5 years, 9 months ago.

Enabling notifications on a BLE Service characteristic in a BLE central cause higher power draw?

We have a BLE central application, that enables notifications on a characteristic of a BLE peripheral service once the discovery process is terminated. I was wondering if enabling notifications results in a higher current draw, as compared to reading data from the BLE peripheral characteristic every 30 seconds for example.

Currently the BLE central application we have is a simple application, which scans for BLE peripheral devices and we have set connection params that are reasonable, such that the BLE central doesn't communicate with the BLE peripheral very often and that has helped drop the BLE peripheral current draw to below 8 uA. However the BLE central draws around 500 uA once connected. We are not sure what is causing such a higher power draw?

The BLE peripheral updates the Service characteristic every 30 seconds and the notifications on the BLE central fires every 30 second as well once the connection is established. During this time the BLE central is doing nothing other than waiting for the Notification event to fire, so I am not sure what is causing the power draw to be so high on the BLE central side. The current draw stays at 500 uA once connected. Its almost as if the BLE central doesn't sleep.

The BLE central application is built on top of mbed OS 5.5.4. Just FYI we did build the mbed os 5.8.5 and the same firmware results in mbed hard faults and so we haven't migrated to that OS version.

Thanks, Ajay

Question relating to: