Programmable gain amplifier

Abstract

The invention relates to a programmable gain amplifier. The programmable gain amplifier comprises an operational amplifier, at least one first complementary metal oxide semiconductor (CMOS) switch array, and a digital control module, wherein the operational amplifier comprises two input ends and at least one output end, at least one input end is in tandem connection with a resistor unit, the operational amplifier is used for amplifying and outputting output signals of the gain amplifier, the first CMOS switch array is composed of a plurality of CMOS switches which are in parallel connection with each other, the first CMOS switch array is connected between one input end and one output end of the operation amplifier in a bridging mode, and the digital control module is used for controlling on-off of all CMOS switches according to digital control signals so as to adjust the first CMOS switch array. The programmable gain amplifier realizes accurate regulation of gain, and is favorable to reducing stray capacitance.

Description

technical field [0001] The present invention relates to wireless communication systems, and more particularly, to a programmable gain amplifier. Background technique [0002] In a wireless communication system, the signal strength received by the receiver will change with the distance between the receiver and the transmitter or obstacles and other factors. In order for the receiver to maintain a relatively stable output signal amplitude under different input signal strengths, it is necessary to set a gain adjustment function in the receiving chain. When the signal is strong, the receiver gain is reduced, and when the signal is weak, the gain is increased. . A programmable gain amplifier needs to have a large gain adjustment range. In most cases, multi-stage programmable gain amplifiers with lower maximum gain are required to be cascaded to obtain a larger gain adjustment range. [0003] A traditional programmable gain amplifier needs to change the ratio of its feedback re...

AI Technical Summary

Problems solved by technology

The on-resistance of the MOS switch will cause the resistance ratio of the feedback resistance of the programmable gain amplifier to the input resistance to be inaccurate, resulting in inaccurate gain of the programmable gain amplifier.

In traditional programmable gain amplifiers, in order to overcome this defect, the area of ​​the MOS switch is usually made larger to reduce the on-resistance, but it also causes parasitic capacitance, which will be detrimental to the stability of the feedback loop of the programmable gain amplifier. influences

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