Supercapacitor based TMS pulse generator design - Experimental results versus Matlab MOSFET simulation model

Abstract

Supercapacitors are ideal for short-term energy storage due to their high instantaneous power capability. Unlike traditional high-voltage DC power supplies typically used in transcranial magnetic stimulation (TMS) applications, a precharged supercapacitor module can serve as a cost-effective alternative for building a pulse generator with adjustable waveform capabilities. This approach utilizes a supercapacitor module with a capacitor bank rated at a few hundred farads and 10 V, combined with a step-up transformer-based converter and medium-voltage MOSFETs to meet TMS requirements. The output of this pulse generator, including the effects of varying gate voltages, can be accurately predicted using a robust model. This paper presents the design of a MOSFET model, incorporating a newly derived equation that effectively captures the subthreshold, near-threshold, and above-threshold regions of the MOSFET operation. Experimental results are provided and compared with Matlab model simulations, demonstrating the model's accuracy and effectiveness.