High-efficiency CMOS rectifier with minimized leakage and threshold cancellation features for low power bio-implants

Desmulliez

2019

Micromachines

Self Cite

The optimization, manufacturing, and performance characterization of a miniaturized 3D receiver (RX)-based wireless power transfer (WPT) system fed by a multi-transmitter (multi-TX) array is presented in this study for applications in capsule endoscopy (CE). The 200 mm outer diameter, 35 μm thick printed spiral TX coils of 2.8 g weight, is manufactured on a flexible substrate to enable bendability and portability of the transmitters by the patients. The 8.9 mm diameter—4.8 mm long, miniaturized 3D RX—includes a 4 mm diameter ferrite road to increase power transfer efficiency (PTE) and is dimensionally compatible for insertion into current endoscopic capsules. The multi-TX is activated using a custom-made high-efficiency dual class-E power amplifier operated in subnominal condition. A resulting link and system PTE of 1% and 0.7%, respectively, inside a phantom tissue is demonstrated for the proposed 3D WPT system. The specific absorption rate (SAR) is simulated using the HFSSTM software (15.0) at 0.66 W/kg at 1 MHz operation frequency, which is below the IEEE guidelines for tissue safety. The maximum variation in temperature was also measured as 1.9 °C for the typical duration of the capsule’s travel in the gastrointestinal tract to demonstrate the patients’ tissues safety.

Section: Resultsmentioning

confidence: 99%

Towards a Miniaturized 3D Receiver WPT System for Capsule Endoscopy

Desmulliez

2019

Micromachines

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“…The power efficiency of 63% and 60% is recorded at 1 MHz operation frequency for the rectifier and regulator circuit, respectively. Application specific integrated circuit (ASIC) of the regulator [33]- [35] and rectifier [36], [37] circuits can offer efficiency of more than 87%. In addition, the efficiency of the WPT link could be increased to more than 85% by increasing the operation frequency to 10 MHz.…”

Section: Discussionmentioning

confidence: 99%

Implementation of a Dual Wireless Power Transfer and Rotation Monitoring System for Prosthetic Hands

Desmulliez

2019

IEEE Access

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This article presents the design, manufacture and test of an inductively coupled wireless power transfer (WPT) system used as a power source for prosthetic hands. Prosthetic hands are the most common artificial limbs among the physically disabled population. Limited storage capacity of the battery places severe limitations regarding the continuous use of this device. A WPT link is therefore proposed to supply power to such devices. The WPT system consists of a transmitter circuit (class-E power amplifier) and WPT coils along with commercially available receiver circuit and multiple motors. Assessment of the unwanted heating of the human tissue due to wireless power transfer was simulated using the commercial electromagnetic simulator ANSYS HFSS TM . Results were experimentally validated by measuring in real-time temperature variations inside a phantom mimicking the properties of human muscle. Monitoring and control the rotation of the prosthetic hand was also demonstrated utilizing rotation-dependent wireless power transfer parameters. The WPT scheme proposed serves therefore the dual property of providing power to the prosthetic limb whilst monitoring the wrist rotation. INDEX TERMSClass-E power amplifier, prosthetic hand, power transfer efficiency, sub-nominal condition, specific absorption rate.

“…Therefore, the lower efficiency of the rectifier can reduce the overall system efficiency of the WPT. To overcome this challenge several application specific integrated circuit (ASIC)-based high efficiency rectifiers have been proposed in offering 93.6% [103], 87% [104] and 86% [105] efficiencies for MIDs.…”

Section: System Designmentioning

confidence: 99%

Wireless Power Transfer Techniques for Implantable Medical Devices: A Review

Pavuluri

Cummins

et al. 2020

Sensors

Self Cite

172

Wireless power transfer (WPT) systems have become increasingly suitable solutions for the electrical powering of advanced multifunctional micro-electronic devices such as those found in current biomedical implants. The design and implementation of high power transfer efficiency WPT systems are, however, challenging. The size of the WPT system, the separation distance between the outside environment and location of the implanted medical device inside the body, the operating frequency and tissue safety due to power dissipation are key parameters to consider in the design of WPT systems. This article provides a systematic review of the wide range of WPT systems that have been investigated over the last two decades to improve overall system performance. The various strategies implemented to transfer wireless power in implantable medical devices (IMDs) were reviewed, which includes capacitive coupling, inductive coupling, magnetic resonance coupling and, more recently, acoustic and optical powering methods. The strengths and limitations of all these techniques are benchmarked against each other and particular emphasis is placed on comparing the implanted receiver size, the WPT distance, power transfer efficiency and tissue safety presented by the resulting systems. Necessary improvements and trends of each WPT techniques are also indicated per specific IMD.