As I read the schematic of QN9080DK Board and found USB_Vbus seems not connected to on board QN9080, I want to ensure it may work before I do the test...
Power Source to on board QN9080 : Lithium Battery
Vcc to on board 9080 : 1.8V
Jumper settings (refering to the QN9080 DK User's Guide, the settings for QN9080)
1. JP7 : 1-2 short (Page 5, item 7)
2. JP16 : Open (Page 24)
3. Remove R48, R49, R50 (Page 24)
Thanks a lot. This linked application note should help us a lot.
By the way, it is noticed that the test was passed with Vcc=3.0V. Is it your recommandation to employ 3.0V when working with USB interface?
Our original idea is using the same DC/DC for lithium battery and USB power to provide 1.8V voltage to QN9080. That is, QN9080 will operated with 1.8V power both in stanalone and USB connection mode.
Thanks for your confirmation again.