An electronic device includes a synthetic voltage generation circuit configured to generate a synthetic voltage by synthesizing a supply voltage a voltage level of which is changed in response to a change in a voltage level of a first external voltage and an upper limit reference voltage a voltage level of which is set in response to a first selection signal and a second selection signal that are generated by detecting a process, voltage, and temperature (PVT) variation, and an internal voltage generation circuit configured to, based on the synthetic voltage, generate an internal voltage that is used as a body voltage of a transistor included in an internal circuit.