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LM5104: max duty cycle

Part Number: LM5104

Hi team,

What is the maximum duty cycle of the LM5104?
Can you guide us how to estimate the maximum duty cycle? Thank you!

Best regards,
Sam Ting

  • HI Sam,

    The maximum duty cycle is dependent on several factors including load and consequently bootstrap circuitry.

    Assuming you're using a bootstrap topology (typically 50%Duty cycle) to provide bias on the high-side, you will need to account for sufficient time for the bootstrap capacitor fully replenish during the low-side on-time AND also allow the bootstrap capacitor enough time during high-side on-time to provide sufficient bias to the HO gate.

    The app note below discusses how to choose the bootstrap topology.

    For high duty cycle operation, bootstrap topology might not work for your applicable, you would need to generate an isolated floating bias to provide and maintain sufficient bias to the high side gate above the VHBR thresholds.

    Please refer to this post previously addressing this topic.

    Please let us know if you have additional questions or press the green button otherwise.