SLUUBD4A April   2016  – November 2022 BQ27220

 

  1.   Read This First
    1. 1.1 About This Manual
    2. 1.2 Formatting conventions used in this document:
    3. 1.3 Related Documentation from Texas Instruments
    4. 1.4 Trademarks
  2. 2General Description
    1. 2.1 Gas Gauging
      1. 2.1.1  CEDV Gas Gauging Operational Overview
      2. 2.1.2  Main Fuel Gauge Registers
      3. 2.1.3  Capacity Learning (FCC Update) and Qualified Discharge
      4. 2.1.4  End-of-Discharge Thresholds and Capacity Correction
      5. 2.1.5  EDV Discharge Rate and Temperature Compensation
      6. 2.1.6  EDV Age Factor
      7. 2.1.7  Self-Discharge
      8. 2.1.8  Battery Electronic Load Compensation
      9. 2.1.9  CEDV Configuration
      10. 2.1.10 Initial Battery Capacity at Device Reset
      11. 2.1.11 Fuel Gauge Operating Modes
      12. 2.1.12 Qmax
      13. 2.1.13 CEDV Smoothing
  3. 3Standard Data Commands
    1. 3.1  Standard Commands
    2. 3.2  Control()/CONTROL_STATUS(): 0x00 and 0x01
      1. 3.2.1  CONTROL_STATUS: 0x0000
      2. 3.2.2  DEVICE_NUMBER: 0x0001
      3. 3.2.3  FW_VERSION: 0x0002
      4. 3.2.4  HW_VERSION: 0x0003
      5. 3.2.5  BOARD_OFFSET: 0x0009
      6. 3.2.6  CC_OFFSET: 0x000A
      7. 3.2.7  CC_OFFSET_SAVE: 0x000B
      8. 3.2.8  OCV_CMD: 0x000C
      9. 3.2.9  BAT_INSERT: 0x000D
      10. 3.2.10 BAT_REMOVE: 0x000E
      11. 3.2.11 SET_SNOOZE: 0x0013
      12. 3.2.12 CLEAR_SNOOZE: 0x0014
      13. 3.2.13 SET_PROFILE_1/2/3/4/5/6: 0x0015–0x001A
      14. 3.2.14 CAL_TOGGLE: 0x002D
      15. 3.2.15 SEALED: 0x0030
      16. 3.2.16 RESET: 0x0041
      17. 3.2.17 OPERATION_STATUS: 0x0054
      18. 3.2.18 GaugingStatus: 0x0056
      19. 3.2.19 EXIT_ CAL: 0x0080
      20. 3.2.20 ENTER_CAL: 0x0081
      21. 3.2.21 ENTER_CFG_UPDATE: 0x0090
      22. 3.2.22 EXIT_CFG_UPDATE_REINIT: 0x0091
      23. 3.2.23 EXIT_CFG_UPDATE: 0x0092
      24. 3.2.24 ENTER_ROM: 0x0F00
    3. 3.3  AtRate(): 0x02 and 0x03
    4. 3.4  AtRateTimeToEmpty(): 0x04 and 0x05
    5. 3.5  Temperature(): 0x06 and 0x07
    6. 3.6  Voltage(): 0x08 and 0x09
    7. 3.7  BatteryStatus(): 0x0A and 0x0B
    8. 3.8  Current(): 0x0C and 0x0D
    9. 3.9  RemainingCapacity(): 0x10 and 0x11
    10. 3.10 FullChargeCapacity(): 0x12 and 0x13
    11. 3.11 TimeToEmpty(): 0x16 and 0x17
    12. 3.12 TimeToFull(): 0x18 and 0x19
    13. 3.13 StandbyCurrent(): 0x1A and 0x1B
    14. 3.14 StandbyTimeToEmpty(): 0x1C and 0x1D
    15. 3.15 MaxLoadCurrent(): 0x1E and 0x1F
    16. 3.16 MaxLoadTimeToEmpty(): 0x20 and 0x21
    17. 3.17 RawCoulombCount(): 0x22 and 0x23
    18. 3.18 AveragePower(): 0x24 and 0x25
    19. 3.19 InternalTemperature(): 0x28 and 0x29
    20. 3.20 CycleCount(): 0x2A and 0x2B
    21. 3.21 StateOfCharge(): 0x2C and 0x2D
    22. 3.22 StateOfHealth(): 0x2E and 0x2F
    23. 3.23 ChargingVoltage(): 0x30 and 0x31
    24. 3.24 ChargingCurrent(): 0x32 and 0x33
    25. 3.25 BTPDischargeSet(): 0x34 and 0x35
    26. 3.26 BTPChargeSet(): 0x36 and 0x37
    27. 3.27 OperationStatus(): 0x3A and 0x3B
    28. 3.28 DesignCapacity(): 0x3C and 0x3D
    29. 3.29 MACData(): 0x40 through 0x5F
    30. 3.30 MACDataSum(): 0x60
    31. 3.31 MACDataLen(): 0x61
    32. 3.32 AnalogCount(): 0x79
    33. 3.33 RawCurrent(): 0x7A and 0x7B
    34. 3.34 RawVoltage(): 0x7C and 0x7D
  4. 4Data Memory Interface
    1. 4.1 Accessing the Data Memory
    2. 4.2 Device Access Modes
    3. 4.3 Sealing and Unsealing Data Memory Access
    4. 4.4 Data Memory Summary
  5. 5Functional Description
    1. 5.1 Device Configuration
      1. 5.1.1 CEDV Smoothing Config Register
      2. 5.1.2 Operation Configuration A (Operation Config A) Register
      3. 5.1.3 Operation Configuration B (Operation Config B) Register
    2. 5.2 External Pin Functions
      1. 5.2.1 Pin Function Code (PFC) Descriptions
      2. 5.2.2 Battery Presence Detection Using the BIN/TOUT Pin
      3. 5.2.3 SOC_INT Pin Behavior
      4. 5.2.4 Power Path Control With the BAT_GD Pin
      5. 5.2.5 Battery Trip Point (BTP) Interrupts
      6. 5.2.6 Wake-Up Comparator
      7. 5.2.7 Autocalibration
    3. 5.3 Temperature Measurement
      1. 5.3.1 Overtemperature Indication
        1. 5.3.1.1 Overtemperature: Charge
        2. 5.3.1.2 Overtemperature: Discharge
    4. 5.4 Charging and Charge Termination Indication
      1. 5.4.1 Detecting Charge Termination
      2. 5.4.2 Charge Inhibit
    5. 5.5 Power Modes
      1. 5.5.1 NORMAL Mode
      2. 5.5.2 SLEEP Mode
