SLVAFG6A December   2022  – November 2023 TPS25762-Q1 , TPS25772-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Terms and Abbreviations
  5. 2 SPM Engine Overview
  6. 3Multi-Port Power Allocation Policy
    1. 3.1 Assured Capacity Policy
    2. 3.2 Shared Capacity Policy
      1. 3.2.1 Fair Share Power Policy
        1. 3.2.1.1 Blind Sink Support
    3. 3.3 Hybrid Mode
  7. 4Power Foldback Policy
    1. 4.1 Thermal Foldback Operation
    2. 4.2 Engine Start or Stop Transition Management
      1. 4.2.1 Engine Start or Stop Power Foldback Operation Example
  8. 5Multi-Port Power Allocation Policy Examples
    1. 5.1 Assured Capacity Policy Example
    2. 5.2 Fair Share Power Policy Example
      1. 5.2.1 FSP Policy Example – Blind Sink Support
      2. 5.2.2 FSP Policy Example – Blind Sink Support with Max Power
    3. 5.3 Hybrid Mode Example
  9. 6References
  10. 7Revision History

5 Multi-Port Power Allocation Policy Examples

This section includes example scenarios of port power allocation and distribution when using the different Multi-Port Power Allocation Policy and Power Distribution Rule options. The examples of when one or two Sinks are connected are shown in table format followed by a flow diagram. The tables concisely summarize what occurs when Sink devices connect to TPS25772-Q1 Source ports: the power requested by the Sinks and the power distributed to the Sinks. The flow diagrams that follow illustrate the PD negotiation between the Source and Sink using the same example scenarios.

A negotiation between Port Partners must successfully complete to establish a PD power contract. Port Partners communicate over the USB Type-C connector's CC wire and the typical PD negotiation process between a Sink and Source is outlined below:

  1. The Source advertises the initial Source Capabilities to the Sink. Assured Capacity Policy, with Max Init Power enabled, will always advertise the Port Max Power upon connection. On the other hand, Shared Capacity Policy will always advertise the Port Min Power first.
  2. The Sink requests power based on the PDOs offered from the advertised Source Capabilities.
  3. The Source accepts the request and provides power accordingly.
  4. The Source follows up with a Get Sink Capabilities message.
  5. After obtaining the Sink Capabilities, the Source resends a new Source Capabilities message based on the Sink's power requirements.
Each time power is reallocated for Source ports via power harvesting or redistribution events, new Source Capabilities messages are automatically sent to Port Partners per the new allocated power. Power harvesting and redistribution events occur upon port connect/disconnect or Power Foldback phase entry/exit.