多 MOSFET 并联均流的高稳定度恒流源研究

摘要

In this paper , an approach for a high stable constant current source is presented , which is based on multi-ple power MOSFETs paralleling connection method , the maxim output of current source is up to 30 A, and it is con-tinuously adjustable .The performance of the designed constant current source has been tested , and the measurement results indicate that the stability of constant source is better than 5 ppm when the current is 30 A.The working princi-ple of the designed constant current circuit is analyzed in detail , and the selection of key components is explained clearly.We use the high precision reference voltage source and current series negative feedback based on high -power precision sample resistor to increase the stability of system .In order to realize the high stable current , multiple MOS-FETs in paralleling connection are used as regulator , and systematic analysis on factors affecting MOSFETs in paralle-ling work are presented as well .The constant current source that we designed has a certain reference value for the de-sign of DC current source .%提出了一种基于多MOSFET并联均流的高稳定度大电流恒流源研究方案，输出电流最高可达30 A且连续可调，输出30 A时，30分钟内电流稳定度优于5 ppm。文中详细分析了恒流源基本稳流电路的工作原理，并对电路中关键元器件的选型进行了分析说明。通过高精度基准电压芯片和基于大功率精密电阻采样的电流串联负反馈方法提高系统的稳流精度，通过多只功率MOSFET并联均流工作作为调整管，实现了输出大电流的高稳定度，同时对影响功率MOSFET并联工作的因素进行了系统分析。提出的恒流源方案，对高稳定度直流电源的设计具有一定的参考价值。