SSI
EPS1U Power Supply Design Guide, V1.1
5.4Efficiency
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.
5.5AC 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. During an AC dropout of one cycle or less the power supply must meet dynamic voltage regulation requirements over the rated load. An AC line dropout of one cycle or less shall not cause any tripping of control signals or protection circuits. If the AC dropout lasts longer than one cycle, the power supply should recover and meet all turn on requirements. The power supply must meet the AC dropout requirement over rated AC voltages, frequencies, and output loading conditions. Any dropout of the AC line shall not cause damage to the power supply.
5.6AC Line Fuse
STATUS
Required
The power supply shall incorporate one input fuse on the LINE side 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. AC inrush current shall not cause the AC line fuse to blow under any conditions. All protection circuits in the power supply shall not cause the AC fuse to blow unless a component in the power supply has failed. This includes DC output load short conditions.
STATUS
Optional
Some system applications may require a second input fuse in the NEUTRAL side of the AC input. In this case two fuses would be required; one in the LINE side and one in the NEUTRAL side of the AC inlet to the power supply.
5.7AC Inrush
STATUS
Required
The power supply must meet inrush requirements for any rated AC voltage, during turn on at any phase of AC voltage, during a single cycle AC dropout condition, during repetitive ON/OFF cycling of AC, and over the specified temperature range (Top). The peak inrush current shall be less than the ratings of its critical components (including input fuse, bulk rectifiers, and surge limiting device).
