Browsing by Author "Cheng, Ming-Seng"

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A 13.56 MHz 40 mW CMOS High-Efficiency Inductive Link Power Supply Utilizing On-Chip Delay-Compensated Voltage Doubler Rectifier and Multiple LDOs for Implantable Medical Devices
(2014-11-01)
Wu, Chung-Yu
;
Qian, Xin-Hong
;
Cheng, Ming-Seng
;
Liang, Yu-An
;
Chen, Wei-Ming
In this paper, a 13.56 MHz CMOS near-field inductive link power supply (ILPS) that can deliver 20 mA output current for implantable medical devices (IMDs) is proposed and fabricated. In the proposed ILPS, the pair of inductive link coils is constructed in the spiral shape with a ferrite core to save space and increase efficiency. Experimental results have shown that the near-field coils can transmit power at the resonant frequency of 13.56 MHz with the transmission efficiency up to 76.3%. The CMOS power regulator is composed of active voltage doubler rectifier (VD) and low-dropout regulators (LDOs). In the active VD with the comparator, the input offset voltage is adjustable for delay compensation and a start-up control circuit is added to achieve robust start-up mechanism. On-chip delay compensation control with SR-latches is proposed to prevent from error glitch switching on offset voltage control and achieve accurate delay compensation so that the reverse current conduction can be avoided and the efficiency can be increased. Three fully-integrated LDOs with rectifier output voltage of 2 V to 1.8 V are realized for analog (ALDO), digital (DLDO), and reference-voltage (RLDO) circuits. Thus the performance of individual LDO can be optimized. The measured output ripple voltage of the active VD is 10.4 mV. The power conversion efficiency (PCE) is 85% under 20 mA output current. The measured dropout voltage is 384 mV. As compared with other designs, the proposed ILPS has lower ripple voltages, lower dropout voltage, and higher PCE.
A CMOS 13.56-MHz High-Efficiency Low-Dropout-Voltage 40-mW Inductive Link Power Supply Utilizing On-Chip Delay-Compensated Voltage Doubler Rectifier and Multiple LDOs for Implantable Medical Devices
(2013)
Qian, Xin-Hong
;
Cheng, Ming-Seng
;
Wu, Chung-Yu
;
電子物理學系
;
Department of Electrophysics
A near-field 13.56-MHz 20mA inductive energy transmission device with ferrite core spiral coils and CMOS power regulator is designed and tested. The power regulator is composed of active voltage doubler (VD) rectifier and low-dropout regulators (LDOs). In order to avoid large space requirement of coil and further increase its efficiency in the implantable medical devices (IMDs), the coils are constructed in the spiral shape with a ferrite core. In the VD with the comparator, the input offset voltage is adjustable for delay compensation and a start-up control circuit is added to achieve robust start-up mechanism. On-chip delay compensation control is implemented to prevent from reverse current conduction and increase the efficiency. Three fully-integrated LDOs with rectifier output voltage of 2V to 1.8V are realized: LDO for analog circuits (ALDO), LDO for digital circuits (DLDO) and LDO for reference-voltage circuits (RLDO). Thus the performance of individual LDO can be optimized. Both ALDO and RLDO have low crosstalk noise from DLDO. The measured ripple voltage of rectifier output is 10.4mV. The power conversion efficiency (PCE) of 85% with 20mA output current. The measured dropout voltage is 384mV. As compared with other designs, the proposed Inductive link power supply has lower ripple voltages and dropout voltage, and higher PCE.
A Fully Integrated 8-Channel Closed-Loop Neural-Prosthetic CMOS SoC for Real-Time Epileptic Seizure Control
(2014-01-01)
Chen, Wei-Ming
;
Chiueh, Herming
;
Chen, Tsan-Jieh
;
Ho, Chia-Lun
;
Jeng, Chi
An 8-channel closed-loop neural-prosthetic SoC is presented for real-time intracranial EEG (iEEG) acquisition, seizure detection, and electrical stimulation in order to suppress epileptic seizures. The SoC is composed of eight energy-efficient analog front-end amplifiers (AFEAs), a 10-b delta-modulated SAR ADC (DMSAR ADC), a configurable bio-signal processor (BSP), and an adaptive high-voltage-tolerant stimulator. A wire-less power-and-data transmission system is also embedded. By leveraging T-connected pseudo-resistors, the high-pass (low-pass) cutoff frequency of the AFEAs can be adjusted from 0.1 to 10 Hz (0.8 to 7 kHz). The noise-efficiency factor (NEF) of the AFEA is 1.77, and the DMSAR ADC achieves an ENOB of 9.57 bits. The BSP extracts the epileptic features from time-domain entropy and frequency spectrum for seizure detection. A constant 30-mu A stimulus current is delivered by closed-loop control. The acquired signals are transmitted with on-off keying (OOK) modulation at 4 Mbps over the MedRadio band for monitoring. A multi-LDO topology is adopted to mitigate the interferences across different power domains. The proposed SoC is fabricated in 0.18-mu m CMOS and occupies 13.47 mm(2). Verified on Long Evans rats, the proposed SoC dissipates 2.8 mW and achieves high detection accuracy 92% within 0.8 s.
A Fully Integrated 8-Channel Closed-Loop Neural-Prosthetic SoC for Real-Time Epileptic Seizure Control
(2013-01-01)
Chen, Wei-Ming
;
Chiueh, Herming
;
Chen, Tsan-Jieh
;
Ho, Chia-Lun
;
Jeng, Chi