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

2.2.1 Cell Voltage Gain Calibration Steps

The below steps are the same for each of the cells. In this example, the steps are shown for a two-point calibration of Cell 1.

  1. Disable Sleep Mode (Subcommand 0x009A) to ensure voltage counts update quickly after applying a voltage.
  2. Apply a known voltage, VCELL1_A, between device pins VC1 and VC0.
  3. After 100ms, read the Cell 1 Voltage Counts (ADC_CountsCELL1_A) using the DASTATUS1 subcommand 0x0071. A full list of commands for calibration voltage readings is provided in Table 2-1. For best accuracy, take multiple readings and calculate the average.
  4. Apply a second known voltage, VCELL1_B, between VC1 and VC0 and read the Cell 1 Voltage Counts.(ADC_CountsCELL1_B).
  5. Calculate the Cell 1 Gain:
    Equation 1. GUID-E97738AE-5D7D-41D9-B888-F9182EBC0FC8-low.gif
  6. Write the new Cell 1 Gain value to RAM.
    • Enter CONFIG_UPDATE mode (Subcommand 0x0090).
    • Write Cell 1 Gain to RAM location 0x9180.
    • Exit CONFIG UPDATE mode (Subcommand 0x0092).
  7. Re-check the Cell 1 voltage reading. If the reading is not accurate, repeat steps 1-6.
Table 2-1 Voltage and Current Measurement Subcommands for Calibration
Subcommand Address Name Offset Data Type
0x0071 DASTATUS1 0 Cell 1 Voltage Counts I4
4 Cell 1 Current Counts I4
8 Cell 2 Voltage Counts I4
12 Cell 2 Current Counts I4
16 Cell 3 Voltage Counts I4
20 Cell 3 Current Counts I4
24 Cell 4 Voltage Counts I4
28 Cell 4 Current Counts I4
0x0072 DASTATUS2 0 Cell 5 Voltage Counts I4
4 Cell 5 Current Counts I4
8 Cell 6 Voltage Counts I4
12 Cell 6 Current Counts I4
16 Cell 7 Voltage Counts I4
20 Cell 7 Current Counts I4
24 Cell 8 Voltage Counts I4
28 Cell 8 Current Counts I4
0x0073 DASTATUS3 0 Cell 9 Voltage Counts I4
4 Cell 9 Current Counts I4
8 Cell 10 Voltage Counts I4
12 Cell 10 Current Counts I4
16 Cell 11 Voltage Counts I4
20 Cell 11 Current Counts I4
24 Cell 12 Voltage Counts I4
28 Cell 12 Current Counts I4
0x0074 DASTATUS4 0 Cell 13 Voltage Counts I4
4 Cell13 Current Counts I4
8 Cell 14 Voltage Counts I4
12 Cell 14 Current Counts I4
16 Cell 15 Voltage Counts I4
20 Cell 15 Current Counts I4
24 Cell 16 Voltage Counts I4
28 Cell 16 Current Counts I4
0xF081 READ_CAL1 0 Calibration Data Counter U2
2 CC2 Counts I4
6 PACK pin ADC Counts I2
8 Top of Stack (TOS) ADC Counts I2
10 LD pin ADC Counts I2
Table 2-2 Cell Voltage Calibration Settings
Parameter Name Physical Start Address Type Min Max Default Units
Cell 1 Gain 0x9180 I2 -32767 32767 12409 -
Cell 2 Gain 0x9182 I2 -32767 32767 12409 -
Cell 3 Gain 0x9184 I2 -32767 32767 12409 -
Cell 4 Gain 0x9186 I2 -32767 32767 12409 -
Cell 5 Gain 0x9188 I2 -32767 32767 12409 -
Cell 6 Gain 0x918A I2 -32767 32767 12409 -
Cell 7 Gain 0x918C I2 -32767 32767 12409 -
Cell 8 Gain 0x918E I2 -32767 32767 12409 -
Cell 9 Gain 0x9190 I2 -32767 32767 12409 -
Cell 10 Gain 0x9192 I2 -32767 32767 12409 -
Cell 11 Gain 0x9194 I2 -32767 32767 12409 -
Cell 12 Gain 0x9196 I2 -32767 32767 12409 -
Cell 13 Gain 0x9198 I2 -32767 32767 12409 -
Cell 14 Gain 0x919A I2 -32767 32767 12409 -
Cell 15 Gain 0x919C I2 -32767 32767 12409 -
Cell 16 Gain 0x919E I2 -32767 32767 12409 -
Vcell Offset 0x91B0 I2 -32767 32767 0 -