Enhance EPS12V Version 2.8 Power Supply Design Guide
SSI
EPS12V
Power Supply Design Guide
A Server System Infrastructure (SSI) Specification
For Entry Chassis Power Supplies
Version 2.8
SSI
EPS12V Power Supply Design Guide, V2.8
Orig./Rev. Description of Changes
2.1
2.8
Posted design guide
Remove references to common and split 12V planes.
Added higher power levels up to 800W.
Reduced holdup time requirements to 75% of max load.
Added cross loading plots.
Added option for tighter 12V regulation.
Add new SSI efficiency requirements (recommended level & loading conditions).
Increase 12V rail currents.
Tpwok_on max time reduced to 500msec.
Change 5VSB to 3.0A for higher power levels.
Added reference to PSMI spec.
Modified SMBus section (FRU and PSMI) to 3.3V with 5V tolerance.
Modified 240VA section; removed common plane, change to <20A for all 12V outputs.
Updated sound power & airflow requirements
Add SATA and PCI-Express GFX connectors
Updated efficiency testing method
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SSI
EPS12V Power Supply Design Guide, V2.8
Disclaimer:
THIS SPECIFICATION IS PROVIDED "AS IS" WITH NO WARRANTIES
WHATSOEVER, INCLUDING ANY WARRANTY OF MERCHANTABILITY,
NONINFRINGEMENT, FITNESS FOR ANY PARTICULAR PURPOSE, OR ANY
WARRANTY OTHERWISE ARISING OUT OF ANY PROPOSAL, SPECIFICATION OR
SAMPLE. WITHOUT LIMITATION, THE PROMOTERS (Intel Corporation, NEC
Corporation, Dell Computer Corporation, Data General a division of EMC Corporation,
Compaq Computer Corporation, Silicon Graphics Inc., and International Business
Machines Corporation) DISCLAIM ALL LIABILITY FOR COST OF PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES, LOST PROFITS, LOSS OF USE, LOSS OF
DATA OR ANY INCIDENTAL, CONSEQUENTIAL, DIRECT, INDIRECT, OR SPECIAL
AMAGES, WHETHER UNDER CONTRACT, TORT, WARRANTY OR OTHERWISE,
ARISING IN ANY WAY OUT OF USE OR RELIANCE UPON THIS SPECIFICATION OR
ANY INFORMATION HEREIN.
The Promoters disclaim all liability, including liability for infringement of any proprietary
rights, relating to use of information in this specification. No license, express or implied,
by estoppel or otherwise, to any intellectual property rights is granted herein.
This specification and the information herein is the confidential and trade secret
information of the Promoters. Use, reproduction and disclosure of this specification and
the information herein are subject to the terms of the S.S.I. Specification Adopter's
Agreement.
Copyright Intel Corporation, Dell Computer Corporation, Hewlett Packard Company, Silicon Graphics Inc., International Business
Machines Corporation, 2002 – 2004.
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EPS12V Power Supply Design Guide, V2.8
Contents
1 Purpose.......................................................................................................................................................... 7
2 Conceptual Overview ................................................................................................................................... 7
3 Definitions/Terms/Acronyms....................................................................................................................... 8
4 Mechanical Overview ................................................................................................................................... 9
4.1 Acoustic Requirements ............................................................................................................................. 10
4.2 Airflow Requirements ................................................................................................................................ 10
4.3 Temperature Requirements ...................................................................................................................... 11
5 AC Input Requirements.............................................................................................................................. 12
5.1 AC Inlet Connector.................................................................................................................................... 12
5.2 AC Input Voltage Specification ................................................................................................................. 12
5.3 Input Under Voltage .................................................................................................................................. 12
5.4 Efficiency ................................................................................................................................................... 12
5.5 AC Line Dropout........................................................................................................................................ 13
5.6 AC Line Fuse ............................................................................................................................................ 13
5.7 AC Inrush .................................................................................................................................................. 13
5.8 AC Line Transient Specification................................................................................................................ 14
5.9 AC Line Fast Transient Specification........................................................................................................ 14
6 DC Output Specification ............................................................................................................................ 15
6.1 Output Connectors .................................................................................................................................... 15
6.1.1 Baseboard power connector.............................................................................................................. 15
6.1.2 Processor Power Connector.............................................................................................................. 15
6.1.3 +12V4 Baseboard Power Connector .................................................................................................16
6.1.4 Peripheral Power Connectors............................................................................................................ 16
6.1.5 Floppy Power Connector ................................................................................................................... 17
6.1.6 Serial ATA Power Connector............................................................................................................. 18
