Enhance LFX12V Version 1.0 Power Supply Design Guide
LFX12V Power Supply Design Guide
Lowprofile Form Factor with 12-Volt Connector
LFX12V
Lowprofile Form Factor with 12-Volt Connector
Power Supply Design Guide
Version 1.0
Revision History
Version Release Date Notes
1.0 April, 2004
• First public release.
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LFX12V Power Supply Design Guide
Lowprofile Form Factor with 12-Volt Connector
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LFX12V Power Supply Design Guide
Lowprofile Form Factor with 12-Volt Connector
Contents
1 Introduction .................................................................................................... 6
1.1 Scope 6
1.2 Terminology ...................................................................................................................6
2 Electrical ......................................................................................................... 7
2.1 AC Input 7
2.1.1 Input Over Current Protection.......................................................................... 8
2.1.2 Inrush Current Limiting .................................................................................... 8
2.1.3 Input Under Voltage......................................................................................... 8
2.1.4 Regulatory ....................................................................................................... 8
2.1.5 Catastrophic Failure Protection ....................................................................... 9
2.2 DC Output .................................................................................................................... 10
2.2.1 DC Voltage Regulation .................................................................................. 10
2.2.2 Remote Sensing ............................................................................................ 10
2.2.3 Typical Power Distribution ............................................................................. 11
2.2.4 Power Limit / Hazardous Energy Levels........................................................ 13
2.2.5 Efficiency General .........................................................................................13
2.2.6 Output Ripple/Noise ......................................................................................14
2.2.7 Output Transient Response........................................................................... 16
2.2.8 Capacitive Load.............................................................................................19
2.2.9 Closed-loop Stability......................................................................................19
2.2.10 +5 VDC / +3.3 VDC Power Sequencing ........................................................ 19
2.2.11 Voltage Hold-up Time.................................................................................... 19
2.3 Timing / Housekeeping / Control..................................................................................20
2.3.1 PWR_OK ....................................................................................................... 20
2.3.2 PS_ON# ........................................................................................................21
2.3.3 +5 VSB .......................................................................................................... 22
2.3.4 Power-on Time .............................................................................................. 22
2.3.5 Rise Time ......................................................................................................22
2.3.6 Overshoot at Turn-on / Turn-off..................................................................... 22
2.3.7 Reset after Shutdown .................................................................................... 23
2.3.8 +5 VSB at AC Power-down ...........................................................................23
2.4 Output Protection ......................................................................................................... 23
2.4.1 Over Voltage Protection ................................................................................23
2.4.2 Short-circuit Protection .................................................................................. 23
2.4.3 No-load Operation ......................................................................................... 24
2.4.4 Over Current Protection................................................................................. 24
2.4.5 Over-temperature Protection ......................................................................... 24
2.4.6 Output Bypass ............................................................................................... 24
3 Mechanical.................................................................................................... 25
3.1 Labeling /Marking.........................................................................................................25
3.2 Physical Dimensions .................................................................................................... 25
3.2 AC Connector............................................................................................................... 29
3.3 DC Connectors............................................................................................................. 29
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LFX12V Power Supply Design Guide
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3.3.1 Main Power Connector .................................................................................. 31
3.3.2 Peripheral Connector(s) ................................................................................31
3.3.3 Floppy Drive Connector................................................................................. 32
+12 V Power Connector ............................................................................................... 32
3.3.4 Serial ATA Power Connector......................................................................... 32
4 Thermal Requirements ................................................................................ 33
4.1 Fan and Venting...........................................................................................................33
4.2 Airflow and Acoustics ................................................................................................... 33
4.3 Airflow / Fan ................................................................................................................. 35
5 Environmental .............................................................................................. 37
5.1 Temperature................................................................................................................. 37
5.2 Thermal Shock (Shipping)............................................................................................ 37
5.3 Relative Humidity ......................................................................................................... 37
5.4 Altitude Requirement.................................................................................................... 37
5.5 Mechanical Shock ........................................................................................................ 37
5.6 Random Vibration ........................................................................................................38
5.7 Acoustics......................................................................................................................38
5.8 Ecological Requirements .............................................................................................38
