An All-digital Programmable Current-limited Discharge Circuitry for a Safe Electrical Stimulation

Biphasic electrical stimulation is used To prevent any charge accumulation during electrical stimulation and to provide a safe stimulation. One of the methods to provide biphasic stimulation is to use passive discharging by electrode shortening. However, discharging an electrode with an unknown impedance may lead to the generation of large and unsafe current that may lead to unintended stimulation. This paper presents an all-digital programmable current-limited discharge circuitry for safe electrical stimulation. Implementing a current-limited discharge circuitry in the digital domain enhances the controllability of the system, and reduces the complexity of the design. In addition, using the proposed system, end-of-discharge is detected and the performance of the system is monitored in real-time. The correct performance of the proposed charge balancer is validated by simulation results obtained from the behavioral model of system using ideal components.