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

2.1 Calibration Accuracy

There are a few options to consider when implementing calibration in production depending on the needed accuracy and production test equipment capability and test time. Let's take cell voltage calibration as an example. Below are a few different options listed ranging from least accurate (1) to most accurate (4).

  1. No production calibration, use default values.
  2. Perform calibration on a fixed number of devices and use the average values of the calibration parameters for all packs. This might be a good option if the variation observed from board to board is small and acceptable.
  3. Calibrate each device individually in production by applying a single accurate voltage applied to the cell input, such as 3.5 V. Averaging the measurement over several readings can further improve accuracy.
  4. Calibrate each device individually in production by applying two precise DC voltages to the cell input, such as 2.5 V and 4.5 V. Averaging each of the measurements over several readings can further improve accuracy. This will not only allow a more accurate calculation of cell gain, but also enables calibration of cell voltage offset.