Intel ATX12V manual Contents

ATX12V Power Supply Design Guide

Version 2.0

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

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