BQ27Z558: Battery Setup Questions

Dmytro Kryvyi

Part Number: BQ27Z558
Other Parts Discussed in Thread: BQ27427, , BQSTUDIO

Tool/software:

Dear TI Support,

We have migrated from the BQ27427 to the BQ27Z558 and are encountering some challenges with the setup and configuration.

Previously, with the BQ27427, we performed a learning cycle before generating the golden image. However, in BQStudio (version 1.3.127), the learning cycle option/tab is no longer available for the BQ27Z558. Despite this, the datasheet indicates that a learning cycle is still required. Could you clarify how the fuel gauge populates the Ra tables in this case? Are there any additional documents or guidelines that outline the proper setup process for this IC?

Additionally, we have observed that the State of Health (SOH) value has dropped to 23. How it can be reset or corrected?

Thank you for your support.

6 months ago

0 Adrian 6 months ago

TI__Mastermind 37761 points

Hello,

For the BQ27z558, there is not a specific learning cycle tab in BQStudio. You will need to just follow the learning cycle document for completing it.

You should complete the learning cycle first and configure the gauge properly before analyzing the SOH register.

https://www.tij.co.jp/jp/lit/an/slua903/slua903.pdf

Regards,

Adrian

0 Dmytro Kryvyi 6 months ago in reply to Adrian

Prodigy 10 points

Hi Adrian,

Thank you for your reply. Just to clarify - are you suggesting that the learning cycle needs to be performed manually by sending commands via BQStudio or the MCU, rather than having a dedicated option in BQStudio for this particular IC?

0 Adrian 6 months ago in reply to Dmytro Kryvyi

TI__Mastermind 37761 points

Hello Dmytro,

That is correct. You will just follow the learning cycle document and send necessary commands manually.

Regards,

Adrian

0 Dmytro Kryvyi 5 months ago

Prodigy 10 points

Hi Adrian,

Thank you for your response.

I'm using a LI-ION (4.2v VDL 73250 110mAh - available in Chemistry Parameters) battery with a 10mΩ shunt resistor and have configured the Data Memory settings accordingly. I’ve also set up the learning cycle following the SLUA903 document you shared.

However, during the Charge step, the FC (Full Charge) bit does not set when charging is complete (as detected by the charger IC). I believe all conditions for Valid Charge Termination are met:

DSG = 0
AvgCurrent < Termination Current
Voltage + Threshold > Charging Voltage
TAPER_VOLT = 0
Charge Capacity > 0.25mAh

Could you please help me identify why the FC bit is not setting and how to resolve this issue?

I have attached the log and Data memory dump here https://limewire.com/d/BnP4X#t4hZpgT0yj

Best regards

0 Adrian 5 months ago in reply to Dmytro Kryvyi

TI__Mastermind 37761 points

Hello,

Please allow me some time to look into this.

Regards,

Adrian

0 Dmytro Kryvyi 5 months ago

Prodigy 10 points

Hello Adrian,

Do you have any updates on my case?

Best regards

0 Adrian 5 months ago in reply to Dmytro Kryvyi

TI__Mastermind 37761 points

Hello Dmytro,

Sorry for taking a while to get back to you, I have been completely back logged at work. I am not able to access the files from the link you sent. TI restricts access to certain outside 3rd party websites. Can you post the log and gg file in the forum directly.

Regards,

Adrian

0 Rez Ameli 5 months ago in reply to Adrian

TI__Intellectual 2855 points

Hi Adrian,

Thanks for your help. Here are the log files Dmytro sent me.

3225.Data memory.gg.csv Learning cycle log.log

regards,

Rez

0 Adrian 5 months ago in reply to Rez Ameli

TI__Mastermind 37761 points

Hello Dmytro,

Sorry for taking a while to get back to you. I was out of office this past Friday. I think we should increase the Charge Term Taper Current to 8mA to see if that setting will trigger VCT.

Regards,

Adrian

0 Dmytro Kryvyi 5 months ago in reply to Adrian

Prodigy 10 points

Hi Adrian,

Thanks for your reply. Could you please explain the reason for changing it? Is there any noise or so affects on that? From the log I'm clearly seeing that we have enough time below tapper current to set VCT.

0 Adrian 5 months ago in reply to Dmytro Kryvyi

TI__Mastermind 37761 points

Hello Dmytro,

I wanted to change taper current to allow more room for the gauge to qualify for setting VCT.

Regards,

Adrian

0 Dmytro Kryvyi 5 months ago

Prodigy 10 points

Hi Adrian,

Thank you for your explanation. However, even after increasing the taper current, the FC flag still doesn't get set. I’ve collected another set of log files and asked Rez Ameli to share them with you, as they're too large to upload here.

Please let me know if you need any additional details.

Power management

Power management forum

BQ27Z558: Battery Setup Questions