Patent ID: 7893769
Filing Date: 2011-02-22
Classification: H03F

Abstract:
1. A power amplifier comprising: a plurality of amplifying blocks each of which includes a bipolar transistor, an output block bias circuit which is connected to a base terminal of an output block bipolar transistor, and which constitutes an output block of the plurality of amplifying blocks, a preceding block bias circuit which is connected to a base terminal of a preceding block bipolar transistor, and which constitutes an amplifying block followed by the output block, an output block distortion compensating circuit that causes the output block bias circuit to have a low output impedance so that the output block bipolar transistor has a maximized saturated output power, and a preceding block distortion compensating circuit that causes the preceding block bias circuit to have an output impedance so that an amplitude distortion of an output power of the power amplifier with respect to an input power is canceled out by (i) a first amplitude distortion characteristic of an output power with respect to an input power of the output block bipolar transistor which has the maximized saturated output power and (ii) a second amplitude distortion characteristic of the preceding block bipolar transistor.