Power semiconductors

International Rectifier is addressing increased power consumption in vehicles as the industry moves to 42-V systems.

The need for speed in today's car is being challenged by the quest for more electrical power. This need for higher power in the vehicle is being driven by two automotive industry trends: the quest for better fuel economy with lower emissions, and the increasing demand for power-hungry features in the vehicle. A 10-12% fuel economy improvement and a significant reduction in emissions can be realized with the stop-start function made possible by the integration of an integrated starter-alternator into the powertrain. Electric steering, electric brakes, electromechanical valves, electronic suspension, and information/entertainment are some of the features driving the demand for more power.

The increasing number and level of vehicle electrical loads will require the vehicle's primary voltage to increase in coming years. The peak and average level of future loads (Table 1) will require a voltage that is higher, yet safe when inadvertent human contact occurs. The need for a new voltage standard to replace the 50-year-old 12-V battery/14-V charging system has brought together automotive companies and their electronic/electrical equipment suppliers, including semiconductor manufacturers. Today, a 42-V standard is being pursued, but the need for even higher voltages for advanced features has already been identified. The desired functions determine the choice of voltages, battery size, and technology.