16-Channel biphasic current-mode programmable charge balanced neural stimulation.

dc.contributor.author

Li, Xiaoran

dc.contributor.author

Zhong, Shunan

dc.contributor.author

Morizio, James

dc.date.accessioned

2023-08-09T17:45:11Z

dc.date.available

2023-08-09T17:45:11Z

dc.date.issued

2017-08

dc.date.updated

2023-08-09T17:45:09Z

dc.description.abstract

Background

Neural stimulation is an important method used to activate or inhibit action potentials of the neuronal anatomical targets found in the brain, central nerve and peripheral nerve. The neural stimulator system produces biphasic pulses that deliver balanced charge into tissue from single or multichannel electrodes. The timing and amplitude of these biphasic pulses are precisely controlled by the neural stimulator software or imbedded algorithms. Amplitude mismatch between the anodic current and cathodic current of the biphasic pulse will cause permanently damage for the neural tissues. The main goal of our circuit and layout design is to implement a 16-channel biphasic current mode programmable neural stimulator with calibration to minimize the current mismatch caused by inherent complementary metal oxide semiconductor (CMOS) manufacturing processes.

Methods

This paper presents a 16-channel constant current mode neural stimulator chip. Each channel consists of a 7-bit controllable current DAC used as sink and source current driver. To reduce the LSB quantization error and the current mismatch, an automatic calibration circuit and flow diagram is presented in this paper. There are two modes of operation of the stimulator chip-namely, stimulation mode and calibration mode. The chip also includes a digital interface used to control the stimulator parameters and calibration levels specific for each individual channel.

Results

This stimulator Application Specific Integrated Circuit (ASIC) is designed and fabricated in a 0.18 μm High-Voltage CMOS technology that allows for ±20 V power supply. The full-scale stimulation current was designed to be at 1 mA per channel. The output current was shown to be constant throughout the timing cycles over a wide range of electrode load impedances. The calibration circuit was also designed to reduce the effect of CMOS process variation of the P-channel metal oxide semiconductor (PMOS) and N-channel metal oxide semiconductor (NMOS) devices that will result in charge delivery to have less than 0.13% error.

Conclusions

A 16-channel integrated biphasic neural stimulator chip with calibration is presented in this paper. The stimulator circuit design was simulated and the chip layout was completed. The chip layout was verified using design rules check (DRC) and layout versus schematic (LVS) design check using computer aided design (CAD) software. The test results we presented show constant current stimulation with charge balance error within 0.13% least-significant-bit (LSB). This LSB error was consistent throughout a variety stimulation patterns and electrode load impedances.
dc.identifier

10.1186/s12938-017-0385-0

dc.identifier.issn

1475-925X

dc.identifier.issn

1475-925X

dc.identifier.uri

https://hdl.handle.net/10161/28709

dc.language

eng

dc.publisher

Springer Science and Business Media LLC

dc.relation.ispartof

Biomedical engineering online

dc.relation.isversionof

10.1186/s12938-017-0385-0

dc.subject

Brain

dc.subject

Neurons

dc.subject

Calibration

dc.subject

Equipment Design

dc.subject

Electric Stimulation

dc.subject

Electrodes

dc.subject

Electric Conductivity

dc.title

16-Channel biphasic current-mode programmable charge balanced neural stimulation.

dc.type

Journal article

duke.contributor.orcid

Morizio, James|0000-0002-1463-9257

pubs.begin-page

104

pubs.issue

1

pubs.organisational-group

Duke

pubs.organisational-group

Pratt School of Engineering

pubs.organisational-group

Electrical and Computer Engineering

pubs.organisational-group

Institutes and Provost's Academic Units

pubs.organisational-group

University Institutes and Centers

pubs.organisational-group

Initiatives

pubs.organisational-group

Nicholas Institute for Energy, Environment & Sustainability

pubs.organisational-group

Nicholas Institute for Energy, Environment & Sustainability

pubs.publication-status

Published

pubs.volume

16

Files

Original bundle

Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
16-Channel biphasic current-mode programmable charge balanced neural stimulation.pdf
Size:
2.21 MB
Format:
Adobe Portable Document Format
Description:
Published version