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A Digital Input Class-D Audio Amplifier  

Jo, Jun-Gi (Department of Electronics Computer Engineering, Hanyang University)
Noh, Jin-Ho (Department of Electronics Computer Engineering, Hanyang University)
Jeong, Tae-Seong (Department of Electronics Computer Engineering, Hanyang University)
Yoo, Chang-Sik (Department of Electronics Computer Engineering, Hanyang University)
Publication Information
Journal of the Institute of Electronics Engineers of Korea SD / v.47, no.11, 2010 , pp. 6-12 More about this Journal
Abstract
A sigma-delta modulator based class-D audio amplifier is presented. Parallel digital input is serialized to two-bit output by a fourth-order digital sigma-delta noise shaper. The output of the digital sigma-delta noise shaper is applied to a fourth-order analog sigma-delta modulator whose three-level output drives power switches. The pulse density modulated (PDM) output of the power switches is low-pass filtered by an LC-filter. The PDM output of the power switches is fed back to the input of the analog sigma-delta modulator. The first integrator of the analog sigma-delta modulator is a hybrid of continuous-time (CT) and switched-capacitor (SC) integrator. While the sampled input is applied to SC path, the continuous-time feedback signal is applied to CT path to suppress the noise of the PDM output. The class-D audio amplifier is fabricated in a standard $0.13-{\mu}m$ CMOS process and operates for the signal bandwidth from 100-Hz to 20-kHz. With 4-${\Omega}$ load, the maximum output power is 18.3-mW. The total harmonic distortion plus noise and dynamic range are 0.035-% and 80-dB, respectively. The modulator consumes 457-uW from 1.2-V power supply.
Keywords
class-D amplifier; sigma-delta modulator;
Citations & Related Records
Times Cited By KSCI : 2  (Citation Analysis)
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