Intel ATX Power Supply Design Guide

1 Intel ATXP ower Supply Design GuideVersion ATX Power Supply Design GuideVersion 2 IMPORTANT INFORMATION AND CORPORATION (AND ANY CONTRIBUTOR) MAKES NOWARRANTIES WITH REGARD TO THIS DOCUMENT AND IN PARTICULAR DOESNOT WARRANT OR REPRESENT THAT THIS DOCUMENT OR ANY PRODUCTSMADE IN CONFORMANCE WITH IT WILL WORK IN THE INTENDED DOES Intel (OR ANY CONTRIBUTOR) ASSUME RESPONSIBILITY FORANY ERRORS THAT THE DOCUMENT MAY CONTAIN OR HAVE ANYLIABILITIES OR OBLIGATIONS FOR DAMAGES INCLUDING, BUT NOT LIMITEDTO, SPECIAL, INCIDENTAL, INDIRECT, PUNITIVE, OR CONSEQUENTIALDAMAGES WHETHER ARISING FROM OR IN CONNECTION WITH THE USE OFTHIS DOCUMENT IN ANY REPRESENTATIONS OR WARRANTIES ARE MADE THAT ANYPRODUCT BASED IN WHOLE OR IN PART ON THE ABOVE DOCUMENT WILL BEFREE FROM DEFECTS OR SAFE FOR USE FOR ITS INTENDED PURPOSE.

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3 All rights , September 1998 Third-party brands and names are the property of their respective ReleaseIntel ATX Power Supply Design GuideVersion 3 Contents1. Scope .. 62. Applicable Documents .. 73. Electrical Specification .. Input Requirements .. Overcurrent Current Limiting .. Undervoltage .. Failure Protection .. Output Requirements .. Voltage Regulation .. Sensing .. Power Distribution .. Limit .. Transient Load .. Loop Stability .. +5 VDC/+ Power Sequencing .. Hold-up Time .. / Housekeeping / Control .. #.. + Time .. at Turn- after Shutdown .. +5 VSB at AC Power Down .. Protection .. Circuit Protection .. Load Operation .. Bypass ..194. Mechanical Requirements .. / Marking .. / ATX Power Supply Design GuideVersion Connector .. Connectors.

4 Main Power Connector .. Power Connector (for 250 W and 300 W Configurations) .. Connector(s).. Drive Connector ..255. Environmental Requirements .. Shock (Shipping) .. Shock .. Vibration ..276. Electromagnetic Compatibility .. Line Current Harmonic Content (Optional) .. Leakage Derating .. Time Between Failures (MTBF)..298. Safety Requirements .. Materials ..31 Intel ATX Power Supply Design GuideVersion 5 FiguresFigure 1: Power Supply Timing ..16 Figure 2: Power Supply Dimensions for Chassis in Which the P/S Does Not Cool Processor ..21 Figure 3: Power Supply Dimensions for Chassis in Which the P/S Cools the 4: ATX Power Supply Connectors ..24 TablesTable 1: AC Input Line Requirements ..8 Table 2: AC Line Voltage Transient 3: DC Output Voltage 4: Typical Power Distribution for a 160 W Configuration.

5 12 Table 5: Typical Power Distribution for a 200 W Configuration ..12 Table 6: Typical Power Distribution for a 250 W Configuration ..13 Table 7: Typical Power Distribution for a 300 W Configuration ..13 Table 8: DC Output 9: PWR_OK Signal Characteristics ..16 Table 10: PS_ON# Signal Characteristics ..17 Table 11: Overvoltage ATX Power Supply Design GuideVersion 61. ScopeThis document outlines a reference ATX Power Supply that complies with the ATXS pecification, Version for motherboards and chassis. It is intended to provideadditional Power Supply Design information not detailed in the ATX specification,including information about the physical form factor of the Power Supply , coolingrequirements, connector configuration, and pertinent electrical and signal document is provided as a convenience only and is not intended to replace orsupplement the user s independent Design and validation activity.

6 It should not be inferredthat all ATX Power supplies must conform exactly to the content of this document. Neitherare the Design specifics described herein intended to support all possible systemconfigurations, as system Power Supply needs will vary widely depending on application(desktop / workstation / server), intended ambient environment (temperature, line voltage),motherboard Power requirements, a few modifications, a standard PS/2 Power Supply can support an ATX form-factorsystem. At a high level, these modifications include consolidating various motherboardconnectors into a single 20-pin connector, adding + and +5 VSB output supplyrails, adding a PS_ON# control input, and possibly repositioning the fan and/or ATX Power Supply Design GuideVersion 72. Applicable DocumentsThe latest revision in effect of the following documents forms a part of this document to theextent European Association of Consumer Electronics Substance List / Recommended Practice on Surge Voltages in Low-Voltage AC Guide on Surge Testing for Equipment Connected to Low-Voltage ACPower Predictions for Electronic conversion Coatings on aluminum and aluminum , Level 3 Safety of Component Power Supplies.

