100-MHz GaN-HEMT Class-G Supply Modulator for High-Power Envelope-Tracking Applications

In this paper, a highly efficient class-G supply modulator targeting high-power wideband envelope tracking applications is presented. The maximum output power using a 50% duty cycle at 100-MHz switching frequency is 62 W for a switching between 30 and 50 V delivered in a 25-<inline-formula> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> load. The modulator including its driver circuit reaches an overall efficiency in the range of 97%–88% for switching frequencies from dc to 100 MHz for passive loads in a wide range. The modulator is designed to operate at various supply voltage levels and is evaluated within the range from 20 to 50 V while powering loads from 25 to 100 <inline-formula> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula>. The modulator is characterized in terms of efficiency, switching frequency, and nonlinearities.

[1]  W. Heinrich,et al.  GaN-HEMTs as switches for high-power wideband supply modulators , 2013, 2013 European Microwave Conference.

[2]  Fabio Filicori,et al.  Envelope Tracking of an RF High Power Amplifier With an 8-Level Digitally Controlled GaN-on-Si Supply Modulator , 2015, IEEE Transactions on Microwave Theory and Techniques.

[3]  Olof Bengtsson,et al.  A Novel Model for Digital Predistortion of Discrete Level Supply-Modulated RF Power Amplifiers , 2016, IEEE Microwave and Wireless Components Letters.

[4]  H. Zirath,et al.  A new empirical nonlinear model for HEMT and MESFET devices , 1992 .

[5]  Michel Campovecchio,et al.  Over 10MHz bandwidth envelope-tracking DC/DC converter for flexible high power GaN amplifiers , 2011, 2011 IEEE MTT-S International Microwave Symposium.

[6]  Dragan Maksimovic,et al.  GaN Microwave DC–DC Converters , 2015, IEEE Transactions on Microwave Theory and Techniques.

[7]  P. J. Tasker,et al.  The effect of baseband impedance termination on the linearity of GaN HEMTs , 2010, The 40th European Microwave Conference.

[8]  J. Jovalusky,et al.  New low reverse recovery charge (QRR) high-voltage silicon diodes provide higher efficiency than presently available ultrafast rectifiers , 2008, 2008 Twenty-Third Annual IEEE Applied Power Electronics Conference and Exposition.

[9]  Dragan Maksimovic,et al.  Envelope tracking GaN power supply for 4G cell phone base stations , 2016, 2016 IEEE Applied Power Electronics Conference and Exposition (APEC).

[10]  Luc Lapierre,et al.  A new GaN-based high-speed and high-power switching circuit for envelope-tracking modulators , 2014 .

[11]  Brian Woods,et al.  Challenges of power amplifier design for envelope tracking applications , 2015, 2015 IEEE Topical Conference on Power Amplifiers for Wireless and Radio Applications (PAWR).

[12]  S. C. Cripps,et al.  RF Power Amplifiers for Wireless Communications , 1999 .

[13]  T. Palacios,et al.  Effect of Gate Leakage in the Subthreshold Characteristics of AlGaN/GaN HEMTs , 2008, IEEE Electron Device Letters.

[14]  M. Berroth,et al.  Power supply modulation for RF applications , 2012, 2012 15th International Power Electronics and Motion Control Conference (EPE/PEMC).

[15]  P. Asbeck,et al.  Microwave power amplifiers with digitally-controlled power supply voltage for high efficiency and high linearity , 2000, 2000 IEEE MTT-S International Microwave Symposium Digest (Cat. No.00CH37017).

[16]  D. Maksimović,et al.  Simulation and characterization of GaN HEMT in high-frequency switched-mode power converters , 2012, 2012 IEEE 13th Workshop on Control and Modeling for Power Electronics (COMPEL).

[17]  C. Weitzel,et al.  RF power amplifiers for wireless communications , 2002, 24th Annual Technical Digest Gallium Arsenide Integrated Circuit (GaAs IC) Symposiu.

[18]  George B. Norris,et al.  High efficiency CDMA RF power amplifier using dynamic envelope tracking technique , 2000, 2000 IEEE MTT-S International Microwave Symposium Digest (Cat. No.00CH37017).

[19]  P. Landin,et al.  Investigation of GaN-HEMT Based Switches
for Hybrid Switching Amplifier Supply-Modulators , 2012 .

[20]  Olof Bengtsson,et al.  Linearity analysis of a 40 W class-G-modulated microwave power amplifier , 2015, 2015 10th European Microwave Integrated Circuits Conference (EuMIC).

[21]  Dragan Maksimovic,et al.  High efficiency 20–400 MHz PWM converters using air-core inductors and monolithic power stages in a normally-off GaN process , 2016, 2016 IEEE Applied Power Electronics Conference and Exposition (APEC).