Review of Factors Affecting Current Sharing and Techniques for Current Balancing in Paralleled Wide Bandgap Devices

MOSFETs are paralleled in a converter in order to enhance its current handling capacity which in turn results in reduced conduction losses and increased efficiency. However, paralleling MOSFETs and ensuring equal current sharing among them is difficult to achieve. The paper identifies the parameters causing current unbalance among parallel devices and uses LT-Spice simulation to study their effects for GaN HEMTs. Further, these simulation results are matched with experimental results for two paralleled GaN HEMTs. The challenges in paralleling of Wide bandgap devices such as GaN and SiC are also presented. A detailed review of various active and passive current balancing techniques for paralleling of SiC and GaN FETs is presented.