TIDUED7A November 2018 – November 2022
There are two forms of conducted emissions. Common mode noise and differential mode noise. To attenuate conducted common mode noise a common mode choke is placed on the input whereas a LC filter is used to attenuate differential mode noise. To reduce radiation and near field coupling, place a metal shield on the design to cover all power stage components. The whole filter consists of L4, C14, C15, C16 and L1 as shown in Figure 2-6. For more details, see Simple Success With Conducted EMI From DC-DC Converters and The Engineer’s Guide To EMI In DC-DC Converters (Part 2): Noise Propagation And Filtering.