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Infrared detectors for astronomy application are supposed to work under cryogenic temperature due to lower dark current and readout noise. A prototype for infrared detector front electronics which can operate under cryogenic temperature is presented on this paper. Several commercial off-the-shelf (COTS) devices from different technologies were extensively characterized at as low as 4K including voltage reference, operational amplifier, ADC, MCU and etc.. The results demonstrate that AD8616 could perfectly work under 4K, Cortex-M4 ARM MCU operates well above roughly around 35K, AD7983 start to loss code at 180K and XFET reference ADR433 begin to show a significant voltage drop at 120K. The failure mechanism of COTS devices is also analyzed based on the cryogenic test results.

The readout chain circuits for time delay integration charge coupled device camera imaging system include CCD focal plane driving circuit, analog-to-digital conversion circuit, high-speed digital data transmission circuit and other parts together. The parasitic factors such as the quality of high frequency clock, high speed data transmission error rate and the aging of printed circuit board will induce more noise to image data of camera. As the longer time circuits working, the noise of readout chain becomes bigger and bigger, then the signal-to-noise becomes worse. This paper proposed a method to make circuit system check its noise as the circuit is working, which is based on pseudo CCD-signal to check the Signal-to-Noise of readout chain of TDICCD, and sends the result to control core of the system. The paper combines the theory calculation and actual measurement as the method for testing. High precision pseudo CCD signal source is used to test the onboard circuit and circuit SNR results of readout chain, harmonic frequency, noise floor and other related parameters are automatic processed.

Current analysis was an important research content for reducing power of cryocooler’s controller. Simulation was done among load current, H bridge current and power current refer to 42V bus power voltage. Then relationship among I L1 , I C1 , ρ and I M1 was established. Simulation results indicate that I L1-max , I L1-ave , I L1-rms , I C1-min and IC1-ave were linearly increasing to ρ and I M1 , especially I L1-rms ≈ 0.612ρ I M1-max . I C1-rms increase firstly then decrease with the increasing of ρ. I C1-rms reaches maximum when ρ=0.8, then I CL-rms =(12.32/R M1 + 0.98) exp -((ρ-0.78)/0.57) 2 . The results were useful for miniaturizing cryocooler’s controller.