SSI EPS1U Power Supply Design Guide, V1.1 EPS1U Power Supply Design Guide A Server System Infrastructure (SSI) Specification For 1U Rack Chassis Power Supplies Version 1.
SSI EPS1U Power Supply Design Guide, V1.1 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.
SSI EPS1U Power Supply Design Guide, V1.1 Contents 1 Purpose .......................................................................................................................................................... 5 2 Conceptual Overview.................................................................................................................................... 5 3 Definitions/Terms/Acronyms ......................................................................................................
SSI EPS1U Power Supply Design Guide, V1.1 9 MTBF............................................................................................................................................................. 30 10 Agency Requirements ................................................................................................................................ 31 Figures Figure 1: Figure 2: Figure 3: Figure 4: Figure 5: Figure 6: Enclosure Drawing.........................................................
SSI EPS1U Power Supply Design Guide, V1.1 1 Purpose This specification defines a non-redundant power supply that supports 1U rack mount entry server systems. The entry-level power supply is not intended to be a hot swap type of power supply. The parameters of this supply are defined in this specification for open industry use. This specification defines a 125W, 250 W and 350 W power supply with six outputs; 3.3 V, 5 V, 12 V, -12 V, and 5 VSB.
SSI EPS1U Power Supply Design Guide, V1.1 3 Definitions/Terms/Acronyms Table 1: Definitions, Terms, and Acronyms (listed alphabetically) Required Recommended Optional Full Ranging CFM Dropout Latch Off Monotonically MTBF Noise Overcurrent PFC PWOK Ripple Rise Time Sag Surge VSB or Standby Voltage The status given to items within this design guide, which are required to meet SSI guidelines and a large majority of system applications.
SSI EPS1U Power Supply Design Guide, V1.1 4 Mechanical Overview There are two physical sizes of the power supply enclosure intended to accommodate power levels of 125W, 250W and 350W. There are two output connector designs. A card edge solution to provide ease of installation and removal and a wire harness to provide a traditional cabled solution. The chassis for the entry 1U power supply is designed for use in 1U rack mounted systems. 4.
SSI EPS1U Power Supply Design Guide, V1.1 4.2 Alternate Enclosure STATUS Small Power Form Factor Systems may require a smaller power supply enclosure. Figure 2 details a smaller power supply enclosure for such systems. This form factor accommodates power levels of 250W and 125W. The supply will provide output power via a wire harness out the interior face of the supply. Refer to the Entry Electronics Bay Specification at the SSI web site (http://www.ssiforum.org/docs/entry_elecbay_spec_v2_0.
SSI EPS1U Power Supply Design Guide, V1.1 4.3 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 shall not exceed a noise level of 38 dBA measured at one meter on all faces. At low fan speed, the power supply shall provide a minimum of 6 CFM of airflow with 0.003 inH2O of system backpressure.
SSI EPS1U Power Supply Design Guide, V1.1 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.
SSI EPS1U Power Supply Design Guide, V1.1 5.4 Efficiency STATUS Required The power supply shall have a minimum efficiency of 68% at maximum load and over the specified AC voltage. There is no efficiency requirement for the 125W version. 5.5 AC Line Dropout STATUS Required An AC line dropout is defined to be when the AC input drops to 0 VAC at any phase of the AC line for any length of time.
SSI EPS1U Power Supply Design Guide, V1.1 STATUS Recommended An additional inrush current limit is recommended for some system applications that require multiple systems on a single AC circuit. AC line inrush current shall not exceed 30 A peak for one-quarter of the AC cycle, after which, the input current should be no more than the specified maximum input current from Table 3. 5.
SSI EPS1U Power Supply Design Guide, V1.1 6 DC Output Specification 6.1 Connector STATUS Required The power supply uses a blind mating type connector with edge fingers (see Figure 1) to connect the power supply’s output voltages and signals to a connector located in the system. The card edge pin assignments are listed in Table 6. Figure 3 shows the card edge layout for the power supply. The connector located in the system is an AMP 1364999-1 or equivalent.
