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A wireless magnetic resonance energy transfer system for micro implantable medical sensors.

Li X, Zhang H, Peng F, Li Y, Yang T, Wang B, Fang D - Sensors (Basel) (2012)

Bottom Line: The energy transfer efficiency of the four-coil system is greatly improved compared to the conventional two-coil system.In addition, the output current varies with changes in the distance.The whole implanted part is packaged with PDMS of excellent biocompatibility and the volume of it is about 1 cm(3).

View Article: PubMed Central - PubMed

Affiliation: School of Electronics and Information Engineering, Beijing Jiaotong University, Beijing 100044, China. lixiuhan@bjtu.edu.cn

ABSTRACT
Based on the magnetic resonance coupling principle, in this paper a wireless energy transfer system is designed and implemented for the power supply of micro-implantable medical sensors. The entire system is composed of the in vitro part, including the energy transmitting circuit and resonant transmitter coils, and in vivo part, including the micro resonant receiver coils and signal shaping chip which includes the rectifier module and LDO voltage regulator module. Transmitter and receiver coils are wound by Litz wire, and the diameter of the receiver coils is just 1.9 cm. The energy transfer efficiency of the four-coil system is greatly improved compared to the conventional two-coil system. When the distance between the transmitter coils and the receiver coils is 1.5 cm, the transfer efficiency is 85% at the frequency of 742 kHz. The power transfer efficiency can be optimized by adding magnetic enhanced resonators. The receiving voltage signal is converted to a stable output voltage of 3.3 V and a current of 10 mA at the distance of 2 cm. In addition, the output current varies with changes in the distance. The whole implanted part is packaged with PDMS of excellent biocompatibility and the volume of it is about 1 cm(3).

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Related in: MedlinePlus

(a) The measurement platform of the whole system; (b) The measurement results of the chip input voltage and the chip output voltage.
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f14-sensors-12-10292: (a) The measurement platform of the whole system; (b) The measurement results of the chip input voltage and the chip output voltage.

Mentions: The performance of the whole system is measured on the experimental platform as depicted in Figure 14(a). On the transmitter side, the Class-E amplifier is implemented based on Figure 5 and the input control signal is generated by an Agilent 33120A function generator. The resonant frequency of the Class-E amplifier is adjusted to 750 KHz, equal to the highest η frequency point of the four-coil power transfer system. On the receiver side, the chip, including the rectifier and LDO voltage regulator, follows the receiver coils. The output of the chip is loaded by a resistor of 330 Ω. When the distance between transmitter coils and receiver coils is 2 cm, a 3.28 V of output voltage is obtained. It is equivalent that a power of 33 mW is received. The wave of the chip input voltage and the chip output voltage is depicted as Figure 14(b). In addition, a power of more than 100 mW can be achieved when the distance is decreased, which can meet the power requirements of most reported biomedical implants consume such as artificial retina, intraocular pressure, and neural recording system.


A wireless magnetic resonance energy transfer system for micro implantable medical sensors.

Li X, Zhang H, Peng F, Li Y, Yang T, Wang B, Fang D - Sensors (Basel) (2012)

(a) The measurement platform of the whole system; (b) The measurement results of the chip input voltage and the chip output voltage.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472828&req=5

f14-sensors-12-10292: (a) The measurement platform of the whole system; (b) The measurement results of the chip input voltage and the chip output voltage.
Mentions: The performance of the whole system is measured on the experimental platform as depicted in Figure 14(a). On the transmitter side, the Class-E amplifier is implemented based on Figure 5 and the input control signal is generated by an Agilent 33120A function generator. The resonant frequency of the Class-E amplifier is adjusted to 750 KHz, equal to the highest η frequency point of the four-coil power transfer system. On the receiver side, the chip, including the rectifier and LDO voltage regulator, follows the receiver coils. The output of the chip is loaded by a resistor of 330 Ω. When the distance between transmitter coils and receiver coils is 2 cm, a 3.28 V of output voltage is obtained. It is equivalent that a power of 33 mW is received. The wave of the chip input voltage and the chip output voltage is depicted as Figure 14(b). In addition, a power of more than 100 mW can be achieved when the distance is decreased, which can meet the power requirements of most reported biomedical implants consume such as artificial retina, intraocular pressure, and neural recording system.

Bottom Line: The energy transfer efficiency of the four-coil system is greatly improved compared to the conventional two-coil system.In addition, the output current varies with changes in the distance.The whole implanted part is packaged with PDMS of excellent biocompatibility and the volume of it is about 1 cm(3).

View Article: PubMed Central - PubMed

Affiliation: School of Electronics and Information Engineering, Beijing Jiaotong University, Beijing 100044, China. lixiuhan@bjtu.edu.cn

ABSTRACT
Based on the magnetic resonance coupling principle, in this paper a wireless energy transfer system is designed and implemented for the power supply of micro-implantable medical sensors. The entire system is composed of the in vitro part, including the energy transmitting circuit and resonant transmitter coils, and in vivo part, including the micro resonant receiver coils and signal shaping chip which includes the rectifier module and LDO voltage regulator module. Transmitter and receiver coils are wound by Litz wire, and the diameter of the receiver coils is just 1.9 cm. The energy transfer efficiency of the four-coil system is greatly improved compared to the conventional two-coil system. When the distance between the transmitter coils and the receiver coils is 1.5 cm, the transfer efficiency is 85% at the frequency of 742 kHz. The power transfer efficiency can be optimized by adding magnetic enhanced resonators. The receiving voltage signal is converted to a stable output voltage of 3.3 V and a current of 10 mA at the distance of 2 cm. In addition, the output current varies with changes in the distance. The whole implanted part is packaged with PDMS of excellent biocompatibility and the volume of it is about 1 cm(3).

Show MeSH
Related in: MedlinePlus