Replacing Relays with Semiconductor Devices in Automotive Applications

New systems and extended warranties have added requirements to controlling automotive loads that will accelerate the rate at which semiconductor switches are used in new models. These requirements could mean the eventual replacement of electro-mechanical relays.

This paper will examine the requirements of the new automotive “relay” and describe three semiconductor technologies - bipolar, power MOS and smart power - that are being used to provide the power-to-load interface for present and future automobiles. The technology used for each approach and its advantages and disadvantages will be discussed and examples of typical automotive applications will be provided. Also, the packaging and mounting considerations for semiconductor devices in the role of a replacement for relays will be discussed.