A 280 mW, 0.07 % THD+N class-D audio amplifier using a frequency-domain quantizer
Description
Pulse Density Modulation- (PDM-) based class-D amplifiers can reduce non-linearity and tonal content due to carrier signal in Pulse Width Modulation - (PWM-) based amplifiers. However, their low-voltage analog implementations also require a linear- loop filter and a quantizer. A PDM-based class-D audio amplifier using a frequency-domain quantization is presented in this paper. The digital-intensive frequency domain approach achieves high linearity under low-supply regimes. An analog comparator and a single-bit quantizer are replaced with a Current-Controlled Oscillator- (ICO-) based frequency discriminator. By using the ICO as a phase integrator, a third-order noise shaping is achieved using only two analog integrators. A single-loop, singlebit class-D audio amplifier is presented with an H-bridge switching power stage, which is designed and fabricated on a 0.18 um CMOS process, with 6 layers of metal achieving a total harmonic distortion plus noise (THD+N) of 0.065% and a peak power efficiency of 80% while driving a 4-ohms loudspeaker load. The amplifier can deliver the output power of 280 mW.
Date Created
The date the item was original created (prior to any relationship with the ASU Digital Repositories.)
2011
Agent
- Author (aut): Lee, Junghan
- Thesis advisor (ths): Bakkaloglu, Bertan
- Committee member: Kiaei, Sayfe
- Committee member: Ozev, Sule
- Committee member: Song, Hongjiang
- Publisher (pbl): Arizona State University