A CMOS Class-G Supply Modulation for Polar Power Amplifiers with High Average Efficiency and Low Ripple Noise

Qing LIU  Jiangtao SUN  YongJu SUH  Nobuyuki ITOH  Toshihiko YOSHIMASU  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E95-A   No.2   pp.487-497
Publication Date: 2012/02/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E95.A.487
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuit Techniques and Related Topics)
power amplifier,  RWDM,  LDO,  supply modulation,  average efficiency,  

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In this paper, a CMOS Class-G supply modulation for polar power amplifiers with high average efficiency and low ripple noise is proposed. In the proposed Class-G supply modulation, the parallel supply modulations which are controlled by switch signals are utilized for low power and high power supplies to increase the average efficiency. A low dropout (LDO) is utilized to suppress the delta-modulated noise and provide a low ripple noise power supply. The proposed supply modulation has high efficiency at large output current as the conventional supply modulation, and it also has high efficiency and low ripple noise at the low output current. To verify the effectiveness of the proposed supply modulation, the proposed supply modulation was designed with 0.13 µm CMOS process. The simulation results show that the proposed supply modulation achieves a maximum efficiency of 85.1%. It achieves an average efficiency of 29.3% and a 7.1% improvement compared with the conventional supply modulations with Class-E power amplifier. The proposed supply modulation also shows an excellent spurious free dynamic range (SFDR) of -73 dBc for output envelope signal.