Intel ATX12V User Manual

Intel

ATX12V Power Supply Design Guide

Version 2.0

3

Contents

1. Introduction ....................................................................................................... 6

1.1. Scope .....................................................................................................................................6

1.2. Key Changes for ATX12V Version 2.0 as Compared with ATX Power Supply......................6

1.2.1. Increased +12 VDC output capability ........................................................................6

1.2.2. Minimum Efficiency....................................................................................................6

1.2.3. Main Power Connector: .............................................................................................7

1.2.4. Separate current limit for 12V2 on the 2x2 connector: ...............................................7

1.3 Terminology.............................................................................................................................7

2. Applicable Documents ..................................................................................... 8

3. Electrical ............................................................................................................ 9

3.1. AC Input..................................................................................................................................9

3.1.1. Input Over-current Protection ....................................................................................9

3.1.2. Inrush Current Limiting ..............................................................................................9

3.1.3. Input Under-voltage ...................................................................................................10

3.1.4. Regulatory..................................................................................................................10

3.1.5. Catastrophic Failure Protection .................................................................................11

3.2. DC Output...............................................................................................................................11

3.2.1. DC Voltage Regulation ..............................................................................................11

3.2.2. Remote Sensing ........................................................................................................12

3.2.3. Typical Power Distribution .........................................................................................12

3.2.4. Power Limit / Hazardous Energy Levels ....................................................................17

3.2.5. Efficiency ...................................................................................................................17

3.2.6. Output Ripple/Noise...................................................................................................19

3.2.7. Output Transient Response.......................................................................................21

3.2.8. Capacitive Load .........................................................................................................21

3.2.9. Closed-loop Stability ..................................................................................................22

3.2.10. +5 VDC / +3.3 VDC Power Sequencing ..................................................................22

3.2.11. Voltage Hold-up Time ..............................................................................................22

3.3. Timing / Housekeeping / Control ............................................................................................22

3.3.1. PWR_OK ...................................................................................................................23

3.3.2. PS_ON#.....................................................................................................................23

3.3.3. +5 VSB.......................................................................................................................24

3.3.4. Power-on Time ..........................................................................................................25

3.3.5. Risetime.....................................................................................................................25

3.3.6. Overshoot at Turn-on / Turn-off.................................................................................25

3.3.7. Reset after Shutdown ................................................................................................25

3.3.8. +5 VSB at AC Power-down........................................................................................25

3.4. Output Protection....................................................................................................................26

3.4.1. Over-voltage Protection .............................................................................................26

3.4.2. Short-circuit Protection ..............................................................................................26