Enhance EPS2U Version 1.2 Power Supply Design Guide
SSI
EPS2U
Power Supply Design Guide
A Server System Infrastructure (SSI) Specification
For Entry Chassis Power Supplies
Version 1. 2
SSI
EPS2U Power Supply Design Guide, V1.2
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 is subject to the terms of the S.S.I. Specification Adopter's
Agreement.
Copyright Intel Corporation, Dell Computer Corporation, Compaq Computer Corporation, Silicon Graphics
Inc., International Business Machines Corporation, 2000.
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SSI
EPS2U Power Supply Design Guide, V1.2
Contents
1 Purpose ..............................................................................................................................................5
2 Conceptual Overview..........................................................................................................................5
3 Definitions/Terms/Acronyms ..............................................................................................................6
4 Mechanical Overview ..........................................................................................................................7
4.1 Airflow Requirements .........................................................................................................................8
4.2 Temperature Requirements................................................................................................................8
5 AC Input Requirements.......................................................................................................................9
5.1 AC Inlet Connector............................................................................................................................9
5.2 AC Input Voltage Specification ...........................................................................................................9
5.3 Efficiency..........................................................................................................................................9
5.4 AC Line Dropout.............................................................................................................................. 10
5.5 AC Line Fuse.................................................................................................................................. 10
5.6 AC Inrush........................................................................................................................................ 10
5.7 AC Line Transient Specification........................................................................................................ 11
5.8 AC Line Fast Transient Specification ................................................................................................ 11
6 DC Output Specification ................................................................................................................... 12
6.1 Output Connectors .......................................................................................................................... 12
6.1.1 Required Baseboard power connector ....................................................................................... 12
6.1.2 Required Processor Power Connector ....................................................................................... 12
6.1.3 Required Peripheral Power Connectors...................................................................................... 13
6.1.4 Required Floppy Power Connector ............................................................................................ 13
6.1.5 Optional Server Signal Connector.............................................................................................. 13
6.2 Grounding....................................................................................................................................... 14
6.3 Remote Sense ................................................................................................................................ 14
6.4 Output Power/Currents .................................................................................................................... 15
6.4.1 Standby Outputs .......................................................................................................................15
6.5 Voltage Regulation ..........................................................................................................................16
6.6 Dynamic Loading .............................................................................................................................17
6.7 Capacitive Loading .......................................................................................................................... 18
6.8 Ripple / Noise.................................................................................................................................. 18
6.9 Timing Requirements .......................................................................................................................19
7 Protection Circuits............................................................................................................................ 22
7.1 Current Limit ................................................................................................................................... 22
7.2 240VA Protection ............................................................................................................................ 22
7.3 Over Voltage Protection ...................................................................................................................23
7.4 Over Temperature Protec tion ........................................................................................................... 23
8 Control and Indicator Functions .......................................................................................................24
8.1 PSON# ........................................................................................................................................... 24
8.2 PWOK (Power OK) ..........................................................................................................................25
8.3 Field Replacement Unit (FRU) Signals.............................................................................................. 26
8.3.1 FRU Data .................................................................................................................................26
8.3.2 FRU Data Format ..................................................................................................................... 26
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SSI
EPS2U Power Supply Design Guide, V1.2
9 MTBF ................................................................................................................................................ 28
10 Agency Requirements ...................................................................................................................... 28
Figures
Figure 1: Enclosure Drawing ...........................................................................................................................7
Figure 2: Output Voltage Timing ................................................................................................................... 19
Figure 3: Turn On/Off Timing (Single Power Supply)...................................................................................... 21
Figure 4: PSON# Signal Characteristics........................................................................................................ 24
Tables
Table 1: Thermal Requirements ......................................................................................................................8
Table 2: AC Input Rating................................................................................................................................9
Table 3: AC Line Sag Transient Performance................................................................................................ 11
Table 4: AC Line Surge Transient Performance............................................................................................. 11
Table 5: P1 Baseboard Power Connector...................................................................................................... 12
Table 6: Processor Power Connector ............................................................................................................ 12
Table 7: Peripheral Power Connectors .......................................................................................................... 13
Table 8: P9 Floppy Power Connector ............................................................................................................ 13
Table 9: Server Signal Connector ................................................................................................................. 13
Table 10: 480 W Load Ratings...................................................................................................................... 15
Table 11: Voltage Regulation Limits.............................................................................................................. 16
Table 12: Optional +5V Regulation Limits...................................................................................................... 16
Table 13: Transient Load Requirements........................................................................................................ 17
Table 14: Capacitve Loading Conditions ........................................................................................................18
Table 15: Ripple and Noise .......................................................................................................................... 18
Table 16: Output Voltage Timing................................................................................................................... 19
Table 17: Turn On/Off Timing ....................................................................................................................... 20
Table 18: Over Current Protection .................................................................................................................22
Table 19: Over Current Protection .................................................................................................................23
Table 20: Over Voltage Limits .......................................................................................................................23
Table 21: PSON# Signal Characteristic.......................................................................................................... 24
Table 22: PWOK Signal Characteristics ........................................................................................................ 25
Table 23: FRU Device Information ................................................................................................................ 26
Table 24: FRU Device Product Information Area............................................................................................ 26
Table 25: FRU Device Product Information Area............................................................................................ 27
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SSI
EPS2U Power Supply Design Guide, V1.2
1 Purpose
This 2U Rack Power Supply Specification defines a common power supply used in entry -level servers. This
supply may range typically from 400 to 700 watts and is used in a non-redundant configuration. The scope of this
document defines the requirement s for one supply in this power range. The parameters of this supply are defined
in this specification for open industry use.
