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 Engine Start or Stop Transition Management

The TPS257xx-Q1 supports dynamic port power management scheme for VIN supply voltage fluctuations in case of Engine Start/Stop transition events. Through dynamic detection of the supply voltage input level, the SPM takes action to enter or exit the appropriate power level. Upon detection of low VIN below normal operating range, the SPM enters a lower power mode to protect the system from overheating. The SPM also filters a fluctuation or temporary glitch on VIN to prevent an abrupt loss of USB port power which in turn enhances the end user experience. Table 4-4 and Table 4-5 show the VIN threshold and timer parameters. All parameters are configured via the GUI except for VIN UVLO. Figure 4-5 depicts an example of how different power modes, as determined by the VIN threshold levels, work in conjunction with the deglitch filter and timers.

Table 4-4 VIN Threshold Parameters
VIN Threshold Parameters Description
VIN>EngOnVth Full Power level entry threshold with EngineOnDeglitch filter(for example, Engine fully ON condition w/ Car Key Knob in ON position)
VIN<EngOffNomVth Full Power to Low power entry threshold with EngineOffDeglitch filter(i.e Car key knob in accessory position with nominal VIN accessory mode voltage level)
VIN>EngineOnMinVth No Power to Low Power entry threshold. This transition triggers entry into Low Power state immediately. If VIN remains above this threshold but below EngOnVth for EngineOffTimer duration, VBUS is disabled after the timer expiration. (for example, Car key knob in accessory position with lower VIN accessory mode voltage level)
VIN<EngineOffMinVth Any to No Power entry threshold after Engine Off Delay expiration. (for example, Car key knob in accessory position with lower VIN accessory mode voltage level)
VIN<UVLO Hardware VIN UVLO voltage level. The SPM Controller is disabled.
Table 4-5 Configurable Timer Parameters
Engine On/Off Timer Parameters Description
EngOn Deglitch Engine On Deglitch timer. Deglitch time to enter engine ON Full Power condition after VIN reaches EngOnVth.
EngOff Deglitch Engine Off Deglitch timer. Deglitch time to enter Low Power condition after VIN reaches EngOffNomVth.
EngOnTimer(Grace Period) Engine On timer (Grace Period Timer). Timeout value after Low Power entry from No Power. Once this timer expires and the VIN supply voltage is still below EngOnVth, VBUS is disabled.
EngOffTimer(Grace Period) Engine Off timer (Grace Period Timer). Timeout value after Low Power entry from Full Power. Once this timer expires, VBUS is disabled.
Engine Off Delay Engine Off Delay timer. Delay time to to enter No Power after VIN falls under EngOffMinVth.
GUID-20230828-SS0I-WLCJ-SCPS-BZMG5BGBLNNS-low.png Figure 4-5 VIN Level and Engine On or Off Power Transition

Figure 4-6 shows the GUI entry example in Advanced Configuration View.

GUID-20230828-SS0I-RBST-RLVJ-PG7C2RVXFQLF-low.png Figure 4-6 Engine On or Off GUI Entry Example