Current Pulse Generator for Deep Brain Stimulation

Realization of a current driver is presented. It provides a stable current amplitude required for electrical stimulation devices. It is possible to increase the output impedance of the current driver as high as possible, that improves the stability of the output current with load resistance variation. However, achieving excessively high output impedances is pointless, as it will not lead to the desired current stabilization due to the presence of a noise current. In this case, the circuit of the current driver becomes unsalable, the chip area grows and power consumption increases. An algorithm for estimating the rational value of the current driver output impedance based on the RMS noise current at the output of the circuit is proposed. The presence of the output impedance limitation relaxes the size requirements of the current driver MOS transistors and its operational amplifier gain. The proposed algorithm is verified by circuit and layout level simulation using 180 nm CMOS technology.