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PMP41062: Reverse Mode

Part Number: PMP41062
Other Parts Discussed in Thread: BQ25756, TPS25750, , TPS25751

Hello forum,

We are currently designing a bidirectional charger using the BQ25756 charger and the TPS25750 power delivery controller for a 10S battery. After reviewing the block diagram (as seen in the image), we are considering whether it's possible to eliminate the TPSM365 buck converter, connect PPHV to PP5V, and utilize the buck-boost converter to step down the battery voltage from 42V to 5V. The 3.3V supply for the integrated circuit would be provided by a separate regulator.

Any insights or suggestions regarding this modification would be greatly appreciated.

Thank you in advance for your assistance.

Best regards,


  • Hi Manuel, I have asked the original design to help here. He is currently out on CNY, but will be back next week. Please give us a few days.

  • Hi Manuel,

    you can not connect PPHV to PP5V, since those are different power path and controlled by different control scheme, although we still need 5V at PP5V, the power requirements for the 5-V power supply was significantly decreased and follow the below load condition requirement.

    If you plan on sourcing >3-A and/or you need to support USB2 (but do not need USB3), you need to add an additional 100mW to the 5-V power supply budget.

    If you plan on using single lane USB-3 (USB 3x1), you instead should add an additional 1-W to the 5-V power supply budget.

    If you plan on using dual lane USB-3 (USB 3x2), you instead should add an additional 1.5-W to the 5-V power supply budget.

    if you need more details, I can involve the PD controller expert to help you clarify on this.



  • Thank you for the information you provided. The system we are designing does not involve data transfer and only utilizes the CC1 and CC2 lines for charging profile transactions. As mentioned, we aim to utilize the BQ25756  in both source and sink modes. Currently, it is functioning correctly as a sink, but we intend to evolve the system so that it can also act as a source. We have observed that the buck-boost converter can take the battery voltage and reduce it to a profile such as 5V, as depicted in the configuration on the right. I do not understand the advantage of using a separate 5V regulator, as shown in the configuration diagram on the left or in this PMP41062. Is it possible to achieve this with the BQ25756, or does it require a separate regulator?


  • Hi Max,

    Just circling back on my previous message. Any insights on whether it can handle our requirements, or if we'll need a separate regulator?

  • Hi Manuel,

    This is something we learned from product line on TPS25751, that we still need a 5V regulator on PP5V, for details of IC internal, you may raise a different ticket on this to specific part. so that a product AE/SE will help you on this. thanks