Characterization of GaN-Based Synchronous Buck Converter Operating in MHz-Range

A discrete synchronous buck converter based on a GaN half-bridge power stage is designed and characterized. The operation of the designed converter is analyzed for different input voltages, load currents, switching frequencies and duty cycles. Depending on the operating condition of the converter, power efficiencies up to 98% can be achieved. Two different topologies of the input capacitive network are designed to analyze their impact on the conducted electromagnetic noise generated by the converter operation. The placement of the input decoupling capacitors on both sides of the two-layer board minimizes the loop inductance of the return current path and reduces the generated conducted noise.