POWER AMPLIFIER INCLUDING VARIABLE CAPACITOR CIRCUIT

摘要

PURPOSE: A power amplifier including a variable capacitor circuit is provided to effectively solve amplitude modulation (AM)-power modulation (PM) distortion and AM-AM distortion. CONSTITUTION: A power amplifier (10) comprises a first amplification stage (100) and a second amplification stage (400) connected to a cascode. The first amplification stage amplifies a radio frequency (RF) input signal. A transistor amplifies the output of the first amplification stage. The second amplification stage includes capacitance which is automatically changed based on the size of the first amplification stage output between the gate of one or more transistors and first power voltage. The second amplification stage includes one or more variable capacitor circuits between the first power voltage and the gate of the transistors. One or more variable capacitor circuits includes the capacitance which is changed based on the voltage swing of the gate corresponding to the one or more transistors. [Reference numerals] (200) Variable capacitor circuit (VCC)