TY - GEN
T1 - A programmable discharge circuitry with current limiting capability for a retinal prosthesis
AU - Sivaprakasam, Mohanasankar
AU - Liu, Wentai
AU - Wang, Guoxing
AU - Weiland, James D.
AU - Humayun, Mark S.
PY - 2005
Y1 - 2005
N2 - Biphasic stimulation is the most commonly used electrical pattern in FES (Functional Electrical Stimulation). In such cases, a charge balanced waveform is essential to prevent any charge accumulation in the biological tissue. In a retinal prosthesis, a charge cancellation circuitry is used to discharge the stimulation sites on the retina periodically to ensure tissue safety. But discharging a node that has high voltage (due to charge accumulation) will induce large currents that might lead to unintended stimulation of the retina. This paper presents a new discharge circuitry which can act as a simple resistive discharge path for smaller voltages and a current limiter for higher voltages. In stimulation circuits which use a dual voltage scheme (positive and negative), the circuit limits the current at both polarities. The discharge profile is programmable digitally. In addition, a method to characterize inter-pixel leakage in a retinal prosthesis using this circuit is proposed.
AB - Biphasic stimulation is the most commonly used electrical pattern in FES (Functional Electrical Stimulation). In such cases, a charge balanced waveform is essential to prevent any charge accumulation in the biological tissue. In a retinal prosthesis, a charge cancellation circuitry is used to discharge the stimulation sites on the retina periodically to ensure tissue safety. But discharging a node that has high voltage (due to charge accumulation) will induce large currents that might lead to unintended stimulation of the retina. This paper presents a new discharge circuitry which can act as a simple resistive discharge path for smaller voltages and a current limiter for higher voltages. In stimulation circuits which use a dual voltage scheme (positive and negative), the circuit limits the current at both polarities. The discharge profile is programmable digitally. In addition, a method to characterize inter-pixel leakage in a retinal prosthesis using this circuit is proposed.
UR - http://www.scopus.com/inward/record.url?scp=33846915135&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33846915135&partnerID=8YFLogxK
U2 - 10.1109/iembs.2005.1615659
DO - 10.1109/iembs.2005.1615659
M3 - Conference contribution
AN - SCOPUS:33846915135
SN - 0780387406
SN - 9780780387409
T3 - Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings
SP - 5234
EP - 5237
BT - Proceedings of the 2005 27th Annual International Conference of the Engineering in Medicine and Biology Society, IEEE-EMBS 2005
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2005 27th Annual International Conference of the Engineering in Medicine and Biology Society, IEEE-EMBS 2005
Y2 - 1 September 2005 through 4 September 2005
ER -