Newer switching power supplies tend to have a high switching frequency
that generate high levels of noise. Noise is especially strong in the
several hundred kHz frequency range, close to the switching frequency.
The figure below shows an example of measured Mains Terminal
Interference Voltage. In this example, noise of 500 kHz or less
frequency is strongly generated. When this noise is broken down into
common mode and differential mode components, it is found that the
noise consists mainly of differential mode components.
Newer switching power supplies tend to strongly generate low-frequency
differential mode noise. Therefore, more effective methods of
suppressing differential mode noise are required. |
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