Design Of The Normal Temperature Terahertz Detector CMOS Readout Circuits

In recent years,terahertz?THz?detection and imaging technologies have broad application prospects in many fields such as physics,astronomy,biology,and information.The readout circuit as the core component of the terahertz detector is critical to the performance of the entire detection and imaging system,so its design research has been the current hotspot.In this thesis,the Nb₅N₆ microbolometer is used as a terahertz detector,and a 4×4 array readout circuit is systematically designed in a TSMC 0.18?m CMOS process to provide reference for the subsequent large-scale array readout circuit.The array readout circuit designed in this thesis is mainly composed of a capacitive feedback transimpedance amplifier?CTIA?,a bandgap reference,a correlated double sampling?CDS?circuit,a switched capacitor amplifier,and a sequential circuit.In order to achieve lower noise and higher dynamic range,this thesis uses a capacitive feedback transimpedance amplifier as the front-end readout circuit,and its op amp adopts a two-stage cascade structure to achieve higher gain,lower noise,and larger Output swing.To improve the integrity of the circuit,some of the bias voltage is generated by the internal bandgap reference.In order to improve the signal-to-noise ratio of the circuit,related double sampling techniques are used to reduce dc offset,low frequency noise,and KTC noise,etc.To suppress column KTC noise and column-fixed pattern noise,switched-capacitor amplifiers are used as output stages and provide a stable DC level for post-stage ADC conversion.To meet the imaging needs,we design a 4×4 array readout circuit the system architecture and timing control circuit,and a multiplexer is used to multiplex low-speed digital signals into one high-speed digital signal output,thereby reducing the number of lead-out pads..The chip area of the whole circuit is 1.9mm×1.2mm.The post-simulation results show that when the power supply voltage is 1.8V and the input master clock is 1MHz,the readout circuit can detect the dynamic range of the signal at about 50dB under the typical-typical process corner.In addition,the output has a good linearity.The reading frame rate is 49,and the power consumption of a single pixel is about0.94 mW,which is suitable for the realization of a large-scale array readout circuit.