Texas Instruments bq26500EVM User manual

User's Guide
SLUU174A –March 2006–Revised October 2013
bq26500EVM Single-Cell Battery Fuel Gauge Evaluation
Module
The bq26500EVM is a complete evaluation system for the bq26500 single cell Li-Ion and Li-Polymer
battery gas gauge device. The EVM includes one bq26500 circuit module, CD ROM including Windows®-
based PC software and support documentation. An EV2300 board for gas gauge evaluation is required to
interface this EVM with the PC and can be purchased separately.
Contents
1 Introduction .................................................................................................................. 2
2 bq26500EVM-Based Circuit Module ..................................................................................... 3
3 bq26500EVM Circuit Module Schematic ................................................................................. 4
4 Circuit Module Physical Layouts .......................................................................................... 5
5 bq26500EVM Circuit Module List of Materials .......................................................................... 7
6 bq26500EVM Circuit Module Performance Specification Summary ................................................. 7
7 EVM Hardware and Software Setup ..................................................................................... 7
8 Operation ..................................................................................................................... 9
List of Figures
1 bq26500EVM Circuit Module Schematic................................................................................. 4
2 bq26500EVM Topside Assembly ......................................................................................... 5
3 bq26500EVM Silkscreen................................................................................................... 5
4 bq26500EVM Layer 1 Layout ............................................................................................. 6
5 bq26500EVM Layer 2 Layout ............................................................................................. 6
6 bq26500EVM Circuit Module Connection to Cells and System Load/Charger ..................................... 8
7 Initial Register Screen...................................................................................................... 9
8 EEPROM Screen.......................................................................................................... 10
9 Pro Screen ................................................................................................................. 11
List of Tables
1 bq26500EVM Ordering Information....................................................................................... 2
2 bq26500EVM Test Points.................................................................................................. 3
3 bq26500EVM Bill of Materials............................................................................................. 7
4 Performance Specification Summary..................................................................................... 7
5 Circuit Module-to-EV2300 Connection................................................................................... 8
6 Example Data Log......................................................................................................... 12
Windows is a registered trademark of Microsoft Corporation.
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Introduction www.ti.com
1 Introduction
The bq26500EVM is a complete evaluation system for the bq26500 single cell Li-Ion and Li-Polymer
battery gas gauge device. The EVM includes one bq26500 circuit module, CD ROM including Windows-
based PC software and support documentation. An EV2300 board for gas gauge evaluation is required to
interface this EVM with the PC and can be purchased separately. The circuit module includes one
bq26500, a current sense resistor and all other components on-board necessary to calculate remaining
battery capacity and predict at rate time to empty. The circuit module connects directly across the cell in a
battery. With the PC interface board and software, the user can read the bq26500 data registers, program
the on-chip configuration EEPROM, and evaluate the functions of the bq26500 under different charge and
discharge conditions.
1.1 Features
• Complete evaluation system for the bq26500 battery gas gauge
• Populated circuit module for quick setup
• PC software and interface board for easy evaluation
• Software allows EEPROM programming and data logging for system analysis
1.2 Kit Contents
1. bq26500 circuit module with sense resistor
2. CD ROM including Windows-based PC software and support documentation
3. Set of support documentation
1.3 Ordering Information
Table 1 contains the ordering information for the EVM
Table 1. bq26500EVM Ordering Information
EVM Part Number PC Interface Board Chemistry Pack Voltage Capacity
bq26500EVM−001 USB Li-Ion 2.6 V to 4.5 V 100 to 2000 mah
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www.ti.com bq26500EVM-Based Circuit Module
2 bq26500EVM-Based Circuit Module
The bq26500EVM based circuit module is an example circuit for battery fuel gauging of a single cell Li-
Ion/Li-Polymer battery pack. There are two separate circuits on the EVM module. One is the active
bq26500 fuel gauging circuitry; the other is the logic and power control to program the on-chip
configuration EEPROM of the bq26500. In a typical application, only the active fuel gauging circuitry is
required. The EEPROM programming circuitry would be required in a test setup to configure the bq26500
for the application by programming the EEPROM.
