Automatic gain amplification circuit with inverse exponential characteristic type digital control circuit

Abstract

The invention discloses an automatic gain amplification circuit with an inverse exponential characteristic type digital control circuit, which is formed by a digital variable gain amplifier, a 2-bit flash analog-to-digital converter of a digital circuit and the inverse exponential characteristic type digital control circuit, wherein the digital variable gain amplifier is formed by cascading a plurality of digital variable gain amplifier stages; the 2-bit flash analog-to-digital converter comprises three comparator circuits, a coding circuit and a fixed reference voltage configuration circuit; and the inverse exponential characteristic type digital control circuit comprises a peak detector, a subtracter circuit, an integrator circuit and a decoding circuit. The inverse exponential characteristic type digital control circuit detects a digital signal output by the 2-bit flash analog-to-digital converter; the detected signal amplitude is compared with a reference value of a reference voltage by the subtracter circuit; and after a comparison result is integrated and decoded, a feedback control signal is output to regulate the gain of the variable gain amplifier PGA (Programmable Gain Amplifier). The automatic gain amplification circuit further comprises a switch for the control circuit, the switching between the inverse exponential characteristic type digital control circuit and an external control circuit can be implemented, and the automatic gain amplification circuit is particularly suitable for a radio frequency front-end circuit with the requirements on few off-chip components and compact structure.

Description

Background technique [0001] 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. Highly integrated radio frequency chips and high-speed control schemes are more and more popular. This kind of radio frequency chip requires the least external components, and at the same time needs to automatically control the response speed of the amplifier circuit to the input signal fast enough to keep up with the change of the input signal. . [0002] As we all know, highly integrated radio frequency chips require as few external components as possible. Traditional feedback automatic gain control amplifier circuits require a large capacitor outside the chip to charge and discharge the charge pump. The value of this capacitor is Generally greater than 1n, this determines that such a capacitor cannot be ...

AI Technical Summary

Problems solved by technology

Although the analog control circuit can continuously adjust the gain and realize the seamless connection of each step, it has obvious disadvantages. The continuous adjustment speed is relatively slow, and the charge pump circuit can only be used to increase the adjustment speed.

The title of the prior art paper is "Design and Realization of Low Power Consumption Charge Pump Programmable Gain Amplifier", which increases the speed of adjustment by increasing the current of the charge pump. This implementation method increases the operating current by an order of magnitude, and at the same time increases the ripple on the control voltage, which directly leads to the reduction of the signal-to-noise ratio of the output signal. Therefore, this analog control circuit can only be suitable for gain-adjustable amplifiers that do not require too high time requirements for stable signals.

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