Analysis of static current imbalance of parallel MOSFET affected by thermal resistance

MOSFET is widely used in modern power electronics technology. In some high current situations, considering the cost, heat dissipation and other issues, using multiple MOSFETs in parallel is an effective method. Regarding the parallel current sharing problem, many literatures have studied its influencing factors and solutions, but rarely consider the influence of ambient temperature and heat dissipation conditions. Under actual working conditions, the influence of temperature on device parameters cannot be ignored. This study is mainly based on the on-resistance model considering thermal resistance. Mathematical methods are used to analyze in detail the influencing factors of static current imbalance, and the influence of parameter differences on the degree of drain current inequality is derived. Finally, the double pulse test circuit model based on PSpice is established to verify the correctness of the theoretical analysis.