Triple wavelength LED driver for optical brain-computer interfaces

Author

Soraghan, C.J. ; Markham, C. ; Matthews, F. ; Ward, T.E.

Author_Institution

Dept. of Exp. Phys., Nat. Univ. of Ireland, Maynooth

Volume

45

Issue

8

fYear

2009

Firstpage

392

Lastpage

394

Abstract

A dedicated triple wavelength LED driver is presented for optical brain-computer interfacing (BCI). The solution caters for the constraints of a common-anode grounded case and modulation up to several kilohertz that allows source separation of light that has back-scattered from the brain. With total harmonic distortion of 0.95- and a frequency range of ~40-kHz, the driver has application in a continuous wave optical BCI. Other modulation strategies such as time division multiplexing (TDM) are catered for, owing to input DC coupling. Linearity in the optical output is maintained by the -load sensing- differential op-amp on the LED-s current limiting resistor, which is the basis for the V-I conversion.

Keywords

biomedical electronics; biomedical equipment; brain-computer interfaces; differential amplifiers; driver circuits; harmonic distortion; light emitting diodes; operational amplifiers; optical modulation; resistors; time division multiplexing; TDM; V-I conversion; back-scattered light; common-anode grounded case; continuous wave optical BCI; current limiting resistor; division multiplexing; input DC coupling; load sensing differential op-amp; modulation strategy; optical brain-computer interfaces; optical output linearity; source separation; total harmonic distortion; triple wavelength LED driver;

fLanguage

English

Journal_Title

Electronics Letters

Publisher

iet

ISSN

0013-5194

Type

jour

DOI

10.1049/el.2009.0214

Filename

4813152