The power switch (SW1) disconnects the VSYS and 1V8 outputs from the nPM1300 Power Management Integrated Circuit (PMIC) (U11).
Disconnecting the 1V8 output also disables the nPM1300 BUCK2 output as the 1V8_SW net is connected to GPIO2 on the nPM1300 PMIC (U11), which on boot is configured to disable BUCK2 when set low. The nPM1300 PMIC (U11) is powered from the battery when the power switch (SW1) is in the off position and retains its configuration. The battery charges when the power switch (SW1) is in the off position.
The following figure describes the power switch.
Figure 1. Power switch
