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TPS2549: Mode change

Jeff YANG
Genius 5085 points
Part Number: TPS2549

Hi,

When TPS2549 work in CTRL1/2/3 = 1/1/1 CDP-SDP auto switch mode.

If this time during charging, then we change the mode to CTRL1/2/3 = 0/0/1 to DCP mode, this behavior is allowed? TPS2549 will active detect mode pin change and reset the charging?

Or we need disable the TPS2549, then change mode, then enable the TPS2549?

Thanks!

Jeff

 

 

  • 0
    Genius 5085 points

    Hi,

    One more question, when  we set CTRL1/2/3 = 1/1/1 CDP-SDP auto switch mode. figure 1 is normal behavior DP/DM waveform.

    Figure 1.

    CH1: DM

    CH2: DP

    But sometimes we connect with Iphone found Vbus have 5V but no charging. DM around 120mV seems be latch.

    Figure 2.

    CH1: DM

    CH2: DP

    I will pass the schematic via privacy message.

    Thanks!

    Jeff

  • 0 in reply to Jeff YANG
    TI__Mastermind 38910 points

    Hello Jeff,

    There is no need to reset the device to change modes. Section 8.4.1 in the datasheet states that "The TPS2549 monitors the CTL inputs and transitions to whichever charging mode it is commanded to go to."

    I believe what you're observing is an iPhone issue and not one with the TPS2549, because some iPhones need a host to enumerate. If there is no host controller, some iPhones will not draw current. 

    1. Did you connect your host controller to the TPS2549?
    2. Which iPhone are you using for this test?

    BR,

    Seong

  • 0 in reply to Seong Kim
    Genius 5085 points

    Hi seong,

    What means "need a host to enumerate"?

    1. Did you connect your host controller to the TPS2549?

               => Yes, We out DP_OUT/DM_OUT connect to USB hub VL822.

                     So we how to inform the host controller to make some action to let iphone charging?

            2. Which iPhone are you using for this test?

               => I need check and feedback you later.

    Thanks!

    Jeff