针对雪崩光电二极管(Si-APD)所加偏压需要随环境温度作调整, 且偏压电路所需的低纹波低噪声等因素, 构建了以Royer振荡器和微控制器为核心的偏压电路。该Si-APD偏压电路以BL8032型同步降压控制器作为Royer振荡器的输入电源, 以MS5221M型DAC作为该输入电源的调整单元, 以AD8606型集成运放和AD7980型ADC作为Royer振荡器输出电压采样单元, 以STM32F103TBU6型微控制器作为计算与时序控制单元。本偏压电路不仅具有温度自适应性, 而且具有低纹波、低噪声、低功耗和电气安全隔离的特点, 能在9~36 VDC宽输入电压范围和-40~70 ℃环境下良好工作。

With consideration of the fact that bias voltage for Si-APD changes in different ambient temperature and the corresponding electric network requires low ripple voltage, a kind of bias circuit is built based on Royer oscillator and MCU. The circuit is made up of four key parts (including their peripheral networks): synchronous Buck-converter controller BL8032, supplying input power source for Royer oscillator; DAC MS5221M, serving as the direct adjustment of the input power source for Royer oscillator; ADC AD7890, with the OPA AD8606 as an buffer, used for sampling output voltage of Royer oscillator; and an MCU STM32F103TBU6, working as the main computing and timing sequence controller. This bias circuit not only provides low ripple, low noise and low power consumption, but also meets requirement of wide input voltage of 9~36 VDC and safety electric isolation. It works well at ambient temperature from -40 ℃ to 70 ℃.