ASFET-Based Approach for Enhanced Dynamic Current Sharing in Paralleled Power Devices

Abstract:
Paralleling of MOSFETs is widely used in high-power systems to overcome the limitations of individual devices. While steady-state current sharing is generally well understood, achieving balanced current during switching events remains challenging due to device parameter variations and PCB layout-induced imbalances. This paper introduces a new class of Application-Specific FETs (ASFETs), optimized at the silicon level for synchronized parallel operation. Key parameters are carefully tuned to enable balanced current distribution, especially during dynamic transitions. A new figure of merit, DeltaID, is proposed to quantify mismatch during switching. Hardware testing confirms that ASFETs enhance dynamic sharing, thermal balance, and avoid overdesigning.