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Using TPS2053B as USB Switch

Michael Dick
Prodigy 30 points
Other Parts Discussed in Thread: TPS2053B, TPS2560, TPS2052C, TPS2552, TPS2051C

Hello,

I want to use TPS2053B as USB Switch. Till now, I used the MAX1946.  

 

  • 0
    Prodigy 30 points

    Hello,

    had a problem with the pictures. Another try:

    I want to use TPS2053B as USB Switch. Till now, I used the MAX1946.  The MAX1946 did watch the current for one sinlge USB-Port to be not above 500

     mA. But in the datasheet of TPS2053B , these vaules are given:

    I wonder if I can use the IC for USB and if yes, do I have to set the current limit by an external component like a resistor?

    In the sample schematic, I cannot so such an external component. So the IC matches for USB without such external control part?

     

    Best regards

    Michael Dick

     

     

  • 0 in reply to Michael Dick
    TI__Expert 7990 points

    I am somewhat unsure what the question was,  It seems to me that your concern was current-limit accuracy.  Looking at the MAX1946 datasheet, the short circuit current and transient protection (see typical characteristic scope shots) would not seem all that different (the degree of difference becomes an argueable debate ...) than TPS2053B.

    I will try and provide a few additional facts and suggestions to help.  Our parts such as the TPS2053B had a higher current-limit trip point (Ioc) than current-regulating point  (Ios) (TPS2053B Ios vs Ioc in datasheet).  The newer parts such as the TPS25XX and TPS20xxC families (single and dual port devices) do not have this characteristic.  Industry trends have been away from triple-and quad limiter devices as the physical layout of portable platforms tends to cluster 1 - 2 ports in any physical location.

    TPS2051C and TPS2052C have current limits tolerances at or better than TPS2053B Ios,  with no Ioc.  Better current-limit accuracy is generally available with adjustable parts such as TPS2552/3, and TPS2560 (accuracy is a function of the program value).

  • 0 in reply to Martin Patoka
    Prodigy 30 points

    The question was, if this IC can be used as a USB switch. As it is not declared as special USB switch (like MAX1946), I was not sure if how the IC can "know", that it has to limit the current to 500 mA per downstream.

    So to answer my question: Can you tell me, if I can use the IC as is (with decoupling caps of course) as a USB switch?

  • 0 in reply to Michael Dick
    TI__Expert 7990 points

    This IC was designed to protect USB ports (as-is).  The USB2.0 specification states the current source provide 500mA min for a high-power port (high power load draws 500mA max) and does not require a "precise" current limit, however better limiting accuracy may help with the hub power system design.    The current-limit tolerance and choices were discussed previously.