[speech-api] Continuous recognition problem

Hello,
I'm using the Speech API for a university project. I need the recognition
to be always active even if no one talks, but if I set the 'continuous'
attribute to true, after more or less a minute the recognition stops. The
audio keeps going , but on my chrome console I can't read further of the
first minute transcription.
Furthermore the 'rec' icon on the chrome tab is visible even after the
first minute.
In this situation no error is raised.