High-Efficiency Transmission for Medical Implants

Paemel, M. Van

doi:10.1109/mssc.2010.939572

Cited by 19 publications

(13 citation statements)

References 3 publications

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“…Many inductively-coupled applications employ the use of class-E power amplifiers on the primary circuit for high efficiency [12]. However, a class-E amplifier requires very precise knowledge of the load impedance in order to operate properly (and therefore at high efficiency) [13].…”

Section: Architecturementioning

confidence: 99%

Near-Field Wireless Power Transfer

Mercier

Chandrakasan

2015

Integrated Circuits and Systems

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Wireless power transfer links are becoming increasingly important for consumer, industrial, and medical electronic devices. There are two principal applications for wireless power transfer that require different optimization criteria: continuous power deliver (e.g., cochlear implant) and periodic charging (e.g., cellular phone). In the former case, optimizing power transfer efficiency is a metric of great importance, while in the latter case, minimizing charging time by maximizing power transfer is important. This chapter presents analytical equations that predict optimal conditions for both applications through first-principals step-bystep reflected load analysis. These equations are then used as the basis for the design of a rapid wireless ultra-capacitor charging circuit that speeds up time-to-charge by 3.7 .

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Section: Architecturementioning

confidence: 99%

Near-Field Wireless Power Transfer

Mercier

Chandrakasan

2015

Integrated Circuits and Systems

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“…For a proof-of-concept prototype, a Panasonic AQY221R2V solid-state optoelectronic relay was chosen as the switching element, as its on-resistance is 0.75 Ω, its parasitic capacitance is 12.5 pF, and it can safely block 40 V. When turned on, the relay requires approximately 5 mW to operate. 2 Many inductively-coupled applications employ the use of class-E power amplifiers on the primary circuit for high efficiency [28]. However, a class-E amplifier requires very precise knowledge of the load impedance in order to operate properly (and therefore at high efficiency) [20].…”

Section: Multi-tapped Secondary Design a Theorymentioning

confidence: 99%

Rapid Wireless Capacitor Charging Using a Multi-Tapped Inductively-Coupled Secondary Coil

Mercier

Chandrakasan

2013

IEEE Trans. Circuits Syst. I

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Abstract-This paper presents an inductive coupling system designed to wirelessly charge ultra-capacitors used as energy storage elements. Although ultra-capacitors offer the native ability to rapidly charge, it is shown that standard inductive coupling circuits only deliver maximal power for a specific load impedance which depends on coil geometries and separation distances. Since a charging ultra-capacitor can be modeled as an increasing instantaneous impedance, maximum power is thus delivered to the ultra-capacitor at only a single point in the charging interval, resulting in a longer than optimal charging time. Analysis of inductive coupling theory reveals that the optimal load impedance can be modified by adjusting the secondary coil inductance and resonant tuning capacitance. A three-tap secondary coil is proposed to dynamically modify the optimal load impedance throughout the capacitor charging interval. Measurement results show that the proposed architecture can expand its operational range by up to 2.5X and charge a 2.5F ultra-capacitor to 5V upwards of 3.7X faster than a conventional architecture.

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“…For a proper operation on the coil driver, C T must be selected such that the resonate frequency of L P and C T given as f LC = 1/2p/(L P C T ) 0.5 is greater than f O [9]. Due to the physical sizes and the location constraints of the coils in the implants and the EC, the coupling coefficient K C and the Q-factors of the coils are relatively small in our applications.…”

Section: Proposed Coil Drivermentioning

confidence: 99%

“…In this case, the power dissipation on M S is minimized. t on will be equal to the optimal on-time given as t on * and the following condition will be satisfied [9]   …”

Section: Proposed Coil Drivermentioning

confidence: 99%

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A feedback controlled coil driver for transcutaneous power transmission

Lee

2012

Proceedings of the IEEE 2012 Custom Integrated Circuits Conference

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A fully integrated feedback controlled coil driver for transcutaneous power transmission was proposed to power biomedical implants. For a normal power transmission operation, the voltage across the switch that energizes the coil is sampled and compared with ground, followed by an integration to obtain an optimal on-time for the switch such that the coil current was maximized for a given DC input power. The coil driver also provides ASK modulation on the coil current by changing the size of the switch according to the input data. In the normal power transmission operation, a peak-to-peak coil current of ~730mA was obtained with a power dissipation of 71.6mW at 5V.

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High-Efficiency Transmission for Medical Implants

Cited by 19 publications

References 3 publications

Near-Field Wireless Power Transfer

Near-Field Wireless Power Transfer

Rapid Wireless Capacitor Charging Using a Multi-Tapped Inductively-Coupled Secondary Coil

A feedback controlled coil driver for transcutaneous power transmission

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