Reduction of conducted EMI levels in an lighting appliance to meet applicable regulatory limits-a case study

Electromagnetic interference (EMI) refers to the impairment of desired operation of equipment by electromagnetic disturbance. Miniaturization of equipment structures as well as increasing complexity of electronic circuitry, their integration and interconnections makes all electric installations and components vulnerable to such EMI disturbances. Conducted interference is one of forms of subject EMI disturbances, which normally exists due to sharing of power bus between different circuits or systems or equipment. Such conducted EMI usually travel normal current paths of electronic equipment and can provide potential impact on its operational states. Often EMI currents are produced due to inadequate EMI design considerations within the equipment. Situations like these, demand the control/reduction of such conducted EMI preferably at design stage. The author in this paper highlights noncompliance of lighting appliances (i.e. electronic ballasts with compact fluorescent lamp load) with applicable conducted regulatory limits. Apart from the analysis part, this paper also deals with remedial measures taken in appliances, which finally leads to compliance with conducted regulatory limits.