Browsing by Author "Chen, Zhi-Xin"

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A 16-Channel CMOS Chopper-Stabilized Analog Front-End Acquisition Circuits for ECoG Detection
(2017-01-01)
Cheng, Cheng-Hsiang
;
Chen, Zhi-Xin
;
Wu, Chung-Yu
;
電子工程學系及電子研究所
;
生醫電子轉譯研究中心
In this paper, a 16-channel analog front-end (AFE) ECoG-signal acquisition circuit for closed-loop seizure control system is presented. It is composed of 16 auto-reset chopper-stabilized capacitive-coupled instrumentation amplifiers (AR-CSCCIA) with band-pass filters, 16 programmable transconductance-gain amplifiers, a multiplexer, a transimpedance amplifier, and a 10-bit SAR ADC. The low input-referred noise is achieved by using chopper modulation technique in AR-CSCCIA. To reduce the undesired effects of chopper modulation, an improved offset reduction loop (ORL) is proposed to reduce output offset generated by input chopper mismatches. The digital ripple reduction loop (RRL) is also used to reduce chopper ripple. Moreover, to prevent from overstress in MOS devices caused by high stimulation voltage, an input protection circuit with high-voltage-tolerant switches is proposed to make the AFE amplifiers sharing the same electrode with high voltage stimulators. The fabricated AFE acquisition circuit has 49.1/59.1/67.9 dB programmable gain and 2.09uV(rms) input referred noise in a bandwidth 0.5-100 Hz. The measured power consumption of AFE is 3.26 uW per channel and the noise efficiency factor (NEF) is 3.78.
A 16-Channel CMOS Chopper-Stabilized Analog Front-End ECoG Acquisition Circuit for a Closed-Loop Epileptic Seizure Control System
(2018-06-01)
Wu, Chung-Yu
;
Cheng, Cheng-Hsiang
;
Chen, Zhi-Xin
;
電子工程學系及電子研究所
;
生醫電子轉譯研究中心
In this paper, a 16-channel analog front-end (AFE) electrocorticography signal acquisition circuit for a closed-loop seizure control system is presented. It is composed of 16 input protection circuits, 16 auto-reset chopper-stabilized capacitive-coupled instrumentation amplifiers (AR-CSCCIA) with bandpass filters, 16 programmable transconductance gain amplifiers, a multiplexer, a transimpedance amplifier, and a 128-kS/s 10-bit delta-modulated successive-approximation-register analog-todigital converter (SAR ADC). In closed-loop seizure control system applications, the stimulator shares the same electrode with the AFE amplifier for effective suppression of epileptic seizures. To prevent from overstress in MOS devices caused by high stimulation voltage, an input protection circuit with a high-voltage-tolerant switch is proposed for the AFE amplifier. Moreover, low input-referred noise is achieved by using the chopper modulation technique in the AR-CSCCIA. To reduce the undesired effects of chopper modulation, an improved offset reduction loop is proposed to reduce the output offset generated by input chopper mismatches. The digital ripple reduction loop is also used to reduce the chopper ripple. The fabricated AFE amplifier has 49.1-/59.4-/67.9-dB programmable gain and 2.02-mu Vrms input referred noise in a bandwidth of 0.59-117 Hz. The measured power consumption of the AFE amplifier is 3.26 mu W per channel, and the noise efficiency factor is 3.36. The in vivo animal test has been successfully performed to verify the functions. It is shown that the proposed AFE acquisition circuit is suitable for implantable closed-loop seizure control systems.
A Fully Integrated 16-Channel Closed-Loop Neural-Prosthetic CMOS SoC With Wireless Power and Bidirectional Data Telemetry for Real-Time Efficient Human Epileptic Seizure Control
(2018-11-01)
Cheng, Cheng-Hsiang
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Tsai, Ping-Yuan
;
Yang, Tzu-Yi
;
Cheng, Wan-Hsueh
;
Yen, Ting-Yang
A 16-channel closed-loop neuromodulation system-on-chip (SoC) for human epileptic seizure control is proposed and designed. In the proposed SoC, a 16-channel neural-signal acquisition unit (NSAU), a biosignal processor (BSP), a 16-channel high-voltage-tolerant stimulator (HVTS), and wireless power and bidirectional data telemetry are designed. In the NSAU, the input protection circuit is used to prevent MOSFET from overstressing by the high-voltage stimulations. Hence, NSAUs can share electrodes with stimulators. The auto-reset chopper-stabilized capacitive-coupled instrumentation amplifiers (AR-CSCCIAs) are designed with the chopper-stabilized technique with a new offset reduction loop. The measured input-referred noise is 2.09 mu V-rms and the noise-efficiency factor (NEF) is 3.78. The entropy-and-spectrum seizure detection algorithm is implemented in the BSP with 0.76-s seizure detection latency and 97.8% detection accuracy. When the seizure onset is detected by the BSP, the HVTS with adaptive supply control delivers 0.5-3-mA biphasic current stimulation to suppress the seizure onset. The proposed SoC is powered wirelessly, and the bidirectional data telemetry is realized through the same pair of coils in 13.56 MHz. The downlink data rate is 211 Kb/s with the binary phase-shift keying (BPSK) modulation and a new BPSK demodulator. The uplink data rate is 106 Kb/s with the load-shift keying (LSK) modulation. The proposed SoC is fabricated in a 0.18-mu m CMOS technology and occupies 25 mm(2). Electrical tests have been performed to characterize the SoC performance. In vivo animal experiments using mini-pigs have been performed to successfully verify the closed-loop neuromodulation functions on epileptic seizure suppression.
A Fully Integrated Closed-Loop Neuromodulation SoC with Wireless Power and Bidirectional Data Telemetry for Real-Time Human Epileptic Seizure Control
(2017-01-01)
Cheng, Cheng-Hsiang
;
Tsai, Ping-Yuan
;
Yang, Tzu-Yi
;
Cheng, Wan-Hsueh
;
Yen, Ting-Yang
This paper presents a 16-channel closed-loop neuromodulation SoC for human seizure control. The SoC includes a 16-ch signal acquisition unit, a bio-signal processor, a 16-ch adaptive stimulator, and wireless telemetry. The signal acquisition unit achieves 3.78 NEF and shares electrodes with stimulator. The seizure detection latency is 0.76s and delivered 0.5-3mA biphasic current stimulation. The SoC is powered wirelessly and bidirectional data telemetry is realized through the same pair of coils in 13.56MHz.