Voltage type automatic gain control circuit

Abstract

The invention discloses a voltage type automatic gain control circuit. The voltage type automatic gain control circuit comprises an amplitude sampler used for sampling a controlled signal and a reference voltage signal respectively, voltage followers which are connected with the amplitude sampler and are used for isolating the sampled controlled signal and the reference voltage signal respectively so as to obtain a stable voltage signal, alternating current resistors which are connected with the voltage followers and are used for calculating an average value of the stable controlled signal and the reference voltage signal respectively by utilizing the resistors, and a bias current source, wherein a bias terminal of the bias current source is connected with the alternating current resistors, and an output terminal of the bias current source is taken as an output terminal of the voltage type AGC (automatic gain control) circuit and is used for outputting control current by utilizing the average value of the stable controlled signal and the average value of the reference voltage signal as bias voltage. According to the voltage type AGC (automatic gain control) circuit of the invention, output current can be stabilized in a short time, and proper locking precision is maintained.

Description

technical field [0001] The invention relates to the field of electronic circuit design in the communication industry, in particular to a voltage-type automatic gain control circuit (Automatic Gain Control, AGC circuit for short) used in a Class E CMOS power amplifier drive circuit. Background technique [0002] In the current low-cost Bluetooth and other constant-envelope transceiver systems for short-distance wireless communication, due to the high efficiency and simple design of Class E CMOS power amplifiers, they are widely used, and AGC circuits are required to provide them with stable bias currents. In order to ensure that the input tube can complete good switching performance. [0003] The AGC circuits used in the prior art for driving class E CMOS power amplifiers are all current-type, which charge and discharge the bias current source by converting the difference between the sampling amplitude voltage and the reference voltage into current to stabilize it. However, ...

AI Technical Summary

Problems solved by technology

However, since a resistor is needed to convert voltage to current, the resistance value of the resistor is affected by the compromise between locking speed and locking accuracy. When the resistance is too large, the locking time is faster, but the accuracy is lower, and the anti-interference ability to voltage disturbance Poor; when the resistance is too small, although the accuracy is improved, the locking time is longer, which is not conducive to the work of duplex mode

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