ATX Version 3 Multi Rail Desktop Platform Power Supply

Design Guide

ID 336521
Date 11/01/2023
Document Table of Contents

Alternative Low Power Mode for Power Supplies

Computers continue to change and introduce new power states. One of these new power states is generically called an Alternative Low Power Mode (ALPM). Some examples of Alternative Low Power Modes are Microsoft* Windows* 10 Modern Standby* or Google* Chrome* Lucid Sleep. These new power states have created requirements for power supplies. Below is a summary of these requirements as they are mentioned throughout the document.

  • Section Section 4.2.4 – Other Lower Power System Requirements:
    • Table 4-5 shows that ALPM requirements are at the 0.55 A and 1.5 A load levels.
  • Section 4.3 - Timing, Housekeeping and Control:
    • Table 4-10 has a note about values of T1 and T3 that are required to support ALPM.
  • Section Section 4.2.2–Reliability – PS_​ON# Toggle for S0ix Mode and 4.2.2Section 10.2:
    • The number of times a PSU toggles on and off is expected to increase.
  • Section Section 4.3.3:
    • PSU response quickly to toggling of PS_​ON# signal.