Uncooled Infrared Focal Plane Array Readout Circuit Design Research

Infrared thermal imaging system is used widely in both military field and civilian field for its many merits. The readout integrated circuit(ROIC) of uncooled infrared focal plane array(UFPA) is the key unit of thermal imaging system, the performances of infrared thermal imaging system are directly affected by ROIC. A kind of architecture of ROIC is introduced in this article after the design parameters of ROIC are mentioned. And then, a novel kind of timing control circuit of readout, a kind of integrating circuit and a kind of sampling circuit of UFPA are designed by lots of simulation.1) At first, a kind of system architecture of ROIC is introduced in this article. The ROIC system can get the faint electric current brought by the changing of the resistance of detector unit through sweeping to UFPA. After that, a calibrated digital signal is send to the monitor by integrating, sampling and holding, conversion from analog to digital and digital calibration of the faint current. Secondly, a kind of single channel architecture of ROIC based on NMOS buffering injection bias is presented after discussing of the bias methods of ROIC. This architecture can get rid of the influence of dark current to efficient signal and increase the S/N of UFPA so that the precision of image output is enhanced extremely. The architecture can be used in UFPA of any size.2) Two kind of waves of timing control of two different resistance-selecting methods are brought forward in the second part of this article by comparing the advantages and disadvantages of the two different methods. And then, a novel kind of timing control circuit of UFPA is presented according to the waves. This timing control circuit not only can decrease the magnitude of ROIC channel easily, but also can decrease the pins of ROIC chip because few control signals are used in this timing control circuit. The timing control circuit can also be used in UFPA of any type and any size.3) In the last part of this article, a type of integrating circuit and a type of sampling circuit are finished after the specification is got. This part includes the following units: the design of operational amplifier of integrating circuit, the simulation of integrating circuit, the design of operational amplifier of sampling and holding circuit and the simulation of sampling and holding circuit. The integrating circuit has a wide voltage...