Intel® Server Platform SR6850HW4 TPS

Power Supply

5.4.9 Fan Speed Control

The power supply provides forced air-cooling through three DC fans that have intake through the circular grill. The cooling fans are 60mm in diameter and 38mm in depth. The fans are mounted to the front (output connector), and exhaust through the rear (AC Inlet connector) of the PS case.

The power supply uses a fan speed controller that is based on the input Fan_Cntl. The input is an analog signal from 0.0V to 3.0V. Control of the fan is linear in relation to the Fan_Cntl signal.

Table 38. Power Supply Fan Voltage

Fan_Cntl Voltage

Minimum Fan Voltage

Maximum Fan Voltage

0.00V

7.00V

7.50V

 

 

 

1.50V

9.55V

10.05V

 

 

 

3.00V

11.50V

12.60V

 

 

 

A fan fault is defined as a fan RPM below 1,000 ±200 RPM during normal operation. This fault is inhibited for 15 ±5 seconds when the power supply outputs are first powered on. This allows time for the fan to come up to speed and the fan detects circuitry to stabilize.

A fault on two fans turns off the power supply. See Section 5.2.

Note: Fan speed control must operate even if no AC is applied to the power supply. Fan power comes from the 12V bus after the OR’ing diode. The control circuit power comes from either the 12V bus and/or the 3.3Vstby bus.

5.4.10Power Supply Module LED indicators

There are three LEDs on the rear of the power supply, next to the AC input power connector.

5.4.10.1Power Supply Fail

The amber power supply fail LED is driven by internal circuitry. It lights when a power rail has failed. The LED is not lit if the supply turns off due to PS_KILL. The LED illuminates even if the power supply is in a latched state. The only time during a fault when it does not illuminate is if the +3.3Vstby is lost.

5.4.10.2Power Good

The green power good LED is driven by internal circuitry. It lights whenever PWRGD is asserted.

5.4.10.3AC OK

The green AC OK LED is driven by internal circuitry. It lights whenever VIN_GOOD is asserted.

Revision 1.0

61

 

Intel order number D23151-001