The PG_STAT bit goes 1 to indicate a good input
source when:
- VVBUS above
VVBUS_UVLO
- VVBUS above battery
(not in sleep)
- VVBUS below
VACOV threshold
- VVBUS above
VPOORSRC (typical 3.8 V) when IBADSRC (typical 30 mA)
current is applied (not a poor source)
- Completed Section 8.3.3.3