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TPS2543 CTL3 timing for CDP

j_yamamoto1
Intellectual 1010 points
Other Parts Discussed in Thread: TPS2543

Hello

customer using TPS2543. and they are evaluating CTL3 timing for CDP detection.

Could you let me know acceptable period(time) between CTL3 change timing and handshake start?

<time delay 196ms between CTL3 change and handshake start>

in this case, device can not change CDP mode. =>NG

<time delay 632ms between CTL3 change and handshake start>

in this case, device can change CDP mode. =>OK

Regards,

  • 0
    TI__Mastermind 42795 points

    Hello,

    Can you provide more detail about steps during the test? When you mention "CTL3 change", please tell us what CTL1, CTL2, CTL3, and ILIM_SEL setting was before CTL3 changed. CDP mode is CTL1=1, CTL2=1, CTL3=1, ILIM_SEL=1. Is CTL3 changing from 0 to 1?

    What does "handshake start" mean? What signals are you monitoring (DP_IN, DM_IN, VOUT, IOUT?)? Or does this mean when the phone get's plugged into the host USB port?

  • 0 in reply to Eric Wright
    TI__Intellectual 1010 points

    Hello Eric,

    Can you provide more detail about steps during the test? When you mention "CTL3 change", please tell us what CTL1, CTL2, CTL3, and ILIM_SEL setting was before CTL3 changed. CDP mode is CTL1=1, CTL2=1, CTL3=1, ILIM_SEL=1. Is CTL3 changing from 0 to 1?

    >>Yes. CTL1=1, CTL2=1, ILIM_SEL=1. Is CTL3 changing from 0 to 1 after Vbus on.

        and we are evaluating CTL3 delay from Vbus ON.

       time period between Vbus ON and CTL3 = 0 => OK

       time period between Vbus ON and CTL3 = 500mS => NG

    What does "handshake start" mean? What signals are you monitoring (DP_IN, DM_IN, VOUT, IOUT?)? Or does this mean when the phone get's plugged into the host USB port?

    >>please see above comment. I corrected CTL3 timing from Vbus ON.

    TPS2543 wave.pdf

  • 0 in reply to j_yamamoto1
    TI__Mastermind 42795 points

    I think it is best to set the CTL lines prior to VBUS turning on. If the CTL line changes after VBUS is on the PD (many different types may work many different ways) there can be issues. Please see this from BC1.2 spec.

    Data line contact detect debounce timing should also be considered (10 ms minimum) and the CTL pins should be stable before the debounce time expires.

    In summary, please set CTL3 pin to the desired value before or at the time when VBUS is applied.