1) I'm not entirely sure how to understand REG_D0 and REG_D1 settings.Table 6 "Regulated Output Working Mode Configuration" describes:
If I want to use LDO I understand REG_D1-> High.But what does "Not appclicable" mean for REG_D0 ? Should it be Float, or I should use setting to disable boost -> REG_D0=Low?2) What happens if I turn on Boost and LDO at the same time. Will there be any permanent damage?
3) Can the POWER_GOOD signal be used to enable LDO?
The table means the REG_D0 controls boost and REG_D1 controls LDO. You can enable them at the same time. When the input power is strong, it works in boost mode. When the input power is weak, it works as LDO mode. The most of energy is from BAT.
The PGOOD can be used as the LDO enabling.