High-frequency power amplifier with bipolar transistor

Abstract

The object of the present invention is to provide a bipolar transistor which is excellent in uniformity of current distribution in spite of a small ballast resistance, and can constitute an amplifier showing high efficiency and low distortion with little deterioration of distortion even when a digital modulation wave is input thereto. A high frequency power amplifier of the present invention comprises a plurality of transistor blocks having a bipolar transistor, wherein each of the transistor blocks includes a resistance connected to an emitter of the bipolar transistor, a reference voltage generation circuit for generating a reference voltage as a base bias of the bipolar transistor, and a bias generation circuit connected to a base of the bipolar transistor, the bias generation circuit generating a base bias voltage by converting the reference voltage.

Description

[0001] This application claims priority from Japanese Patent Application No. P2000-89060, filed on March 28, 2000, at 35 U.S.C. 119, the entire contents of which are incorporated herein by reference. technical field [0002] The present invention relates to high frequency power amplifiers employing bipolar transistors, and more particularly, the present invention relates to high efficiency, low distortion high frequency power amplifiers employing heterojunction bipolar transistors. Background technique [0003] For the latest mobile phones and mobile information terminals, transistors that can efficiently amplify power in the 1 GHz or higher frequency band have become an essential component. Among these transistors, a heterojunction bipolar transistor formed on a gallium arsenide (hereinafter abbreviated: GaAs) substrate has good high frequency characteristics and high operating efficiency at a low voltage. Thus, heterojunction bipolar transistors meet the social need to red...

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Problems solved by technology

[0018] As a result, at the base terminals of the bipolar transistors 1a, 1b, 1c, and 1d, two signals (for example: the original modulating signal and the envelope signal) cause cross-modulation, which exacerbates the distortion

Therefore, from the viewpoint of suppressing distortion components, there is a problem that the ballast resistance cannot be made too large, and an amplifier applied to digital modulation, which has recently been increasingly in demand, cannot be constructed

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