BQ27530-G1: Query on Fuel Gauge Learning cycle in BQSTUDIO(VOK and RUPDIS bit setting issue)

Hi Mythili,

Is it possible to receive the .gg file of this gauge?

From what I can see from the log file, the gauge is entering sleep mode at 31542.6 seconds, making the voltage almost drop to 0V. The .gg file will allow us to see what thresholds are causing this to enter sleep mode.

Regards,

Anthony Baldino

Hi Anthony,

I have attached .gg file for your reference

7028.GG_file.zip

Warm Regards,

Mythili B

Hi Mythili,

Thank you for sending the .gg file.

Regarding the log file, can you please confirm if there something occurring that would make the voltage reading go to 0V such as the cells being disconnected?

Regards,

Anthony Baldino

Hi Anthony,

Nowhere I have seen 0V in log file. Only current it is 0mA because it is in relaxation time

Fuel Gauge is entering into sleep mode during relaxation time because Sleep current threshold is set as 10mA.

We have cleared OPCONFIG[SLEEP] bit after that fuel gauge has not entered into sleep mode, Is it ok to proceed with clearing the SLEEP bit?

While calibration after clearing SLEEP bit, VOK and RUPDIS bits are updating properly

Warm Regards,

Mythili B

Hi Mythili,

Below is the voltage graph of the sent learning cycle where the voltage is dropping to around 5mV:

During this time, there is still communication occurring between the gauge and the host, so we do not believe that this is being caused by the gauge is entering sleep mode. Can you please tell us if your battery pack has any attached protections on it? This discharge cycle could be triggering one of them and sending the battery cell into this state.

Regards,

Anthony Baldino

Hi Anthony,

Yes, battery has over discharge protection and it will not discharge beyond 3V

Still I2C communication is happening because fuel gauge is getting power from battery charger and we have disabled charging since it is in relaxation period

In learning cycle process, we have cleared OPCONFIG[SLEEP] bit after that fuel gauge has not entered into sleep mode

We have done Discharge-Relaxation-Charge-Relaxation-Discharge cycle. At the final discharge cycle, RDIS bit is set in between the discharging process and second QMAX value is not updated. But when we proceeded with another charging cycle QMAX value updated and UPDATE_STATUS also updated to 0x02

So, Can we consider that the learning cycle is completed. Please suggest us what could be the reason for QMAX update failure after discharge cycle.

I have attached logs and GG files for your reference.

Learning_Cycle_20-01-2024.zip

Warm Regards,

Mythili B

Hi Mythili,

Is there a way to disable the over discharge protection on the battery for the learning cycle?

The voltage drop being caused by this protection is most likely what is causing the problems with this learning cycle, since the OCV reading during relax (when the read voltage is 0V) will not be correct. This will also effect the algorithm and the gauging measurements will not be accurate if used after the learning cycle.

Regards,

Anthony Baldino

Hi Anthony,

Thanks for your response, now QMAX has updated properly and the UPDATE_STATUS is also updated to 0x02.

As per the reference document, once UPDATE_STATUS is updated to 0x02 IT_ENABLE will be disabled. But in our application, IT_ENABLE is not disabled automatically

How to proceed further for generating the golden image?

Will QMAX be updated even after flashing Golden file into the fuel gauge?

Please provide your inputs on the above Queries

Warm Regards,

Mythili B

Hi Mythili,

When the Update Status is changed to 0x02, how long does it take for IT_ENABLE to be disabled?

Mythili Balakrishnan said:

How to proceed further for generating the golden image?

To generate the golden image file (.srec), please go to the bqStudio Golden Image tab and click Create Image:

Mythili Balakrishnan said:

Will QMAX be updated even after flashing Golden file into the fuel gauge?

Yes, Qmax will be updated after flashing the golden image if IT_ENABLE is set. More information about how this is calculated during application is below:

https://e2echina.ti.com/cfs-file/__key/telligent-evolution-components-attachments/00-24-00-00-00-00-02-91/Theory-and-Implementation-of-Impedance-Track-Battery-Fuel_2D00_Gauging-Algorithm.pdf 

Regards,

Anthony Baldino

Hi Anthony,

Once after Update Status changed to 0x02, IT_ENABLE is not disabled at all, Do we need to disable it manually before generating golden file?

Once after flashing the golden image to another fuel gauge, IT_ENABLE should be enabled or disabled before sealing the flash?

Will Qmax be updated even after sealing the flash?

Also, please let us know why the difference between Full Charge Capacity True and Full Charge Capacity Smooth is more sometimes and exactly the values are matching sometimes, Is this an expected one?

Warm Regards,

Mythili B