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TPS65911: TPS65911 power-on seaquence

Mitsuharu Iwasaki7
Intellectual 540 points
Part Number: TPS65911

Hello all,

Question1

 TPS65911 is supllying 3.3V and 5V based on SWCU187A.

1st 5.0V is supplied after 3.3V is supplied, it has 20ms delay.

Do you have any concerns? Do you have any specification about both timing?

Question2

SWCU187A showed an external hiside-FET is connected to 12V.  

What is the minimum voltage that can be supplied to the external FET?

Best Regards.,

Mitsuharu Iwasaki 

  • 0
    TI__Mastermind 49231 points
    Hi Mitsuharu,
    Thank you for your interested in our devices! Please see my answers below:
    A1: According to the same document "Figure 4. Power Sequencing", 5.0V should be supplied BEFORE 3.3V is supplied; and the 20ms delay is also not allowed, since the boot sequence time slot duration either 0.5 ms or 2 ms; there is no 10 time slot from 5V on to 3.3V on.
    A2: Since it has 400nS minimum off-time and highest switching frequency is 368 kHz, so, its highest duty cycle is about 85%, and then the minimum voltage that can be supplied to the external FET is Vout/0.85.
  • 0 in reply to Phil Yi
    TI__Mastermind 49231 points
    Hi Mitsuharu,
    The minimum voltage that can be supplied to the external FET is Vout/0.85 is correct only when Vout>2.55V, since datasheet has 3V as the absolute minimum voltage as input voltage for external FETs.