Design of an alternator voltage regulator immune to EMI

The paper deals with the susceptibility of smart power integrated circuits to electromagnetic interference (EMI). In particular, the integrated circuit (AVR) that control the operation of automotive voltage alternator is considered and its susceptibility to radio frequency interference is investigated. To this purpose, the paper shows how the immunity to EMI of such integrated circuit can be significantly increased by a proper design of both the control loop low-pass filter and the integrated voltage reference. In order to verify the effectiveness of the new circuits, a new AVR has been designed, fabricated and experimentally characterized by the bulk current injection method. The results of these tests have shown that the new AYR is compliant to the European Standards on EMC, without any EMI filter added into the package or in the brush holder.