An 80.4% peak power efficiency adaptive supply class H power amplifier for audio applications

This paper presents a novel class H power amplifier aiming for audio applications on battery-powered electronic devices. The power supply of the amplifier is adaptively adjusted to track the instantaneous input signal amplitude for higher power efficiency. By embedding audio input signal amplitude information into the class AB amplifier's output common-mode voltage level, the amplifier is able to operate with only single-rail power supply and demonstrates more smooth transitions between the light load and heavy load mode, hence achieves lower total harmonic distortion (THD) for a wide load range. Fabricated in the AMS 0.18-μm CMOS process, the chip consumes 3.52 mW quiescent power and is able to deliver 526 mW peak output power to a 16 Ω load. The measurement results indicate that the amplifier incurs no deterioration on THD when entering the supplytracking mode and achieves a lowest THD+N ratio of -80 dB. The peak power efficiency of the system is 80.4%; moreover, it demonstrates significant higher efficiency for medium load range compared to other linear mode amplifiers.Economic Development Board (EDB)The authors would like to thank EDB and Broadcom Singapore Pte Ltd. for providing the scholarship

Dynamic Voltage Rail Audio Amplifier

The goal of this project is to create a high-quality, power-efficient audio amplifier. Most modern audio amplifiers use a constant amount of power regardless of the signal that is being amplified. This means that both loud and quiet portions of the audio signal require the same amount of power to amplify. The idea for this high-quality, power-efficient audio amplifier is that the quieter portions of the audio signal can be amplified using less power. This will be achieved by first analyzing the audio signal and controlling the power source based on the signal’s needs. Therefore, louder parts of the audio signal will use the typical amount of power, while quieter parts of the signal will not use as much power. When comparing a standard audio amplifier and the high-quality power-efficient audio amplifier, the average power usage for the power-efficient amplifier should be less than the standard amplifier

Efficient Low Power Headphone Driver

In recent years, the consumer electronics market for battery-powered devices such as smartphones and tablets has been rapidly expanding. The requirements for audio CODEC in these portable devices have extended from merely supporting voice calls to high-fidelity music playback. As a result, audio driver performance has become one of the most important differentiating factors among products from different suppliers. There are three basic performance metrics that are typically used to benchmark audio modules: the maximum delivered output power, the audio fidelity measured in terms of dynamic range, THD+N, and finally the battery life. Maximizing all three of these performance metrics has proven to be an exceptionally hard task as portrayed by the research publications.This work presents an attempt to push all three of these metrics together and provide an acceptable balance which is achieved by selecting the right topology. Conventionally, headphone drivers are designed using a linear amplifier topology for many reasons- most prominently- to achieve a superior THD+N and PSRR requirement which in the past was essentially the only key performance metric needed. This came at the expense of realizing mediocre power efficiency targets, thereby wasting battery life. This picture changed dramatically over the last decade with smartphones and other portable devices becoming the first choice of the young generation. These devices are extremely power hungry due to the unlimited functions and features they provide and therefore battery life has come to the spotlight as a key resource that need to be preserved. As a result, in this work a headphone driver is based on a switching topology that is able to deliver more than 230mW of power (or equivalently 2Vrms) to a 16Ω load while achieving better than -98dB of THD+N , more than 108dB of SNR, and about 108dB PSRR while still maintaining a peak power efficiency of more than 84%