| 摘要 |
<p>PROBLEM TO BE SOLVED: To eliminate the need for providing a monitor circuit to all power supplies by delaying the starting of a computer until a plurality of power lines are set at stable operating levels and making an integrated circuit monitor only the output voltage of a main power supply. SOLUTION: A single power monitor integrated circuit having a single input main voltage pin monitors and controls the power which is supplied from a computer ATX power supply. The 3.3 and 5.0 V supply sources are connected to a 12 V supply source. A comparator circuit 22 compares a signal showing the main power voltage of 12 V with a reference signal. Then this power supply functions to set both 3.3 and 5.0 V supply sources at 90% of their value within 40 ms after the 12 V supply source reached 90% of its value. A proper delay circuit 25 delays an action to switch the dual supply of both 3.3 and 5.0 V from the standby voltage supply to the active voltage supply until the main 3.3 and 5.0 V operate.</p> |
