Analog Integrated Circuits and Signal Processing

, Volume 74, Issue 2, pp 417–423 | Cite as

A 2.65 W high-fidelity filterless class D audio amplifier using multiple loop filters

Article

Abstract

The design of a 2.65 W, high-fidelity, filterless Class D audio amplifier in a standard 0.5 μm CMOS technology is proposed in this paper, where an architecture with multiple loop filters is utilized. This structure attenuates residual clock signals around the loop allowing very low total harmonic distortion (THD) and intermodulation distortion to be achieved in conjunction with high power supply rejection ratio (PSRR). The active area of this circuit is about 1.5 × 1.5 mm2. The THD + N is <0.03 % at 1 kHz input frequency and 100 mW output power. The PSRR is −80 dB at 217 Hz and maximum output power at 10 % THD is 2.658 W. A Figure of merit is defined to estimate the excellent performance which can meet the demands of portable communication devices greatly.

Keywords

High fidelity Filterless Class D amplifier Loop filter THD IMD PSRR 

References

  1. 1.
    Rojas-González, M. A., & Sánchez-Sinencio, E. (2009). Low-power high-efficiency Class D audio power amplifiers. IEEE Journal of Solid-State Circuits, 44(12), 3272–3284.CrossRefGoogle Scholar
  2. 2.
    Yeh, M.-L., Liou, W.-R., Hsieh, H.-P., & Lin, Y.-J. (2010). An electromagnetic interference (EMI) reduced high-efficiency switching power amplifier. IEEE Transactions on Power Electronics, 25(3), 710–718.CrossRefGoogle Scholar
  3. 3.
    Teplechuk, M., Gribben, T., & Amadi, C. (2011). Filterless integrated Class-D audio amplifier achieving 0.0012% THD+N and 96 dB PSRR when supplying 1.2W. In IEEE ISSCC Digest of Technical Papers (pp. 240–242).Google Scholar
  4. 4.
    Yu, J., Tan, M., Cox, S., & Goh, W. (2012). Time-domain analysis of intermodulation distortion of closed-loop Class-D amplifiers. IEEE Transactions on Power Electronics, 27(5), 2453–2461.CrossRefGoogle Scholar
  5. 5.
    Metzler, B. (1993). Audio measurement handbook. Beaverton, OR: Audio Precision.Google Scholar
  6. 6.
    Neesgaard, C., & Risbo, L. (2006). PWM amplifier control loops with minimum aliasing distortion. In Proceedings of the 120th AES Convention, Vol. 6693.Google Scholar
  7. 7.
    Shu, W., & Chang, J. S. (2010). IMD of closed-loop filterless Class D amplifiers. IEEE Transactions on Circuits and Systems. I: Regular Papers, 57(2), 518–527.MathSciNetCrossRefGoogle Scholar
  8. 8.
    Huijsing, J. H. (2001). Operational amplifiers theory and design (pp. 140–176). Boston: Kluwer Academic Publishers.Google Scholar
  9. 9.
    Gray, P., Hurst, P. J., Lewis, S. H., et al. (2001). Analysis and design of analog integrated circuits (4th ed., pp. 382–394). New York: Wiley.Google Scholar

Copyright information

© Springer Science+Business Media New York 2012

Authors and Affiliations

  1. 1.State Key Laboratory of Electronic Thin Films and Integrated DevicesUniversity of Electronic Science and Technology of ChinaChengduChina

Personalised recommendations