Polarization voltage supply for multiple stage power amplifier for use in mobile telephones, has first and second polarization supplies for specific transistor in amplifier first and second stages, respectively

摘要

The polarization voltages (Va,Vb,Vc) supply circuit (3) delivers a polarization voltage to each stage according to a control signal (Vapc) from a control circuit (17). The circuit comprises a first voltage supply circuit (22b) to provide a polarization voltage to a heterojunction bipolar transistor in the first amplifier stage. There is a second voltage supply circuit (22c) to control the supply voltage to a heterojunction bipolar transistor of each second stage of power amplification, and subsequent stages, according to the control signal. The polarization circuit applies the control signal via a resistor (21) as the polarization voltage (Va) to a heterojunction bipolar transistor of the first amplifier stage. The first and second voltage supply circuits (22b,22c) are voltage stabilizers controlled by the signal Vapc for the application of constant voltages (Vb,Vc) to heterojunction bipolar transistors of subsequent amplifier stages. In the second embodiment, the polarization circuit comprises a voltage supply circuit for each amplifier stage, so that the first polarization voltage is not referenced to the control signal. Independent claims are included for a method of supplying a polarization signal.