Grounding, Remote Sense | SSI America EPS2U instruction

SSI

EPS2U Power Supply Design Guide, V2.1

If the optional server signal connector is not used on the power supply or the connector is unplugged, the power supply shall utilize the 3.3RS on the baseboard connector (Pin 1).

Connector housing: 5-pin Molex 50-57-9405 or equivalent

Contacts: Molex 16-02-0088 or equivalent (gold plated)

Table 13: Server Signal Connector

Pin	Signal	24 AWG Color
1	I2C Clock	White/Green Stripe

2	I2C Data	White/Yellow Stripe

3	Reserved	NA

4	ReturnS	Black/White Stripe

5	3.3RS	Orange/White Stripe

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 for the +3.3V (3.3VS) and return (ReturnS) if the Optional Server Signal connector is implemented. The remote sense return (ReturnS) is used to regulate out ground drops for all output voltages; +3.3V, +5 V, +12V1, +12V2, +12V3, -12 V, and 5 VSB. The 3.3V remote sense (3.3VS) is used to regulate out drops in the system for the +3.3 V output. The remote sense input impedance to the power supply must be greater than 200 W 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.

- 16 -