ATX12VO (12V Only) Desktop Power Supply
Design Guide
ID
613768
Date
01/03/2022
Public
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Introduction
Processor Configurations
PCI Express* Add-in Card Considerations
Electrical
Mechanical
Acoustics
Environmental
Electromagnetic Compatibility
Safety
Reliability
CFX12V Specific Guidelines 2.0
LFX12V Specific Guidelines 2.0
ATX12V Specific Guidelines 3.0
SFX12V Specific Guidelines 4.0
TFX12V Specific Guidelines 3.0
Flex ATX Specific Guidelines 2.0
DC Output (Required)
DC Voltage Regulation (Required)
DC Output Current (Required)
Remote Sensing (Optional)
Other Low Power System Requirements (Required)
Output Ripple Noise (Required)
Capacitive Load (Recommended)
Closed Loop Stability (Required)
Multiple 12V Rail Power Sequencing (Required)
Voltage Hold-Up Time (Required)
Over Voltage Protection (OVP) (Required)
Short Circuit Protection (SCP) (Required)
No-Load Situation (Required)
Over Current Protection (OCP) (Required)
Over Temperature Protection (OTP) (Required)
Output Bypass (Required)
Separate Current Limit for 12V2 (Optional)
Overall Power Supply Efficiency Levels
Power Supply Efficiency for Energy Regulations - ENERGY STAR* and CEC PC Computers with High Expandability Score (Recommended)
SFX12V Specific Guidelines 4.0
Lower Profile Package – Physical Dimensions (Required)
Fan Requirements (Required)
Top Fan Mount Package – Physical Dimensions (Required)
Fan Requirements (Required)
Reduced Depth Top Mount Fan – Physical Dimensions (Required)
Fan Requirements (Required)
Standard SFX Profile Package – Physical Dimensions (Required)
Fan Requirements (Required)
PS3 Form Factor – Physical Dimensions (Required)
Fan Requirements (Required)
Timing, Housekeeping, and Control (Required)
Figure 4-2: Power on Timing
Table 4-8: Power Supply Timing
Parameter | Description | Value | |
Required | Recommended | ||
T0 | AC power on time4 | <2s | |
T1 | Power-on time3 | <150ms1 | <100 ms |
T2 | Rise time | 0.2–20 ms | |
T3 | PWR_OK delay3 | 1ms – 150ms1 | 1–100 ms |
T4 | PWR_OK rise time | < 10 ms | |
T5 | AC loss to PWR_OK hold-up time3 | > 16 ms2 | |
T6 | PWR_OK inactive to DC loss delay | > 1 ms |
- T1 and T3 required values are set to meet timing requirement for computers that use ALPM.
- T5 to be defined for both max/min load condition.
- 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.
- T0 is shown in Section 4.3.3, Figure 4-4.