辐射定标光源多路LED恒流驱动设计

为应对积分球辐射定标光源系统中LED阵列的电流稳定可控性对积分球开口处光谱匹配度的影响，设计了一款多通道、高精度以及高稳定性的LED电流驱动电路。该电路是一种压控恒流驱动电路，可通过模拟调光的方式实现对LED阵列驱动电流的线性控制，其以FPGA为控制核心，通过SPI接口对AD5371芯片寄存器进行读写操作，通过AD5371数模转换电路实现对LED驱动电流的高精确度控制。基于循环液体制冷设备和水槽制冷底座实现对LED阵列的温度控制。实验结果表明，该电路可实现LED阵列驱动电流在0~1050 mA连续线性可调，电流调节精度可达量程的0.14%。在控制LED灯座温度为10 ℃时，LED输出光光谱稳定度为0.2%。

Design of multi-channel LED constant current driver in radiometric calibration light source

In order to deal with the influence of the current stability controllability of LED array in integrating sphere radiometric calibration light source system on the spectrum matching degree at the opening of integrating sphere, a multi-channel, high-precision and high-stability LED current driving circuit was designed. This circuit was a voltage controlled constant current driving circuit, which can realize the linear control of LED array driving current by means of analog dimming. It took FPGA as the control core, read and wrote the AD5371 chip register through SPI interface, and realized high precision control of LED driving current through AD5371 digital-to-analog conversion circuit. The temperature control of LED array was realized based on circulating liquid refrigeration equipment and sink refrigeration base. The experimental results show that the current of LED array can be continuously and linearly adjustable in the range of 0-1 050 mA, and the current adjustment accuracy can reach 0.14% of the range. When the LED lamp holder temperature is controlled at 10 ℃, the LED output light spectral stability is 0.2%.