Efficiency Improvement of Flying-Capacitor Linear Amplifier by Unequal Capacitor Voltage Ratio

Abstract

This paper proposes a flying-capacitor linear amplifier (FCLA) with unequal capacitor voltages to realize higher efficiency and low electromagnetic interference. The efficiency of the FCLA can be improved by increasing the number of series MOSFETs. However, it causes a higher cost of the MOSFETs and gate drivers. In this paper, it is clarified that the efficiency can be improved by defining the voltage values of each flying-capacitor properly even in the same numbers of MOSFETs. The effectiveness of the proposed method is evaluated and compared to other topologies of the multilevel linear amplifier. It has been clarified that the efficiency of the proposed FCLA can be improved, especially when the number of devices is small and modulation factor is high. The result of this paper is useful for design and implementation of multilevel-topology-based linear amplifiers with higher efficiency and lower noise.