A CMOS multichannel electrical stimulation prototype system

Summary In this paper, a buck‐boost converter circuit for wireless power transfer via inductive links in bio‐implantable systems is presented. The idea is based on reusing the power receiver coil to design a regulator. This method employs five switches to utilize the coil inductor in a frequency other than the power‐receiving signal frequency. Reusing the coil inductor decreases the on‐chip regulator area and makes it suitable for bio‐implants. Furthermore, in the proposed technique, the regulator efficiency becomes almost independent of the coil receiving voltage amplitude. The proposed concept is employed in a buck‐boost regulator, and simulation results are provided. For a 10 MHz received signal with the amplitude variation within 3 ~ 6 V and with the converter switching rate of 200 kHz, the achieved maximum efficiency is 78%. The proposed regulator can also deliver 10 μA to 4 mA to its load while its output voltage varies from 0.6 to 2.3 V. Simulations of the proposed converter are performed in Cadence‐Spectre using TSMC 0.18 μm CMOS technology. Copyright © 2017 John Wiley & Sons, Ltd.

Section: Simulation Resultsmentioning

confidence: 99%

“…For this to be realized, several solutions have been already reported. The traditional alternative is to employ a linear regulator at the rectifier output . The variation of the regulator input voltage level is the main problem in this method.…”

Section: Introductionmentioning

confidence: 99%

A power efficient buck‐boost converter by reusing the coil inductor for wireless bio‐implants

Barati

Yavari

2017

“…In the technology‐filled and information‐filled lifestyles today, battery‐powered electronics are essential to everyone's life. From mobile learning devices to implantable biomedical monitor to remote sensors , the limited energy sources have been one of the most difficult design challenges for the circuit designers. On one hand, to provide fast‐responding performance, large biasing current is necessary.…”

Section: Introductionmentioning

confidence: 99%

Digitally‐assisted constant‐on‐time dynamic‐biasing technique for bandwidth and slew‐rate enhancement in ultra‐low‐power low‐dropout regulator

Guo

Leung

et al. 2015

SUMMARYA digitally-assisted constant-on-time dynamic-biasing (COT-DB) technique has been proposed to enable significant enhancement in dynamic performances, while the average current consumption can be kept to ultralow level. This dynamic-biasing technique has a predefined magnitude and duration on biasing current boost, which is beneficial to estimate power budget in systems with finite energy source. The proposed technique has been applied to a low-dropout regulator (LDO) to demonstrate the effectiveness. Experimental results show that significant improvements in settling times during load-transients and line-transients are as much as 880×, while the current consumption is only 1.02 μA. In fact, for the same dynamic performances, the average current consumption of LDO with COT-DB technique can be as low as 0.39% of the LDO with heavy static biasing. The digitally-assisted implementation of the technique also allows robust augmentation of the technique onto almost all analog systems.

“…Recently, Louis et al [19] have developed a multi-chip neurostimulator based on two-wire protocol for visual prosthesis, but the authors have generalized the application and considered electrode impedance up to 60 kΩ only. The design and implementation of a complete wireless microstimulation prototype for retinal prosthesis have been reported in [20] by Cihun et al The used electrode impedance by this system is only 10 kΩ.…”

Section: Introductionmentioning

confidence: 99%

High‐voltage compliant microelectrode array drivers for intracortical microstimulation

Hasanuzzaman

Raut

2015

SUMMARYWe present in this paper two low-power high-impedance microelectrode array drivers (MEDs) dedicated for visual intracortical microstimulation. These output stages of a new microstimulator are highly configurable and able to deliver higher compliance voltage (20 V for anodic and cathodic phases) across microelectrode-tissue interface impedance compared with previously reported designs. Each MED is featured with a high-voltage switch-matrix, 3.3 V/20 V current mirrors, an on-chip 32-bit serial-in parallel-out shift register, and the new forbidden state logic circuits. Both systems are able to deliver eight bipolar or 16 monopolar stimulation simultaneously. The first MED is able to deliver one stimulation current level and the second one provides four different current amplitudes simultaneously to 16 electrodes. Two microchips have been designed and fabricated using Teledyne DALSA 0.8 μm 5V/20V double-diffused metal-oxidesemiconductor field-effect transistor (Teledyne DALSA Semiconductor, Bromont, Québec, Canada) technology to meet the required high-voltage compliance. The nominal values of largest supply voltages are ±10 V. The maximum stimulation current per input channel is 400 μA and per output channel through an emulated microelectrode impedance of 100 kΩ is 100 μA. The measured output compliance voltage is 10 V/phase (anodic or cathodic) for the specified supply voltages. Increment of supply voltages to ±13 V allows 220 μA stimulation current per output channel enhancing the output compliance voltage up to 20 V/phase. The measured quiescent power consumptions of the proposed microelectrode array drivers are 316 and 735 μW, respectively. Post-layout simulation and measurement results of two MEDs and comparison with other designs have been reported in this paper.