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...

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...