The Design Of Temperature Control Circuit Of Uncooled Infrared Focal Plane Arrays

Uncooled Infrared Focal Plane Array (UFPA) is the most eye-catching technicalrevolution in the history of Infrared (IR) Imaging, as well as one of the hotspot of the currentIR technology that full of market prospects. Because of its low cost, low power consumptionand high reliability, UFPA has found an increasingly wide utilization in most fields.Two kinds of UFPA was widely used: pyroelectric UFPA and microbolometer UFPA.They do not need the ultralow temperature environment, but need a steady room temperaturebecause of the demand of well image quality.Semiconductor Thermal Electrical Cooler (TEC) was used to control the temperature ofUFPA. Semiconductor TEC was made up of simple P and N type semiconductor. It wasintegrated in UFPA, and controlled the temperature by the outside compensation circuit.On the basis of theoretical analyses and mathematical deduction, we build model for thetemperature control circuit. Take advantage of the simulation tools of MATLAB, weanalyzed the behavior of the control system. With the help of this model, we find the suitablework parameters of the control system, and provide theory principle for the subsequentdesign and debug.At last, after a overall consideration of the integration level and control accuracy, wechoose MAX1978as the main chip of the circuit. And realize the control module byhardwire circuit. The control circuit is simple and occupies very small footprint, but isextraordinary accurate. The control precision achieved to0.045°С by testing.