Hi there,
there is NO sleep mode for the respeaker mic array v2.0. To distinguish the hardware issue/software issue, we suggest to use audacity to record the audio from PC and see if it has the sleep issue. please make sure you have the good connection on the usb cable both sides.
For the mic array v2.0, we only have the wiki page. thanks.
http://wiki.seeedstudio.com/ReSpeaker_Mic_Array_v2.0/