A power efficient, differential multichannel adiabatic electrode stimulator for deep brain stimulation
An energy efficient multichannel adiabatic switching based stimulator with high driving current capability (up to 10 mA) is presented in this paper. The high output current is needed especially for deep brain stimulation system. The stored energy in the electrode-tissue capacitor in the first phase of stimulation will be mostly recovered in the second phase. The proposed stimulator consists of a dynamic differential power supply which makes the biphasic stimulation possible without the need of H-bridge or midrail power supply in the output stage. The stimulation current is directly sensed and controlled by a current-controlled loop which makes the stimulation safe and flexible. In the proposed design, the simultaneous multichannel stimulation with independent electrode-tissue characteristics is possible by making use of the proposed simple digital control scheme. This feature is attained without the need of duplicating the inductors for each channel. A self-voltage-boosting bootstrap circuit is also introduced in order to drive the power MOSFETS of the power supply efficiently. The stimulator is simulated in a 0.18 µ, 32 V HV-CMOS technology for evaluating the effectiveness of the system. The simulation results show up to 1.5–2X efficiency improvement compared to the conventional constant current stimulators with adaptive power supply and around 5–10% efficiency improvement relative to the most recent state-of-the-art switching stimulators.
KeywordsAdiabatic Deep brain stimulation Switching stimulator Power efficient
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