Examination of electromagnetic interference in switched mode power supplies and electromagnetic filter design

Switched mode power supplies that are widely used thanks to the developing technology have several advantages against other power supplies. Inspite of these advantages, they make conducted emission because they switch on-off at known frequencies. Reduction of these distortions is very important for devices that are coupled with switch mode power supplies. At that thesis, determination of ATX power supply's interference was worked. At first, power supply's transmision lines was assayed based on CISPR 22 standard. After showing that the interferences exceed limits, proper noise separator was designed to separate noise common-mode and differential-mode interference components. After proving noise separator's success, an electromagnetic filter that includes common-mode and differential-mode filters was designed. After proper cut off frequency was determined for noise suppression, value of circuit components of EMI filter was calculated and than layout was implemented with calculating and determining. The filter designed at simulation. Next, conclusion of design was submitted.