BQ27510-G3: Low Current Application

Andrew Orosz

Part Number: BQ27510-G3
Other Parts Discussed in Thread: BQ27510, BQSTUDIO, EV2400

A product that I am working on is using the BQ27510-G3. It has been observed that the fuel gauge has reported incorrectly in the following instance.

When testing the device's battery life in shelf mode, the device did not report a linear discharge, which was expected. The reported discharge was closer to an exponential trend line. Current draw while in shelf mode is in the range of 50 - 100 uA. The biggest difference observed between expected and actual SoC was roughly 20%.

It seems that the BQ27510 relies on open circuit voltage (OCV) measurements when the current is low. Is it possible that there is something in the implementation of the BQ27510 that would cause the OCV measurements to be off?

over 5 years ago

0 Dominik Hartl11 over 5 years ago

TI__Guru 62076 points

Do both filtered and unfiltered RM and both smoothed SOC and true SOC change unexpectedly or only the filtered/smoothed values?

0 Andrew Orosz over 5 years ago in reply to Dominik Hartl11

Prodigy 30 points

The SOC value I was referring to is shown below. RM was not being used.

The SOC value appears to not be smoothed. See below the data returned from a read of OpConfig D register.

0 Kang Kang over 5 years ago in reply to Andrew Orosz

TI__Mastermind 24870 points

Hello Andrew,

Can you provide a bqStudio log file and your gg.csv file at the beginning of the test?

What do you mean the SOC is not being smoothed?

0 Andrew Orosz over 5 years ago in reply to Kang Kang

Prodigy 30 points

There is no log file for the test because the test was ran on a fully assembled device to determine the shelf mode battery life. I have attached the gg.csv file.

Regarding the SOC not being smoothed, the previous reply shows 00 at register 5E. This seems to show that bit6 (SMTHEN) is low, meaning that the SOC value is not being smoothed/filtered. See picture below taken from SLUUA97.

2337.0510_4_00-bq27510G3.gg.csv

0 Kang Kang over 5 years ago in reply to Andrew Orosz

TI__Mastermind 24870 points

In order to further debug, is it possible to take the battery out and put it on EV2400 + bqStudio to get a log file to look at RSOC performance?

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BQ27510-G3: Low Current Application