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TPS62933: Looking for advise on a Buck regulator that can work between 5V and 24V to give a 5V output with minimal noise

Ben Jackson
Prodigy 40 points
Part Number: TPS62933
Other Parts Discussed in Thread: TPS54302

Tool/software:

Good day,

I am currenlty designing a product that needs to have a stable 3A 5V output from a supply ranning from 5V up to 24V.

Part of this supply will be coming from a USB-C PD power supply, and im strugging to see how to achieve a 5V supply when the source voltage is 5V. The current regulator we have been using from a competitor needs at least 6V to achieve a stable 5V output, which is not really feasable with a 5V USB source.

Would a buck regulator such as the TPS54302 with 100% duty cycle be the way to go, though i believe the low frequency would require a larger inductor. But the buck regulators that can go multiple Mhz dont look to be able to achieve 100% switching, such as the TPS62933

Any advise for a suitable power regulator would be greatly appreciated.

Is there any guidance on designing a Multi power source USB-C PD device that can handle voltages from 5-20V@~3A


Kind regards

Ben J

  • 0
    TI__Mastermind 27276 points

    Hi Ben

    The TPS62933 Dmax is 98%, which means Vout is around 4.9 when Vin=5V. For TPS54302, the Dmax is around 100%( Although there is still some power loss on the power path impedance)

    For tps54302, when Vin and Vo_set is really close, it decrease the fsw to achieve larger Duty cycle.

    "though i believe the low frequency would require a larger inductor."--During the dropout operation, the Vin and Vo are close, the ΔiL is small as the (Vin-Vo)is small .No need to select a larger inductor, the inductor design still follow the 8.2.3.5.1 Inductor Selection in datasheet. 

    Thanks and best regards.