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Original question:

TPS2544: current issue check

TPS2544: Mode switch related issue ： CDP mode to SDP1 mode

April Jiang
Intellectual 830 points
Part Number: TPS2544

      My customer uses TPS2544 in their MB.  When the MB states goes from S0 to S3, S4 or S5, we would switch the TPS2544 work mode from CDP (1111) to SDP1 (0101/0), and this action have done in the process of entering S3, S4 or S5. Because the TPS2544 have discharge the power about 2s. The Keyboard/ Mouse on this USB port will be remove first, and link again when the power rise again. Because this action makes the Keyboard/ Mouse unable to wake up this platform. But I see in DS, in SDP1 mode, it could be waked up through KB/MS.  please help to double check this issue?( question1 )

        

        question2 :  If the MB states goes from S0 to S3, S4 or S5, we switch the work mode from CDP (1111) to SDP2 (1110), any risk? 

        question3 :  How about the line loss inside our chip? My customer found U2 data from in to out( TPS2544) loss, "eye pic" is not so good.  could you please provide a data?

         The SCH have uploaded. please see the attachment. TPS2544.pdf

        Please note that:   When the MB enter into S3, S4 mode from S0. USB Power will be keep always. (Because the wake up function support)

  • 0
    TI__Mastermind 29370 points

    April,

    Question 1:

    The hid(keyboard/mouse) wake function is explained in this section of the specification:

    Question 2:

    There will be no discharge on a switch between CDP(1111) and SDP2(1110) so there should be no disconnect on the bus.  I see no issue with this desetup in the statated power states.

    Question 3:

    The Eye Diagram of the system will be highly dependent on the system implementation.  The insertion loss of the design is about 0.2dB based on Figure 10 and the 3dB bandwith of the system is greater than 1GHz, so this design is highly competitive with typical USB switches in the market.