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UCC28600: Importance of Diode and Resistor from status pin to CS pin

Part Number: UCC28600


We designed a Power supply using UCC28600. In the EVAL. board (19.6V,6A) schematic, we observed a diode and resistor connected from status pin to CS pin. We could not find the purpose of it from datasheet. Could you please share details of it? We observed that CS pin modifications has some impact while we perform surge test.At present we are not using these diode and resistor.We are wondering adding this might help to pass surge test by eliminating transient noise at CS pin.

Thanks in advance

  • Siddartha,

    This is explained in the 120 W EVM user guide:

    From page 6:

    The series combination of R41 and D18 adds an offset voltage to the current sense signal that effectively reduces
    audible noise during standby operation by limiting the current in the transformer during operation in the
    audible frequency range.

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