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TPS92200D2EVM: TPS92200 Max Current

Roman Marjamaa
Prodigy 85 points
Part Number: TPS92200D2EVM
Other Parts Discussed in Thread: TPS92200

I have questions regarding the 1.5A drive current for TPS92200.

Why does the TPS92200 have a max current rating listed as 1.5A when the Min current limit of the HS switch is 2.9A and the Min current limit of the LS source is 2.4A?

There is a Min current limit sink rating of 1.4A for LS sink.  How is this applicable to a buck circuit?

I have an app that requires 1.7A output with 12V SLA to parallel string of LEDs with nominal load voltages between 2.4V and 3.6V.

Is the 1.5A Max drive current applicable to this application?

Is it applicable to a 4.8V supply feeding the same load?

My simulations show that the active switch currents do not exceed 2A with a 1.7A load.

Best Regards,

Roman

  • 0
    TI__Mastermind 18140 points

    Hi Roman,

    Roman Marjamaa said:
    Why does the TPS92200 have a max current rating listed as 1.5A when the Min current limit of the HS switch is 2.9A and the Min current limit of the LS source is 2.4A?

    There is no such "1.5A" max current rating listed in the datasheet as a specification item. We write "1.5A" in the datasheet just based on our assumption of normal working condition for TPS92200. Actually, it is possible for TPS92200 to output more than 1.5A if you keep all the parameters (like high-side current) within the specifications and ratings shown in the datasheet.

    Roman Marjamaa said:
    There is a Min current limit sink rating of 1.4A for LS sink.  How is this applicable to a buck circuit?

    For example, when you dim the output current to a small value like 0.1A, and your inductor current ripple (peak-to-peak)  = 0.5A, then the LS FET will need to sink 0.5A / 2 - 0.1A = 0.15A current during LS FET turning-on period.

    Roman Marjamaa said:
    I have an app that requires 1.7A output with 12V SLA to parallel string of LEDs with nominal load voltages between 2.4V and 3.6V.

    Sorry but what do you mean by "SLA"? Does it stand for sealed lead acid battery?

    Roman Marjamaa said:
    Is the 1.5A Max drive current applicable to this application?

    Yes. It is possible to get 1.5A max current output in this application condition.

    Roman Marjamaa said:
    Is it applicable to a 4.8V supply feeding the same load?

    It is applicable to a 4.8V supply if you can make sure the input voltage never falls below 4V (Please refer to Section 6.3 Recommended Operating Conditions from the datasheet).

    Best Regards,

    Steven