6 Safety............................................................................................................. 39
6.1 North America .............................................................................................................. 39
6.2 International .................................................................................................................40
7 System Cooling Considerations................................................................. 41
8 Reliability ...................................................................................................... 42
9 Applicable Documents ................................................................................ 43
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LFX12V Power Supply Design Guide
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Figures
Figure 1: Cross Loading Graph for 180W configuration ............................................................11
Figure 2. Cross Loading Graph for 200W Configuration............................................................ 12
Figure 3. Differential Noise Test Setup ...................................................................................... 16
Figure 4. Power Supply Timing..................................................................................................20
Figure 5. PS_ON# Signal Characteristics.................................................................................. 21
Figure 6. Mechanical Outline ..................................................................................................... 26
Figure 7. Mechanical Details...................................................................................................... 27
Figure 8. PSU Slot Feature Detail..............................................................................................28
Figure 9. Recommended Chassis Tab Feature ......................................................................... 29
Figure 10. Connectors (Pin-side view, not to scale) ..................................................................30
Figure 11. Serial ATA Connector ................................................................................................ 32
Figure 12. AMCA* Standard 210 ...............................................................................................35
Tables
Table 1. AC Input Line Requirements.......................................................................................... 8
Table 2. DC Output Voltage Regulation..................................................................................... 10
Table 3. Typical Power Distribution for 180 W Configurations................................................... 11
Table 4. Typical Power Distribution for 200 W Configurations................................................... 12
Table 5. Efficiency Vs Load ......................................................................................................13
Table 6. Loading Tables for Efficiency Measurements ............................................................. 13
Table 7. Energy Star* Input Power Consumption....................................................................... 14
Table 8. DC Output Noise/Ripple............................................................................................... 16
Table 9. DC Output Transient Step Sizes.................................................................................. 18
Table 10. Output Capacitive Loads............................................................................................. 19
Table 11. PWR_OK Signal Characteristics................................................................................. 20
Table 12. PS_ON# Signal Characteristics .................................................................................. 21
Table 13. Over Voltage Protection.............................................................................................. 23
Table 14. Airflow and Acoustic Recommendations..................................................................... 34
Table 15. Loading for Acoustic Test for 180 Watts ..................................................................... 34
Table 16. Loading for Acoustic Test for 200 Watts ..................................................................... 34
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LFX12V Power Supply Design Guide
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1 Introduction
1.1 Scope
This document provides design suggestions for power supply(s) that support Balanced
Technology Extended (BTX) form factor systems. The power supply(s) are primarily
intended for use with ultra small form factor system designs (6 –9 liters in total system
volume). It should not be inferred that all power supplies built to support Balanced
Technology Extended based systems must conform exactly to the content of this document,
though there are key parameters that define mechanical fit across a common set of
platforms. Since power supply needs vary depending on system configuration, the design
specifics described are not intended to support all possible systems.
1.2 Terminology
The following terms are used in this document:
Term Description
Required
Recommended
Optional
B
A
CFM
Monotonically
The status given to items within this design guide, which are required
to meet design guide and a large majority of system applications.
The status given to items within this design guide, which are not
required to meet design guide, however, are required by many system
applications.
The status given to items within this design guide, which are not
required to meet design guide, however, some system applications
may optionally use these features.
Declared sound power, LwAd. The declared sound power level shall
be measured according to ISO* 7779 for the power supply and
reported according to ISO 9296.
Cubic Feet per Minute (airflow).
A waveform changes from one level to another in a steady fashion,
without oscillation.
Noise
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The periodic or random signals over frequency band of 0 Hz to 20
MHz.
Lowprofile Form Factor with 12-Volt Connector
Term Description
LFX12V Power Supply Design Guide
Overcurrent
PFC
Ripple
Rise Time
Surge
VSB or Standby
Voltage
MTBF
PWR_OK
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 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.
PWR_OK is a “power good” signal used by the system power supply
to indicate that the +5VDC, +3.3 VDC and +12VDC outputs are above
the undervoltage thresholds of the power supply.
2 Electrical
The following electrical requirements are required and must be met over the
environmental ranges as defined in Section 5 (unless otherwise noted).
2.1 AC Input
Table 1, lists AC input voltage and frequency requirements for continuous operation.
The power supply shall be capable of supplying full-rated output power over the
voltage ranges shown in
environment may be either switch-selectable or auto-ranging. The power supply
shall automatically recover from AC power loss. The power supply must be able to
start up under peak loading at 90 VAC.
Table 1. The correct input range for use in a given
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LFX12V Power Supply Design Guide
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Table 1. AC Input Line Requirements
Parameter Minimum Nominal
Vin (115 VAC) 90 115 135 VAC
Vin (230 VAC) 180 230 265 VAC
Vin Frequency 47 -- 63 Hz
Iin (115 VAC) 6 A rms
Iin (230 VAC) 3 A rms
(1)
Note:
Nominal voltages for test purposes are considered to be within ±1.0 V of nominal.
