The board is powered through the USB port and contains two LDO regulators, one to generate 3.3V for the on-board debugger and an adjustable LDO regulator for the target AVR64DD32 microcontroller and its peripherals. The voltage from a USB connector can vary between 4.4V to 5.25V (according to the USB specification) and will limit the maximum voltage supplied to the target. The figure below shows the entire power supply system on AVR64DD32 Curiosity Nano.
Figure 1. Power Supply Block Diagram
