A Class-D Piezoelectric Speaker Driver Using A Quadrature Feedback Chopping Scheme achieving 29dB Large-Signal THD+N Improvement

This paper presents a Class-D piezoelectric speaker driver that employs a quadrature feedback chopping scheme (QCS). Compared to a conventional single feedback chopping scheme (SCS), the use of QCS can eliminate the timing skew between low-voltage (LV) and high-voltage (HV) choppers, greatly improving large-signal linearity. A prototype...

3.1 A 120.9dB DR, -111.2dB THD+N Digital-Input Capacitively-Coupled Chopper Class-D Audio Amplifier

Class-D amplifiers (CDAs) are widely used in audio applications where a high power efficiency is required. As most audio sources are digital nowadays, implementing digital-input CDAs results in higher levels of integration and lower cost. However, prior open-loop digital-input CDAs suffer from high jitter sensitivity and output-stage...

A 121.4dB DR, -109.8dB THD+N Capacitively-Coupled Chopper Class-D Audio Amplifier

Class-D amplifiers (CDAs) are often used in audio applications due to their superior power efficiency. Due to the sensitivity of the human ear, a large dynamic range (DR) is desired, and audio DACs with up to 130dB DR are commercially available [1]. However, the DR of the CDAs they drive is typically much lower [2]-[4], mainly due to the...

A -109.1 dB/-98 dB THD/THD+N Chopper Class-D Amplifier with >83.7 dB PSRR Over the Entire Audio Band

This paper reports a chopper Class-D audio amplifier that obtains high PSRR over the entire audio band. A chopping scheme is proposed to minimize intermodulation distortion between pulse-width modulation (PWM) and chopping in the audio band. A high-voltage chopper is developed to handle a 14.4 V PWM signal. Timing matching techniques are...

A-121.5 dB THD Class-D Audio Amplifier with 49 dB Suppression of LC Filter Nonlinearity and Robust to +/-30% LC Filter Spread

This paper reports a Class-D audio amplifier that uses multiloop feedback to suppress output LC filter nonlinearity by 49 dB, enabling the use of small, low-cost LC filters with ±30% spread while maintaining low distortion. Fabricated in a 180 nm BCD process, the prototype achieves a THD of-121.5 dB and a THD+N of-107.1 dB. It delivers 12W...

A -107.8 dB THD+N Low-EMI Multi-Level Class-D Audio Amplifier

This paper describes a class-D audio amplifier with a multilevel output stage that reduces both EMI and idle power. High loop gain, and thus high linearity, are enabled by a relatively high (4.2 MHz) switching frequency, which relaxes the requirements on its output LC filter. Fabricated in a 180nm BCD technology, it can drive 14 W into an 8-Ω...

A 28W -108.9dB/-102.2dB THD/THD+N Hybrid ΔΣ-PWM Class-D Audio Amplifier with 91% Peak Efficiency and Reduced EMI Emission

Class-D amplifiers are often used in high-power audio applications due to their high power efficiency. They typically employ pulse-width modulation (PWM) at a fixed carrier frequency, which may cause electromagnetic interference (EMI). Setting this frequency f_PWM) below the AM band (535 to 1605kHz) helps mitigate this, but its...