Integrated Inductor Class-D Audio Amplifier Modeling & Simulation

Abstract

during the last few years, there has been a growing market demand for audio amplifiers with a high output power and a large number of channels. This requires integrated audio amplifiers with a small number of external components and low power dissipation. Traditional class AB (linear) amplifiers, which are still largely used, are not suited to meet these demands. In addition, recent demand for smaller devices with longer battery life has confirmed the replacement of class AB with class D (switching amplifiers). Class D amplifiers provide the balance between efficiency and distortion required by portable devices and audio systems, as they utilize the switching operation where the transistors are either fully on or fully off resulting in amplification with zero power dissipation ideally. One possible drawback to the switching topology of the Class D amplifier is its tendency to emit electromagnetic radiation that can potentially interfere with other nearby electronic devices. External passive filtering can moderate this interference, but it adds area and complexity to the end product. This paper presents integrated inductor approaches that provide saving in area and ease of design. In addition, shielding and compact construction of the proposed integrated inductor reduces the conducted and radiated noise that can couple into the traces of the printed circuit board.