Modeling and Analysis of PSRR in Analog PWM Class D Amplifiers

1. Tong Ge; Chang, J.S.; Wei Shu; Circuits and Systems, 2006. ISCAS 2006. Proceedings. 2006 IEEE International Symposium on0-0 0 Page(s):4 pp. Digital Object Identifier 10.1109/ISCAS.2006.1692853 指導教授：易昶霈 學 生：杜彥諴 學 號：98662006 Modeling and Analysis of PSRR in Analog PWM Class D Amplifiers

2. NCUE-Graduate Insititute of Integrated Circuit Design OUTLINE • INTRODUCTION • MODELING OF PWM CDAS • INVESTIGATION INTO THE PARMETERS AFFECTING PSRR • RESULTS • CONCLUSIONS

3. NCUE-Graduate Insititute of Integrated Circuit Design INTRODUCTION • Power Efficiency • CDA modulation method • PSRR

4. NCUE-Graduate Insititute of Integrated Circuit Design INTRODUCTION Power Efficiency note : CDA’s MOS operate in triode and cut-off regions that have low quiescent power.

5. NCUE-Graduate Insititute of Integrated Circuit Design INTRODUCTION • CDA modulation method • Pulse Width Modulation • Sigma-Delta Modulation • Bang-Bang Control Moudlation

6. NCUE-Graduate Insititute of Integrated Circuit Design INTRODUCTION • CDA modulation method • Pulse Width Modulation

7. NCUE-Graduate Insititute of Integrated Circuit Design INTRODUCTION • CDA modulation method • Sigma-Delta Modulation(Pulse-Density-Modulated-like)

8. NCUE-Graduate Insititute of Integrated Circuit Design INTRODUCTION • CDA modulation method • Bang-Bang Control Modulation (Pulse-Density-Modulated-like)

9. NCUE-Graduate Insititute of Integrated Circuit Design INTRODUCTION • CDA modulation method • Digital CDA modulation method

10. NCUE-Graduate Insititute of Integrated Circuit Design INTRODUCTION • PSRR(Power Supply Rejection Ratio) 嚴格來說就是電源IC對輸入電壓所挾帶來的雜訊(Vin Ripple)清除的能力 • 電源斥拒比(PSRR)影響輸出訊號的因素除了電路本身之外還有電源級. PSRR 是一個用來描述輸出訊號受電源影響的量. PSRR 越大輸出訊號越不受電源影響. Critical parameter • Gain of integrator • Gain of PWM • Gain of feedback factor

11. NCUE-Graduate Insititute of Integrated Circuit Design MODELING OF PWM CDAs • Modeling an open-loop PWM CDA • Modeling a close-loop PWM CDA

12. NCUE-Graduate Insititute of Integrated Circuit Design MODELING OF PWM CDAs • Modeling an open-loop PWM CDA

13. NCUE-Graduate Insititute of Integrated Circuit Design MODELING OF PWM CDAs • Modeling an open-loop PWM CDA Gpwm = gain of PWM stage N = noise in supply rail

14. NCUE-Graduate Insititute of Integrated Circuit Design MODELING OF PWM CDAs • Modeling a close-loop PWM CDA 積分器 Feedback network(R1 and Rfb)

15. NCUE-Graduate Insititute of Integrated Circuit Design MODELING OF PWM CDAs • Modeling a close-loop PWM CDA

16. NCUE-Graduate Insititute of Integrated Circuit Design MODELING OF PWM CDAs • Modeling a close-loop PWM CDA G1=amp input to inverting input of integrator H1= feedback factor Aop = op-amp open –loop gain

17. NCUE-Graduate Insititute of Integrated Circuit Design MODELING OF PWM CDAs • Modeling a close-loop PWM CDA

18. NCUE-Graduate Insititute of Integrated Circuit Design INVESTIGATION INTO THE PARMETERS AFFECTING PSRR • The gain of integrator • The gain of PWM stage • The feedback factor

19. NCUE-Graduate Insititute of Integrated Circuit Design INVESTIGATION INTO THE PARMETERS AFFECTING PSRR • The gain of integrator Eq10中Gint可以大幅的增加PSRR,所以Aop越大越好.會在fig6再一次看到

20. NCUE-Graduate Insititute of Integrated Circuit Design INVESTIGATION INTO THE PARMETERS AFFECTING PSRR • The gain of PWM stage

21. NCUE-Graduate Insititute of Integrated Circuit Design INVESTIGATION INTO THE PARMETERS AFFECTING PSRR • The feedback factor Increasing H1 results in twomajor shortcomings • reduced dynamic range of the amplifier • reduced amplifier gain

22. NCUE-Graduate Insititute of Integrated Circuit Design RESULTS

23. NCUE-Graduate Insititute of Integrated Circuit Design CONCLUSIONS 這篇PAPER表現了,一個分析CDA中PSRR的方法 探討了影響PSRR的三個因素

24. NCUE-Graduate Insititute of Integrated Circuit Design Thanks for pay attention.