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LM61480: 12V-24Vin, 12vout, 8A

Nicholas Carley
Expert 8785 points
Part Number: LM61480

Hello,

In this application, the customer will have either 12Vin or 24Vin and they need a regulator to buck that down to 12V, output current up to 8A.

If the input is 12V they don't need to regulate it we can just pass it through. Do we have a buck that could handle a passthrough /100% duty cycle mode for when the input is 12V?

Or do we need to go with an external bypass solution?

Thanks,
Nick

  • 0
    TI__Guru 50120 points

    Hi Nick,

    I believe there will still be some minimum on-time requirement that prevents this device from being in 100% duty cycle.

    When the device's input is drops down close to the output, the device enters dropout condition and the frequency will start to scale back and achieve the needed duty factor. See Section 8.4.3.5 for the specifics of dropout. The output voltage will start to drop linearly to the input voltage.

    Though the datasheet only has examples of 5Vout and 3.3Vout, a similar characteristic is expected for 12Vout in dropout. Please refer to Figure 9-22 for an example of 5V output dropout. In such a case, the operation can only achieve "near 100% duty cycle".

    Jimmy