6.1.7 Server Signal Connector.................................................................................................................... 19
6.1.8 Workstation Power Connector for High Power Graphics Cards........................................................ 19
6.2 Grounding.................................................................................................................................................. 20
6.3 Remote Sense .......................................................................................................................................... 20
6.4 Output Power/Currents ............................................................................................................................. 20
6.4.1 Standby Outputs ................................................................................................................................ 27
6.5 Voltage Regulation.................................................................................................................................... 27
6.6 Dynamic Loading ...................................................................................................................................... 28
6.7 Capacitive Loading.................................................................................................................................... 28
6.8 Ripple / Noise............................................................................................................................................ 28
6.9 Timing Requirements ................................................................................................................................ 29
7 Protection Circuits...................................................................................................................................... 33
7.1 Current Limit.............................................................................................................................................. 33
7.2 240VA Protection ...................................................................................................................................... 33
7.3 Over Voltage Protection ............................................................................................................................ 34
7.4 Over Temperature Protection.................................................................................................................... 34
8 Control and Indicator Functions ............................................................................................................... 35
8.1 PSON# ...................................................................................................................................................... 35
8.2 PWOK (Power OK) ................................................................................................................................... 36
8.3 SMBus Communication............................................................................................................................. 36
8.4 Power Supply Management Interface....................................................................................................... 36
8.5 Field Replacement Unit (FRU) Signals ..................................................................................................... 37
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EPS12V Power Supply Design Guide, V2.8
8.5.1
FRU Data ........................................................................................................................................... 37
8.5.2 FRU Data Format............................................................................................................................... 37
9 MTBF ............................................................................................................................................................ 38
10 Agency Requirements................................................................................................................................ 39
Figures
Figure 1: Enclosure Drawing .................................................................................................................................... 9
Figure 2 System Airflow Impedance........................................................................................................................ 10
Figure 3 Cross Loading Graph for 550W Configuration.......................................................................................... 21
Figure 4 Cross Loading Graph for 600W Configuration.......................................................................................... 22
Figure 5 Cross Loading Graph for 650W Configuration.......................................................................................... 23
Figure 6 Cross Loading Graph for 700W Configuration.......................................................................................... 24
Figure 7 750W Cross loading graph........................................................................................................................ 25
Figure 8 Cross Loading Graph for 800W Configuration.......................................................................................... 26
Figure 9: Output Voltage Timing............................................................................................................................. 30
Figure 10: Turn On/Off Timing (Single Power Supply)........................................................................................... 32
Figure 11: PSON# Signal Characteristics .............................................................................................................. 35
Tables
Table 1 Recommended Acoustic Sound Power Levels .......................................................................................... 10
Table 2: Thermal Requirements ............................................................................................................................. 11
Table 3: AC Input Rating ........................................................................................................................................ 12
Table 4: Efficiency .................................................................................................................................................. 13
Table 5 Efficiency Loading Table .............................................................................. Error! Bookmark not defined.
