Publications
274 results found
Constandinou TG, Georgiou J, 2008, A Micropower Arcsine Circuit for Tilt Processing, Electronics Letters, Vol: 44, Pages: 1336-1338, ISSN: 0013-5194
This letter describes an analogue circuit for producing an arcsine transfer based on a differential pair with source degeneration. The application uses this circuit to post-process an accelerometer signal by normalising with respect to the gravitational acceleration vector to extract inclination. Using diode-connected MOS devices operating in weak inversion, the appropriate trigonometric function, i.e. an arcsine, has been realised to compute tilt. The hardware has been implemented in AMS 0.35μm 2P4M CMOS technology.
Constandinou TG, Georgiou J, Toumazou C, 2008, A Partial-Current-Steering Biphasic Stimulation Driver for Vestibular Prostheses, IEEE Transactions on Biomedical Circuits and Systems, Vol: 2, Pages: 106-113, ISSN: 1932-4545
This paper describes a novel partial-current-steering stimulation circuit for implantable vestibular prostheses. The drive hardware momentarily delivers a charge-balanced asymmetric stimulus to a dummy load before steering towards the stimulation electrodes. In this fashion, power is conserved while still gaining from the benefits of current steering. The circuit has been designed to be digitally programmable as part of an implantable vestibular prosthesis. The hardware has been implemented in AMS 0.35μm 2P4M CMOS technology.
Constandinou TG, Georgiou J, Toumazou C, 2008, Micropower front-end interface for differential-capacitive sensor systems, Electronics Letters, Vol: 44, Pages: 470-472, ISSN: 0013-5194
A front-end circuit for interfacing to differential capacitive sensors, including certain microelectromechanical systems, is presented. The system combines a self-resetting, biphasic integrator with a difference timer, producing a word parallel output representing the differential capacitance. The measurable capacitance range is tunable by means of an input current bias and system clock frequency. For an input bias of 10 nA and system clock of 128 KHz, the measurable capacitance range is +/-5pF (to 8 bit resolution) consuming below 26 µW total system power.
Prodromakis T, Georgiou P, Constandinou TG, et al., 2008, Batch Encapsulation Technique for CMOS based Chemical Sensors, IEEE Biomedical Circuits and Systems (BioCAS) Conference, Publisher: IEEE, Pages: 321-324
Constandinou TG, Georgiou J, 2008, Micro-Optoelectromechanical Tilt Sensor, Journal of Sensors, Pages: 1-7, ISSN: 1687-725X
This paper presents a novel hybrid CMOS/MEMS tilt sensor with a 5∘ resolution over a 300∘ range. The device uses a MEMS-based semicircular mass suspended from a rigid body, projecting a shadow onto the CMOS-based optical sensor surface. A one-dimensional photodiode array arranged as a uniformly segmented ring is then used to determine the tilt angle by detecting the position of the semicircular mass. The complete sensor occupies an area of under 2.5 mm × 2.5 mm.
Constandinou TG, Georgiou J, Toumazou C, 2008, Towards an Integrated, Fully-Implantable Vestibular Prosthesis for Balance Restoration, Journal of Advances in Science and Technology, Vol: 57, Pages: 210-215
Neuroprosthetics is a relatively new topic but it has already shown its potential. Since the application of this science, it has already significantly improved the quality of life of over 60,000 individuals who previously suffered from severely impaired hearing or total deafness. Today, through use of cochlear implants, children born totally deaf can enjoy going to regular schools and communicating normally. Individuals suffering from dizziness and balance disorders can also benefit from the progress made in cochlear prosthetics. The inner ear's vestibular system provides cues about self-motion and help stabilise vision during movement. Damage to this system can result in dizziness, imbalance, blurred vision and instability in locomotion, a leading cause of death in the elderly. We propose a hybrid CMOS/MEMS platform for bypassing a dysfunctional pathway in individuals that suffer from balance-related disorders. Combining MEMS-based inertia sensing with CMOS-based neural monitoring and processing electronics, this prosthesis aims to deliver a corrective artificial stimulus to the vestibulocochlear (VIII) nerve. We describe a novel system outlining the architectural aspects and implementation methodology used in the design.
Constandinou TG, Georgiou J, Andreou C, 2008, An Ultra-Low-Power Micro-Optoelectromechanical Tilt Sensor, IEEE International Symposium on Circuits and Systems (ISCAS), Pages: 3158-3161
Constandinou TG, Georgiou J, Toumazou C, 2008, A Micropower Front-end Interface for Differential-Capacitive Sensor Systems, IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: IEEE, Pages: 2474-2477
Constandinou TG, Georgiou J, Toumazou C, 2008, A Partial-Current-Steering Biphasic Stimulation Driver for Neural Prostheses, IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: IEEE, Pages: 2506-2509
Constandinou TG, Georgiou J, Toumazou C, 2008, A Fully-Integrated Semicircular Canal Processor for an Implantable Vestibular Prosthesis, IEEE International Conference on Electronics, Circuits and Systems (ICECS), Publisher: IEEE, Pages: 81-84
Lande TS, Constandinou TG, Burdett A, et al., 2007, Running cross-correlation using bitstream processing, Electronics Letters, Vol: 43, Pages: 1181-1183, ISSN: 0013-5194
A novel architecture for running cross-correlation and convolution using bitstream processing is proposed. The computationally intensive multiplications inherent in cross-correlation and convolution are replaced by simple logic operations (AND XOR) using bitstream representation. The reduced complexity enables compact and energy efficient silicon solutions suitable for small, portable devices such as wearable heartbeat detecting electronics embedded in the actual ECG patch.
