A Programmable Gain Amplifier with High Gain Accuracy

Abstract

The invention discloses a programmable gain amplifier with high gain accuracy and belongs to the field of semiconductor integrated circuit design. The programmable gain amplifier is mainly used to meet the requirement that a communication system requires the programmable gain amplifier with high gain accuracy. The programmable gain amplifier structurally comprises a programmable gain amplifier stage with adjustable and accurate gain, and three fixed gain amplifier stages used for coarse adjustment, wherein the programmable gain amplifier stage and the three fixed gain amplifier stages are in cascade connection. An approximate gain of an input signal is firstly determined through switching the three fixed gain amplifier stages, then accurate gain adjustment is carried out through the programmable gain amplifier stage based on the approximate gain so as to obtain a high-precision gain, wherein the programmable gain amplifier stage with adjustable and accurate gain controls the strength of a feedback resistance network through switching so as to obtain the high-precision gain, and the three fixed gain amplifier stages carry out coarse adjustment through gating switches. The programmable gain amplifier has the advantages of high gain accuracy, simple gain control, good linearity and the like.

Description

technical field [0001] The invention belongs to the field of semiconductor integrated circuit design, in particular to a programmable gain amplifier with high gain and precision. Background technique [0002] In fields such as wireless communication, disk reading, and medical equipment, the signals to be processed by analog systems often have a large dynamic range. For example, a gain change of about 80dB is required in a GSM radio receiver. In order to obtain a relatively constant signal, a variable gain amplifier (Variable Gain Amplifier, VGA) is needed to adjust the amplitude of the received signal. Specifically, a control signal is generated by comparing the output signal of the VGA with the reference signal, and the gain of the VGA is controlled so that the amplitude of the output signal is equal to the reference signal. Therefore, the higher the gain accuracy of the VGA, the greater the dynamic range of the gain, the better the dB linearity of the gain with the contr...

AI Technical Summary

Problems solved by technology

The control signal of VGA is an analog signal, and the gain is continuously adjustable, but the gain control is complicated; the control signal of PGA is a digital signal, so its gain varies discretely, but the gain control is simple

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