BQ40Z50EVM-561: Detecting wrong number of cells

Nosherwan Ahmed

Part Number: BQ40Z50EVM-561
Other Parts Discussed in Thread: BQ40Z50, BQSTUDIO

Hello,

I just started working with the EVM for BQ40Z50. I set up everything according to the user guide and am using 3 resistors to simulate a 3S configuration for Li-ion battery. The pack+ and pack- are coming from the power supply @ 10.8V (3.6V per Li-ion cell). However when i open up bqStudio, it shows 0V for cell 3 and cell 4 which leads me to believe that it thinks only two cells in series are connected but that is not the case. I double checked the CC bits in the DA Configuration register and it is indeed set to (10)b .Can anyone help to figure out a solution to this issue?

Thanks

Nosherwan

over 6 years ago

0 Batt over 6 years ago

TI__Mastermind 42535 points

Set DA config to 10 and short cells 3 and 4, 3P and 4P. If your resistors are matched you should see nearly the same voltage across them. You have to connect your pack across GND and 4P.

0 Nosherwan Ahmed over 6 years ago in reply to Batt

Prodigy 170 points

I have tried it right now. I can read the voltage on the pins manually using a DMM however bqStudio still shows 0 mv for cell 3 and cell 4 Voltage

0 Batt over 6 years ago in reply to Nosherwan Ahmed

TI__Mastermind 42535 points

Send a reset. POR the evm.

0 Nosherwan Ahmed over 6 years ago in reply to Batt

Prodigy 170 points

I sent a reset command from the gui but that did not fix it. Instead now it is showing a non-zero value for cell 1 voltage

0 Batt over 6 years ago in reply to Nosherwan Ahmed

TI__Mastermind 42535 points

What fw are you using? Send me your srec and screenshot of the ram registers and a small log of the ram registers with a 1s logging interval.

0 Nosherwan Ahmed over 6 years ago in reply to Batt

Prodigy 170 points

bq40z50_r1_v1_06_build_36.zipI am using the most recent srec file from TI website. I have attached it as well. However, I programmed the firmware again and that does seem to have fixed the issue. That raises the question that do i need to reprogram it every time i power the evaluation board up?

0 Batt over 6 years ago in reply to Nosherwan Ahmed

TI__Mastermind 42535 points

No, you don't need to program it all the time when you power up.

Power management

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BQ40Z50EVM-561: Detecting wrong number of cells