1. 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

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

3. 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

4. Envelope Elimination and Restoration
Envelope Elimination and Restoration (EER)
/ Kahn technique (proceedings IRE 1952)
s(t)
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5. 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
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6. 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
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7. Improvements (I): Multiple Level PWM
Twice equivalent switching frequency
Higher Bandwidth (fixed Ripple)
Lower Ripple (fixed LC)
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8. Improvements (II): Linear Assisted Switching Converter
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9. 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
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10. Circuit/System co-characterizationL 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
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11. 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
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12. Thanks for your attendance. Questions?
High Efficiency RF Power Amplification for 3G Mobile Communications
Lázaro Marco
Thanks for your attendance. Questions?
1st Barcelona Forum on Ph.D. Research in Electronic Engineering