell learning is required, but only on one 'golden' pack. The
chemical information learned from one pack is quickly transferred to all production units prior to
calibration. Doing this correctly requires a series of charge and discharge cycles. The discharge part
can be automated with bqEASY if the simple load circuit for the chemistry selection is available. Follow
the screen instructions.
Electronic Load or
Resistor ~ C/5
EVM
LOAD+
EV2300 HDQ Connector
VOUT
GND
LOADFigure 12. Load and Switch
SLUU273 – February 2009
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bq27541EVM Single-Cell Impedance Track™ Technology
Evaluation Module
19
Send HDQ Screen
www.ti.com
Figure 13. bqEasy Welcome Screen
12
Send HDQ Screen
To configure a bq27541 into HDQ mode, navigate to the Send HDQ screen. It is possible that all the
screen options on the left are not visible depending on screen resolution. If needed scroll within the left
menu to access the Send HDQ link. Click on the "Change comm to HDQ8" button while having the
bq27541 connected to the EV2300 via I2C. Clicking on the button causes a message to appear indicating
that the process is not reversible and to confirm if the actions are desired. Also, it explains what to do
once the HDQ mode has been activated.
Once converting the bq27541 into HDQ mode, it is required that you connect the HDQ terminal of the
EV2300 with the HDQ connector (J4) of the bq27541 EVM, then restart the EVSW, and select the
"bq27541HDQR1" with the proper firmware version from the list of supported devices within the EVSW.
20
bq27541EVM Single-Cell Impedance Track™ Technology
Evaluation Module
SLUU273 – February 2009
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Related Documentation From Texas Instruments
www.ti.com
Figure 14. Send HDQ Screen
13
Related Documentation From Texas Instruments
•
bq27541, Single Cell Li-Ion Battery Fuel Gauge for Battery Pack Integration data sheet (SLUS861)
SLUU273 – February 2009
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bq27541EVM Single-Cell Impedance Track™ Technology
Evaluation Module
21
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please be aware that these devices may be very warm to the touch.
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