RF power amplifier with dynamic bias control circuit for high efficiency

Abstract

With increased mobile communication system, many research about several devices used in RF transceiver in handset was performed. Power amplifier, which drives the biggest output, dissipates the highest amount of DC power compare to other device and directly related to the battery size. In other words, efficiency of power amplifier is very important considering resent trend of smaller handset. But in CDMA system, efficiency of power amplifier is low because of not only using class A power amplifier, but also power control technique of CDMA system. In this paper, a bias control circuit that improves the efficiency in lower output power condition and simulated/measurement result of power amplifier with that circuit are represented. For appropriate comparison, power amplifier without bias control circuit is also designed and all test results support the suggested theory of bias control.