Contacts on the circuit module provide direct connection to the cell (J1−1, J2−2), the serial
communications port (J1−3). The system load and charger connect across J1−1 and J2−1.
2.1 Test Points
Table 2 describes the EVM test points and lists their signal names.
Table 2. bq26500EVM Test Points
Test Point Signal Name description
J1−1 PACK+ Cell positive/pack positive
J1−2 GPIO GPIO pin of the bq26500
J1−3 HDQ Serial communications port
J2−1 PACK−Pack negative
J2−2 BAT−Cell negative
J3−1 21V High voltage for EEPROM programming
J3−2 PROG Input for timing of EEPROM programming
pulse
J3−3 VSS Programming ground
J4 1−2 jumper position for programming EEPROM
2−3 jumper position for normal bq26500 operation (fuel
gauging)
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bq26500EVM Circuit Module Schematic www.ti.com
3 bq26500EVM Circuit Module Schematic
Figure 1 shows the circuit module schematic diagram.
Figure 1. bq26500EVM Circuit Module Schematic
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www.ti.com Circuit Module Physical Layouts
4 Circuit Module Physical Layouts
This chapter contains the board layout and assembly drawings for the bq26500EVM circuit module.
4.1 Board Layout
Figure 2 through Figure 5 show the PCB layers and assembly drawing for the bq26500EVM circuit
module.
Figure 2. bq26500EVM Topside Assembly
Figure 3. bq26500EVM Silkscreen
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Circuit Module Physical Layouts www.ti.com
Figure 4. bq26500EVM Layer 1 Layout
Figure 5. bq26500EVM Layer 2 Layout
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www.ti.com bq26500EVM Circuit Module List of Materials
5 bq26500EVM Circuit Module List of Materials
Table 3 displays the EVM bill of materials.
Table 3. bq26500EVM Bill of Materials
Ref QTY Description MFR Part Number
Designators
C1, C2, C3, C4 4 Capacitor, ceramic, 0.1 µF, 16 V, X7R, 603 muRata GRM39X7R104K16
D1 1 Diode, Zener, 22 V, 350 mW, SOT23 Diodes, Inc. BZX84C22
D2, D3 2 Diode, Zener, 5.6 V, 350 mW, SOT23 Diodes, Inc. BZX84C5V6T
Q1 1 MOSFET, N-channel, 2N7002, 60 V, 115 mA, 1.2 Ω, Vishay−Liteon 2N7002DICT
SOT23
Q2 1 MOSFET, P-channel, ZVP3306F, −60 V, 0.09 A, 14 Ω, Zetex ZVP3306F
SOT23
R1, R2, R4, R5, 5 Resistor, chip, 100 Ω, 1/16 W, 5%, 603 Std Std
R11
R13, R14 2 Resistor, Chip, 1 M, 1/16 W, 5%, 603 Std Std
R6, R7, R12 3 Resistor, Chip, 100 kΩ, 1/16 W, 5%, 603 Std Std
R8 1 Resistor, Chip, 0.020 Ω, 1/2 W, 2%, 2010 Dale WSL2010−R020
U1 1 Single cell Li-Ion/Polymer gas gauge device, TSSOP−08 Texas Instruments bq26500PW
J1, J3 2 Terminal blocks, 3 position OST ED1515
J2 1 Terminal blocks, 2 position OST ED1514
J4 1 Header, 3-pin, 100-mil spacing, (36-pin strip) Sullins PTC36SAAN
N/A 1 Shunt Any HPA033
N/A 1 PCB Any HPA033
6 bq26500EVM Circuit Module Performance Specification Summary
This section summarizes the performance specifications of the bq26500EVM circuit module. Table 4 gives
the performance specifications of the circuit.
Table 4. Performance Specification Summary
Specification MIN TYP MAX Units
Input Voltage PACK+/BAT−2.6 4.5 V
Charge and Discharge Current 3(1) A
(1) Charge and discharge max. is limited by the PCB design and power dissipation of the 20-mΩ, 1/2-W sense resistor, included in
the kit.
7 EVM Hardware and Software Setup
This section describes how to install the bq26500EVM PC software and how to connect the different
components of the EVM.
