Neural stimulation interface with ultra-low power signal conditioning circuit for fully-implantable cochlear implants

Ulusan, Hasan
Chamanian, Salar
Zorlu, Ozge
Muhtaroglu, Ali
Külah, Haluk
This paper presents an ultra-low power interface circuit to stimulate auditory nerves through fully-implantable cochlear implants (FICIs). The interface circuit senses signals generated from a multi-frequency piezoelectric sensor array, and generates neural stimulation current according to input sound level. Firstly, piezoelectric sensor output is amplified, and compressed with an ultra-low power logarithmic amplifier (LA). This significantly reduces power by eliminating the compression in the next stages. Then, amplified signal is envelope-detected, and utilized as a reference for stimulation current generation using a voltage controlled current source. Finally, biphasic stimulation current is delivered to the nerves through a switch matrix. The circuit has been designed and fabricated in 180nm high-voltage CMOS technology. 8-channel stimulator dissipates about 667 μW as it generates 110 μA biphasic stimulation current, while the front-end signal conditioning unit dissipates only 51.2 μW.


Fully Implantable Cochlear Implant Interface Electronics With 51.2-mu W Front-End Circuit
Ulusan, Hasan; Chamanian, Salar; Ilik, Bedirhan; Muhtaroglu, Ali; Külah, Haluk (2019-07-01)
This paper presents an ultralow power interface circuit for a fully implantable cochlear implant (FICI) system that stimulates the auditory nerves inside cochlea. The input sound is detected with a multifrequency piezoelectric (PZT) sensor array, is signal-processed through a front-end circuit module, and is delivered to the nerves through current stimulation in proportion to the sound level. The front-end unit reduces the power dissipation by combining amplification and compression of the sensor output thr...
A Pulse-Width Modulated Cochlear Implant Interface Electronics with 513 μW Power Consumption
Yigit, Halil Andac; Ulusan, Hasan; Yüksel, Muhammed Berat; Chamanian, Salar; Çiftci, Berkay ; Koyuncuoglu, Aziz; Muhtaroglu, Ali; Külah, Haluk (2019-07-01)
The fully implantable cochlear implant (FICI) interface circuit proposed in this work senses sound harmonics from 8 different piezoelectric cantilever sensors, and generates pulse width modulated biphasic current outputs to stimulate the auditory neurons. Signals from the piezoelectric sensors are amplified, rectified, and sampled. The sampled voltage is held and converted to current by a novel logarithmic voltage-to-current converter. The current is then digitized with a current comparator to determine the...
Thin Film PZT Acoustic Sensor for Fully Implantable Cochlear Implants
İlik, Bedirhan; Koyuncuoğlu, Aziz; Uluşan, Hasan; Chamanıan, Salar; Işık Akçakaya, Dilek; Şardan Sukas, Özlem; Külah, Haluk (2017-09-06)
This paper presents design and fabrication of a MEMS-based thin film piezoelectric transducer to be placed on an eardrum for fully-implantable cochlear implant (FICI) applications. Resonating at a specific frequency within the hearing band, the transducer senses eardrum vibration and generates the required voltage output for the stimulating circuitry. Moreover, high sensitivity of the sensor, 391.9 mV/Pa @900 Hz, decreases the required power for neural stimulation. The transducer provides highest voltage ou...
Thin-Film PZT based Multi-Channel Acoustic MEMS Transducer for Cochlear Implant Applications
Yüksel, Muhammed Berat; Külah, Haluk (2021-01-01)
AuthorThis paper presents a multi-channel acoustic transducer that works within the audible frequency range (250-5500 Hz) and mimics the operation of the cochlea by filtering incoming sound. The transducer is composed of eight thin film piezoelectric cantilever beams with different resonance frequencies. The transducer is well suited to be implanted in middle ear cavity with an active volume of 5 mm × 5 mm × 0.62 mm and mass of 4.8 mg. Resonance frequencies and piezoelectric outputs of the bea...
Ultra-low power interface electronics design for fully implantable cochlear implants
Uluşan, Hasan; Külah, Haluk; Muhtaroğlu, Ali; Department of Electrical and Electronics Engineering (2018)
Cochlear implants are one of the most successful neural prosthesis where users could go from being profoundly deaf to enjoying high degree of speech perception. However, subsequent aesthetic concerns, damage risks and high power dissipation associated with bulky external units of cochlear implants have redirected recent studies to fully implantable cochlear implants (FICI). Although, implantable sensors occupies the largest portion of the previous researches on FICIs, design of the low powered signal condit...
Citation Formats
H. Ulusan, S. Chamanian, O. Zorlu, A. Muhtaroglu, and H. Külah, “Neural stimulation interface with ultra-low power signal conditioning circuit for fully-implantable cochlear implants,” 2018, Accessed: 00, 2020. [Online]. Available: