Title :
A CMOS neurostimulator with on-chip DAC calibration and charge balancing
Author :
Greenwald, Elliot ; Cheng Chen ; Thakor, Nitish ; Maier, Christian ; Cauwenberghs, Gert
Author_Institution :
Dept. of Biomed. Eng., Johns Hopkins Univ., Baltimore, MD, USA
fDate :
Oct. 31 2013-Nov. 2 2013
Abstract :
A multi-channel biphasic neural stimulator with on-chip DAC calibration and current matching capabilities is presented. Each channel consists of two sub-binary radix DACs, for the anodic and cathodic stimulation phases, and a wideswing high output impedance current source and sink. A single integrator is shared among channels and serves to calibrate DAC coefficients and to closely match the anodic and cathodic stimulation phases. After calibration, the differential non-linearity is bounded between +/- 0.5 LSBs at 8-bit resolution, and the two stimulation phases can be matched to better than 50 nA. We demonstrate operation with stimulation through a tungsten microelectrode in saline, and show stimulator induced modulation of neural activity in the cortex of a rat. Our novel architecture allows for blind self-calibration, amenable to implantable neural interfaces.
Keywords :
CMOS integrated circuits; biomedical electrodes; biomedical electronics; constant current sources; digital-analogue conversion; integrating circuits; microelectrodes; neurophysiology; prosthetics; CMOS neurostimulator; anodic stimulation phase; blind self calibration; cathodic stimulation phase; charge balancing; cortical neural activity; current matching capabilities; current sink; implantable neural interfaces; integrator; multichannel biphasic neural stimulator; on chip DAC calibration; stimulator induced neural activity modulation; subbinary radix DAC; tungsten microelectrode; wideswing high output impedance current source; Calibration; Capacitors; Computer architecture; Electrodes; Firing; Random access memory; Transistors;
Conference_Titel :
Biomedical Circuits and Systems Conference (BioCAS), 2013 IEEE
Conference_Location :
Rotterdam
DOI :
10.1109/BioCAS.2013.6679646
