BQ27426: Calibration during production

Yoshinobu Kagawa

Expert 2030 points

Part Number: BQ27426

Tool/software:

The above thread mentions “As I have read, it is recommended to calibrate at least 10 gauges in the end device and average the numbers to load the right value in the RAM memory.".

Performing current calibration will cause the values of the following three items to fluctuate.
・CC Offset
・CC Gain
・CC Delta

TRM states that “CC Offset, CC Gain, and CC Delta are internal calibration parameters that require no customer changes　and are provided for debug purposes only.” as following.

Is it correct to understand that current calibration is not necessary?
Is the average value only written for other data?

Regards,
Kagawa

24 days ago

0 Alan Frias 24 days ago

TI__Mastermind 26945 points

Hello,

This question has been assigned and will be reviewed when possible.

Thank you,
Alan

0 Yoshinobu Kagawa 18 days ago in reply to Alan Frias

Expert 2030 points

Hi Alan-san,

How about this ?

Regards,

Kagawa

0 Dominik Hartl11 18 days ago in reply to Yoshinobu Kagawa

TI__Guru 62006 points

Calibration is only necessary if the sense resistor that you use is not 10mOhm. If you use a 10mOhm +/-1% sense resistor then you do not have to calibrate the gauge,

0 Yoshinobu Kagawa 18 days ago in reply to Dominik Hartl11

Expert 2030 points

Hi Dominik-san,

The Board Offset Calibration section of bq40zxx Manufacture, Production, and Calibration (SLUA734A) states the following.
Is the same procedure acceptable for the BQ27426?

Regards,
Kagawa

0 Dominik Hartl11 17 days ago in reply to Yoshinobu Kagawa

TI__Guru 62006 points

Board Offset is almost always negligible. There is no need to calibrate this unless something is seriously problematic on the board (a constant voltage offset on the board for SRP-SRN, which is usually not the case).

0 Yoshinobu Kagawa 12 days ago in reply to Dominik Hartl11

Expert 2030 points

Hi Dominik-san,

Data before and after calibration for three BQ27426 devices. Is calibration unnecessary for differences of this magnitude?

Regards,
Kagawa

0 Dominik Hartl11 12 days ago in reply to Yoshinobu Kagawa

TI__Guru 62006 points

CC Offset and CC Delta are automatically calibrated during use so these values will change regularly.

Board Offset is basically the same in your examples. There is no need to calibrate individually.

Power management

Power management forum

BQ27426: Calibration during production