Abstract: In view of problems encountered in the application of intelligent MOSFET ( Metal-Oxide-Semiconductor Field-Effect Transistor) in automotive electronic system，the corresponding technical solutions are put forward． Aiming at the damage problems of Smart MOSFET under the condition of power reverse，short circuit，over load and load dump，the hardware protection circuit and software control strategy are put forward．Aiming at the low current feedback accuracy of Smart MOSFET，which can not meet the control accuracy，the method of improving the sensing accuracy through calibration is put forward． The on-resistance is reduced by parallel Smart MOSFET to improve the current capacity． To increase the capacity of the clamping energy，a TVS (Transient Voltage Suppressor) is connected with smart MOSFET in parallel． The feasibility and validity of the schemes are verified by experiments and real automotive tests．

Key words: electromechanical relay, shortcircuit protection, flow capacity, smart metal-oxide-semiconductor field-effect transistor( MOSFET) , clamping energy capacity