The Power Profiler Kit II (PPK2) is driven by the nRF52840 System on Chip (SoC), which uses its analog-to-digital converter (ADC) to measure a voltage drop over a series of measurement resistors. Resistor values are used to calculate the power consumption. The PPK2 has five different measurement ranges, which are managed by an automatic switch circuitry.
To send the data to the desktop application, the nRF52840 SoC uses Universal Serial Bus (USB) Communication Device Class (CDC) Abstract Control Model (ACM) which all major operating systems support without the need for extra driver installations.