Design and realization of a 200 A low-cost high-side switch for automotive applications

The realization of a high side power switch for driving a motor with a load current of 200 A in a hostile environment is presented. For such high currents currently electromechanical devices are used which have reliability and wear problems when working in environments with high temperature and humidity. The proposed solution was developed by connecting in parallel five commercial switches mounted on an FR4 support. An accurate thermal design, aided by finite element analysis, made it possible to avoid the use of an external heat sink, thus minimizing the weight and cost of the assembled circuit. Experimental tests under actual operating conditions have demonstrated the reliability of the proposed solution.