Transponder and method for a wireless data transmission

Abstract

A transponder and a method for wireless data transmission is provided. The transponder comprises an input circuit with input terminals for connecting an antenna coil for data transmission to a base station by means of inductive coupling, a first controllable switching means, at least one resistor, which is looped in series with the first controllable switching means between the input terminals of the input circuit, and a controller which is designed in such a way that it connects through the first switching means as soon as a voltage applied at the input terminals falls below a first settable threshold value, and again interrupts it as soon as the voltage applied at the input terminals for a settable duration is above the first settable threshold value and/or above a second settable threshold value.

1 . A transponder comprising
 an input circuit having input terminals for connecting an antenna coil for facilitating data transmission to a base station by inductive coupling;   a first controllable switch;   at least one resistor that is looped in series with the first controllable switch between the input terminals of the input circuit; and   a controller that connects the first controllable switch when a voltage applied at the input terminals falls below a first settable threshold value and interrupts the first controllable switch when the voltage applied at the input terminals for a settable duration is above the first settable threshold value and/or above a second settable threshold value.   
     
     
         2 . The transponder according to  claim 1 , wherein the transponder is a passive transponder. 
     
     
         3 . The transponder according to  claim 1 , wherein the first controllable switch is a transistor or a MOS transistor. 
     
     
         4 . The transponder according to  claim 1 , wherein the input circuit processes frequencies within a frequency range of 50 kHz to 250 kHz. 
     
     
         5 . The transponder according to  claim 1 , wherein the input circuit for the data transmission to the base station comprises a modulation unit with a controllable voltage limiting unit, which limits the voltage applied at the input terminals to a first settable maximum value or to a second settable maximum value. 
     
     
         6 . A method for wireless data transmission via inductive coupling between a base station and a transponder, which has an input circuit with input terminals for connecting an antenna coil, the method comprising:
 turning on a resistive load that is provided between the input terminals when a voltage applied at the input terminals falls below a first settable threshold value; and   turning off the resistive load when the voltage applied at the input terminals for a settable duration is above the first settable threshold value and/or above a second settable threshold value.