Development of advanced power electronics with unprecedented functionality, efficiency, reliability, and reduced form factor will provide the United States a critical technological advantage in an increasingly electrified world economy. The projects that comprise ARPA E’s CIRCUITS (Creating Innovative and Reliable Circuits Using Inventive Topologies and Semiconductors) program seek to accelerate the development and deployment of a new class of efficient, lightweight, and reliable power converters, based on wide-bandgap (WBG) semiconductors. CIRCUITS projects will establish the building blocks of this class of power converter by advancing higher efficiency designs that exhibit enhanced reliability and superior total cost of ownership. In addition, a reduced form factor (size and weight) will drive adoption of higher performance and more efficient power converters relative to today’s state-of-the-art systems. Past ARPA-E programs have focused on challenges associated with fabricating WBG high-performance switching devices. Program developments led to a new generation of devices that operate at much higher powers, voltages, frequencies, and temperatures than traditional silicon-based semiconductor devices. CIRCUITS projects will build on these earlier ARPA-E programs by designing circuit topologies optimally suited for WBG attributes to maximize overall electrical system performance. Innovations stemming from CIRCUITS projects have the potential to affect high-impact applications wherever electrical power is generated or used, including the electric grid, industrial motor controllers, automotive electrification, heating, ventilation and air conditioning, solar and wind power systems, datacenters, aerospace control surfaces, wireless power transfer, and consumer electronics.