High-Precision Current Source with Lumped Current Outer Loop-Distributed Current Inner Loop for the Application of Sintered Powder Materials

Pulse electric current sintering is a new powder material synthesis technology. Due to the limited output accuracy of the current source, it is difficult to precisely control the amount of charge that passes through the sample and the mold, to precisely adjust the temperature rise rate of the target sample. Based on the topology of the linear current source, a high-precision current source with lumped current outer loop and the distributed current inner loop is designed in this paper, which consists of two parts: the distributed current inner loop power stage unit and the current outer loop feedback calibration unit. The working principle and characteristic parameters of the double closed loop current source are analyzed through the circuit structure. The influence of the power transistor on the output current accuracy is analyzed through verification experiments, and it is proved that the current source can output extremely high current accuracy, achieve a static error of mA level, and realize rapid temperature rise during sintering.