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Original question:

PMP11302: PMP11302 Re-Design Support

PMP11302: Need support in EMI Filter component sizing

Amal Babu
Prodigy 90 points

Part Number: PMP11302
Other Parts Discussed in Thread: TIDA-00940

Tool/software:

Hi,

I have come with a pi-filter at the input for noise suppression for my PMP11302 Re-design. With the help of TIDA-00940 i have calculated the values and happy to inform that the filter works well.

The CLC Filter is able to provide at least 15dB Margin for EN55011 Class B Standard. 

  1. My concern here is regarding the sizing of the inductor used in the design. My concern is mainly regarding the voltage rating of the inductor to be used for the pi- filter. Do i need to choose a high voltage rated inductor? Should i be expecting a high voltage drop across it?
  2. My next concern is regarding the output inductor. The same query stands for this inductor as well. Do we need a high voltage rated inductor here as the peak voltage at the one end of the inductor is exposed to the entire input voltage during certain times.

Please share necessary details regarding both the concerns.

Amal

  • 0
    TI__Mastermind 24375 points

    Hi Amal,

    Thank you for reaching out. For both your inductor choice, it is important to remember that most inductors work by impeding current flow, not through high voltage induction. Almost all commercial inductors are good for a few volts or even tens of volts with no worries. So for most applications, inductor voltage rating is not a concern. As the turn to turn voltage is not a cause for concern. 

    For applications that operate from high line voltages or work by induction of high voltage across the winding, it is necessary to consider the possible breakdown of the inductor windings. Voltage above the maximum rating may cause short circuits between turns, through the insulation, or from the windings to core or frame. So these factors needs to be considered while designing indctor. Impedance drop will be there depending on the DC series resistance.

    Regards,

    Harish