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TPS65983B: Using external power path instead of internal 5V, 3A power path

Ronnie Hughes
Expert 3090 points
Part Number: TPS65983B
Other Parts Discussed in Thread: TPS65982,

We’re currently looking to use the TPS65982 in a new design. Could I please get help in answering the questions I have below?

 

Is there any concerns/caution in implementing a PP_EXT only source (i.e. to turn off the PP_5V0 and PP_HV) that would provide 5V to the VBUS? (Note: we would be implementing the TPS65982 as a source only + DFP along with the alpine ridge chip)

          • Could we also just use one of the FETs for the PP_EXT? As we would only be sourcing 5V (3A)?
        • Could the voltage sensing and current sensing also work for the 5V (3A) use case? I.e. to limit the current at 3A and set the over voltage protection to just over 5?
        • Can this be configured via the TI configuration tool?
        • The interest of using the external power to support the 5V and 3A is to reduce the max voltage drop that would occur within the TI chip (RDSon of up to 60mOhm would equate to up to 180mV of drop from 5V going to the USB C connector, based on the max 3A current) and also avoid excessive heat dissipation on the part.

              Would it be possible to route the PCH USB lines to the USB_RP on the TPS65982 (for the multiplexor function) instead of from the alpine ridge USB port?

      Should we be using the TPS65983 of TPS65983B instead for Alpine Ridge?

      • 0
        TI__Guru 50120 points

        Hi Ronnie,

        The TPS65982 PP_HV external can source up to a maximum limi of USB PD 20V/5A as defined in the datasheet(Section 8.3.3.10). The reason why there is a need for back to back FETs is for protective measures for the system against large differential voltage across the FETs and block reverse current flow. Using the Application Customization Tool, overvoltage protection trip point can be configured in System Configuration(0x28) and the current can be limited in Transmit Source Capabilities(0x32) to whichever setting you want.

        I'll get back to you for the routing of the PCH USB lines to USB_RP after more thinking and considerations.

        Regards,

        Jimmy

      • 0
        TI__Expert 6430 points
        Hi Ronnie,

        As Jimmy mentioned using just one of the FET's won't work as our chip needs two FETs to implement protections required by Type-C spec.

        By PCH do you mean Platform Controller Hub? If yes then this can't be done as the USB 3.0 and USB 2.0 signals should come from the same source i.e. from the Alpine Ridge.

        Thanks,
        Rahul
      • 0 in reply to Rahul Sharma16
        TI__Expert 3090 points

        We need the configuration tool for the TPS65983 and TPS65983A.  This part is not listed in the configuration tool available on ti.com.

      • 0 in reply to Ronnie Hughes
        TI__Expert 6430 points

        Hi Ronnie,

        I'll share it with over your email.

        Thanks,

        Rahul