Circuitry for generating non-overlapping pulse trains

Abstract

A two phase waveform generator for producing nonoverlapping pulses is designed with a CMOS inverter modified to include a resistor between the drain electrodes of the complementary inverter transistors and three conventional CMOS inverter circuits. The resistor n-type transistor interconnection exhibits a fast negative signal transition but a slower positive transition due to the resistor. This effect tends to shorten the duration of pulses applied to the inverter input. The shortened pulses are applied to a cascade connected pair of inverters to sharpen the waveform and produce a first phase output signal. The resistor-p-type transistor interconnection of the modified inverter exhibits a fast positive signal transition but a slower negative transition. This effect tends to widen pulses applied to the input. The widened pulses are applied to another inverter which complements the widened pulses ultimately generating narrower pulses which comprise a second phase signal. The first and second phase signals are antiphase with no pulse overlap.