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TPS53513: High duty cycle application

Part Number: TPS53513
Other Parts Discussed in Thread: TPS54824

Hi Sir,

Coulde I use TPS53513 in the applacation as below:

Vin=5V Vout=4V Iout=3.5A

The concern is could TPS53513 handle the big duty cycle? the worst case should be at the start up.

and also there is a 5V LDO inside, if the input voltage is below 5V, could the Vreg supply for the device and the gatedriver?

If TPS53513 can't support this application, could TPS54824 support? this one suport 100% duty cycle.

Thank you very much.

  • Coulde I use TPS53513 in the applacation as below:

    Vin=5V Vout=4V Iout=3.5A

    The concern is could TPS53513 handle the big duty cycle? the worst case should be at the start up.

    and also there is a 5V LDO inside, if the input voltage is below 5V, could the Vreg supply for the device and the gatedriver?

    If TPS53513 can't support this application, could TPS54824 support? this one suport 100% duty cycle.

    The TPS53513 has maximum off time of  310ns which will limit  high duty cycle applications.  Higher switching frequency will be impacted greater.

    fsw = switching frequency, toff in the max off time

    Vin min =(Vout/1-fsw*toff)

    See section 7.3.13  of the TPS54824 data sheet regarding the 100% duty cycle operation.   As long the boot capacitor voltage is greater than 2.2V, the high side will remain on.   So in the approximately ~100%.

    I would consider the TPS54824 over TPS53513 for the size and the ~100% duty cycle. 

    David