A Method for Improving Transient Response of the Source Measure Unit Based on PID+LPF Controller

The current NI SourceAdapt technology is unable to effectively eliminate overshoot, shorten rise time and settling time of the transient response in a source measure unit (SMU). A method based on the proportion-intergration-differentiation controller with a low pass filter is proposed to improve the performance of the transient response. The method utilizes Simulink to establish simulation models of the SMU and PID+LPF controller, takes advantage of PID Tuner to determine PID+LPF parameters, and implements the controller in terms of Verilog HDL program. In the condition that transient response of the PID+LPF controller tested in Modelsim is consistent with the simulation result in Simulink, the Verilog HDL program is downloaded to FPGA to realize PID+LPF controller. Demonstration of the method on HP6633A SMU shows that PID+LPF controller, compared to NI SourceAdapt technology, can significantly improve rapidity and stability of the transient response in a SMU.