FAILSAFE OSCILLATOR MONITOR AND ALARM

摘要

A failsafe oscillator monitor and alarm circuit receives clock pulses from an external oscillator that if a failure thereto occurs, the failsafe oscillator monitor and alarm circuit will notify a digital processor of the external oscillator failure. The failsafe oscillator monitor and alarm circuit is a very low current usage circuit that charges a storage capacitor with clock pulses from the external oscillator when functioning normally and discharges the storage capacitor with a constant current sink if the external oscillator stops functioning. When the voltage charge on the storage capacitor becomes less than a reference voltage an alarm signal is sent to the digital processor for exception or error handling of the failed external oscillator.