Timing, Housekeeping and Control – REQUIRED

Figure 4-3: Power on Timing

Table 4-10: Power Supply Timing

1. Value in the Legacy column list timings for power supplies designed before the year 2020. In 2020, the T1 and T3 timings have moved from the Legacy timing to the new Required column for all new power supply designs.
2. T3 minimum time faster than 100 ms is not recommended for previous generation motherboards and systems. All design tolerances must be considered before allowing T3 faster than 100 ms.
   1. A T3 time less than 100 ms may be designed based on system requirements and a need to provide faster PSU and system turn on capability. However, PSU and system designers are highly recommended to verify and ensure no PSU and system compatibility problems exist, especially for previous generation motherboards and systems.
3. T5 Required value to be defined for both Full/Light load conditions.
4. T5 Recommended value is defined for 80% of full load condition.
5. T6 Required value to be defined for coming from both Full/Light load conditions.
6. T6 Recommended value is defined for coming from 80% of full load condition.
7. PSUs are recommended to label or indicate the timing value for system designer and integrator reference for T1 and T3. This allows system designers to optimize “turn on” time within the system.
8. Timing values recommended for systems that use ALPM.