Interface circuit, power conversion device, and vehicle-mounted electric machinery system

摘要

An interface circuit capable of reliably transmitting signal even when there is fluctuation in the potential difference in reference potentials between circuits between which signal transmission is carried out. An interface circuit 4 is comprised of a level shift circuit 20 and a potential selection circuit 10 for selecting the potential of a power supply voltage for operating the level shift circuit 20. The potential selection circuit 10 selects one of a plurality of input potentials. The level shift circuit 20 receives a voltage pulse having a first potential as reference potential and outputs a voltage pulse having a second potential as reference potential. The level shift circuit 20 is operated on the basis of both a potential difference between the output potential from the potential selection circuit and the first potential and a potential difference between the selected potential and the second potential.