UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

An Implantable Stimulator with Safety Sensors in Standard CMOS Process for Active Books

Liu, X; Valente, V; Zong, Z; Jiang, D; Donaldson, N; Demosthenous, A; (2016) An Implantable Stimulator with Safety Sensors in Standard CMOS Process for Active Books. IEEE Sensors Journal , 16 (19) pp. 7161-7172. 10.1109/JSEN.2016.2577688. Green open access

[thumbnail of 07486019.pdf]
Preview
Text
07486019.pdf

Download (6MB) | Preview

Abstract

This paper presents a second-generation integrated circuit for the Active Books neural stimulation microsystem. It provides multi-channel stimulation with versatile control of stimulation profiles and reduced crosstalk from other stimulation channels. The new design features enhanced safety by monitoring the temperature and humidity inside the micropackage, and the peak electrode voltage at any stimulating electrode. The humidity sensor uses an interdigitated capacitor covered by a passivation layer and a polyimide covering. To boost sensitivity in the operating range of interest, the temperature sensor uses a temperature-insensitive current that is subtracted from a proportional-to-absolute-temperature current. A 3-b analog-todigital converter is used to record the peak electrode voltage. All sensor data is sent to an implanted central hub using bidirectional connection with error checking. Both the stimulation electronics and sensors are integrated on a 6.2 mm × 4 mm silicon die using XFAB's 0.6-μm CMOS high-voltage process. No post-processing steps are involved. The stimulator uses a fivewire cable to provide the power supply and bidirectional data signals. The chip operates from a 7.5-18 V power supply and can generate stimulation currents of 1 mA, 4 mA or 8 mA with a pulse duration of 2 μs-1.07 ms. The humidity sensor output varies linearly with relative humidity (RH) with a normalized sensitivity of 0.04%/%RH over the range of 20-90%RH. The temperature sensor has a nonlinearity of 0.4% over the range of 20-90 °C and a resolution of 0.12 °C. The stimulator is the first of its kind to include integrated temperature and humidity sensors. Index Terms-Active Books, humidity sensor, implant safety, integrated stimulator, temperature sensor, voltage sensor.

Type: Article
Title: An Implantable Stimulator with Safety Sensors in Standard CMOS Process for Active Books
Open access status: An open access version is available from UCL Discovery
DOI: 10.1109/JSEN.2016.2577688
Publisher version: http://dx.doi.org/10.1109/JSEN.2016.2577688
Language: English
Additional information: This work is licensed under a Creative Commons Attribution 3.0 License. For more information, see http://creativecommons.org/licenses/by/3.0/
Keywords: Temperature sensors, Humidity, Electrodes, Temperature measurement, Safety, Metals
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Med Phys and Biomedical Eng
URI: https://discovery.ucl.ac.uk/id/eprint/1504847
Downloads since deposit
103Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item