7.1 Software Installation
Install the bq26500 evaluation software with steps through through :
1. Insert CD ROM into a CD ROM drive.
2. Select the CD ROM drive using My Computer or File Manager.
3. Select the ReadMeFirst.txt file.
4. Follow the instructions to install USB drivers for EV2300.
5. After installing the USB drivers for EV2300, double-click on the Setup.exe icon.
6. The setup program installs a windows application group.
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7.2 Hardware Connection
The three hardware components to the bq26500EVM are:
• The bq26500EVM circuit module,
• The PC interface board,
• And the PC
7.2.1 Connecting the bq26500EVM Circuit Module to a Battery Pack
Figure 6 shows how to connect the bq26500EVM circuit module to a Li-Ion cell and the system
load/charger.
Figure 6. bq26500EVM Circuit Module Connection to Cells and System Load/Charger
7.2.2 PC Interface Connection
The following steps configure the hardware for interface to the PC:
1. Connect colored wires that are included with EV2300 to bq26500EVM using Table 5 as a guide.
2. Connect the connector with colored wires to the HDQ connector that is on EV2300. HDQ connection is
located on the top right of EV2300.
3. Connect the PC USB cable to the EV2300 and the PC USB port.
The bq26500EVM is now set up for operation.
Table 5 lists the circuit module-to-EV2300 connections.
Table 5. Circuit Module-to-EV2300 Connection
bq26500EVM Color
HDQ BROWN
PACK−BLACK
PROG WHITE
PACK+(1) RED
(1) This connection is not useful when using a system load, charger or a power source (battery or external power supply).
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www.ti.com Operation
8 Operation
This section details the operation of the bq26500EVM software.
8.1 Starting the Program
Run the program from the Start→Programs→Texas Instruments→bq26500 Battery Monitor menu
sequence. The software defaults to PC USB port for communication. If the EV2300 is connected to USB
port, the program should load and display the initial data screen as shown in Figure 7.
Figure 7. Initial Register Screen
If the EV2300 is not connected to a USB port, the program will display a USB error message and then
display the initial data screen with no data in the register locations.
The com port can be changed by selecting the port under the options menu.
8.2 Initialization
This section describes the settings that must be made before the bq26500 is evaluated.
8.2.1 Loading the Sense Resistor Value
The bq26500EVM comes with a 20-mΩsense resistor on the circuit board. Make sure the sense resistor
value is entered in the RS box at the top of the initial register screen. This value is used by the PC
program to convert the bq26500 data set to engineering units. Checking the display engineering units box
displays the data set in engineering units. No check mark displays the data set just as the bq26500
calculates them, ie, in units of 3.0-µVh counts.
8.2.2 Programming the bq26500 EEPROM
Each bq26500 is programmed at the factory with default values in the EEPROM. The values in EEPROM
should be changed to match specific applications. The EEPROM values can be read by using the
EEPROM screen (Figure 8).
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Figure 8. EEPROM Screen
The values in the EEPROM can be easily changed using the EVM’s auto programming feature. To use the
auto program feature:
1. Make sure VOUT of the EV2300 is connected to PROG of the EVM.
2. Connect a 21-V supply across 21 V (J3−1) and VSS (J3−3).
3. Click on the use auto-programming box to enable auto EEPROM programming.
To change the EEPROM values simply click on the value to be changed, enter the new value, and press
enter.
The EEPROM values can be stored in a file on the PC by using the File|Save Gas Gauge Flash
Constants command from the pull down menu. Similarly, a saved file can be load by using the File|Open
Gas Gauge Flash Constants command. Once the file is called up, the Write all EEPROM button can be
used to write all the EEPROM values at once.
NOTE: Changing EEPROM data affects critical aspects of the bq26500 operation. Please review the
bq26500 data sheet to determine how to develop new data for the EEPROM based on your
application. It is recommend to first save the default EEPROM data as a file first before
changing the data. In this way, the default data programming can easily be restored.
The bq26500 automatically uses the new EEPROM in its calculations, once programmed.
8.2.3 Resetting the bq26500
The bq26500 can be reset at anytime by using the Options|Special Options|Reset bq26500 from the
pulldown menu. When reset, the bq26500 loads the configuration values from EEPROM and set the
remaining capacity registers to zero.
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