Patent ID: 9614482
Date: 2017-04-04
CPC Classifications: H03F

Claim:
1. An amplifier comprising: a pair of power input terminals configured to receive differential transmission signals, the differential transmission signals being two-tone signals; a pair of power output terminals; a coil configured to have a first terminal and a second terminal, the first terminal and the second terminal being connected with the pair of power input terminals, respectively, and to have a center tap; a first transistor configured to have a first gate connected with the first terminal of the coil, and a first output terminal connected with one of the pair of power output terminals; a second transistor configured to have a second gate connected with the second terminal of the coil, and a second output terminal connected with another of the pair of power output terminals; a diode configured to have a third terminal and a fourth terminal, the third terminal being connected with the center tap of the coil; a gate voltage generation unit configured to have a seventh terminal connected with the fourth terminal of the diode, the seventh terminal outputting a predetermined gate voltage to turn on the first transistor and the second transistor; and a capacitor configured to have a fifth terminal and a sixth terminal, the fifth terminal being connected with a point between the fourth terminal of the diode and the seventh terminal of the gate voltage generation unit, the sixth terminal being connected with a reference potential point, wherein an inductance of the coil and a capacitance of the capacitor are set to respective values so that a resonance frequency obtained in an LC resonance circuit including the coil and the capacitor becomes a frequency of a double harmonic wave of the transmission signals input into the pair of power input terminals, and wherein the diode is configured to adjust a voltage at the third terminal depending on a signal level of the double harmonic wave of the transmission signals supplied to the third terminal from the center tap of the coil.