BQ76942: OTP programming bq76942

Rajesh Gulati

Part Number: BQ76942
Other Parts Discussed in Thread: BQSTUDIO

We have fabricated and assembled the two layer test board avaiable on TI website for 7 cell BMS(3.7V*7=25.9V battery).

Using the bqstudio and BQ76942EVM we are able to communicate with the 2 layer board device using jumpers.

Pls help us generate the OTP image file for the device on 2layer test board to work in standalone mode (without processor).

Below is our specs:-

1.) Over voltage protection:30V(4.28V per cell)

2.) Under Voltage protection:19.8V(2.82V per cell)

3.) Operating temp range:- -30 C to +55C

Kindly share the OTP file which we can directly burn in the OTP on the test board available on TI website so that the above specs are met, when device boots in standlaone mode.

Or atleast share the configuration file generation steps.

over 1 year ago

0 Luis H. S. over 1 year ago

TI__Mastermind 42060 points

Hello Rajesh,

Please follow the BQ769x2 Calibration and OTP Programming Guide to understand how to perform OTP on the device. This highlights every step to successfully perform OTP.

You can also OTP with bqStudio with your desired settings.

There is also an FAQ that you can refer to:

Common questions for OTP programming with the Bq769x2 Device Family

Best Regards,

Luis Hernandez Salomon

0 Rajesh Gulati over 1 year ago in reply to Luis H. S.

Prodigy 75 points

is callibration necessary on all the boards??or it is required only on one board.

Also can u pls share the programming OTP steps using bqstudio.

0 Luis H. S. over 1 year ago in reply to Rajesh Gulati

TI__Mastermind 42060 points

Hello Rajesh,

The way we usually recommend it is to get the calibration values for 5-10 boards, then take an average and use those calibration values for all the boards in manufacturing. Follow the steps in BQ769x2 Calibration and OTP Programming Guide for guidelines/recommendations.

To program in bqStudio, you just have to use the "Program Data Memory to OTP Memory". See this previous E2E thread: https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1190999/bq76952-using-bqstudio-to-partially-program-otp

Best Regards,

Luis Hernandez Salomon

0 Rajesh Gulati over 1 year ago in reply to Luis H. S.

Prodigy 75 points

We have generated OTP file using BQStudio for our below specs:---

1.) Over voltage protection:30V(4.28V per cell)

2.) Under Voltage protection:19.8V(2.82V per cell)

We have fabricated 2layer test board for 7cell configuration.(given on TI website)

The output came once on PACK+ and PACK-, however when short circuit happened on PACK+ and PACK- pins pins the output has got disabled.

Even on resetting the device ,output is not coming.Pls suggest.The BQStudio OTP config file is attached.final.gg.csv

The board schematic is also attachedPR2387(001)_Sch.PDF

0 Luis H. S. over 1 year ago in reply to Rajesh Gulati

TI__Mastermind 42060 points

Hello Rajesh,

So OVP was set to 4.28-V and UVP was set to 2.82-V, correct?

What is the REG18 voltage? Are there any faults being triggered? Do you have a bqStudio or way to check what faults were triggered? Was the part damaged during the short-circuit event?

Waveforms during the SCD on the BAT+ and PACK+ may be good to see.

Best Regards,

Luis Hernandez Salomon

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BQ76942: OTP programming bq76942