Modeling and Analysis of PSRR in Analog PWM Class D Amplifiers Tong Ge; Chang, J.S.; Wei Shu; Circuits and Systems, ISCAS Proceedings IEEE International Symposium on Page(s):4 pp. Digital Object Identifier /ISCAS 指導教授：易昶霈 學生：杜彥諴 學號：

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

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

NCUE-Graduate Insititute of Integrated Circuit Design 4 INTRODUCTION Power Efficiency note : CDA’s MOS operate in triode and cut-off regions that have low quiescent power. TypePerformance Class A<25% Class B<78.5% Class AB25%~78.5% Class D>80%

NCUE-Graduate Insititute of Integrated Circuit Design 5 INTRODUCTION CDA modulation method 1.Pulse Width Modulation 2.Sigma-Delta Modulation 3.Bang-Bang Control Moudlation

NCUE-Graduate Insititute of Integrated Circuit Design 6 INTRODUCTION CDA modulation method 1.Pulse Width Modulation

NCUE-Graduate Insititute of Integrated Circuit Design 7 INTRODUCTION CDA modulation method 2.Sigma-Delta Modulation (Pulse-Density-Modulated-like)

NCUE-Graduate Insititute of Integrated Circuit Design 8 INTRODUCTION CDA modulation method 3.Bang-Bang Control Modulation (Pulse-Density-Modulated-like)

NCUE-Graduate Insititute of Integrated Circuit Design 9 INTRODUCTION CDA modulation method 4.Digital CDA modulation method

NCUE-Graduate Insititute of Integrated Circuit Design 10 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 1.Gain of integrator 2.Gain of PWM 3.Gain of feedback factor

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

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

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

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

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

NCUE-Graduate Insititute of Integrated Circuit Design 16 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

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

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

NCUE-Graduate Insititute of Integrated Circuit Design 19 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

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

NCUE-Graduate Insititute of Integrated Circuit Design 21 INVESTIGATION INTO THE PARMETERS AFFECTING PSRR The feedback factor Increasing H1 results in two major shortcomings 1.reduced dynamic range of the amplifier 2.reduced amplifier gain

NCUE-Graduate Insititute of Integrated Circuit Design 22 RESULTS

NCUE-Graduate Insititute of Integrated Circuit Design 23 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

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