Triantis IF, Woods V, Eftekhar A, et al., 2007, Advances in Neural Interfacing, IEEE Circuits and Systems Society Newsletter, Vol: 1
Constandinou TG, Georgiou J, Doumanidis CC, et al., 2007, Towards an Implantable vestibular prosthesis: The surgical challenges, 3rd International IEEE/EMBS Conference on Neural Engineering, Publisher: IEEE, Pages: 40-+
Li X, Constandinou TG, Eftekhar A, et al., 2007, Towards a bionic neural link for implantable prosthetics, IEEE EMBS Conference on Neural Engineering, Publisher: Institute of Electrical and Electronics Engineers (IEEE), Pages: 85-88
Georgiou P, Triantis IF, Constandinou TG, et al., 2007, Spiking Chemical Sensor (SCS): A new platform for neuro-chemical sensing, IEEE EMBS Conference on Neural Engineering, Publisher: Institute of Electrical and Electronics Engineers (IEEE), Pages: 126-129
Georgiou J, Constandinou TG, Toumazou C, 2007, A Micropower Cochlear Prosthesis System Demonstrator, IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: Institute of Electrical and Electronics Engineers (IEEE), Pages: 1219-1219
Eftekhar A, Constandinou TG, Triantis IF, et al., 2007, Towards a Reconfigurable Sense-and-Stimulate Neural Interface Generating Biphasic Interleaved Stimulus, 3rd International IEEE/EMBS Conference on Neural Engineering (CNE), Publisher: IEEE, Pages: 438-441
Georgiou P, Constandinou TG, Toumazou C, 2006, Low-power spiking chemical pixel sensor, Electronics Letters, Vol: 42, Pages: 1331-1332, ISSN: 0013-5194
Degenaar P, Constandinou TG, Toumazou C, 2006, Adaptive ON-OFF spiking photoreceptor, Electronics Letters, Vol: 42, Pages: 196-198, ISSN: 0013-5194
An adaptive spike generator circuit for intelligent vision chips is presented. A pulse frequency modulation spike encoder, capable of providing very high dynamic ranges with power consumption similar to an animal retina, has been developed. The circuit is inspired by the ON-OFF opponency algorithm used by the human eye.
Constandinou TG, Toumazou C, 2006, A micropower centroiding vision processor, Solid-State Circuits, IEEE Journal of, Vol: 41, Pages: 1430-1443, ISSN: 0018-9200
constandinou TG, Degenaar P, Toumazou C, 2006, An adaptable foveating vision chip, 2006 IEEE International Symposium on Circuits and Systems, Publisher: IEEE, Pages: 3566-3569
Constandinou TG, Toumazou C, 2006, A Micropower Vision Processor for Parallel Object Positioning and Sizing, IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: Institute of Electrical and Electronics Engineers (IEEE), Pages: 943-946
Constandinou TG, 2005, Bio-inspired Electronics for Micropower Vision Processing, PhD Thesis, London, UK, Publisher: Imperial College of Science, Technology and Medicine, University of London
Constandinou TG, 2005, ORASIS Algorithm Simulator, United Kingdom, Publisher: Imperial College London
Constandinou TG, Toumazou C, 2004, Neuromorphic electronics for real-time biomedical image processing, The Neuromorphic Engineer, Vol: 1
Constandinou TG, Degenaar P, Bradley D, et al., 2004, An on/off spiking photoreceptor for adaptive ultrafast/ultrawide dynamic range vision chips, IEEE Workshop on Biomedical Circuits and Systems (BioCAS), Publisher: Institute of Electrical and Electronics Engineers (IEEE), Pages: 9-12
Constandinou TG, Georgiou J, Toumazou C, 2004, A nano-power tuneable edge-detection circuit, New York, IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: IEEE, Pages: 449-452
Constandinou TG, Georgiou J, Toumazou C, 2004, Towards a bio-inspired mixed-signal retinal processor, New York, IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: Institute of Electrical and Electronics Engineers (IEEE), Pages: 493-496
Constandinou TG, Georgiou J, Toumazou C, 2003, Nano-power mixed-signal tunable edge-detection circuit for pixel-level processing in next generation vision systems, Electronics Letters, Vol: 39, Pages: 1774-1776, ISSN: 0013-5194
A useful nano-power circuit is presented for edge detection in integrated vision systems. Based on a compact front-end of only five MOS devices, this circuit features a tunable threshold and discrete output and is ideal for interfacing to digital electronics.
Constandinou TG, 2003, Stepper Motors Uncovered (2), Elektor Electronics, Vol: 2003, ISSN: 0268-4519
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