SSI

EPS2U Power Supply Design Guide, V2.1

3Definitions/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

 

meet SSI guidelines, however, some system applications may optionally

 

use these features.

 

 

Autoranging

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.

 

 

CFM

Cubic Feet per Minute (airflow).

 

 

Dropout

A condition that allows the line voltage input to the power supply to drop to

 

below the minimum operating voltage.

Latch Off

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.

 

 

Monotonically

A waveform changes from one level to another in a steady fashion, without

 

intermediate retracement or oscillation.

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

 

the amount for which it is rated. This commonly occurs if there is a "short

 

circuit" condition in the load attached to the supply.

 

 

PFC

Power Factor Corrected.

 

 

Ripple

The periodic or random signals over a frequency band of 0 Hz to 20 MHz.

 

 

Rise Time

Rise time is defined as the time it takes any output voltage to rise from

 

10% to 95% of its nominal voltage.

Sag

The condition where the AC line voltage drops below the nominal voltage

 

conditions.

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

 

inputs of the supply.

MTBF

Mean time between failure.

 

 

PWOK

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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SSI America EPS2U manual Definitions/Terms/Acronyms, Required