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TPS54620: Over current limit

Pao Wu
Intellectual 920 points
Part Number: TPS54620

Hi All,

The real TPS54620 application parameters are shown in Figure 2 as below,

In Figure 2, we calculator the maximum inductor current is 7.17A,

It exceed the minimum current limit 7A show in datasheet,

Please help to confirm have risk to trigger the current in maximum loading?

Thanks!

 

Vin = 4.75~5.25V, Iout = 6.4A(Max), Fsw = 500KHz, Inductor = 1.2uH 

 

(Figure 1)

 

 

(Figure 2)

  • 0
    TI__Guru**** 191445 points

    No, that is 7 A is the low side current limit.  Your peak current is 7.17 A, which occurs at the end of the on time (high side current limit is 8 A minimum).  At the end of the off time, your current would be 5.63 A relative to the low side current limit of 7 A.  You subtract one half of the ILp-p current from the load current fo the low side limit.

  • 0 in reply to JohnTucker
    Intellectual 920 points

    Hi John,

    Thank you for your reply. I have some question.

    So, Is the Low side current sensing point B?? (Valley sense??)

    Following waveform is inductor current.

    As following picture.

    When High side turn off, Low side MOSFET current(IRECT) = Inductor current. (Green)

    So, The TPS5462x isn't peak current protect, Right??

    Many Thanks.

  • 0 in reply to Pao Wu
    TI__Guru**** 191445 points
    TPS54620 has both high side (peak current) limit sensing at point A and low side (valley current) limit sensing at point B. There is also low side sinking current limit for the case when point B is negative.