Single Cell Gas Gauge Application Book

bq27500 Application Book Literature Number: SLUA458 July 2008 www.ti.com Contents Chapter 1 Glossary ..................................................... ..................................................... 7 Introduction ........................................................... ........................................................... 9 Chapter 2 Single-Cell Impedance Track™ Gas Gauge for Novices ................... ................... 10 2.1 Introduction ................................................... ................................................... 11 2.2 The Basics ................................................... ................................................... 12 2.3 Next Steps.................................................... .................................................... 17 2.4 Glossary ..................................................... ..................................................... 18 Data Flash Glossary..................................................... ..................................................... 21 Chapter 3 Configuring the bq27500 Data Flash ................................. ................................. 22 3.1 Glossary ..................................................... ..................................................... 22 3.2 Configuration .................................................. .................................................. 23 3.3 System Data .................................................. .................................................. 29 3.4 Gas Gauging .................................................. .................................................. 30 3.5 Ra Tables .................................................... .................................................... 34 3.6 Default Ra Tables ............................................... ............................................... 37 3.7 Calibration.................................................... .................................................... 38 Evaluation ........................................................... ........................................................... 41 Chapter 4 Feature Set Comparison of bq27x00, bq27x10, bq27500 and bq27510 ......... ......... 42 Chapter 5 Theory and Implementation of Impedance Track™ Battery Fuel-Gauging Algorithm in bq2750x Family ................................................... ................................................... 43 5.1 Summary of the Algorithm Operation .................................... .................................... 43 5.2 Parameters Updated by the Gas Gauge in More Detail ......................... ......................... 43 5.3 Real Application Example........................................... ........................................... 49 Chapter 6 bq2750xEVM System Side Single-Cell Impedance Track™ Technology Evaluation Module ......................................................... ......................................................... 53 6.1 Features ..................................................... ..................................................... 54 6.2 bq2750x-Based Circuit Module........................................ ........................................ 54 6.3 bq2750x Circuit Module Schematic ..................................... ..................................... 55 6.4 Circuit Module Physical Layouts and Bill of Materials........................... ........................... 55 6.5 EVM Hardware and Software Setup..................................... ..................................... 60 6.6 Troubleshooting Unexpected Dialog Boxes................................. ................................. 60 6.7 Hardware Connection ............................................. ............................................. 60 6.8 Operation .................................................... .................................................... 62 6.9 Calibrate Screen ................................................ ................................................ 64 6.10 I2C Pro Screen ................................................. ................................................. 66 6.11 bqEasy...................................................... ...................................................... 66 6.12 Related Documentation from Texas Instruments ............................. ............................. 70 6.13 Important Notice ................................................ ................................................ 71 Chapter 7 Quick Start Guide for bq2750x Family Gas Gauge ....................... ....................... 73 7.1 Introduction ................................................... ................................................... 73 7.2 Getting Started With the bq2750x Evaluation Module........................... ........................... 74 7.3 Software Communication and Trouble Shooting.............................. .............................. 78 7.4 bq2750x Evaluation Software Sections ................................... ................................... 82 7.5 Creating Your Golden Image ......................................... ......................................... 86 SLUA458–July 2008 3 Submit Documentation Feedback www.ti.com 7.6 Example Procedures.............................................. .............................................. 88 Chapter 8 bqEASY™ for Single Cell Impedance Track™ Devices .................... .................... 95 8.1 Introduction ................................................... ................................................... 95 8.2 Software Installation .............................................. .............................................. 96 8.3 Program Navigation and Flowchart ..................................... ..................................... 98 8.4 Configuration Procedures .......................................... .......................................... 100 8.5 bqEASY Data Files.............................................. .............................................. 100 8.6 Completion Checkmarks........................................... ........................................... 101 8.7 Device Detection ............................................... ............................................... 102 Chapter 9 Updating Firmware With the bq2750x and EVM ........................ ........................ 107 9.1 Save Data Flash Content Before and After Firmware Update ..................... ..................... 107 9.2 Update Firmware in the EVM ........................................ ........................................ 111 Design and Development ................................................ ................................................ 113 Chapter 10 Host-Side Gas-Gauge-System Design Considerations for Single-Cell Handheld Apps .............................................................. .............................................................. 114 Chapter 11 Single Cell Gas Gauge Circuit Design .............................. .............................. 115 11.1 Introduction .................................................. .................................................. 116 11.2 High-Current Path............................................... ............................................... 116 11.3 Gas Gauge Circuit .............................................. .............................................. 117 11.4 Current and Voltage Protection....................................... ....................................... 119 11.5 Reference Design Schematic ........................................ ........................................ 120 Chapter 12 Single Cell Impedance Track Printed-Circuit Board Layout Guide .......... .......... 121 12.1 Introduction .................................................. .................................................. 121 12.2 Power Supply Decoupling Capacitor.................................... .................................... 121 12.3 Capacitors ................................................... ................................................... 122 12.4 Communication Line Protection Components............................... ............................... 122 12.5 Protector FET Bypass and Pack Terminal Bypass Capacitors..................... ..................... 122 12.6 Ground System ................................................ ................................................ 122 12.7 Kelvin Connections.............................................. .............................................. 123 12.8 Board Offset Considerations ........................................ ........................................ 123 12.9 ESD Spark Gap................................................ ................................................ 124 12.10 Unwanted Magnetic Coupling........................................ ........................................ 124 Chapter 13 ESD and RF Mitigation in Handheld Battery Pack Electronics ............. ............. 127 13.1 ESD Issues .................................................. .................................................. 127 13.2 ESD Mitigation ................................................ ................................................ 127 13.3 RF Issues ................................................... ................................................... 129 13.4 RF Mitigation ................................................

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