Readout circuit of uncooled infrared focal plane array

Abstract

The embodiment of the invention discloses a readout circuit of an uncooled infrared focal plane array. The readout circuit comprises a first bias circuit producing a detection output signal, a second bias circuit producing a first reference output signal, a first integration circuit and an analog-to-digital conversion circuit. The analog-to-digital conversion circuit includes a ramp signal generator which generates a ramp signal based on the output of a second reference microbolometer in a third bias circuit. According to the readout circuit, 'difference calculation' and 'amplification' of the detection output signal and the first reference output signal are completed by an integrator in an analog domain, 'ratio solution' is completed by an analog-to-digital converter in the process of analog-to-digital conversion, and analog-to-digital conversion and infrared detection are integrated more closely. Moreover, only one reference microbolometer is adopted in a column-level integrated readout channel, only one reference microbolometer is adopted in the chip-level ramp signal generator, and the readout circuit occupies a smaller area and has a smaller number of noise sources.

Description

technical field [0001] The invention relates to the technical field of infrared focal plane arrays, in particular to a readout circuit of an uncooled infrared focal plane array. Background technique [0002] The microbolometer infrared imaging system is a heat-sensitive infrared detector. If no special compensation method is used, the detection result is related to the substrate temperature. In actual use, it is hoped that the result of infrared detection is only related to the temperature of the detection target, and has nothing to do with other factors. [0003] A thermoelectric cooler (Thermo-Electric Cooler, TEC) is used in traditional uncooled microbolometer infrared imaging systems to achieve substrate temperature compensation. However, the TEC itself has a certain volume and power consumption, which affects the application of the uncooled infrared focal plane array detector to a certain extent, so people try to remove the TEC. However, the microbolometer infrared im...

AI Technical Summary

Problems solved by technology

[0006] In the readout circuit of the prior art, the analog-to-digital conversion has nothing to do with the infrared detection itself

Also, due to the use of two reference microbolometers in each column readout channel, there is an added noise source in the circuit, which also adds a larger chip area

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