BQ27Z746: UNUSUAL LIFETIME DATA

Hello Yichong,

When the Impedance Track Algorithm is enabled ([QEN] set in Operation Status), the maximum
current in the discharge direction as measured by Average Current is updated continuously in a
lifetime reserved RAM location. To prevent flash wear out, this RAM only updates Lifetime Max Dsg
Current in Data Flash with any one of the following 3 conditions:
1. Whenever the internal RAM location is greater than (-) Lifetime Max Dsg Current for 60 seconds.
2. If the internal RAM location is greater than (-) Lifetime Max Dsg Current by at least 100 mA.
3. Any other Lifetime Data was updated in data flash with the same criteria as step 1 and 2 for their
respective RAM and Flash locations.

Regards,

Adrian

Hi Adrian, thanks for your respond, I tried to reproduced this  phenomenon, but still can't do that, please  kindly give me an advise how to reproduce, here is the test steps:

1,reset lifetime;

2, discharge with 0.5 A for 1 minute, set shutdown, then wake up, result: max discharge current -502mA, Max Avg Dsg Current -502mA;

3, discharge with 1 A for 1 minute, set shutdown, then wake up, result: max discharge current -1004mA, Max Avg Dsg Current -996mA;

4,discharge with 1.2 A for 1 minute, set shutdown, then wake up, result: max discharge current -1203mA, Max Avg Dsg Current -1203mA;

5,discharge with 0.2 A for 1 minute, set shutdown, then wake up, result: max discharge current -1203mA, Max Avg Dsg Current -1203mA;

Hello Yichong,

You can try to send large current pulses. So, discharge at 100mA and then have -1A pulse for 2 seconds, in intervals of every 5 seconds. Test this and see if this can replicate those results.

Regards,

Adrian

Hi  Adrian:

         thanks for you feedback , I tested in this way and can't replicate those results. below is the log data , please help to check .

lifetime evaluation.log

Hello Yichong,

I will need to look through our firmware code to see if there is any further insight on being able to replicate this phenomenon.

Regards,

Adrian

Hi Adrian,

OK, looking forward for your feedback.

Hello Yichong,

Please allow a delay in response since this week is a holiday in America.

Regards,

Adrian

Hi Adrian:

 of course , hope you enjoy your Thanksgiving Day.

Hello Yichong,

I won't be able to look into the FW code until the FW team is back in office next week. In the mean time, try that testing again when the gauge is sealed and unsealed. Sometimes the FW will behave differently when the gauge is unsealed vs sealed

Regards,

Adrian

Hi Adrian, hope you doing well , could you discuss with FW team and give some feedback?

Hello, 

We are looking into this with the FW team. In the mean time, were you able to perform the test when the gauge is sealed and unsealed? 

Regards, 

Robert. 

HI  Robert, thanks for your feedback, I already performed the test when seal and unseal, but both of them performed the same ( Lifetime Max Discharge Current higher than Lifetime Max Avg Dsg Current )

Hello Yichong,

FW team has been backlogged and they are still looking into my request. Ideally, if you are able to replicate this issue on multiple ICs then this can help the FW team look into it. 

Regards,

Adrian

Hi Adrian, 

Unfortunately , I've tried for several times but  can't replicate this issue on other IC, so I really need your help to find out the root cause.