(1)
Maximum Unit
2.1.1 Input Over Current Protection
The power supply is required to incorporate primary fusing for input over current
protection to prevent damage to the power supply and meet product safety
requirements. Fuses should be slow-blow–type or equivalent to prevent nuisance
trips.1
rms
rms
2.1.2 Inrush Current Limiting
Maximum inrush current from power-on (with power-on at any point on the AC sine)
and including, but not limited to, three line cycles, shall be limited to a level below
the surge rating of the input line cord, AC switch if present, bridge rectifier, fuse, and
EMI filter components. Repetitive ON/OFF cycling of the AC input voltage should
not damage the power supply or cause the input fuse to blow.
2.1.3 Input Under Voltage
The power supply is required to contain protection circuitry such that the application
of an input voltage below the minimum specified in Section 2.1, Table 1, shall not
cause damage to the power supply.
2.1.4 Regulatory
The power supply is required to be tested and comply with the most current version
of the following regulatory specification requirements and/or standards
2.1.4.1 PRODUCT SAFETY
UL* 60950, 3
EN*60 950, 3rd Edition
rd
Edition –CAN/CSA-C22.2-60950-00,
IEC*60 950, 3rd Edition (CB Report to include all national deviations)
1
For Denmark and Switzerland international safety requirements, if the internal over current protective devices exceed 8A for
Denmark and 10A for Switzerland, then the power supply must pass international safety testing to EN 60950 using a
maximum 16A over-current protected branch circuit, and this 16A (time delay fuse) branch circuit protector must not open
during power supply abnormal operation (output short circuit and component fault) testing.
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LFX12V Power Supply Design Guide
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EU* Low Voltage Directive (73/23/EEC) (CE Compliance)
GB4943-90 CCIB* (China)
2.1.4.2 ELECTROMAGNETIC CAMPATIBILITY
FCC*, Class B, Part 15 (Radiated & Conducted Emissions)
CISPR* 22 / EN55022, 3rd Edition (Radiated & Conducted Emissions)
EN55024 (ITE Specific Immunity)
EN 61000-4-2 – Electrostatic Discharge
EN 61000-4-3– Radiated RFI Immunity
EN 61000-4-4– Electrical Fast Transients.
EN 61000-4-5 – Electrical Surge
EN 61000-4-6 – RF Conducted
EN 61000-4-8 – Power Frequency Magnetic Fields
EN 61000-4-11 – Voltage Dips, Short Interrupts and Fluctuations
EN61000-3-2 (Harmonics)
EN61000-3-3 (Voltage Flicker)
EU EMC Directive ((8/9/336/EEC) (CE Compliance)
2.1.4.3 Other Certifications and/or Declarations
GB925 (China/CCC*), CNS13438 (Taiwan/BSMI*), AS/NZ3548 (Australia/C-tick*
based on CISPR22)
2.1.5 Catastrophic Failure Protection
Should a component failure occur, the power supply should not exhibit any of the
following:
• Flame
• Excessive smoke
• Charred PCB
• Fused PCB conductor
• Startling noise
• Emission of molten material
• Earth ground fault (short circuit to ground or chassis enclosure)
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LFX12V Power Supply Design Guide
Lowprofile Form Factor with 12-Volt Connector
2.2 DC Output
2.2.1 DC Voltage Regulation
The DC output voltages are required to remain within the regulation ranges shown in
Table 2, when measured at the load end of the output connectors under all line, load,
and environmental conditions specified in Section 5.
Table 2. DC Output Voltage Regulation
Output Range Min. Nom. Max. Unit
(1)
±5% +11.40 +12.00 +12.60 Volts
+5VDC ±5% +4.75 +5.00 +5.25 Volts
(2)
±5% +3.14 +3.30 +3.47 Volts
+5VSB ±5% +4.75 +5.00 +5.25 Volts
Note:.
(2)
+12VDC
+3.3VDC
-12VDC ±10% -10.80 -12.00 -13.20 Volts
(1)
At +12 VDC peak loading, regulation at the +12 VDC output can go to ± 10%.
Voltage tolerance is required at main connector and S-ATA connector (if used).
2.2.2 Remote Sensing
The +3.3 VDC output should have provisions for remote sensing to compensate for
excessive cable drops. The default sense should be connected to pin 13 of the main
power connector. The power supply should draw no more than 10 mA through the
remote sense line to keep DC offset voltages to a minimum.
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LFX12V Power Supply Design Guide
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2.2.3 Typical Power Distribution
DC output power requirements and distributions will vary based on specific system
options and implementation.
Significant dependencies include the quantity and types of processors, memory, addin card slots, and peripheral bays, as well as support for advanced graphics or other
features. Table 3 through Table 4 and Figure 1 through Figure 2 shows the power
distribution and cross loading tables for power supplies in the range of 180 W to
200W. These are recommendations but it is ultimately the responsibility of the
designer to define a power budget for a given target product and market.
