Patent ID: 8847686
Filing Date: 2014-09-30
Classification: H03F,H03G

Abstract:
1. A radio frequency (RF) power amplifier, amplifying a RF input signal, comprising: a bias current generating unit, receiving a reference voltage; a first impedance unit, electrically connected to the bias current generating unit; a second impedance unit, electrically connected to the first impedance unit, wherein there is a first voltage with a negative temperature coefficient between the first impedance unit and the second impedance unit, and the second impedance unit receives a ground current; a third impedance unit, electrically connected to the second impedance unit, wherein there is a second voltage between the third impedance unit and the second impedance unit, and the second voltage is a partial voltage of the first voltage, wherein the bias current generating unit is electrically connected between the second impedance unit and the third impedance unit, and the bias current generating unit outputs a bias current with a positive temperature coefficient according to the second voltage; and an output stage unit, electrically connected between the first impedance unit and the second impedance unit, and the output stage unit receiving an input current; wherein the bias current is a sum of the input current and the ground current, and the input current has a characteristic of a positive temperature coefficient, when a ratio constant of the output current to the input current of the output stage unit is a negative temperature coefficient, a temperature coefficient of the output current is substantially equal to a zero temperature coefficient.