基于FPGA的光电倍增管APD偏压控制电路设计

The Design of the Circuit for APD Bias Control Base on FPGA

为了减小光子谱仪PHOS中信号通道增益的离散性,需要调整光电倍增管APD的偏压来补偿系统中的以下几个方面:APD增益的宽离散性、前置放大器增益的离散性和钨酸铅晶体光产额的离散性等。因此,设计了基于FPGA的APD偏压控制电路。该控制电路通过FPGA对10-bit DAC进行控制,使输出高压的调节范围达到210V～400V,调节精度达到0.2V/bit。文中具体介绍了APD偏压控制电路的设计思路,给出了测试结果,并对测试结果进行了深入的分析。

In order to minimize the dispersal of Photon Spectrometer（PHOS） channel gains, we have to adjust the bias voltage of APD so as to compensate the following factors： wide dispersal of the APDs gain factors, gain dispersal of the preamplifiers and light yield dispersal of the PWO crystals. So, we designed the cireuit for APD bias control based on FPGA. This circuit control the 10-bit DAC via FPGA to make the range of bias voltage achieved 210V-400V, the adjust precision of the range of bias voltage achieved 0.2V/bit. This paper introduced the APD bias control circuit design in detail, gave the test results and analyzed the results in depth.