The main power source on the Nordic Thingy:53™ is a rechargeable Lithium-polymer (Li-Poly) battery. The battery has a nominal capacity of 1350 mAh on Nordic Thingy:53 v1.0.0 or lower and 1500 mAh on Nordic Thingy:53 v1.1.0 or higher. The battery can be recharged through USB.
The Li-Po battery is connected directly to the nPM1100 Power Management Integrated Circuit (PMIC) (U3), which ensures that the Nordic Thingy:53 is charged regardless of the position of the power switch (SW1). In the ON position, the nPM1100 PMIC supplies power to the rest of the Nordic Thingy:53 board through its VSYS and VOUTB voltage domains. When the power switch is in the OFF position, the two voltage domains of the nPM1100 PMIC are disconnected. With the power switch in the OFF position, a circuit drains the voltage charge across the capacitors that are connected to the VOUTB power domain.
The following schematic describes the power switch.