Intel EPS1U Benutzerhandbuch

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EPS1U Power Supply Design Guide, V1.1 
8.3  ACWarning 
 
STATUS 
Optional 
This is an output signal from the power supply which provides a warning to the system that the power supply has 
lost its AC input.  This signal also provides a signal to synchronize the turn on of multiple power supplies.  At turn 
on, this signal is pulled LOW when the supply’s internal bulk voltage has reached a level that allows it to turn on.  
At turn off ACWarning goes HIGH when the internal bulk voltage drops low enough.  The characteristics of the 
ACWarning signal is shown in Table 22:  ACWarning Signal Characteristics.  Refer to Figure 5 for timing diagram. 
Table 22:  ACWarning Signal Characteristics 
Signal Type 
 
Open collector/drain output from power supply.  Pull-
up to VSB located in system. 
ACWarning = Low 
Input voltage within operating range and power 
supply is ready to turn on. 
ACWarning = High 
Input voltage is less than the operating range and the 
power supply is turning off. 
 
MIN 
MAX 
Logic level low voltage, Isink=4mA 
0V 
0.4V 
Logic level high voltage, Isink=50
µA  
 
5.25V 
Sink current, ACWarning = low 
 
4mA 
Sink current, ACWarning = high 
 
50
µ
ACWarning Delay:     T
acwarning_delay
 
8msec 
 
ACWarning rise and fall time 
 
100
µ
sec 
Power supply turn on voltage 
75VAC 
85VAC