SLUAA32A October   2020  – September 2021 BQ769142 , BQ76922 , BQ76942 , BQ76952

 

  1.   Trademarks
  2. 1Production Programming of BQ769x2 Device Family
  3. 2Calibration
    1. 2.1 Calibration Accuracy
    2. 2.2 Cell Voltage Gain Calibration
      1. 2.2.1 Cell Voltage Gain Calibration Steps
    3. 2.3 Cell Voltage Offset Calibration
      1. 2.3.1 Cell Voltage Offset Calibration Steps
    4. 2.4 TOS (Top-of-Stack), PACK, and LD Pin Voltage Calibration
      1. 2.4.1 TOS / PACK / LD Voltage Calibration Steps
    5. 2.5 ADC Gain Calibration
    6. 2.6 Current Calibration
      1. 2.6.1 Board Offset Calibration Steps
      2. 2.6.2 CC Gain Calibration Steps
    7. 2.7 Temperature Calibration
      1. 2.7.1 Temperature Calibration Steps
    8. 2.8 COV and CUV Calibration
      1. 2.8.1 COV Calibration Steps
      2. 2.8.2 CUV Calibration Steps
    9. 2.9 Calibration Code Example
      1. 2.9.1 Code Example
      2. 2.9.2 Code Output
  4. 3OTP Programming
    1. 3.1 Recommended Steps for Writing OTP in Production
  5. 4References
  6. 5Revision History

2.4.1 TOS / PACK / LD Voltage Calibration Steps

The below steps are the same for each of the three voltage measurements. In this example, the steps are shown for a two-point calibration of the PACK pin voltage.

  1. Disable Sleep Mode (Subcommand 0x009A) to ensure voltage counts update quickly after applying a voltage.
  2. Apply a known voltage, VPACK_A, between PACK+ and VSS.
  3. After 100ms, read the PACK Pin ADC Counts (ADC_CountsPACK_A) using the READ_CAL1 subcommand 0xF081. For best accuracy, take multiple readings and calculate the average.
  4. Apply a second known voltage, VPACK_B, between PACK+ and VS and read the PACK Pin ADC Counts. (ADC_CountsPACK_B).
  5. Calculate the Pack Gain:
    Equation 2. GUID-A8BE12AB-962C-45D1-91FF-6D6BE3501E00-low.gif
  6. Write the new Pack Gain value to RAM.
    • Enter CONFIG_UPDATE mode (Subcommand 0x0090).
    • Write Pack Gain to 0x91A0.
    • Exit CONFIG UPDATE mode (Subcommand 0x0092).
  7. Re-check the Pack voltage reading. If the reading is not accurate, repeat steps 1-5.
Table 2-3 TOS, PACK, LD Voltage Calibration Settings
Parameter Name Physical Start Address Type Min Max Default Units
Pack Gain 0x91A0 I2 0 65535 35507 -
TOS Gain 0x91A2 I2 0 65535 35507 -
LD Gain 0x91A4 I2 0 65535 35507 -
Vdiv Offset 0x91B2 I2 -32767 32767 0 userV
ADC Gain 0x91A6 I2 -32767 32767 4166 -