针对KDP晶体随环境温度升高而需要的四分之一波长电压增大的现实因素, 应考虑适时调整相应电路的输出电压。采用数字电位计AD5259作为Boost变换器反馈回路中的输出电压采样电阻, 以C8051F330微控制器从温度传感器ADT7320采集到的环境温度值为依据, 调整数字电位计的滑动端阻值, 从而实现了Boost变换器输出电压的实时调节, 进而与高速射频场效应管和脉冲变压器构建了一个温度自适应的加压式电光Q开关。该电光调Q电路已应用于多种脉冲激光测距仪中, 工作于?30~65 ℃的大范围环境温度条件下, 相应的四分之一波长电压可由1 500~7 000 V。

With consideration of the fact that quarter wavelength voltage of boost electro-optical Q switch for KDP crystal needs to increase while the ambient temperature rises, a kind of circuit is proposed to solve it. A MCU, C8051F330, can set the output resistance between wiper and end of a digital potential-meter AD5259, which is in the voltage feedback loop for Boost converter, on the basis of the MCU reading temperature data from a sensor ADT7320. There by the output voltage of the converter can be adjusted automatically in real time. So an RF-MOSFET, a pulsed transformer and the above output stage of the Boost converter build up a temperature-adaptive electro-optical Q switch. This Q switch is verified well by applying it in several pulsed laser range-finders at ambient temperature from -30℃ to 65℃, thus the quarter wavelength voltage can be changed from 1 500 V to 7 000 V accordingly.