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

4.2.1 Engine Start or Stop Power Foldback Operation Example

The example below depicts the Power Foldback operation upon detection of VIN voltage level changes. Table 5-10 shows the configurable SPM Engine parameters used in this section's example.

Table 4-6 SPM Engine Parameters - Engine Start or Stop Power Foldback Example
SPM Engine Parameters Configuration Description
Total USB VBUS Power (System Max Power) 60 W Total system power capacity that is allocated for Port A and Port B
Port A Max Power 45 W Maximum Port A Power
Port B Max Power 45 W Maximum Port B Power
Port A Min Power 15 W Minimum Port A power
Port B Min Power 15 W Minimum Port B power
VIN Max Power Engine Off 30 W Total VBUS Power allocated for Port A and B when VIN < EngOffNomVth (EngineOnToAny)
Sharing Mode Fair Share Power Policy Port Min Power is guaranteed for each port and remaining power is intelligently distributed
Table 4-7 Engine Start or Stop Power Foldback Operation Example
Port A Port B
Scenario 1: Port A connects in Normal Operation VIN > EngOnVth
Power Required by Sink 45 W
Power Distributed to Sink 45 W
Scenario 2: Port B connects in Normal Operation VIN>EngOnVth
Power Required by Sinks 45 W 45 W
Power Distributed to Sinks 30 W 30 W
Start of Power Foldback Operation
VIN < EngOffNomVth (EngineOnToAny) w/ reduced power = 30 W 30 W 30 W
After EngOffDeglitch time, 15 W Source Capabilities resent to Port A and Port B 30 W 30 W
Sink accepts and Grace Period (EngOffTimer) starts 15 W 15 W
VIN remains <EngOffNomVth(EngineOnToAny) 15 W 15 W
Ports disable after Grace Period (EngOffTimer) expires 0 W 0 W
VIN transitions to >Engine On Vth(AnyToEngineOn) 0 W 0 W
After EngOnDeglitch Time, 15 W Source Capabilities is sent to both ports 15 W 15 W
Sink Accepts 15 W 15 W
Sink Requests 45 W 15 W 15 W
30 W Source Capabilities resent to Port A and Port B 15 W 15 W
Sink Accepts 30 W 30 W