Browsing by Author "Wang, Sung-Hao"

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Design and In Vivo Verification of a CMOS Bone-Guided Cochlear Implant Microsystem
(2019-11-01)
Qian, Xin-Hong
;
Wu, Yi-Chung
;
Yang, Tzu-Yi
;
Cheng, Cheng-Hsiang
;
Chu, Hsing-Chien
Objective: To develop and verify a CMOS bone-guided cochlear implant (BGCI) microsystem with electrodes placed on the bone surface of the cochlea and the outside of round window for treating high-frequency hearing loss. Methods: The BGCI microsystem consists of an external unit and an implanted unit. The external system-on-chip is designed to process acoustic signals through an acquisition circuit and an acoustic DSP processor to generate stimulation patterns and commands that are transmitted to the implanted unit through a 13.56 MHz wireless power and bidirectional data telemetry. In the wireless power telemetry, a voltage doubler/tripler (2X/3X) active rectifier is used to enhance the power conversion efficiency and generate 2 and 3 V output voltages. In the wireless data telemetry, phase-locked loop based binary phase-shift keying and load-shift keying modulators/demodulators are adopted for the downlink and uplink data through high-Q coils, respectively. The implanted chip with four-channel high-voltage-tolerant stimulator generates biphasic stimulation currents up to 800 mu A. Results: Electrical tests on the fabricated BGCI microsystem have been performed to verify the chip functions. The in vivo animal tests in guinea pigs have shown the evoked third wave of electrically evoked auditory brainstem response waveforms. It is verified that auditory nerves can be successfully stimulated and acoustic hearing can be partially preserved. Conclusion and Significance: Different from traditional cochlear implants, the proposed BGCI microsystem is less invasive, preserves partially acoustic hearing, and provides an effective alternative for treating high-frequency hearing loss.
The Design of CMOS 13.56-MHz High Efficiency 1X/3X 1.99V/6.29V Active Rectifier for Implantable Neuromodulation Systems
(2018-01-01)
Wang, Sung-Hao
;
Lee, Yueh-Hsuan
;
Qian, Xin-Hong
;
Wu, Chung-Yu
;
電子工程學系及電子研究所
A 13.56MHz high efficiency CMOS 1X/3X active rectifier with a novel active triple-voltage(3X) rectifier is proposed and verified. The proposed rectifier is specially designed for medical implant systems. It provides 1X/3X dual output voltage (1.99V and 6.29V) allowing the implantable neuromodulation system to operate with high power conversion efficiency (PCE) while stimulating simultaneously. A start-up control circuit is also added to achieve robust start-up mechanism. On-chip delay compensation control is implemented to increase the conduction time, avoid reverse current, and enhance the efficiency. In addition, the rectifier can sustain a higher input inductive voltage without the overstress problem by adding cascode power transistors. The measured dual output voltages of the 1X/3X rectifier are 1.99V and 6.29V while the input inductive voltage is 2.75V. The proposed rectifier achieves 84.2% in PCE with total 57mW output power under 13.56 MHz operation frequency. Based on its capability to provide large output voltage for stimulation with high PCE, the proposed 1X/3X active rectifier is suitable for implantable neuro-modulation systems.