7 Intended for use with Electronic DataProcessing Equipment and Office , 3rd editionSafety of Information Technology Equipment including Electrical 1950 without D3 Deviation, 3rd editionSafety of Information Technology Equipment including Electrical 950 plus A1, A2, A3, A4 Safety of Information Technology Equipment including Business 950 plus A1, A2, A3, A4 Safety of Information Technology Equipment including Business (74-SEC) 207/94 Nordic National Requirement in addition to 22 and EN 55022 Limits and Methods of Measurements of Radio Interference Characteristics ofInformation Technology Equipment, Class 1992 American National Standard for Methods of Measurement of Radio-NoiseEmissions from Low-Voltage Electrical and Electronic Equipment in theRange of 9 kHz to 40 GHz for EMI (1992)Electromagnetic compatibility/generic immunity for Harmonic Current Emission, Class Electric AssociationGuidelines for the Suppression of Harmonics in Appliances and General / IEC1000-4-Electromagnetic compatibility for industrial-process measurement and -2: ESD -3: Immunity to Radiated Electromagnetic -4: Electrical Fast Transients/Burst -5.

8 Surge Immunity Publication 417 International Graphic Symbol Standard 7000 Graphic Symbols for Use on 47, Part 15, Subpart BFCC 50082-1: 1995 Electromagnetic compatibility, generic , Part 1: Residential, commercial and light 50140 Radio frequency electromagnetic field test standard, Amplitude 50204 Radio frequency electromagnetic field-test standard, Keyed 50141 Radio frequency common mode test 61000-4-11 Voltage dips and interruptions test ATX Power Supply Design GuideVersion 83. Electrical SpecificationThe electrical requirements that follow are to be met over the environmental rangesspecified in Section 5 unless otherwise AC Input RequirementsThe Power Supply shall be capable of supplying full rated output Power over two inputvoltage ranges rated 100-127 VAC and 200-240 VAC RMS nominal.

9 The correct inputrange for use in a given environment may be either switch-selectable or auto-ranging. Thepower Supply shall automatically recover from AC Power loss. The input voltage, current,and frequency requirements for continuous operation are stated below. (Note that nominalvoltages for test purposes are considered to be within V of nominal.) The powersupply must be able to start up under peak loading at 90 1: AC Input Line RequirementsParameterMinNomMaxUnitVin (115 VAC)90115135 VACrmsVin (230 VAC)180230265 VACrmsVin Frequency47--63 HzIin (115 VAC) (230 VAC) Input Overcurrent ProtectionThe Power Supply shall incorporate primary fusing for input overcurrent protection. Fusesshould be slow-blow type or equivalent to prevent nuisance Inrush Current LimitingMaximum inrush current from Power -on (with Power on at any point on the AC Sine) andincluding, but not limited to, three line cycles, shall be limited to a level below the surgerating of the input line cord, AC switch if present, bridge rectifier, fuse, and EMI filtercomponents.

10 Repetitive ON/OFF cycling of the AC input voltage should not damage thepower Supply or cause the input fuse to Input UndervoltageThe Power Supply shall contain protection circuitry such that the application of an inputvoltage below the minimum specified in Section , Table 1, shall not cause damage to thepower ATX Power Supply Design GuideVersion Slow TransientsThe DC output(s) shall not exceed the limits specified in Section as a result of theinput Power line noise defined in Table 2 under any load condition per EN 2: AC Line Voltage Transient LimitsDurationSag /SurgeOperating AC VoltageLineFrequencyPerformance Criteria0 to 500 ms10%Rated AC voltages50/60 HzNo loss of function orperformance0 to 15minutes15%Mid-point of rated ACvoltages50/60 HzNo loss of function orperformance0 to ACcycle30%Mid-point of rated ACvoltages50/60 HzNo loss of function orperformance0 to 5 ACcycles50%sag onlyMid-point of rated ACvoltages50/60 HzLoss of function acceptable,self- Surge VoltagesInput Surge Withstand Capability (Line Transients).