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TPS25750: USB-C PD application

Daria Kiseleva
Intellectual 2735 points
Part Number: TPS25750
Other Parts Discussed in Thread: LM74502, TPS26750, PMP41115

Tool/software:

Good day, collegues,

My customer would like to integrate USB-C PD 3.1 EPR charging into design.
Objectives are:

  1. To enable charging of my battery via USB-C across the full power range defined by the USB-C PD 3.0 and 3.1 standards.
  2. To also allow charging of a smartphone from my battery.

For voltage conversion, I am using an I²C-controllable Buck/Boost converter. I plan to implement the TPS25750 together with the TPD4S480RUKR, and I have a few questions:

  1. Why does the TPS25750 provide an internal power path for SPR mode, while in EPR mode the circuit switches to an external MOSFET?
  2. Is it possible to use the TPS25750 purely as a controller, routing power through an external MOSFET in both SPR and EPR modes?
  3. In my design, the power path will use two NMOS devices driven by the LM74502. If I do not use the internal power path of the TPS25750, can the POWER PATH EN pin be used to drive the Enable input of the LM74502, or does this signal necessarily need to be handled by my microcontroller?
  4. If I use only an external power path, am I correct that I don’t need to connect the following pins?
    1. TPD4S480RUKR: VBUS_LV, EPR_BLK_G, VBUS, VBIAS, EPR_EN
    2. TPS25750: VBUS

Thank you,

Daria

  • 0
    TI__Mastermind 34676 points

    Hi Daria, 

    Just to clarify when you mention TPS25750, are you referring to TPS26750? These are two different devices, TPS25750 is a SPR PD3.0 PD controller while TPS26750 is a EPR PD3.1 PD controller. 

    Daria Kiseleva said:
    Why does the TPS25750 provide an internal power path for SPR mode, while in EPR mode the circuit switches to an external MOSFET?

    TPS26750 does not have the capability to support EPR voltage natively on its own pin (i.e. VBUS and VSYS). Internally it contains a 5V source only power path (PP5V) that is also used to supply power for the CCx pins and Vconn. 

    Daria Kiseleva said:
    Is it possible to use the TPS25750 purely as a controller, routing power through an external MOSFET in both SPR and EPR modes?

    I'm not sure what exactly you mean by this question, can you elaborate? TPS26750 will automatically enable/disable the external MOSFET depending on the scenario. 

    Daria Kiseleva said:
    In my design, the power path will use two NMOS devices driven by the LM74502. If I do not use the internal power path of the TPS25750, can the POWER PATH EN pin be used to drive the Enable input of the LM74502, or does this signal necessarily need to be handled by my microcontroller?

    Refer to PMP41115 schematic: https://www.ti.com/tool/PMP41115 

    TPS26750 uses the POWER_PATH_EN pin to control LM74502 EN pin as shown below:

    Daria Kiseleva said:
    1. If I use only an external power path, am I correct that I don’t need to connect the following pins?
      1. TPD4S480RUKR: VBUS_LV, EPR_BLK_G, VBUS, VBIAS, EPR_EN
      2. TPS25750: VBUS

    These pins are all necessary for the full system to work, please refer to PMPM41115 schematic to see how everything is connected. 

    Thanks and Regards,

    Raymond Lin