| 摘要 |
PURPOSE: A power amplifier circuit is provided to strengthen Power Added Efficiency(PAE) of a power amplifier by controlling a bias point, that is bias voltage or bias current according to a size of input current in a system needed for amplifying a power. CONSTITUTION: A power amplification circuit comprises an impedance buffer(10), a peak detector, a voltage comparator(30), a first analog switch(40), a second analog switch(50),a power amplifier(60). The impedance buffer(10) rectifies in a half-wave, and buffers an input RF(Radio Frequency) signal. The peak detector(20) outputs 2-bit combination signals(C0, C1) according to a size of an output signal by comparing the output signal of the impedance buffer(10) with reference voltage of two comparators(OP1, OP2). The first analog switch(40) selectively outputs a bias for adjusting a gate, bias voltage of a base, or current when 2-bit combination signals of the voltage comparator(30) are inputted. The second analog switch(50) selectively outputs a bias for adjusting a drain, bias voltage of a collector, or current when 2-bit combination signals of the voltage comparator(30) are inputted. The power amplifier(60) outputs by amplifying the RF signals according to the bias selected by the first analog switch(40) and the second analog switch(50) of the voltage comparator(30).
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