Emission analysis & compliance practices of SMPS

The use of SMPS is increasing day by day in our electronics devices due to certain advantages over to linear power supply. SMPS works on the principle of high frequency switching & result it lot of emission poured back in power line as well radiated in atmosphere. Most of manufacturers faces the problem of non compliance to relevant specification. Around 60% to 70% of SMPS fails in conducted emission requirements. After designing the products, the retrofit solution are provided to meet the requirement. Implementation of retrofit solution may not be feasible due to certain constraints for all designed products. Therefore, we should try to meet the requirements by using design practices. In view of these, emission analysis of SMPS, common mode & differential mode noise aspects, various causes of conducted noise has been discussed in this article to understand logics of non compliance & techniques to achieve the compliance while designing the same. Besides these, retrofit solutions also have been discussed to comply the relevant requirements.