Table 6: AC Line Sag Transient Performance........................................................................................................ 14
Table 7: AC Line Surge Transient Performance .................................................................................................... 14
Table 8: P1 Baseboard Power Connector.............................................................................................................. 15
Table 9: Processor Power Connector..................................................................................................................... 16
Table 10: Peripheral Power Connectors................................................................................................................. 17
Table 11: Floppy Power Connector........................................................................................................................ 17
Table 12: Floppy Power Connector ....................................................................................................................... 18
Table 13: Server Signal Connector ........................................................................................................................ 19
Table 14 PCI Express Graphic Card Power Connector .......................................................................................... 19
Table 15: 550 W Load Ratings ............................................................................................................................... 21
Table 16: 600 W Load Ratings ............................................................................................................................... 22
Table 17: 650 W Load Ratings ............................................................................................................................... 23
Table 18: 700 W Load Ratings ............................................................................................................................... 24
Table 19: 750W Load Ratings ................................................................................................................................ 25
Table 20: 800 W Load Ratings ............................................................................................................................... 26
Table 21: Voltage Regulation Limits....................................................................................................................... 27
Table 22: Optional +5V Regulation Limits .............................................................................................................. 27
Table 23: Transient Load Requirements ................................................................................................................ 28
Table 24: Capacitive Loading Conditions............................................................................................................... 28
Table 25: Ripple and Noise .................................................................................................................................... 29
Table 26: Output Voltage Timing............................................................................................................................ 30
Table 27: Turn On/Off Timing................................................................................................................................. 31
Table 28: Over Current Protection.......................................................................................................................... 33
Table 29: Over Current Limits ................................................................................................................................ 34
Table 30: Over Voltage Limits ................................................................................................................................ 34
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Table 31: PSON
Table 32: PWOK Signal Characteristics................................................................................................................. 36
Table 33: FRU Device Information ......................................................................................................................... 37
Table 34: FRU Device Product Information Area ................................................................................................... 37
Table 35: MultiRecord information Area................................................................................................................. 38
#
Signal Characteristic .................................................................................................................. 35
EPS12V Power Supply Design Guide, V2.8
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EPS12V Power Supply Design Guide, V2.8
1
Purpose
This specification defines a non-redundant power supply that supports entry server computer systems.
Recommendations for 550 W, 600 W, 650 W, 700W, 750W, and 800W power supplies with 8 outputs (3.3 V, 5 V,
12V1, 12V2, 12V3, 12V4, -12 V, and 5 VSB) are provided. The form factor is based on the PS/2 power supply,
with three enclosure lengths defined to support various output power levels. Connector/cable assemblies are
required for the motherboard power, remote sensing, control functions, and peripheral power. Because of its
connector leads, the entry-level power supply is not intended to be a hot swap type of power supply. The cooling
fan should meet the acoustical requirements for the system, while providing system cooling.
The parameters of this supply are defined in this specification for open industry use.
2
Conceptual Overview
In the Entry server market, the bulk power system must source power on several output rails.
These rails are typically as follows:
• +3.3 V
• +5 V
• +12 V
• –12 V
• +5 V standby
NOTES
Local DC-DC converters shall be utilized for processor power, and will ideally convert power from the +12 V
rail, however, they may also convert power from other rails.
The +12V rail may be separated into three +12V rails to meet regulatory requirements for energy hazards
(240VA).
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EPS12V Power Supply Design Guide, V2.8
3 Definitions/Terms/Acronyms
Required
Recommended
Optional
Autoranging
CFM
Dropout
Latch Off
Monotonically
The status given to items within this design guide, which are required to
meet SSI guidelines and a large majority of system applications
The status given to items within this design guide which are not required to
meet SSI guidelines, however, are required by many system applications
The status given to items within this design guide, which are not required to
meet SSI guidelines, however, some system applications may optionally
use these features
A power supply that automatically senses and adjusts itself to the proper
input voltage range (110 VAC or 220 VAC). No manual switches or
manual adjustments are needed
Cubic Feet per Minute (airflow)
A condition that allows the line voltage input to the power supply to drop to
below the minimum operating voltage
A power supply, after detecting a fault condition, shuts itself off. Even if the
fault condition disappears the supply does not restart unless manual or
electronic intervention occurs. Manual intervention commonly includes
briefly removing and then reconnecting the supply, or it could be done
through a switch. Electronic intervention could be done by electronic
signals in the Server System
A waveform changes from one level to another in a steady fashion, without
intermediate retracement or oscillation
Noise
Overcurrent
PFC
Ripple
Rise Time
Sag
Surge
VSB or Standby Voltage
MTBF
PWOK
The periodic or random signals over frequency band of 0 Hz to 20 MHz
A condition in which a supply attempts to provide more output current than
the amount for which it is rated. This commonly occurs if there is a "short
circuit" condition in the load attached to the supply
Power Factor Corrected
The periodic or random signals over a frequency band of 0 Hz to 20 MHz
Rise time is defined as the time it takes any output voltage to rise from
10% to 95% of its nominal voltage
The condition where the AC line voltage drops below the nominal voltage
conditions
The condition where the AC line voltage rises above nominal voltage
An output voltage that is present whenever AC power is applied to the AC
inputs of the supply
Mean time between failure
A typical logic level output signal provided by the supply that signals the
Server System that all DC output voltages are within their specified range
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EPS12V Power Supply Design Guide, V2.8
4 Mechanical Overview
STATUS
Required
Three enclosure size options are defined to accommodate various power levels. Recommended power levels for
each enclosure length are shown below. Refer to Figure 1 for details. The two rear mounting tabs on the
enclosure are OPTIONAL and may not be required for many systems.