SSI EPS1U Power Supply Design Guide, V1.1 All dimensions are in millimeters. 3.3V 1.6 5V 12V1 GROUND Keying Notch 12V2 Reserved 3.3VS Reserved Reserved PSON# SDA SCL PSAlert# ReturnS Reserved Top View of Power Supply 7.62 MIN 62 1.27 +/-0.05 21.59 +/-0.05 1.27 6.35 +/-0.05 6.35 +/-0.05 9 spaces @ 2.54 6.35 +/-0.05 1.07 +/-0.05 29.03 +/-0.05 32 6.35 +/-0.05 0.38 x 45 51.89 +/-0.05 2x 1.57 x 45 1 31 2x Bottom view of power supply Figure 3: Edge Finger Layout 3.
SSI EPS1U Power Supply Design Guide, V1.1 6.2 Grounding STATUS Required The ground of the pins of the power supply wire harness provides the power return path. The wire harness ground pins shall be connected to safety ground (power supply enclosure). 6.3 Remote Sense STATUS Optional The power supply may have remote sense return (ReturnS) to regulate out ground drops for all output voltages; +3.3 V, +5 V, +12 V1, +12 V2, -12 V, and 5 VSB. The power supply may use remote sense (3.
SSI EPS1U Power Supply Design Guide, V1.1 STATUS Low Power Recommendation Voltage Table 7: 125 W Load Ratings Load Range Minimum Continuous Maximum Continuous +3.3 V +5 V +12 V1 +12 V2 -12 V 0.5 A 0.5 A 0.25 A Not used for 125W version. 0A 6A 12 A 3A 0.1 A 1.0 A +5 VSB 1. 2. 3. Peak 6A 0.2 A Maximum continuous total DC output power should not exceed 125 W. Peak total DC output power should not exceed 161 W. Peak power and current loading shall be supported for a minimum of 12 seconds.
SSI EPS1U Power Supply Design Guide, V1.1 STATUS High Power Recommendation Voltage Table 9: 350 W Load Ratings Load Range 1 Minimum Continuous Maximum Continuous +3.3 V +5 V +12 V1 +12 V2 -12 V +5 VSB 1.5 A 1.0 A 1.5 A 1.5 A 0A 0.1 A Voltage Load Range 2 Minimum Continuous Maximum Continuous +3.3 V +5 V +12 V1 +12 V2 -12 V +5 VSB 0.2 A 0.2 A 0.2 A 0.2 A 0A 0.1 A 1. 2. 3. 4. 5. 6.4.1 16 A 12 A 16 A 16 A 0.5 A 2.0 A 5.0 A 5.0 A 8.0 A 2.0 A 0.5 A 2.0 A Peak See note 2 See note 2 Peak 5.
SSI EPS1U Power Supply Design Guide, V1.1 6.5 Voltage Regulation STATUS Required The power supply output voltages must stay within the following voltage limits when operating at steady state and dynamic loading conditions. These limits include the peak-peak ripple/noise specified in Section 6.8. All outputs are measured with reference to the return remote sense (ReturnS) signal. The 5 V, 12 V1, 12 V2, –12 V and 5 VSB outputs are measured at the power supply connectors referenced to ReturnS. The +3.
SSI EPS1U Power Supply Design Guide, V1.1 6.7 Capacitive Loading STATUS Required The power supply shall be stable and meet all requirements with the following capacitive loading ranges. Output 6.8 Table 13: Capacitive Loading Conditions MIN MAX Units +3.3 V +5 V +12 V 10 10 10 6,800 4,700 11,000 µF µF µF -12 V +5 VSB 1 1 350 350 µF µF Ripple / Noise STATUS Required The maximum allowed ripple/noise output of the power supply is defined in Table 14 below.
SSI EPS1U Power Supply Design Guide, V1.1 6.9 Timing Requirements STATUS Required These are the timing requirements for the power supply operation. The output voltages must rise from 10% to within regulation limits (Tvout_rise) within 5 to 70 ms. The +3.3 V, +5 V and +12 V output voltages should start to rise at about the same time. All outputs must rise monotonically. The +5 V output needs to be greater than the +3.3 V output during any point of the voltage rise.
