High Efficiency RF Power Amplification for 3G Mobile Communications Lázaro Marco, Thesis Advisor: Eduard Alarcón (UPC) Dragan Maksimović (University Of Colorado) Electronic Engineering Department Universitat Politècnica de Catalunya

Outline Motivation EER Technique Implementation Improvements Circuit/System co-characterization Conclusions 1st Barcelona Forum on Ph.D. Research in Electronic Engineering

Motivation Audio, data and video streaming Increased data rates High number of users/cell Actual standards pushed to the limit Improved modulations: Non-constant envelope modulation techniques High bandwidth modulations “Actual” modulations: Constant envelope modulation techniques Non linear amplifiers High linearity in amplifiers Miniaturization reduces battery size Extended capabilites increase the overall power consumption Long battery life required New schemes of highly efficient and highly linear amplification Linear Amplifiers exhibit Low Efficiency

Envelope Elimination and Restoration Envelope Elimination and Restoration (EER) / Kahn technique (proceedings IRE 1952) s(t) 1st Barcelona Forum on Ph.D. Research in Electronic Engineering 4

Envelope Elimination and Restoration Implementation Issues Numerous limits due to its high bandwidth COMPONENT SEPARATOR EA env envOUT 1 Delay mismatch between paths AM/PM and supply distortion modulation RFIN RFPA RFOUT Ф or RF 1st Barcelona Forum on Ph.D. Research in Electronic Engineering 5

EER: Successful Implementation Successful EDGE envelope tracking with the new prototype including 4.3MHz switcher High-efficiency class-E PA 50% system efficiency Complete prototype system meets EDGE spectral mask 1st Barcelona Forum on Ph.D. Research in Electronic Engineering 6

Improvements (I): Multiple Level PWM Twice equivalent switching frequency Higher Bandwidth (fixed Ripple) Lower Ripple (fixed LC) 1st Barcelona Forum on Ph.D. Research in Electronic Engineering 7

Improvements (II): Linear Assisted Switching Converter 1st Barcelona Forum on Ph.D. Research in Electronic Engineering 8

Improvements (III): Time-optimal nonlinear control Output voltage error Capacitor current Switch control Example: Vg = 6.5 V, L = 1 mH, C = 288 mF, fs = 780 KHz, Vref = 1.3 V, Iload = 0-10 A V. Yousefzadeh, A. Babazadeh, B. Ramachandran, L. Pao,, D. Maksimovic, E. Alarcón, “Proximate Time-Optimal Digital Control for DC-DC Converters” IEEE PESC 2007 1st Barcelona Forum on Ph.D. Research in Electronic Engineering 9

Circuit/System co-characterization L DC j (t) M 1 R load C b r i o sw V bat PWM Cartesian to Polar v in e(t) ou t f s =1/2 p LC 1st Barcelona Forum on Ph.D. Research in Electronic Engineering 10

Conclusions EER Technique is ready to be used in some mid-generation wireless standards Future-generation standards require sophisticated converter topologies and control methods Circuit/System co-characterization to validate new envelope trackers for wideband power management Eventual target is complete circuit-level co-design aiming appropriate system performance in the communications layer 1st Barcelona Forum on Ph.D. Research in Electronic Engineering

Thanks for your attendance. Questions? High Efficiency RF Power Amplification for 3G Mobile Communications Lázaro Marco (lmarco@eel.upc.edu) Thanks for your attendance. Questions? 1st Barcelona Forum on Ph.D. Research in Electronic Engineering