BMI270 Significant Motion - Lowest Power

[mjanke]

Hi,

We are successfully using the significant motion feature to generate an interrupt. We have come across and application requiring better battery efficiency and we want to ensure that we setup sig motion for the lowest possible uA draw while still being able to detect a bump on the BMI270. Think a sharp drop or bump with duration of 300mSec or more and g-force of 3g or more.

Table 1 in Section 1 of the BMI270 datasheet indicates 10 uA for Vdd of 1.8 and ODR of 25 Hz (40mSec sample time). To measure bumps lasting 300 mSec or more, I think we can drop the ODR to 12.5 Hz. Will that drop the current much below the 10 uA? Even 5 uA would make a large difference for our battery efficiency. Also, we are using a Vdd of 3.3 Vdc, does that mean less current is required (ie the chip uses a consistent power level, so increasing Vdd reduces the current for the same functionality)?

Thanks,

Mark J

[BSTRobin]

Hello mjanke,

Normally, 50 Hz or greater ODR will achieve better performance.
What are your requirements for power consumption?

[mjanke · Accepted solution]

Hi @BSTRobin,

Please see my original note. We would like to get down to 5 uA (or lower). I realize that better performance results from a higher ODR, but if that uses a battery in far less time, there will be no point as our customer won't accept this. Please consider that increased battery life is key in this application.

I expect that 12.5 Hz will be ok if the duration of an event is >= 300 mSec. My challange is determining what the current draw will be at ODR of 12.5 Hz and Vdd of 3.3 Vdc.

Thanks,

Mark J

[BSTRobin · Accepted solution]

Hello mjanke,

The minimum requirement of the algorithm for ODR is 50 Hz. It is unrealistic to use significant motion and the power consumption should be less than 5 uA.

If you can accept the performance of 12.5 Hz ODR, the reference power consumption is 11.10 uA.