Legic Identsystems Ag

Gebruder Loepfe Ag

Matthias Schnaubelt

Marcel Plüss

Peter Hausmann

Marcel Pluss

For detecting within a communication range of an antenna a contactless data storage device which is configured for inductive coupling with an electromagnetic field emitted by the antenna, a return signal is detected (S) at the antenna during emission of an electromagnetic field pulse. During amplitude build-up of carrier oscillation at the beginning of the electromagnetic field pulse, an evaluation signal is generated (S) based on the return signal, and the data storage device is detected (S) based on the evaluation signal. By detecting the presence of the data storage device based on an evaluation signal generated during amplitude build-up, the detection of the data storage device can be initiated before carrier oscillation of the electromagnetic field pulse is stable. Consequently, the width of the electromagnetic field pulse can be shortened and, therefore, energy consumption for detecting the presence of the data storage device can be reduced.

Detection of a contactless data storage device

An electronic circuit comprising a circuit module, a capacitor connected to the circuit module and a shutdown line providing a shutdown signal to the circuit module for suspending the circuit module. The electronic circuit further comprises a switching module for switching the capacitor such as to reduce discharging of the capacitor, depending on the shutdown signal. Particularly, the switching module disconnects the capacitor from ground. Disconnection takes effect when the circuit module is suspended or in power down mode because of the shutdown signal being provided.

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Lindau, Switzerland

Matthias Schnaubelt