BQ34110: Will the Coulomb Counter miss fast transient currents?

Austin Brown1

Part Number: BQ34110

Hi all, I'm looking to use the BQ34110 as a battery gas gauge on my electric bike. I was looking at the datasheet and saw that the coulomb counter conversion time is quite slow, taking an entire second for a full conversion, and therefore I'm worried that the IC might miss many of the faster current transients in the system leading to gas gauge inaccuracy. Is this a real worry or am I missing something?

Options:

1. Use the IC anyways and accept any inaccuracy.

2. Use an RC filter on the shunt with a 1 second time constant on it. It will take the average of the current I guess.

3. Use a different IC. Any suggestions?

Please advise! Thanks.

over 5 years ago

0 Kang Kang over 5 years ago

TI__Mastermind 24870 points

Hello Austin,

Please try it on the EVM. The coulomb counter integrates the voltage across the SRN and SRP pins. I don't believe it should miss Qpass. You can test it by running the battery to empty and reading the Qpass register.

0 Austin Brown1 over 5 years ago in reply to Kang Kang

Prodigy 20 points

I understand that it integrates the voltage between SRN and SRP, but the concern is that if the integral is only computed at 1Hz, it will miss fast transients in current.

0 Kang Kang over 5 years ago in reply to Austin Brown1

TI__Mastermind 24870 points

Hello Austin,

It works slightly differently than discrete time. It integrates the voltage across SRN and SRP. Please test on EVM.

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BQ34110: Will the Coulomb Counter miss fast transient currents?