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ISOW7744: Switching frequency of DCDC

Part Number: ISOW7744

Hi,

The features on page 1 of data sheet says "Low frequency power converter at 25 MHz"

But the ripple graphs (Figure 7-24 to Figure 7-27) show a switching period of approx 4.5us to 13us (222kHz to 77kHz).

What is the actual switching frequency of the DCDC converter?

Thanks, Ken

  • Hi Ken,

    Thank you for posting to E2E! The DC/DC converter switching frequency of ISOW77xx devices is 25MHz.

    The output voltage ripple seen on Visoout can vary based on load configurations and conditions. The higher frequency in the datasheet curves is most likely due to switching in the rectifier circuit, not the 25MHz switching across the isolation transformer. Please allow me to confirm this with our team and follow up early next week.


    Thank you,
    Manuel Chavez

  • Thanks Manuel,

    I look forward to the reply form your team and any further info on this ripple.

    It is mainly to understand the ripple in order to design a filter for our application.

    Thanks, Ken

  • Hi Ken,

    Thank you for your patience. I've confirmed the ripple observed in datasheet Figures 7-24 to 7-27 is due to the output regulation circuitry. Its feedback loop operates at a frequency that can be as high as 250kHz.

    Let us know if you have any additional questions by creating a new thread using the red and yellow buttons in the upper right corner of this window.


    Thank you,
    Manuel Chavez