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PMP40261: Bridgeless Totempole PFC rectifier

Dhivyarajesri S
Prodigy 40 points

Part Number: PMP40261

Tool/software:

I would like to know the purpose of the 2 diode bridges at the beginning .Why is it termed bridgeless PFC rectifier when it consists of 2 diode bridges. Bridgeless PFC rectifier is supposed to give a better efficiency than conventional boost PFC rectifiers ,but wouldn't the diode bridges in the starting reduce the efficiency as it increases losses?

tidryk5-schematic.pdf

  • 0
    TI__Intellectual 1125 points

    Hi, Dhivyarajesri,

    These two diode bridge is not for normal operating since we know the HV_DC voltage is bigger than line and neutral. It is just for surge test in order to protect the main switching FET Q1, Q3.

  • 0
    Prodigy 40 points

    Thank you for your reply.

    I have 2 other questions.

    1.Can I replace the 2 inductors L1&L4(130uH each) with a single  260uH?

    2.There are 2 inductors L5,L6(2.5mH) used for the purpose of EMI filter. Can it be replaced with a single 5mH inductor?

  • 0 in reply to Dhivyarajesri S
    TI__Intellectual 1125 points

    Hi, Dhivyarajesri,

    1. The reason we use two 130uH on L1 & L4 is it is hard to find the slim core to meet this power level. If your application is not height limitation, that's fine you change it to 260uH single inductor.

    2. If changed to one single inductor, it become two stage EMI filter instead of three stage EMI filter.L5&L6 is used for EMI filter, I strongly recommend you reserve these two placeholder for optimizing EMI performance.