If ADP5090 no voltage VIN Input into, at this VBAT Pin have 4.2V,1200mA/HR lithium-ion battery, available provide to VSYS working power, VSYS will within a few volts? if VSYS need a 5V,ADP5090 VBAT is boost Mode to VSYS? if VSYS do 3.3V ADP5090 VBAT is buck Mode to VSYS? still with my VBAT voltage change that?
I saw ADP5090 Datasheet PrF "Figure 23. Detailed Functional Block Diagram "If VIN Input voltage into all of the BOOSTCONTROLLER and BATTERYBOOSTCONTROL are not actions, voltage OPA is only VABT when a comparator and MOSFET output directly to VSYS is the path?