1. A filter free class D audio amplifier with 86% power efficiency Muggler, P., Chen, W., Jones, C., Dagli, P., Yazdi, N., ISCAS '04. Proceedings of the 2004 International Symposium on Circuits and Systems, 2004. Volume 1, 23-26 May 2004 pp.I - 1036-9 Vol.1 指導老師：易序忠 學 生：楊正元 國立彰化師範大學積體電路設計研究所

2. Outline  Abstract  Schematic  Result

3. Abstract  2.5W output power and 86 ％ efficiency with an 8 ohm load.  It operates with a 2.5 V to 6.5 V supply voltage in a 7V, 1.2 um, double-poly, triple-metal, BiCMOS process.  It has an area of 1.5 x 1.5 mm 2 and it achieves a THD as low as 0.04%, with a flatband response between 20 Hz and 20 kHz.

4. Modulation Scheme  Double-sided natural sampling pulse width modulation scheme.  The selected PWM scheme provides current to the load only when needed, and once delivered the current is maintained. This is accomplished by using all four states available to a full H-bridge. The modulation scheme uses any of the states in any order, dependent upon the audio input signal.

5. Different kinds of PWM modulations

6. Advantage  The amount of information contained in each period is twice the amount of single sided modulation.  There is the possibility of having all of the significant distortion components to be outside the audio band thus enabling a filter free class D audio amplifier.

7. Signal Spectrum showing Distortion Components

8. Schematic of the Designed Class D Audio Power Amplifier

9. Cross-Coupling

10. Example

12. Efficiency versus Power Curve

13. Total Harmonic Distortion versus Power Curve

14. Die Photo

15. SUMMARY OF MEASUREMENT RESULTS

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