Length Recommended power levels
140mm < 450W
180mm 450W to 750W
230mm > 800W
Top View
12 mm
55 mm
Optional mounting tab Optional mounting tab
130 mm
11 mm
16 mm
Length
+ 6mm
146 mm
110 mm
97.2 mm
Airflow
Label Area
Up
150 mm
138 mm
Warning
Label
AC
Inlet
15 mm
86 mm
6x32 THREADED HOLE
(4x)
74 mm
Length
0 m
14 m
6 mm 114 mm
Figure 1: Enclosure Drawing
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EPS12V Power Supply Design Guide, V2.8
4.1 Acoustic Requirements
STATUS
Recommended
It is recommended the power supply have a variable speed fan based on temperature and loading conditions.
There are three different acoustic sound power levels defined at different ambient temperatures and loading
conditions.
Table 1 Recommended Acoustic Sound Power Levels
Idle Typical Max
Ambient Temperature 35ºC 40ºC 45ºC
% Loading 40% 60% 100%
Sound Power (BA) 4.0 4.7 6.0
4.2 Airflow Requirements
STATUS
Recommended
It is recommended the power supply have no less than 14 CFM of airflow to provide proper airflow to system
components. The air shall exit the power supply on the AC inlet face. The power supply shall meet all
requirements with the below system airflow impedance presented to the power supplies airflow path.
Figure 2 System Airflow Impedance
0.6
0.5
0.4
0.3
0.2
(in H2O)
0.1
System Pressure
0
System Flow Impedance
0 10203040
Power Sup ply Airflow (CFM)
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EPS12V Power Supply Design Guide, V2.8
4.3 Temperature Requirements
STATUS
Recommended
The power supply shall operate within all specified limits over the Top temperature range. The average air
temperature difference (∆T
below in Table 2. All airflow shall pass through the power supply and not over the exterior surfaces of the power
supply.
ITEM DESCRIPTION MIN MAX UNITS
) from the inlet to the outlet of the power supply shall not exceed the values shown
ps
Table 2: Thermal Requirements
Top
T
non-op
The power supply must meet UL enclosure requirements for temperature rise limits. All sides of the power supply
with exception of the air exhaust side, must be classified as “Handle, knobs, grips, etc. held for short periods of
time only”.
Operating temperature range. 0 45 °C
Non-operating temperature range. -40 70 °C
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EPS12V Power Supply Design Guide, V2.8
5 AC Input Requirements
STATUS
Required
The power supply shall incorporate universal power input with active power factor correction, which shall reduce
line harmonics in accordance with the EN61000-3-2 and JEIDA MITI standards.
5.1 AC Inlet Connector
STATUS
Required
The AC input connector shall be an IEC 320 C-14 power inlet. This inlet is rated for 15 A/250 VAC.
5.2 AC Input Voltage Specification
STATUS
Required
The power supply must operate within all specified limits over the following input voltage range. Harmonic
distortion of up to 10% THD must not cause the power supply to go out of specified limits. The power supply shall
operate properly at 85 VAC input voltage to guarantee proper design margins.
Table 3: AC Input Rating
PARAMETER MIN RATED MAX
Voltage (110) 90 V
Voltage (220) 180 V
Frequency 47 Hz 63 Hz
100-127 V
rms
200-240 V
rms
140 V
rms
264 V
rms
rms
rms
5.3 Input Under Voltage
STATUS
Required
The power supply shall contain protection circuitry such that application of an input voltage below the minimum
specified in Section 5.2 shall not cause damage to the power supply.
5.4 Efficiency
STATUS
Recommended / Required
The following table provides recommended and required minimum efficiency levels. These are provided at three
different load levels; 100%, 50% and 20%. The “required” minimum efficiency levels are for the purpose of proper
power supply cooling when installed in the system. The “recommended” minimum efficiency levels are for the
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