Patent ID: 7504935
Filing Date: 2009-03-17
Classification: G06K

Abstract:
1. A transponder comprising: a transponder oscillating circuit comprising an oscillating circuit capacitor and an oscillating circuit coil which has an inductive coupling to a base station for inductive transmission of energy and/or data; an energy store which provides a discharge current when sending; and a starter device which is arranged between the transponder oscillating circuit and the energy store and which generates an adjustable reference voltage, wherein the starter device has a reference voltage generator which forms the reference voltage on the basis of parameters supplied on the input side from a charge voltage sensor, from a send duration sensor having adjustable send duration, and from a switching parameter sensor for storing physical switching parameters, wherein the parameter from the charge voltage sensor corresponds to the initial charging voltage of the energy store as measured during receipt of energy and/or data, wherein the starter device also has a difference device which forms a send voltage desired value from the difference between the discharge voltage of the energy store and the reference voltage, and wherein the send voltage which is present at the transponder oscillating circuit is regulated by means of the starter device in such a way that an envelope curve of the send voltage is constant over a send duration, wherein the constant discharge current from the energy store supplies the transponder oscillating circuit and a discharge voltage of the energy store, which discharge voltage is dependent on the reference voltage, drops linearly down to the reference voltage at an end of sending.