A Dual Band Wireless Power and FSK Data Telemetry for Biomedical Implants

Abstract

A dual-link coil arrangement and a novel digital frequency-shift keying (FSK) demodulator are presented. The primary application of this system is for inductively powered biomedical implants. The implant is provided with data and power via two separate links. Two sets of coils are used in an arrangement such that the magnetic interference between the two pairs is minimized. The demodulator circuitry presented relies solely on delaying elements, utilizing a delayed digital FSK signal to sample the original digital FSK signal. A synchronized clock can be derived from the FSK signals alone, however, by utilizing the power signal to obtain a synchronized clock, a higher data rate and a decrease in complexity of the receiver circuitry can be achieved. The system was implemented on the bench and experimentally tested at a data rate of 2.083 Mbps with zero bit error rate while receiving a 4.17/6.25 MHz FSK carrier signal synchronized with 2.083 MHz clock derived from the power carrier. The power link was set to provide 58mW.

Low-power circuit structures for chip-scale stimulating implants

“…This is particularly true when the incoming signal is a square-wave as is the case for our two-wire interface: the signal level detection has already been done in the active rectifier and the decoding can be carried out with simple digital circuits. Our data receiver [19] is shown in Fig. 5(a).…”

Research on the Key Issues in Power and Data Wireless Transmission of Implantable Medical Devices

“…The communication quality is affected by the interference between the two sets of coils [1][2][3][4][5][6]. Wang et al [4] and Zhou et al [5] adopt orthogonal coils configuration to reduce the interference, whereas it is difficult to completely eliminate interference by using the orthogonal coils configuration.…”

A single-bit sampling demodulator for biomedical implants

“…Inductive links are widely used in this band. While power and data can be transferred through separate links for efficient power transmission [3,4,7,11,12], a single link transferring data and power simultaneously offers a simpler structure [2,5,8,10], which is of great advantage for implantation applications. Fig.…”

“…Both external and implanted units have data modulation and recovery blocks while only the implanted unit includes power recovery block. To transmit data and power simultaneously downlink (from the external unit to the implanted device), constant-amplitude modulation schemes such as pulse-width modulation [2], frequency-shift keying (FSK) [5][6][7] and phase-shift keying (PSK) [8][9][10][11] are often used since they are compatible with rectifier-based power recovery [8].…”