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28.4 A high-Q resonant inductive link transmit modulator/driver for enhanced power and FSK/PSK data transfer using adaptive-predictive phase-continuous switching fractional-capacitance tuning

28.4 A high-Q resonant inductive link transmit modulator/driver for enhanced power and FSK/PSK data transfer using adaptive-predictive phase-continuous switching fractional-capacitance tuning
28.4 A high-Q resonant inductive link transmit modulator/driver for enhanced power and FSK/PSK data transfer using adaptive-predictive phase-continuous switching fractional-capacitance tuning

As well as transferring power, inductively coupled systems such as RFID and wireless charging commonly require a downlink channel to transfer data to the receiving function, for simplicity usually using the same carrier frequency used for the power transfer. A high-Q resonant transmitter coil is highly desirable to create the strong magnetic field required fora practical operating range. However, this not only raises major problems with sensitivity to tolerances and environmental factors, but also seriously restricts the available bandwidth and hence downlink data-rate. Amplitude Shift or On-Off Keying (ASK/OOK) are commonly used to allow simple demodulation, but in addition to the 0 factor restricting the data-rate, the average power transfer will be reduced by around 50%. Frequency Shift Keying (FSK) or Phase Shift Keying (PSK) are attractive inasmuch as the nominally constant envelope provides a potentially higher power throughput, but the data-rate issue with a high-Q transmitter still remains. This is obvious for FSK, where by definition operation cannot be maintained away from the transmitter antenna's resonance frequency. Less obviously, for PSK applied to a nominally constant frequency carrier, the stored energy in the transmit tuned circuit will slow the phase transitions making demodulation more difficult; for binary PSK the amplitude will also drop significantly at each symbol transition. Note that the receiver 0 factor is usually lower to avoid the need for active tuning in a micropower circuit.

444-446
IEEE
Kennedy, Henry
c5126d0a-7d40-4c1b-95fd-412700da946f
Bodnar, Rares
37f4be97-985b-401d-bd9a-a4d3caf007e9
Lee, Teerasak
dc9a50a6-f921-4a0d-b34e-ccea3403babc
Redman-White, William
d5376167-c925-460f-8e9c-13bffda8e0bf
Kennedy, Henry
c5126d0a-7d40-4c1b-95fd-412700da946f
Bodnar, Rares
37f4be97-985b-401d-bd9a-a4d3caf007e9
Lee, Teerasak
dc9a50a6-f921-4a0d-b34e-ccea3403babc
Redman-White, William
d5376167-c925-460f-8e9c-13bffda8e0bf

Kennedy, Henry, Bodnar, Rares, Lee, Teerasak and Redman-White, William (2019) 28.4 A high-Q resonant inductive link transmit modulator/driver for enhanced power and FSK/PSK data transfer using adaptive-predictive phase-continuous switching fractional-capacitance tuning. In 2019 IEEE International Solid-State Circuits Conference, ISSCC 2019. vol. 2019-February, IEEE. pp. 444-446 . (doi:10.1109/ISSCC.2019.8662329).

Record type: Conference or Workshop Item (Paper)

Abstract

As well as transferring power, inductively coupled systems such as RFID and wireless charging commonly require a downlink channel to transfer data to the receiving function, for simplicity usually using the same carrier frequency used for the power transfer. A high-Q resonant transmitter coil is highly desirable to create the strong magnetic field required fora practical operating range. However, this not only raises major problems with sensitivity to tolerances and environmental factors, but also seriously restricts the available bandwidth and hence downlink data-rate. Amplitude Shift or On-Off Keying (ASK/OOK) are commonly used to allow simple demodulation, but in addition to the 0 factor restricting the data-rate, the average power transfer will be reduced by around 50%. Frequency Shift Keying (FSK) or Phase Shift Keying (PSK) are attractive inasmuch as the nominally constant envelope provides a potentially higher power throughput, but the data-rate issue with a high-Q transmitter still remains. This is obvious for FSK, where by definition operation cannot be maintained away from the transmitter antenna's resonance frequency. Less obviously, for PSK applied to a nominally constant frequency carrier, the stored energy in the transmit tuned circuit will slow the phase transitions making demodulation more difficult; for binary PSK the amplitude will also drop significantly at each symbol transition. Note that the receiver 0 factor is usually lower to avoid the need for active tuning in a micropower circuit.

Text
28.4 A High-Q Resonant Inductive Link Transmit ModulatorDriver for Enhanced Power and FSKPSK Data Transfer Using Adaptive-Predictive Phase-Continuous Switching Fractional-Capacitance Tuning - Accepted Manuscript
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More information

Accepted/In Press date: 17 February 2019
Published date: 6 March 2019
Venue - Dates: 2019 IEEE International Solid-State Circuits Conference, ISSCC 2019, San Francisco, United States, 2019-02-17 - 2019-02-21

Identifiers

Local EPrints ID: 430067
URI: https://eprints.soton.ac.uk/id/eprint/430067
PURE UUID: a208de34-f127-4820-96b3-afa0579eab4a

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Date deposited: 11 Apr 2019 16:30
Last modified: 14 May 2019 16:30

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