Analog/digital configurable variable-gain amplifier

Abstract

The invention discloses an analog / digital configurable variable-gain amplifier, which comprises a variable-gain amplifier module VGA and an analog / digital configurable control circuit. The variable-gain amplifier module is formed by a plurality of variable-gain amplifiers and a fixed-gain amplifier in concatenation connection. The analog / digital configurable control circuit comprises an analog mode control circuit and a digital mode control circuit. A comparator and a charge pump of the analog mode control circuit detect the size of amplitude of an output signal, output an appropriate control voltage and feed back the control voltage to the VGA so as to regulate the gain of the VGA. The digital mode control circuit controls an internal switch circuit by means of an external signal, generates the control voltage by means of a decoder and an I-V converter according to an input signal provided by a digital baseband processing module chip and feeds back the control voltage to the VGA so as to change the gain of the VGA. The analog / digital configurable variable-gain amplifier can flexibly switch between an analog mode and a digital mode and is especially suitable for a radio-frequency front end circuit for different baseband chips.

Description

Contents of the invention [0001] The invention belongs to the technical field of radio frequency communication, and relates to a variable gain amplifier, in particular to an analog / digital configurable variable amplifier used in a radio frequency receiver, which can work in either an analog control mode or a digital Control mode, the switching between the two modes is realized through external control signals. Background technique [0002] In recent years, with the continuous emergence of new technologies in the field of information technology and the continuous progress of technology, the RF front-end and baseband chips of various receiver systems have achieved great development. The development of chips with a single function is becoming more and more mature, but because of its single function, people turn their attention to the development of chips with multiple functions, including multi-function chips that support multiple operating frequency bands and multi-functional ...

AI Technical Summary

Problems solved by technology

[0006] There are many disadvantages in the prior art controllable gain amplifier: first, the analog control gain amplifier or the digital control gain amplifier of the traditional structure can only be suitable for a kind of baseband chip, not suitable for sharing with different demodulation chips, and jointly integrating

Second, in the traditional design, the digital control gain amplifier and the analog control gain amplifier are two independent modules. When designing, the cascading of the two amplifiers with the front and rear stages and the matching and isolation between the front and rear stages should be considered. The switching of different working modes on the signal chain, as well as some special connection requirements, etc., not only increase the difficulty of design, but also increase the complexity of the module circuit

Third, the traditional circuit structure of two parallel chips greatly increases the chip area and makes it more difficult to cooperate with the baseband, which deteriorates the signal-to-noise ratio of the RF receiver system and ultimately affects system performance

Fourth, there is interference between different amplifiers in parallel, as well as substrate noise problems, which seriously restrict the performance of the entire system and high-demand applications

Programmable makes the control more flexible and can achieve the required characteristics more easily, but it also has a digital feedback control signal that will cause the discontinuity of the VGA gain change and the discontinuity of the signal phase, and the discontinuous change of the gain limits the its purpose

Images