Method and Device for Active Load Modulation by Inductive Coupling
AssigneeInside Secure
InventorsBruno CHARRAT, Florian PERNISEK
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Abstract
A data emission/reception device by inductive coupling includes an inductive antenna circuit in which an antenna signal appears, a mechanism configured to for extracting a first periodic signal from the antenna signal, a synchronous oscillator receiving the first periodic signal and supplying a second periodic signal, and an active load modulation circuit configured to apply bursts of the second periodic signal to the antenna circuit. The device is configured to place the oscillator in the synchronous oscillation mode before each application of a burst of the second periodic signal to the antenna circuit, then place the oscillator in the free oscillation mode.
Claims16
A method of emitting data by inductive coupling, the method comprising:
- receiving an antenna signal using an inductive antenna circuit in the presence of an alternating external magnetic field,
- extracting from the antenna signal a first periodic signal,
- producing a second periodic signal using a synchronous oscillator having a synchronization input receiving the first periodic signal, the oscillator having a synchronous oscillation mode set in phase with the first periodic signal and a free oscillation mode,
- applying to the antenna circuit bursts of the second periodic signal to generate an active load modulation magnetic field,
- placing the oscillator in the synchronous oscillation mode before each application of a burst of the second periodic signal to the antenna circuit, and
- placing the oscillator in a free oscillation mode during the application of a burst of the second periodic signal to the antenna circuit.
A data emission/reception device by inductive coupling comprising:
- an inductive antenna circuit in which an antenna signal appears in the presence of an alternating external magnetic field,
- a mechanism configured to extract a first periodic signal from the antenna signal,
- a synchronous oscillator having a synchronization input receiving the first periodic signal, supplying a second periodic signal, the oscillator having a synchronous oscillation mode set in phase with the first periodic signal and a free oscillation mode, and
- an active load modulation circuit configured to apply bursts of the second periodic signal to the antenna circuit and to generate an active load modulation magnetic field, wherein the device is configured to:
- place the oscillator in the synchronous oscillation mode before each application of a burst of the second periodic signal to the antenna circuit, and
- place the oscillator in the free oscillation mode during the application of a burst of the second periodic signal to the antenna circuit.
Dependencies are inferred from the claim text.