Method and apparatus for detecting an operating voltage level in an integrated circuit

摘要

A Zener diode is used to simplify a circuit for detecting the level of an operating voltage with respect to a specified range of use. The semiconductor junction of this Zener diode is biased alternately by one voltage or another. Under these conditions, the avalanche voltage of this Zener diode changes. The operating voltage to be monitored is connected to the cathode of this Zener diode. If the monitored operating voltage is higher than the avalanche voltage of this Zener diode, the diode alternately conducts. If the operating voltage is outside this range, this diode is either permanently on or permanently off. The variations that result therefrom are detected to report whether the operating voltage is correct.