LOW NOISE AMPLIFIER AND RECEIVER

摘要

A low noise amplifier is disclosed. The low noise amplifier comprises a current mirror circuit, a bias circuit, a cascode amplifying circuit and a power gain compensating circuit. The current mirror circuit is used for providing a first current and third current. The bias circuit is used for receiving a first current and third current and outputting a first bias voltage and a second bias voltage according to the first current and third current. The cascode amplifying circuit respectively receives the first bias voltage and the second bias voltage, and accordingly to work at an operation bias point. The power gain compensating circuit is used for receiving a RF output signal and accordingly outputs a gain compensating signal to the current mirror circuit so as to dynamically adjust current value of the first current and third current and further to compensates power gain of the low noise amplifier in order to increase 1 dB gain compression point (P1dB).

主权项

1. A low noise amplifier, comprising:
a current mirror circuit, providing a first current and a third current according to a system voltage and a preset current, wherein the first current and the third current are mapping current of the preset current; a bias circuit, electrically connected to the current mirror circuit, the bias circuit receiving the first current and third current and outputting a first bias voltage and a second bias voltage according to the first current and the third current; a cascode amplifying circuit, electrically connected to the bias circuit so as to respectively receive the first bias voltage and the second bias voltage, and accordingly to work at an operation bias point, the cascode amplifying circuit is used for receiving and amplifying a radio frequency (RF) input signal and accordingly outputting a RF output signal; and a power gain compensating circuit, electrically connected between the cascode amplifying circuit and the current mirror circuit, the power gain compensating circuit receiving the RF output signal and accordingly outputting a gain compensating signal to the current mirror circuit so as to dynamically adjust current values of the first current and the third current and change bias region of the cascode amplifying circuit, further compensating power gain of the low noise amplifier in order to increase 1 dB gain compression point (P1 dB).