    6. 5.6 CONFIG UPDATE Mode
    7. 5.7 BAT INSERT CHECK Mode
    8. 5.8 Application-Specific Information
      1. 5.8.1 Battery Profile Storage and Selection
      2. 5.8.2 First OCV Measurement
    9. 5.9 Additional Data Memory Parameter Descriptions
      1. 5.9.1  Calibration
        1. 5.9.1.1 CC Gain
        2. 5.9.1.2 CC Delta
      2. 5.9.2  Coulomb Counter Offset
      3. 5.9.3  Board Offset
      4. 5.9.4  Int Temp Offset
      5. 5.9.5  Ext Temp Offset
      6. 5.9.6  Pack VOffset
      7. 5.9.7  Internal Temp Model
      8. 5.9.8  Ext a Coef and Ext b Coef
      9. 5.9.9  Filter
      10. 5.9.10 Deadband
      11. 5.9.11 CC Deadband
      12. 5.9.12 SOC Flag Configuration A (SOC Flag Config A) Register
      13. 5.9.13 SOC Flag Configuration B (SOC Flag Config B) Register
      14. 5.9.14 CEDV Gauging Configuration (CEDV Config) Register
      15. 5.9.15 EMF
      16. 5.9.16 C0
      17. 5.9.17 R0
      18. 5.9.18 T0
      19. 5.9.19 R1
      20. 5.9.20 TC
      21. 5.9.21 C1
      22. 5.9.22 Age Factor
      23. 5.9.23 Fixed EDV0
      24. 5.9.24 Fixed EDV1
      25. 5.9.25 Fixed EDV2
      26. 5.9.26 Battery Low %
      27. 5.9.27 Low Temp Learning
      28. 5.9.28 Overload Current
      29. 5.9.29 Self Discharge Rate
      30. 5.9.30 Electronic Load
      31. 5.9.31 Near Full
      32. 5.9.32 Reserve Capacity
      33. 5.9.33 Charge Efficiency
      34. 5.9.34 Discharge Efficiency
      35. 5.9.35 Qmax Cell 1 and Qmax Pack
      36. 5.9.36 Learned Full Charge Capacity
      37. 5.9.37 DOD at EDV2
      38. 5.9.38 Cycle Count
      39. 5.9.39 Design Capacity
      40. 5.9.40 Design Voltage
      41. 5.9.41 Cycle Count %
      42. 5.9.42 Charge Inhibit Temp Low
      43. 5.9.43 Charge Inhibit Temp High
      44. 5.9.44 Temp Hys
      45. 5.9.45 Fast Charge Current
      46. 5.9.46 Charging Voltage
      47. 5.9.47 Taper Current
      48. 5.9.48 Taper Voltage
      49. 5.9.49 SOC Delta
      50. 5.9.50 Clock Control Register
      51. 5.9.51 Sleep Current
      52. 5.9.52 Offset Calibration Inhibit Temperature Low
      53. 5.9.53 Offset Calibration Inhibit Temperature High
      54. 5.9.54 Sleep Voltage Time
      55. 5.9.55 Sleep Current Time
      56. 5.9.56 Dsg Current Threshold
      57. 5.9.57 Chg Current Threshold
      58. 5.9.58 Quit Current
      59. 5.9.59 Dsg Relax Time
      60. 5.9.60 Chg Relax Time
      61. 5.9.61 Quit Relax Time
      62. 5.9.62 OT Charge
        1. 5.9.62.1 OT Charge Time
      63. 5.9.63 OT Chg Recovery
      64. 5.9.64 OT Discharge
        1. 5.9.64.1 OT Discharge Time
      65. 5.9.65 OT Dsg Recovery
      66. 5.9.66 Initial Standby Current
      67. 5.9.67 Default Temperature
      68. 5.9.68 Device Name
      69. 5.9.69 System Down Set Voltage
      70. 5.9.70 System Down Set Voltage Time
      71. 5.9.71 System Down Clear Voltage
      72. 5.9.72 Full Reset Counter
      73. 5.9.73 Reset Counter Watchdog
  6. 6Communications
    1. 6.1 I2C Interface
    2. 6.2 I2C Time Out
    3. 6.3 I2C Command Waiting Time
    4. 6.4 I2C Clock Stretching
  7. 7Application Examples
    1. 7.1 Data Memory Parameter Update Example
  8. 8Open-Circuit Voltage Measurement Background
    1. 8.1 Background
      1. 8.1.1 OCV Qualification and Calculation
      2. 8.1.2 OCV Calculation Assumption
      3. 8.1.3 OCV Timing
    2. 8.2 OCV Timing and OCV_CMD Use Recommendations
      1. 8.2.1 ACTIVE Mode (Fuel Gauge Is Not in SLEEP Mode)
      2. 8.2.2 SLEEP Mode
      3. 8.2.3 Initial OCV – POR
  9. 9Updating BQ27220 Configuration Parameters
    1. 9.1  Gauge Mode FlashStream (gm.fs) Files
      1. 9.1.1 Write Command
      2. 9.1.2 Read and Compare Command
      3. 9.1.3 Wait Command
      4. 9.1.4 CONFIG UPDATE Mode
    2. 9.2  OTP Mode FlashStream (ot.fs) Files
      1. 9.2.1 Write Command
      2. 9.2.2 Read and Compare Command
      3. 9.2.3 Wait Command
      4. 9.2.4 CONFIG UPDATE Mode
    3. 9.3  Programming Instructions
      1. 9.3.1 Using gm.fs Files
      2. 9.3.2 Using ot.fs Files
    4. 9.4  General Setup and Software Installation to Program OTP
    5. 9.5  Launch BQStudio Software
    6. 9.6  Load .GG File
    7. 9.7  Confirm or Update Data Memory Parameters
    8. 9.8  Save .OTFS File
    9. 9.9  Launch SmartFlash Software
    10. 9.10 Open Ot.fs File
    11. 9.11 Program OTP
    12. 9.12 Confirm Success
  10.   A Battery Gauge Glossary
    1.     A.1 Glossary
  11.   B Revision History

