Broadband amplifying circuit

Abstract

The invention relates to an optoelectronic integrated circuit technology, in particular to a broadband amplifying circuit. The broadband trans-impedance amplifying circuit comprises a first trans-impedance amplifier, a first trans-conductance amplifier, a second trans-conductance amplifier, a current mirror and a second trans-impedance amplifier, wherein the input of the first trans-conductance amplifier is connected with the output of the first trans-impedance amplifier, and the output of the first trans-conductance amplifier is connected with the input of the current mirror; the second trans-conductance amplifier is a mirror circuit of the first trans-conductance amplifier; the input of the second trans-conductance amplifier is connected with the input of the first trans-impedance amplifier, and the output of the second trans-conductance amplifier is connected with a first input end of the second trans-impedance amplifier; and the output of the current mirror is connected with a second input end of the second trans-impedance amplifier. The broadband amplifying circuit has the beneficial effects that the trans-impedance amplifiers with relatively small gains are taken as circuit input stages, and a current gain is realized by the current mirror, so that the gain of the circuit can be increased while the circuit bandwidth is increased, and the trans-impedance amplifying circuit meets the requirements of broadband and high gain at the same time.

Description

technical field [0001] The invention belongs to the technical field of optoelectronic integrated circuits, and in particular relates to a broadband amplifier circuit. Background technique [0002] As the basis of modern communication systems, optical communication systems play a very important role in modern society. In the optical communication system, the preamplifier is a key part of the optical receiver, and its function is to convert the weak current pulse signal output by the photodiode into a certain voltage pulse signal. To improve the performance of the optical receiver, it is necessary to improve the performance of the preamplifier, which requires the preamplifier to have a higher gain on the one hand, so as to avoid the decrease of the signal-to-noise ratio caused by the noise of the main amplifier connected afterwards; On the other hand, it has as wide a bandwidth as possible under the existing technology, so as to meet the high rate requirement of the system. ...

AI Technical Summary

Problems solved by technology

The circuit structure using the voltage mode gain stage is still limited in the trade-off between bandwidth and gain. When the voltage amplification factor is relatively large, the position of the main pole of the amplifier moves forward, resulting in a decrease in bandwidth, and it is impossible to further optimize the bandwidth and gain of the circuit at the same time.

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