SSI EPS1U Power Supply Design Guide, V1.1 Table 16: Turn On/Off Timing MIN Item Description Tsb_on_delay Delay from AC being applied to 5 VSB being within regulation. Delay from AC being applied to all output voltages being within regulation. Time all output voltages stay within regulation after loss of AC. Delay from loss of AC to deassertion of PWOK T ac_on_delay Tvout_holdup Tpwok_holdup Tpson_on_delay Delay from PSON# active to output voltages within regulation limits.
SSI EPS1U Power Supply Design Guide, V1.
SSI EPS1U Power Supply Design Guide, V1.1 7 Protection Circuits STATUS Required Protection circuits inside the power supply shall cause only the power supply’s main outputs to shutdown. If the # power supply latches off due to a protection circuit tripping, an AC cycle OFF for 15 seconds and a PSON cycle HIGH for 1 second shall be able to reset the power supply. 7.1 Current Limit STATUS Required The power supply shall have current limit to prevent the +3.
SSI EPS1U Power Supply Design Guide, V1.1 7.3 Over Voltage Protection STATUS Required The power supply over voltage protection shall be locally sensed. The power supply shall shutdown and latch off # after an over voltage condition occurs. This latch shall be cleared by toggling the PSON signal or by an AC power interruption. Table 19 contains the over voltage limits. The values are measured at the output of the power supply’s connectors.
SSI EPS1U Power Supply Design Guide, V1.1 8 Control and Indicator Functions The following sections define the input and output signals from the power supply. Signals that can be defined as low true use the following convention: # signal = low true 8.1 PSON# STATUS Required # # The PSON signal is required to remotely turn on/off the power supply. PSON is an active low signal that turns on the +3.3 V, +5 V, +12 V, and –12 V power rails.
SSI EPS1U Power Supply Design Guide, V1.1 8.2 PWOK (Power OK) STATUS Required PWOK is a power OK signal and will be pulled HIGH by the power supply to indicate that all the outputs are within the regulation limits of the power supply. When any output voltage falls below regulation limits or when AC power has been removed for a time sufficiently long so that power supply operation is no longer guaranteed, PWOK will be de-asserted to a LOW state.
SSI EPS1U Power Supply Design Guide, V1.1 8.3 ACWarning STATUS Optional This is an output signal from the power supply which provides a warning to the system that the power supply has lost its AC input. This signal also provides a signal to synchronize the turn on of multiple power supplies. At turn on, this signal is pulled LOW when the supply’s internal bulk voltage has reached a level that allows it to turn on. At turn off ACWarning goes HIGH when the internal bulk voltage drops low enough.
SSI EPS1U Power Supply Design Guide, V1.1 8.4 Field Replacement Unit (FRU) Signals STATUS Optional Two pins will be allocated for the FRU information on the power supply connector. One pin is the Serial Clock (SCL). The second pin is used for Serial Data (SDA). Both pins are bi-directional and are used to form a serial bus. The FRU circuits inside the power supply must be powered off of 5 VSB output and grounded to ReturnS (remote sense return).
SSI EPS1U Power Supply Design Guide, V1.1 8.4.2.2 MultiRecord Area As defined by the IPMI FRU document. The following record types shall be used on this power supply: • Power Supply Information (Record Type 0x00) • DC Output (Record Type 0x01) • No other record types are required for the power supply.
SSI EPS1U Power Supply Design Guide, V1.1 8.5 LED Indicator STATUS Required There will be a single GREEN LED to indicate power supply status. When AC is applied to the PSU and standby voltages are available the LED shall BLINK GREEN. The LED shall turn ON GREEN to indicate that all the power outputs are available. Refer to Table 26 for conditions of the LED.
SSI EPS1U Power Supply Design Guide, V1.1 10 Agency Requirements STATUS Recommended The power supply must comply with all regulatory requirements for its intended geographical market. Depending on the chosen market, regulatory requirements may vary. Although a power supply can be designed for worldwide compliance, there may be cost factors that drive different versions of supplies for different geographically targeted markets.
