HIGH-FREQUENCY AMPLIFIER

摘要

Between resistors 13, 14 and an NPN bipolar transistor 12 are interposed PNP bipolar transistors 21, 22 forming a current mirror 20 that uses a collector current of the NPN bipolar transistor 12 as a reference current, and determines a collector current of an NPN bipolar transistor 11. This makes possible to design a size ratio A of the PNP bipolar transistors 21, 22 so as to approximate a voltage drop DELTA Vb to a value close to zero, and to suppress the voltage drop DELTA Vb of the base voltage Vb accordingly to achieve a high power output and high efficiency when a high frequency input signal Pin increases and generates a base rectified current. <IMAGE>