Intel SPSH4 - Server Platform - 0 MB RAM, Technical Product Specification

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Power supply Subsystem SPSH4 Server System External Product Specification
Revision 1.11 36
4.2.6.6 Power supply Present Indicator
The PRESENT
#
signal is used to sense the number of power supplys in the system (operational
or not). This signal is connected to the power supply’s output ground.
Table 31: PRESENT
#
Signal Characteristics
Signal Type Output from power supply that is connected to ground.
Pull-up to VSB located in system.
PRESENT
#
= Low Present
PRESENT
#
= High Not Present
MIN MAX
Logic level low voltage, Isink=4mA 0V 0.4V
Logic level high voltage, Isink=50
µ
A
5.25V
Sink current, PRESENT
#
= low
4mA
Sink current, PRESENT
#
= high
50
µ
A
4.2.6.7 Power supply Fan Control
The power supply fan speed is controlled by the FANC signal. The fan speed (even during sleep
mode) is controlled by a variable voltage on this pin. This signal allows the system to request
control of the power supply fan. The control circuit in the system supplies voltage to this pin
from 12V to 0V for the fan control request. If the FANC signal is left open the fan control
defaults to power supply control.
Table 32: Fan Speed Control
Signal Type Accepts an input voltage from the system. Pull-up to
12V located in power supply.
FANC < 1V Fan in SLEEP mode
1
2V < FANC < 3V Fan in LOW speed
1
3V < FANC < 10.5V
Fan ramps from LOW to HIGH speed 1
FANC > 10.5V Fan in HIGH speed
1
MIN MAX
Source current
2mA
Fan SLEEP mode output power 2
50W
Fan LOW speed ambient temperature
35
°
C
Notes
1. This is a request from the system to the power supply to operate the fan at this condition. The power supply
can over ride this request and increase the fan speed if the power supply requires more cooling. See note 2
for fan SLEEP mode requirements.
2. When the power supply fan is in SLEEP mode the fan must be operating at its minimum RPM, which is slow
enough to not output any noticeable audible levels. The power supply must be able to supply 0W to 50W of
output power at 50
°
C ambient (any combinations of 3.3V, 5V, and 12V output currents) in the power supply
fan SLEEP mode condition without the power supply over riding and turning the fan to LOW or HIGH speed.