| 摘要 |
<p>PURPOSE:To enhance reliability by detecting the rise of an output level by a power source level rise detecting means and outputting an initial power source input detection signal. CONSTITUTION:The initial power source input detecting circuit is equipped with DFF circuits 10 and 20 and a microcomputer 30 and has a switch 11 to operate a system. When the switch 11 is closed, a power source VSW becomes on. A power source VB is impressed on a data input terminal D of the FF circuit 10 and a signal CLR1 to become effective when it lowers is impressed on a clear input terminal. Consequently, the FF circuit 10 is not cleared immedi ately even when the power source VB is cut off for an instant but outputs until the supply of power is cut off. The FF circuit 20 impresses the VB on the data input terminal and impresses the Q output of the FF circuit 10 on an edge trigger input terminal. Consequently, the <->Q output of the FF circuit 20 falls at the rise of the Q output of the FF circuit 10 and rises to a reset signal. The initial power source input detection signal is outputted to the micro computer 30.</p> |