2 General Description

The BQ27220 fuel gauge, using compensated end-of-discharge voltage (CEDV) technology, accurately predicts the battery capacity and other operational characteristics of a single series, Li-based rechargeable cell. It can be interrogated by a system processor to provide cell information such as time-to-empty (TTE), state-of-charge (SOC), and the SOC interrupt signal to the host.

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(), read and write information contained within the device control and status registers, as well as its data memory locations. Commands are sent from system to gauge using the I2C serial communications engine, and can be executed during application development, system manufacture, or end-equipment operation.

Cell information is stored in the device in One-Time Programmable (OTP) memory. Many of these data memory locations are accessible during application development. They cannot, in general, be accessed directly during end-equipment operation. Access to these locations is achieved by either using the companion evaluation software, through individual commands, or through a sequence of data-flash–access commands. To access a desired data memory location, the correct data memory address must be known.

The fuel gauge measures charge and discharge activity by monitoring the voltage across a small-value series sense resistor (5 mΩ to 20 mΩ, typical) located between the system VSS and the battery PACK– terminal. When a cell is attached to the device, information is based on cell current, cell open-circuit voltage (OCV), and cell voltage under loading conditions.

The external temperature sensing is optimized with the use of a high-accuracy negative temperature coefficient (NTC) thermistor with R25 = 10.0 kΩ ±1%. B25/85 = 3435 kΩ ± 1% (such as Semitec NTC 103AT). Alternatively, the fuel gauge can be configured to use its internal temperature sensor or receive temperature data from the host processor. The fuel gauge uses temperature to monitor the battery-pack environment, which is used for gas gauging and cell protection functionality.

To minimize power consumption, the fuel gauge has several power modes: INITIALIZATION, NORMAL, SLEEP, and SHUTDOWN. The fuel gauge passes automatically between these modes, depending upon the occurrence of specific events, though a system processor can initiate some of these modes directly.