By Topic

Class-EM switching-mode tuned power amplifier-high efficiency with slow-switching transistor

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

3 Author(s)
Telegdy, Attila ; Dept. of Broadband Infocommunication Syst., Budapest Univ. of Technol. & Econ., Hungary ; Molnar, Bela ; Sokal, N.O.

In class-E switching-mode power amplifiers, the switch-current waveform includes a step change ("jump"), approximated by a ramp of <15% of the period. At a transistor's highest useful frequency, the large input drive required for fast-enough switching yields marginal power gain. Objective: a high-efficiency power amplifier with jumpless current and voltage waveforms. Previously, that was proven impossible for amplifiers using only linear passive components and an ideal switch. We present the theory of a new topology that does achieve the objective: a class-E amplifier with nonlinear passive or active components in the load network. A "biharmonic" version was simulated, built, and tested. It comprises a main stage switching at the output frequency f1, drawing DC power of approximately 3/4(POUT RF/drain efficiency), and an auxiliary amplifier switching at 2f1, injecting 2f1-current into the circuit node at the main-stage transistor's output port to shape jumpless voltage and current waveforms. That switching (nonlinear) output port converts 2f1 power from the auxiliary amplifier to approximately 1/4 of the f1 power at the load. Computer simulation, and measurement on a scaled-frequency 3.5-MHz prototype, show that switching losses practically disappear when the main-stage switch is operated in the jumpless regime.

Published in:

Microwave Theory and Techniques, IEEE Transactions on  (Volume:51 ,  Issue: 6 )