An integrable CMOS transconductors-based differentiated input/frequency-constant PWM signal generator

This article presents a novel approach to implement PWM signal generator using CMOS transconductors, its scheme comprises CMOS Schmitt trigger and voltage to current converter. It can originate PWM signal over a wide frequency range arising from differentiation of modulating input signal in the provided time. The outstanding feature of the proposed scheme is that the PWM output has frequency-constant, which does not depend on amplitude of the modulating signal. This makes it suitable to use in application of adjacent frequency between carrier and modulating signal, which differs from the conventional PWM signal generators. The proposed circuit has relatively simpler scheme. It consists of exclusively 12 MOS transistors, 3 current sources, 1 capacitor and 2 resistors, thus it is suitable for further fabrication through CMOS technology. Furthermore, its frequency and amplitude of PWM output signal can be independently adjusted by electronic method. The SPICE simulation results are shown, which are in correspondence to theoretical anticipation.