BQ35100: bq35100 minimal current sensing

Foulques de Varine

Part Number: BQ35100
Other Parts Discussed in Thread: TIDA-01546

Hello,

I'm interested in monitoring the consumption of an application powered by a primary battery Li-SoCl2 (Very flat discharge). The application a want to monitor has a consumption of few micro amps 99% of the time.

The bq35100 seems like a perfect fit because of the EOS mode. In this mode the bq35100 measures the temperature, voltage and the current to determine the resitance of the battery.

My question is " is the Bq35100 has a sensitivity for this type of current (below 10 to 20µA), or do I need like in the evaluation board TIDA-01546 (using Bq35100) an amplifier with an ADC to see any increese of the current consumption ?"

I hope I've been clear.
Thank you in advanced.

Foulques

over 5 years ago

0 Onyx Ahiakwo over 5 years ago

TI__Guru* 76230 points

Hi Foulques

What is the capacity of the battery? Your load has to be significant enough for the voltage to see a dip for the device to be able to calculate resistance.

thanks
Onyx

0 Foulques de Varine over 5 years ago in reply to Onyx Ahiakwo

Prodigy 20 points

Hi Onyx

Thanks for the quick answer.

The battery we are currently using is an LS17500. The capacity of it is 3.6Ah.
If the current sense resistor between SRN and SRP is large enought (I Ohm) , the bq35100 will be able to measure the current and so the variation of the battery resistance ?

Also, on the technical reference manual in 11.9 Current(), it's written that the current flowing into the current sense resistor has a resolution of 1mA per bit.
"Current(): 0x0C/0x0D This read-only command pair returns a signed integer value that is the average current flowing through the sense resistor. It is updated every 1 second with units of 1 mA per bit."

Thanks
Foulques

0 Onyx Ahiakwo over 5 years ago in reply to Foulques de Varine

TI__Guru* 76230 points

Hi Foulques

The delta voltage under High Pulse Load must be ≥ 100mV for the EOS algorithm to work.

thanks
Onyx

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BQ35100: bq35100 minimal current sensing