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A self-tuning resonant-inductive-link transmit driver using quadrature symmetric delay trimmable phase-switched fractional capacitance

A self-tuning resonant-inductive-link transmit driver using quadrature symmetric delay trimmable phase-switched fractional capacitance
A self-tuning resonant-inductive-link transmit driver using quadrature symmetric delay trimmable phase-switched fractional capacitance

The efficiency of inductively coupled power transfer systems is increased when high-Q inductor-capacitor circuits are used, maximizing the magnetic field strength at the transmitter for a given drive amplitude. Such circuits require precise tuning to compensate environmental effects and component tolerances, which modify the resonant frequency. A single zero-voltage-switched fractional capacitance may be used to accurately tune the circuit to resonance, reducing implementation costs compared with classical tuning techniques. However, integration into a chip presents challenges, which must be addressed, such as operating with large voltage excursions and compensating for high-voltage driver delays. We describe here the operation of a self-tuning LC resonant circuit driver using a symmetrically switched fractional capacitance. An architecture for a fully integrated system for operation at 75 kHz-2.6 MHz is presented. Implemented in a 0.18-μm 1.8-50 V CMOS/laterally diffused MOSFET(LDMOS) technology, the integrated circuit uses high-voltage interfaces for capacitance switching and sampling inputs and includes digital phase trimming to compensate propagation delays in large driver devices. Correct operation of the self-tuning functionality is verified across the available frequency range, with results presented for static and dynamic tuning responses.

Automatic tuning, inductive coupling, phase compensation, radio-frequency identification systems (RFID), resonant circuits, wireless power.
0018-9200
1694 - 1706
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 (2018) A self-tuning resonant-inductive-link transmit driver using quadrature symmetric delay trimmable phase-switched fractional capacitance. IEEE Journal of Solid State Circuits, 53 (6), 1694 - 1706. (doi:10.1109/JSSC.2018.2810206).

Record type: Article

Abstract

The efficiency of inductively coupled power transfer systems is increased when high-Q inductor-capacitor circuits are used, maximizing the magnetic field strength at the transmitter for a given drive amplitude. Such circuits require precise tuning to compensate environmental effects and component tolerances, which modify the resonant frequency. A single zero-voltage-switched fractional capacitance may be used to accurately tune the circuit to resonance, reducing implementation costs compared with classical tuning techniques. However, integration into a chip presents challenges, which must be addressed, such as operating with large voltage excursions and compensating for high-voltage driver delays. We describe here the operation of a self-tuning LC resonant circuit driver using a symmetrically switched fractional capacitance. An architecture for a fully integrated system for operation at 75 kHz-2.6 MHz is presented. Implemented in a 0.18-μm 1.8-50 V CMOS/laterally diffused MOSFET(LDMOS) technology, the integrated circuit uses high-voltage interfaces for capacitance switching and sampling inputs and includes digital phase trimming to compensate propagation delays in large driver devices. Correct operation of the self-tuning functionality is verified across the available frequency range, with results presented for static and dynamic tuning responses.

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A Self-Tuning Resonant-Inductive-Link Transmit Driver Using Quadrature Symmetric Delay Trimmable Phase-Switched Fractional Capacitance - Accepted Manuscript
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More information

Accepted/In Press date: 14 February 2018
e-pub ahead of print date: 21 March 2018
Published date: June 2018
Keywords: Automatic tuning, inductive coupling, phase compensation, radio-frequency identification systems (RFID), resonant circuits, wireless power.

Identifiers

Local EPrints ID: 419958
URI: https://eprints.soton.ac.uk/id/eprint/419958
ISSN: 0018-9200
PURE UUID: 62c12231-da00-4073-9d85-0c9218202d62

Catalogue record

Date deposited: 24 Apr 2018 16:30
Last modified: 04 Nov 2019 18:09

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Contributors

Author: Henry Kennedy
Author: Rares Bodnar
Author: Teerasak Lee
Author: William Redman-White

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