IEEE Transactions on Biomedical Circuits and Systems · 2011 · 107 citations · 22 references
EngineeringBiomedical EngineeringElectrical EngineeringBiomemsNeural CircuitryNeural EngineeringImplantable Biomedical DevicesImplantable MicrosystemsImplantable Neural DevicesNeural ProstheticsNeural Signal AcquisitionNeurostimulationElectrode FabricationImplantable Bioelectronic DevicesImplantable MicroelectrodesImplantable Neural ElectrodesImplantable Neural StimulationNeural Electrode DesignNeural ElectrodesNeural Stimulation Devices
This paper presents a power-efficient neural stimulator integrated circuit, designed to take advantage of our understanding of iridium-oxide electrode impedance. It efficiently creates a programmable set of voltage supplies directly from a secondary power telemetry coil, then switches the target electrode sequentially through the voltage steps. This sequence of voltages mimics the voltage of the electrode under the constant current drive, resulting in approximately constant current without the voltage drop of the more commonly used linear current source. This method sacrifices some precision, but drastically reduces the series losses seen in traditional current sources and attains power savings of 53%-66% compared to these designs. The proof-of-concept circuit consumes 125 μW per electrode and was fabricated in a 1.5-μm CMOS process, in a die area of 4.76 mm(2).
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