硒化铅(PbSe)中红外探测器是CO气体检测仪中的核心部件,其响应率会随温度变化。对中红外探测器进行精确的温度控制 可以有效地改善系统稳定性,提高检测系统信噪比。首先分析了 PbSe探测器温度特性,根据CO检测仪设计指标提出了温控 系统的高稳定性要求;介绍了热电制冷器(Thermoelectric cooling, TEC)的工作原理;提出了基于温湿度控制芯 片ADN8830的温度控制方案并设计了输入电桥电路、TEC功放电路和PID补偿电路。根据设计方案搭建了实验测试系统 在室温环境下进行测试。测试结果表明:该温控系统应用于大气CO浓度检测仪器可在30 s内进入稳定状态,且1 min内 温度波动小于±0.02℃,优于CO检测仪1 ppm精度指标所需的温度波动不大于±0.1℃的要求。

The PbSe mid-infrared detector is the core component of the CO gas detector and its response rate varies with temperature. Accurate temperature control of the mid-infrared detector can effectively improve the stability of the system and signal-to-noise ratio. Firstly, the temperature characteristics of PbSe detector are analyzed. According to the design index of CO detector, the high stability requirements of temperature control system are put forward. Then the working principle of thermoelectric cooler (TEC) is introduced. The temperature control scheme based on temperature and humidity control chip ADN8830 is proposed, and the corresponding input bridge circuit, TEC power amplifier circuit and PID compensation circuit are designed. Finally the experimental test system is built according to the design scheme and tested at room temperature. The test results show that, when the temperature control system is applied in the atmospheric CO concentration detection instrument, it can enter a stable state within 30 s, and the temperature fluctuation within 1 min is less than 0.02℃, which is superior to the requirement that the temperature fluctuation required for the 1 ppm accuracy index of the CO detector is not more than 0.1℃.