Current sensing trench power MOSFET for automotive applications

Current-sensing power MOSFET incorporating current sensing feature with a power MOSFET offers a simple solution for overcurrent protection without additional sensing elements. In this work a low R
_DS-ON
(<2 mOmega), high sense ratio (>10,000:1) trench current sensing MOSFET is designed and evaluated. Critical factors affecting the current sense ratio, including gate drive voltage, switching current, and device temperature are characterized. Sense ratio changes of 2.7% at gate drive voltage of 5 V-10 V, and 2.9% over-50degC-150degC are realized. The device is implemented in a low frequency motor drive module for automotive applications; initial circuit evaluation results demonstrated feasibility and advantages of the current sensing scheme