基于DSP的雪崩光电二极管数控偏压源设计

Design of Numerical Control Bias Source of Avalanche Photodiode Based on DSP

为保证雪崩光电二极管(APD)增益恒定,不受温度变化的影响而处于最佳工作状态,通过分析APD的增益和温漂特性,设计了一种APD偏压随温度按一定规律变化的数控偏压电路。采用DSP芯片TMS320F2812为主控制器,启动A/D转换对温度传感模块输出的电压信号进行采集,经计算处理得到APD的温度,然后由DSP输出相应的PWM信号来调节APD的偏压,从而保持APD增益恒定。该电路通用性好、可靠性高、操作性强,适合于高频连续信号检测的光电系统。

According to analysis of gain instability of the avalanche photodiode （APD） with the temperature drift characteristic,a new type of Numerical Control （NC） bias circuit is designed that APD bias changes regularly with temperature.The DSP chip TMS320F2812 is the core controller of the circuit.Voltage signal of the temperature sensing module is acquired by A/D and the temperature of the APD is obtained through processing the voltage signal.Thus,APD bias will be controlled by PWM signal from the DSP to make the gain a constant.High reliability and excellent operability makes it very suitable for opto- electronic system of high frequency continuous signal detection.