BQ40Z50-R1 Overcharge Alert

Hong Tay

Expert 2465 points

Other Parts Discussed in Thread: BQ40Z50-R1

Hi Sir/Madam,

We are using BQ40Z50-R1 in battery pack design.

We are getting an OC (overcharge alert) even though the criteria for OC was not met.

Criteria: Remaining Capacity >= Full charge capacity and Internal Charge > 0

Our OC threshold is set at 456mA.

The OC alert happened during the test when:

Remaining Capacity = 4329mAh

Full charge capacity = 4373mAh

Voltage = 4.187V

Current = 735mA

Please advise. Thank you very much.

over 9 years ago

0 Hong Tay over 9 years ago

Expert 2465 points

Hi Sir/Madam,

Any advice? Thank you.

0 Hong Tay over 9 years ago in reply to Hong Tay

Expert 2465 points

Hi Sir/Madam,

Any advice? Thank you very much.

0 Hong Tay over 9 years ago in reply to Hong Tay

Expert 2465 points

HI Sir/Madam,

Any response from you guys?

Thanks.

0 ThomasCosby over 9 years ago in reply to Hong Tay

TI__Guru 73830 points

The [OC] should not be set for those RM and FCC conditions. Please export an srec from the pack and we will check it.

0 Hong Tay over 9 years ago in reply to ThomasCosby

Expert 2465 points

Hi Thomas,

Thanks for your support. SREC file is attached. Hope to hear from you soon.https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/196/_2300_2-sample-SREC.7z

0 ThomasCosby over 9 years ago in reply to Hong Tay

TI__Guru 73830 points

Is this the same [OC] fault case that Zenn Tan reported in this e2e forum link?

e2e.ti.com/.../1902849

If it is, then the [OC] alert is valid, because RemCap does exceed FCC inside the gauge, but it is clamped until charge termination, because RSOCL is set. It should be ok after the optimization cycle has completed. You srec file shows that the optimization cycle has completed not. You try another run and see f the fault occurs. Log the data, so that we will have something to analyze.

0 Hong Tay over 9 years ago in reply to ThomasCosby

Expert 2465 points

Hi Thomas,

Thanks for the advice.

Two test has been conducted and attached is the log file with the result as below.

#1 test log, OC alert turned on when charging continued for about 10secs after VCT flag is raised.

Because CSYNC is on, Rem Cap was updated to FCC. Because the charging continued, I think

OC alert turned on.

#2 test log, we turned off CYSNC and left RSOCL on. OC alert did not turn on but RSOC did not

reach 100%

Is there a way to prevent OC alert with RSOC becoming 100%?

Thank you very much.

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/196/logfile.7z

0 Hong Tay over 9 years ago in reply to Hong Tay

Expert 2465 points

Hi Thomas,

Any advice?

Thank you very much.

0 Hong Tay over 9 years ago in reply to Hong Tay

Expert 2465 points

Hi Thomas,

Any update?

Thanks.

0 ThomasCosby over 9 years ago in reply to Hong Tay

TI__Guru 73830 points

I the case where the SOC did not reach 100%, the pack had not been allowed to rest long enough to set a DOD point and clear the Passed Charge register. This caused RemCap to delay counting at the beginning of discharge. teh SOC should have reached 100%, if Passed Charge had cleared. Setting the RSOCL will allow SOC to be forced to 100%, even if Passed Charge has not cleared.

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BQ40Z50-R1 Overcharge Alert