OCPRF100 MP Server System Technical Product Specification Revision 1.0

POWER

GOOD

SIGNAL

 

Vn

+5VDC

Vm

OUTPUT

 

t 1

VOLTAGE

 

 

 

 

 

 

 

(100-1500msec)

Vn Nominal Output Voltage +5 VDC

Vm Minimum Output Voltage +4.75 VDC t1 Delay Turn-on (100-1500msec)

t2 Delay Turn-off(1msec min)

TTL HIGH

TTL LOW

t2

(1msec min.)

Figure 5-5: Power Good Signal Characteristics

5.6.4Power Supply Present Indicator (Output)

This signal is used to sense the number of power supplies in the system (operational or not). A pin on the output connector must be allocated to pull the power supply present signal on the power supply backplane to DC output ground. Without this pull-down, the power supply present signal will be pulled up through a pull-up resistor to +5 V standby on the backplane. The power supply present is an output signal from the power supply to the system.

5.6.5Predictive Failure Signal (Output)

This signal is available on the power supply connector. A “high” state in this signal indicates that the power supply is likely to fail in the near future due to a poorly performing fan. The predictive fan failure signal going “high” will not cause the power supply to shut down, but it must cause the “PRED FAIL” LED to turn on. The predictive failure is an output signal from the power supply to the system.

Table 5-11: Predictive Failure Signals

Predictive Failure Signal

Voltage Level †

Current

 

 

 

LOW STATE (power supply OK)

0.4 V max

4 mA min sink current

 

 

 

HIGH STATE (poorly performing fan)

4 V min

0.5 mA max source current

 

 

 

† Measured relative to the power supply DC common output ground pins

.

5.6.6Power Supply Failure Signal (Output)

This signal is available on the power supply connector. Upon receiving this signal, the system informs the operator that the appropriate power supply has failed, and therefore, a replacement

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