1. Comparative Efficiency Analysis of Dynamically Supplied Power Amplifiers (PA) Orlando Lazaro, Student Member, IEEE, and Gabriel A. Rincón-Mora, Senior Member, IEEE Georgia Institute of Technology Georgia Tech Analog, Power, Energy IC Research Lab

2. Efficiency Schemes To Apply on to Linear Amplifiers  (a) Static Bias and VDD  (b) Power Tracking  (c) Envelope Tracking

3. Methodology For Comparison  Use ideal circuit to define clear boundaries  Look at backed Off Power (BOP)  Then calculate efficiency with PDF

4. Input Power Output Power Peak-Load Efficiency Peak-Load α = 2πd C Fourier Series P IN = V DD I D

5. Backed-Off Power Output power related to v o Use output power to find α*, then use α *, to find I MAX * Can use these to find new P IN * and P O Backed-Off

6. Power Tracking Supply Envelope Probability Density For a given power level, the power tracking scheme adapts and rebiases. Power envelope not important only signal envelope

7. Envelope-Tracking Supply Envelope Probability Density For a given power level, the envelope tracking scheme adapts and rebiases V DD. While V DD dynamically adapts, I D does not because of intermodulation distortion.

8. Comparison of both Schemes Efficiency is dependent on supply efficiency feeding the output Even with ET PS being less efficient, the overall efficiency of ET is larger for all conduction values

9. Question?  Thanks!