Numerical Analysis of the Supply Voltage of a Switching Mode RF CMOS Power Amplifier to Enhance Its Efficiency

In this work, we analyzed numerically the effects of an interstage capacitor related to the power-added efficiency of a power amplifier. In particular, we calculated the power consumption values induced by the on-resistances and short-circuit current of the class-D-type driver-stage. After analyzing the results, the interstage capacitor between the driver and the power stages was removed to improve the overall efficiency. By removing the interstage capacitor, the supply voltage for the driver stage can be decreased compared to a normal power amplifier. The power consumption at the on-resistance of the driver stage can be reduced and the power consumption induced by the short-circuit current can be reduced. Additionally, we measured the power consumption at the driver stages to verify the calculated results. In the experimental results, we noted improved efficiency of the proposed amplifier, while its output power was nearly identical to that of a normal amplifier. (c) 2013 Wiley Periodicals, Inc.