SLVAFG6B December   2022  – November 2024 TPS25762-Q1 , TPS25763-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 On/Off Transition Management
      1. 4.2.1 Engine On/Off 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

5.1 Assured Capacity Policy Example

This section provides examples of power distribution when Source ports are configured as Assured Capacity Policy and Max Init Power mode is selected. Table 5-10 shows the SPM Engine parameters used in this section's example.
Table 5-1 SPM Engine Parameters - Assured Capacity Policy Example
SPM Engine Parameters Configuration Description
System Max Power 105W(1) Total system power capacity allocated for Port A and B
Port A Max Power 60W Maximum Port A Power
Port B Max Power 45W Maximum Port B Power
Port A Min Power 15W Minimum Port A power
Port B Min Power 15W Minimum Port B power
Assured Mode Max Init Power Source initially sends Source Capabilities advertising max power
(1) The System Max Power is 105W; the sum of Port A Max Power and Port B Max Power.

Three example scenarios of Assured Capacity Policy are listed in Table 5-2. Note that the power distributed to each port is independent of the other port's status as is expected with the Assured Capacity Policy.

Table 5-2 Assured Capacity Policy Example
Port A Port B
Initially Allocated 60W 45W
Scenario 1: Port A connects to a Sink that requires 27 W. Port B is unconnected.
Power Required by Sink 27W
Power Distributed to Sink 27W
Scenario 2: Port B connects to a Sink that requires 45 W.
Power Required by Sink 27W 45W
Power Distributed to Sinks 27W 45W
Scenario 3: Port A changes the requirement to 60 W.
Power Required by Sink 60W 45W
Power Distributed to Sinks 60W 45W

The following diagrams show the flow of the PD negotiation when Assured Capacity Policy is enabled and where one Sink first connects to Port A (Figure 5-1) and a second Sink connects to Port B (Figure 5-2).

Assured Capacity Policy Negotiation Flow - Port A Connected Figure 5-1 Assured Capacity Policy Negotiation Flow - Port A Connected
Assured Capacity Policy Negotiation Flow - Port B Connected Figure 5-2 Assured Capacity Policy Negotiation Flow - Port B Connected