OSCILATION STOP DETECTION CIRCUIT

摘要

PURPOSE:To detect the oscillation stop with simple circuit constitution employing mainly passive elements by detecting the oscillation stop by the logic coincidence of output signals of each differentiation circuit. CONSTITUTION:One of two inputs of an AND circuit 6 is at a high level and the other is at a low level at all times when the oscillation of an oscillation circuit to be supervised inputted to an input terminal IN is normal and then the logics of them differe from each other. When the oscillation of the oscillation circuit to be supervised is stopped, the level of the AND circuit 6 rises gradually by the charging of a capacitor C2 and reaches a high level in excess of the threshold value after a detection time T decided by a time constant comprising a capacitor C2 and a resistor R3 elapses. Thus, the oscillation stop is detected by a change in an output signal (e) of the AND circuit 6.