I'm trying to design an EMI filter for a buck converter and I'm following steps on: AN-2162
Here is the question:
At page:6, for the Cf capacitor; two different capacitor values are calculated and highest value is taken(Cfa, Cfb). In my situation, calculations for Cfa results a negative cap. value.
Since there is no negative capacitance, should I neglect this result or take it as a positive value?
Here is the calculation:
0.000002 / ((0.000002) x (0.001) x (((2 x 3.14 x 30000)/10)^2)-1)
0.000002 / ((0.000002) x (0.001) x (355000000))-1
0.000002 / (0.71-1)
0.000002 / -0.29