Complementary digital variable gain amplifier

Abstract

The invention discloses a complementary digital variable gain amplifier. The variable gain amplifier comprises a transconductance amplifier and a transimpedance amplifier. The transconductance amplifier is formed by connecting four transconductance stages of the same structure in parallel and used for converting input voltage into output current, and controls over the equivalent transconductance value of the transconductance stage and the gain of the variable gain amplifier is achieved by controlling the stage number of the accessed transconductance stage. And the transimpedance amplifier is used for converting the output current obtained by the transconductance amplifier into the output voltage of the transimpedance amplifier. The transimpedance amplifier comprises a first transimpedanceamplifier (A1), a first resistor (R1) and a second resistor (R2). The step length and gain adjustable range of the variable gain amplifier are determined through selection of the transconductance value of each transconductance stage and selection of the number of the transconductance stages, and control over the transconductance value of the transconductance stage amplifier is achieved. Half current can be saved under the same gain requirement, and power consumption can be reduced when the same equivalent gain is achieved.

Description

technical field [0001] The invention relates to a complementary digital variable gain amplifier, belonging to the technical field of variable gain amplifiers. Background technique [0002] In the radio frequency receiving system, it is necessary to adjust the amplification factor of the signal according to the size of the received signal, and the variable gain amplifier is the key module to realize this function. According to the needs of the system, the variable gain amplifier considers issues such as gain control range, gain control accuracy, bandwidth, linearity, and power consumption. According to different control amplification and implementation, variable gain amplifiers are mainly divided into analog variable gain amplifiers (VGA) and digital variable gain amplifiers (PGA), and because the gain control implementation method of digital variable gain amplifiers is simple, the gain control accuracy High, simple and clear structure and other reasons, gradually become the...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to solve the problem that the traditional digital controllable amplifier controls the circuit gain by controlling the feedback coefficient of the fully differential amplifier, but the change of the feedback coefficient will affect The bandwidth and DC gain of the fully differential amplifier lead to the problem of increased power consumption. A complementary digital variable gain amplifier is provided, which saves half of the transconductance stage current when achieving the same equivalent gain, significantly reduces power consumption, and Guaranteed constant output transimpedance amplifier gain and bandwidth

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