Dynamic resistance nonuniformity compensation circuit for uncooled microbolometer detector arrays


Yildirim O. O. , AKIN T.

32nd Conference on Infrared Technology and Applications, Florida, United States Of America, 17 - 21 April 2006, vol.6206 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 6206
  • Doi Number: 10.1117/12.665650
  • City: Florida
  • Country: United States Of America

Abstract

This paper presents a new approach for compensating resistance nonuniformity of uncooled microbolometers by adjusting the bias currents of both detector and reference pixels. Contrary to conventional nonuniformity compensation circuits, this approach eliminates the need for digital-to-analog converters (DACs), which usually occupy a large area, dissipate high power, and require complicated external circuitry with high frequency data transfer to the microbolometer chip. The proposed circuit uses a feedback structure that dynamically changes the bias currents of the reference and detector pixels and does not need complicated external circuitry. A special feature of the circuit is that it provides continuous compensation for the detector and reference resistances due to temperature changes over time. The circuit is implemented in a 0.6 mu m 5V CMOS process and occupies an area of only 160 mu m x 630 mu m. Test results of the prototype circuit show that the circuit reduces the offset current due to resistance nonuniformity about 2.35% of its uncompensated value, i.e., an improvement of about 42.5 times is achieved, independent of the nonuniformity amount. The circuit achieves this compensation in 12 mu sec. Considering its simplicity and low cost, this approach is suitable for large array commercial infrared imaging systems.