TPS51285B: TPS51285B : Behavior of Max Duty

Nariaki Ogasawara

Part Number: TPS51285B

Hi Team,

The datasheet does not mention about Max Duty Cycle, but the parametric in device production web is 100%.

Is Max duty 100% correct?

What is behavior of 100% duty? Does VBSTx pin not boot, because SWx pin does not toggled?

For example VIN=5.5V, VOUT=5.0V, Iout=4.5A, what kind of behavior will it take?

Regards,

Ogasawara

0 Edwin Zang over 7 years ago

Hello Ogasawara,

TPS51285B doesn't support 100% duty. In EC table, minimum off time is given. due to minimum off time limit, IC couldn't work with 100% duty.

TPS51285B has on time extension function. When Vin is near Vout, frequency will decrease. You can refer datasheet page 11.

If 5.5Vin couldn't support 5Vout @4.5A, Vout will decrease until 5.5Vin can support.

best regards,

edwin.

0 Nariaki Ogasawara over 7 years ago in reply to Edwin Zang

Hi Edwin,

Thanks, I understood.

Regards,
Ogasawara

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