A simple frequency adjustable self-oscillation class D amplifier using OTA

Abstract

In this paper, a frequency adjustable self-oscillation class D amplifier circuit is proposed, where it can adjust the frequency in the wide band from 50kHz to 500kHz. This proposed circuit uses the feedback principle to compare with the information input signal at hysteresis comparator circuit. The proposed circuit has compact size since it uses only one OTA and one buffer gate. From the experimental results, its THD is in a range 0.75 to 1.59% with the input sinusoidal frequency range from 20Hz to 20kHz. For the frequency response, this circuit can respond well to the audio frequency, i.e., from 20Hz to 20kHz. The proposed circuit can easily adjust the frequency of the selfoscillating circuit by tuning the resistors in circuit. From the experimental result, this proposed circuit corresponds well with the principle and the analytic theory. © 2014 ISSN 1881-803X.