Trans-impedance amplifier

Abstract

The invention provides a trans-impedance amplifier. The amplifier comprises an equivalent secondary amplification module, an anti-phase amplification unit and a feedback resistor; the input end of the equivalent secondary amplification module is coupled to a photodiode and used for inputting a voltage signal, and the output end of the equivalent secondary amplification module outputs a first voltage signal subjected to secondary amplification; the anti-phase amplification unit is coupled to the output end of the equivalent secondary amplification module and used for connecting the first voltage signal and outputting an amplified voltage signal subjected to anti-phase amplification, the anti-phase amplification unit comprises a third N-shaped transistor and a fourth N-shaped transistor coupled with the third N-shaped transistor, the third N-shaped transistor is used for receiving a third direct voltage signal, the fourth N-shaped transistor is used for receiving the first voltage signal output through the equivalent secondary amplification module, and the common connection end of the third N-shaped transistor and the fourth N-shaped transistor outputs an amplified voltage signal; the feedback resistor is couple with the input end of the equivalent secondary amplification module and the output end of the anti-phase amplification unit. The trans-impedance amplifier can not be constrained by original conditions, and can increase the resistance, reduce the input noise, and improve the sensitivity.

Description

technical field [0001] The invention relates to the technical field of CMOS, in particular to a transimpedance amplifier with enlarged gain, reduced noise and simple design. Background technique [0002] The full name of transimpedance amplifier (TIA) is trans-impedance amplifier, which is a type of amplifier. The type of amplifier is defined according to the type of its input and output signals. Due to the advantages of high bandwidth, TIA is generally used in high-speed circuits, such as optical transmission and communication systems. [0003] The equivalent input noise of a transimpedance amplifier is one of the important indicators to measure its transmission performance. In order to improve the sensitivity of the transimpedance amplifier, it is necessary to reduce the noise output, and one of the ways to reduce the noise output can be by increasing the transimpedance. In theory, the larger the transimpedance, the smaller the noise, but the transconductance is limited b...

AI Technical Summary

Problems solved by technology

In order to provide a stable voltage operating point, the existing transimpedance amplifier uses a combination of PMOS and NMOS to achieve the above effects, but due to the limitation of the working characteristics of PMOS, its f T Smaller, larger equivalent capacitance, which leads to a smaller gain-bandwidth product to a certain extent, making it difficult to further increase the value of the transconductance, and the output noise of the transimpedance amplifier cannot be further reduced

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