Power on reset circuit

摘要

A CMOS power on reset circuit is provided which operates with low power supply voltages and yet uses a minimum amount of DC power. The circuit includes a threshold detector which provides an output when the power supply voltage exceeds the transistor threshold voltage by approximately half a volt. A capacitor is connected to the positive power supply terminal to avoid having a narrow output pulse when the power supply rises at a low rate. An output buffer/inverter can be used to provide a better output pulse and to provide a desired output polarity.