This specification defines a 480 W power supply with 6 outputs; 3.3 V, 5 V, 12V1, 12V2, -12 V, and 5 VSB.
Because of its connector leads, the power supply is not intended to be a hot swap type of power supply.
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
NOTE
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 bulk power system may be a n+1 redundant power system or a non-redundant power system.
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SSI
EPS2U Power Supply Design Guide, V1.2
3 Definitions/Terms/Acronyms
Required The status given to items within this design guide, which are required to
meet SSI guidelines and a large majority of system applications.
Recommended The status given to items within this design guide which are not required to
meet SSI guidelines, however, are required by many system applications.
Optional The status given to items within this design guide, which are not required to
Autoranging A power supply that automatically senses and adjusts itself to the proper
CFM Cubic Feet per Minute (airflow).
Dropout A condition that allows the line voltage input to the power supply to drop to
Latch Off A power supply, after detecting a fault condition, shuts itself off. Even if the
Monotonically A waveform changes from one level to another in a steady fashion, without
Noise The periodic or random signals over frequency band of 0 Hz to 20 MHz.
Overcurrent A condition in which a supply attempts to provide more output current than
PFC Power Factor Corrected.
Ripple The periodic or random signals over a frequency band of 0 Hz to 20 MHz.
meet SSI guidelines, however, some system applications may optionally
use these features.
input voltage range (110 VAC or 220 VAC). No manual switches or
manual adjustments are needed.
below the minimum operating voltage.
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.
intermediate retracement or oscillation.
the amount for which it is rated. This commonly occurs if there is a "short
circuit" condition in the load attached to the supply.
Rise Time Rise time is defined as the time it takes any output voltage to rise from
Sag The condition where the AC line voltage drops below the nominal voltage
Surge The condition where the AC line voltage rises above nominal voltage.
VSB or Standby Voltage An output voltage that is present whenever AC power is applied to the AC
MTBF Mean time between failure.
PWOK A typical logic level output signal provided by the supply that signals the
10% to 95% of its nominal voltage.
conditions.
inputs of the supply.
Server System that all DC output voltages are within their specified range.
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SSI
top access
EPS2U Power Supply Design Guide, V1.2
4 Mechanical Overview
STATUS
Required (Optional)
Note: Some features are noted as optional in the enclosure drawing figure below. These features may be use in
some chassis designs where only top access is allowed for the cage mounting.
The EPS2U is a power supply enclosure intended to handle a power range of 400W to 700W. A mechanical
drawing of the power supply cage is shown below in .
Optional mounting features for
mounting of the power supply.
Allow for 1.2mm
protrusion (x4)
Figure 1: Enclosure Drawing
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SSI
EPS2U Power Supply Design Guide, V1.2
4.1 Airflow Requirements
STATUS
Recommended
The power supply shall have a two-speed fan(s) and provide cooling to both the supply and the system. , During
low-speed fan operation, the power supply must not exceed a noise level of 43 dBa measured at one meter on all
faces. At low fan speed, the power supply shall provide a minimum of 12 CFM of airflow with 0.003 inH2O of
system backpressure. At high fan speed, the power supply shall provide a minimum of 20 CFM with 0.006 inH2O
of system backpressure.
4.2 Temperature Requirements
STATUS
Recommended
The power supply shall operate within all specified limits over the Top temperature range. The average air
temperature difference (∆Tps ) from the inlet to the outlet of the power supply shall not exceed the values shown
below in Table 1. All airflow shall pass through the power supply and not over the exterior surfaces of the power
supply.
Table 1: Thermal Requirements
ITEM DESCRIPTION MIN MAX UNITS
Top
∆Tps
T
non-op
The power supply must meet UL enclosure requirements for temperature rise limits. All sides of the power supply
with exception to the air exhaust side, must be classified as “Handle, knobs, grips, etc. held for short periods of
time only”.
Operating temperature range. 0 45
Temperature rise from inlet air to outlet air of power supply.
480 W output power, 20 CFM, Sea level, 25 °C inlet air
480 W output power, 12 CFM, Sea level, 25 °C inlet air
Non-operating temperature range. -40 70
21
35
°C
°C
°C
°C
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SSI
EPS2U Power Supply Design Guide, V1.2
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 2: AC Input Rating
PARAMETER MIN RATED MAX Max Input
Current
Voltage (110) 90 V
Voltage (220) 180 V
Frequency 47 Hz 63 Hz
1 Maximum input current at low input voltage range shall be measured at 90VAC. A 480 W output load shall be applied.
2 Maximum input current at high input voltage range shall be measured at 180 VAC. A 480 W output load shall be applied.
3 This is not intended to be used for determining agency input current markings.
4 Maximum rated input current is measured at 100 VAC and 200 VAC.
100-127 V
rms
200-240 V
rms
140 V
rms
264 V
rms
8.4 A
rms
4.2 A
rms
1,3
7.6 A
rms
2,3
rms
Max Rated Input
Current
4
rms
4
3.8 A
rms
5.3 Efficiency
STATUS
Required
The power supply shall have a minimum efficiency of 65% at maximum load and over the specified AC voltage.
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