AC450NX Rack Server System Product Guide
172

Detection Signals

Signal Name Description
Present When the presence detect line is low, the power supply is present.
AC OK When the power-good signal on the midplane goes high, it signifies that all power
supply voltages are available and stable.
Predictive Failure The predictive failure signal from the power supply alerts the front panel controller
(FPC) in case the supply is likely to fail because of a poorly performing fan—running
at a slower RPM than normal. When the signal goes high, the FPC warns the user
about the upcoming failure but it does not shut down the power supply.
Fault When the fault signal from the power supply goes low, it indicates that the power
supply has failed. To clear the fault, you must remove and reapply AC power to the
power supply.
Power On When the power-on signal on the midplane goes high, the power supplies power up
if there is no 240 VA shutdown condition.

5 V Quick Discharge

The quick discharge circuit speeds up discharging the 5 V bus after power is turned off. The

circuit starts discharging the bus as the voltage drops to around 1 V.