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TPS2549: how to do high current charge without iAP authentication chipset？

Alpha Han
Expert 3750 points
Part Number: TPS2549

Hi,Team:

Can you help to advise how to do high current charge without iAP authentication chipset when connect to iPhone?

My understanding TPS2549 can support this with out data line connection to CPU but in customer application, they still need the data connection for U-disk function.

Need special command from CPU to iPhone?

  • 0
    TI__Mastermind 30000 points

    Hello Alpha,

    Would you mind explaining to me what iAP authentication is? I couldn't find anything online and no one else on my team has heard of this term before.

    As far as detection from the portable device connected to the TPS2549, it follows BC1.2 protocol of being able to implement a dedicated charging port (DCP), a standard downstream port (SDP), and a charging downstream port (CDP). Here is a diagram showing the configuration of each one.

    DCP applications are typically used for when you only care about charging, and not about data transfer as the D+ and D- lines are shorted together (ex. wall adaptors) SDP applications are used for when you do want data transfer, but the amount of current supplied is not that high an importance as SDP can only supply a max of 500mA at 5V (ex flashdrive/external hard drive). Finally CDP applications re used for when you want the ability to transfer data but also charge at a higher rate as you can supply up to 1.5A (ex laptop ports for phone connections).

    As far as commands between the devices to determine which mode to go into, and allow for the phone to start charging, everything is done internal of the TPS2549. I'll give an example for communication between a BC1.2 source device (which to TPS2549 is) and a portable device. The portable device starts the conversation by sending a signal on the shared D+ line.  The source device detects this, and sends a response back on the D- line. The Portable device receives this response, and to verify that the D+ and D- lines are not shorted together (DCP mode), it sends another signal back through the D- line. The source device receives this signal through the D- line, but does not send back a response. Since the portable device never received a signal back on the D+ line, it knows that the D+ and D- lines are not shorted together, thus it is in CDP mode.

    I believe this answers your question. If so, please click This resolved my issue to close this thread.