HIGH FREQUENCY POWER AMPLIFIER AND COMMUNICATION EQUIPMENT

摘要

PROBLEM TO BE SOLVED: To realize efficient operation through RF output in a wide range by varying the collector bias voltage of a transistor for amplification in a high frequency power amplifier using a heterojunction bipolar transistor. SOLUTION: This invention is provided with a detector 24 for detecting the collector output power (which can be base input power) of an amplifying transistor 21 and a DC/DC converter 25 for varying the collector voltage of the transistor 21 in proportion to the detected power to control DC power to be consumed by the transistor 21. Furthermore, a resistor 23 for the base bias of the transistor 21 is connected to the converter 25 to link base bias control with the control of the converter 25.