High-linearity and high-injection-efficiency CTIA (capacitor trans-impedance amplifier) unit circuit

Abstract

The invention discloses a high-linearity and high-injection-efficiency CTIA (capacitor trans-impedance amplifier) unit circuit, relating to a unit circuit amplifier. The invention provides the high-linearity and high-injection-efficiency CTIA unit circuit with a simple unit circuit structure and little influence of process variations to performance. The high-linearity and high-injection-efficiency CTIA unit circuit comprises a detector capacitor, an integrating capacitor, an integrating reset transistor and a sampling holding transistor and is structurally characterized in that M1 and M2 geminate transistors are used as an input transistor, M3, M4, M6 and M7 transistors form a cascade current mirror load, C1 is used as the detector capacitor, Cint is used as the integrating capacitor, Iint is used as an integrating current, Mrst is used as the reset integrating transistor, and Msh1, Msh2 and a load capacitor form a correlated double sampling structure.

Description

Technical field: [0001] The invention relates to a unit circuit amplifier, in particular to a CTIA unit circuit with high linearity and high injection efficiency. Background technique: [0002] The readout circuit (ROIC) is one of the key parts of the infrared focal plane array (IRFPA), and its function is to perform pre-processing (such as integration, sample / hold, amplification, etc.) Parallel conversion. The readout circuit is the same as the detector, its performance directly affects the performance of the focal plane. Commonly used readout circuits are Active Stage Follower (SFD), Direct Injection (DI) and Capacitive Transimpedance Amplifier (CTIA). Compared with these structures, in addition to the disadvantages of relatively large area and power consumption, the CTIA-type readout circuit has low noise, constant detector bias control, integrated capacitance can be flexibly designed according to the application situation, large dynamic range, and uniformity. It has a...

AI Technical Summary

Problems solved by technology

The detector bias can not only affect the dark current, injection efficiency, detector 1 / f noise, but also affect the sensitivity and linearity of the readout circuit

[0003] The power supply suppression ability of the cascode amplifier of the traditional CTIA unit circuit is very poor. When the power supply voltage fluctuates, the bias voltage of the detector follows the change of the power supply voltage due to the constant tail current, so that the integral output introduces nonlinearity, which leads to the readout circuit The linearity of

The instability of the bias voltage also causes the change of the dark current of the detector, which has a certain influence on the injection efficiency of the CTIA unit circuit

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