Analysis of switching frequency variation in self-oscillating class-D audio amplifiers

Constant Switching Frequency Self-Oscillating Controlled Class-D Amplifiers

Investigation of switching frequency variations in self-oscillating class D amplifiers

Class D audio amplifiers have gained significant influence in sound reproduction due to their high efficiency. One of the most commonly used control methods in class D amplifiers is known as self-oscillation. An parameter of key interest in self-oscillating class D amplifiers is the switching frequency, which can be directly related to the performance of the amplifier. This paper will clearify ...

THD Analysis in Closed-Loop Analog PWM Class-D Amplifiers

In this paper, we investigate the parameters affecting Total Harmonic Distortion (THD) and Power Supply Rejection Ratio (PSRR) in PWM Class D Amplifiers (CDAs) on the basis of linear models with feedback. From our mathematical analysis, we show that the THD of a PWM Class D amplifier with feedback can be improved by increasing the gain of the integrator through adding another amplifier at the o...

Class-D Audio Amplifiers with Negative Feedback

There are many different designs for audio amplifiers. Class-D, or switching, amplifiers generate their output signal in the form of a high-frequency square wave of variable duty cycle (ratio of on time to off time). The square-wave nature of the output allows a particularly efficient output stage, with minimal losses. The output is ultimately filtered to remove components of the spectrum above...

Self-Oscillating Class-D Audio Amplifier With A Phase-Shifting Filter in Feedback Loop

A self-oscillating class-D audio amplifier adopting the phase-shifting looap filter in the feedback filter is proposed. To validate the design, a mathematical model is proposed. It is alleged in a very simple form which describes the switching frequency variation as the function of the modulation depth to be applied to any general structure: phase shifting, time delay of the loop, and the hyste...