The chip is designed with "sleep modes" that consume microamps. For TWS earbuds, this translates to hours of playback time on small lithium-polymer batteries.
If you are a developer looking to program the BR21, here is the workflow: jieli br21
The Jieli BR21 is often recognized by operating systems not as a generic Bluetooth adapter, but as a or USB Sound Card . This is because it often integrates multiple functions into a single silicon package: The chip is designed with "sleep modes" that