Table 3. Typical Power Distribution for 180 W Configurations
Output
+12 VDC 1.0 13.0 14.0
+5 VDC 0.3 8.0
+3.3 VDC 0.5 5.0
-12 VDC 0 0.3
+5 VSB 0 2.0 2.5
Note: Total combined output of 3.3 V and 5 V is ≤ 50 W
Minimum Current
(amps)
Rated Current
(amps)
Peak Current
(amps)
Figure 1: Cross Loading Graph for 180W configuration
180W Cross Regulation
(5V rail + 3.3V rail vs. 12V)
60
50
40
30
20
Combined Power
(5V rail + 3.3V rail)
10
5V + 3.3V power (watts)
0
050100150200
12V power (watts)
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LFX12V Power Supply Design Guide
Lowprofile Form Factor with 12-Volt Connector
Table 4. Typical Power Distribution for 200 W Configurations
Output
+12 VDC 1.0 13.5 14.5
+5 VDC 0.3 9.0
+3.3 VDC 0.5 6.0
-12 VDC 0 0.3
+5 VSB 0 2.0 2.5
Note: Total combined output of 3.3 V and 5 V is ≤ 60 W
Minimum Current
(amps)
Rated Current
(amps)
Peak Current
(amps)
Figure 2. Cross Loading Graph for 200W Configuration
200W Cross Regulation
(5V rail + 3.3V rail vs. 12V)
70
60
50
40
30
20
Combined Power
(5V rail + 3.3V rail)
10
5V + 3.3V power (watts)
0
0 50 100 150 200
12V p o wer (watts)
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LFX12V Power Supply Design Guide
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2.2.4 Power Limit / Hazardous Energy Levels
Under normal or overload conditions, it is required that no output shall continuously
provide more than 240 VA under any conditions of load including output short
circuit, per the requirement of UL 1950/CSA 950 / EN 60950/IEC 950 specification.
2.2.5 Efficiency General
The power supply should have a required minimum efficiency as stated in Table 5
and when cost effective provide the recommended efficiency in Table 5. The
efficiency of the power supply should be tested at nominal input voltage of 115VAC
input and 230VAC input, under the load conditions defined in Table 5, and under the
temperature and operating conditions defined in Section 3. The loading condition for
testing efficiency shown in Table 5 represents a fully loaded system, a 50% loaded
system (typical load), and a 20% loaded (light load) system.
Table 5. Efficiency Vs Load
Loading
Required: Minimum Efficiency
Recommended: Minimum Efficiency
Full load Typical load Light load
70% 70% 60%
75% 80% 67%
Table 6. Loading Tables for Efficiency Measurements
180W (loading shown in Amps)
Loading +12V +5V +3.3V -12V +5Vsb
Full 11.0 7.0 4.0 0.2 0.5
Typical 6.0 3.0 3.0 0.1 0.5
Light 2.8 0.3 0.5 0 0.1
200W (loading shown in Amps)
Loading +12V +5V +3.3V -12V +5Vsb
Full 11.5 8.0 6.0 0.2 1.0
Typical 7.0 3.0 4.0 0.1 1.0
Light 3.0 0.4 0.5 0 0.5
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LFX12V Power Supply Design Guide
Lowprofile Form Factor with 12-Volt Connector
2.2.5.1 Energy Star*
The “Energy Star” efficiency requirements of the power supply depend on the
intended system configuration. In the low power / sleep state (S1 or S3) the system
should consume power in accordance with the values listed in Table 7.
Table 7. Energy Star Input Power Consumption
Maximum Continuous Power Rating of
Power Supply
< 200 W < 15 W
> 200 W < 300 W < 20 W
> 300 W < 350 W < 25 W
> 350 W < 400 W < 30 W
> 400 W 10% of the maximum continuous output rating
Note: To help meet the “Energy Star” system requirements, it is recommended that the power supply have ≥ 50%
efficiency at light load and in standby mode.
RMS Watts from the AC Line in Sleep/low-Power
Mode
2.2.5.2 Other Low Power System Requirements
To help meet the Blue Angel* system requirements, RAL-UZ 78, US
Presidential executive order 13221, future EPA requirements, and other low
Power system demands, it recommended that the +5 VSB standby supply
efficiency should be as high as possible. Standby efficiency is measured with
the main outputs off (PS_ON# high state). Standby efficiency should be
greater than 50% with a load of 100mA.
2.2.6 Output Ripple/Noise
The output ripple/noise requirements listed in
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