Pixel-level Current Mirroring Injection with 2-step Bias-current Suppression for 2-D Microbolometer FPAs

Title & Authors
Pixel-level Current Mirroring Injection with 2-step Bias-current Suppression for 2-D Microbolometer FPAs
Hwang, Chi Ho; Woo, Doo Hyung;

Abstract
A pixel-level readout circuit is studied for 2-dimensional microbolometer focal plane arrays (FPAs). A current mirroring injection (CMI) input circuit with 2-step current-mode bias suppression is proposed for a pixel-level architecture with high responsivity and long integration time. The proposed circuit has been designed using a $\small{0.35-{\mu}m}$ 2-poly 4-metal CMOS process for a $\small{320{\times}240}$ microbolometer array with a pixel size of $\small{50{\mu}m{\time}$$\small{s}50{\mu}m}$. The proposed 2-step bias-current suppression has sufficiently low calibration error with wide calibration range, and the calibration range and error can be easily optimized by controlling some design parameters. Due to high responsivity and a long integration time of more than 1 ms, the noise equivalent temperature difference (NETD) of the proposed circuit can be improved to 26 mK, which is much better than that of the conventional circuits, 67 mK.
Keywords
Uncooled infrared detector;microbolometer;readout integrated circuit;current mode background suppression;
Language
Korean
Cited by
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