Intel EPS1U manual Grounding, Remote Sense, Output Power/Currents

SSI

EPS1U Power Supply Design Guide, V1.1

6.2Grounding

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).

6.3Remote 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 (3.3VS) to regulate out drops in the system for the +3.3 V output. The +5 V, +12 V1, +12 V2, –12 V, and 5 VSB outputs only use remote sense referenced to the ReturnS signal. The remote sense input impedance to the power supply must be greater than 200 Ω on 3.3 VS and ReturnS. This is the value of the resistor connecting the remote sense to the output voltage internal to the power supply. Remote sense must be able to regulate out a minimum of 200 mV drop on the +3.3 V output. The remote sense return (ReturnS) must be able to regulate out a minimum of 200 mV drop in the power ground return. The current in any remote sense line shall be less than 5 mA to prevent voltage sensing errors. The power supply must operate within specification over the full range of voltage drops from the power supply’s output connector to the remote sense points.

6.4Output Power/Currents

The following tables define three power and current ratings for a 125W, 250 W and a 350 W power supply. These were selected to cover different types of systems and configurations. The 125W power level is targeted for use in “today’s” low power server systems. The 250W power level is targeted for use in “today’s” higher power 1U server systems. The 350W power level is directed at “tomorrow’s” higher power 1U server systems. The combined output power of all outputs shall not exceed the rated output power. The tables show the load ranges for each of the two power supply power levels. The power supply must meet both static and dynamic voltage regulation requirements for the minimum loading conditions.