Patent ID: 7693504
Filing Date: 2010-04-06
Classification: G06K

Abstract:
1. A method for reducing the power consumption of a mobile data memory for contactless data transmission with a read/write device, comprising: providing at least one depletable energy store and energy consuming components for the mobile data memory; generating a first clocking signal in a first oscillator, the first clocking signal having a first clock frequency; controlling the first oscillator to continuously generate the first clocking signal; supplying the mobile data memory with electrical energy from the energy store during a cycle inactive idle mode, wherein power consumption during the idle mode comprise a first power consumption magnitude; cyclically generating a second clocking signal in a second oscillator, the second clocking signal having a second clock frequency higher than the first clock frequency; monitoring a signal level corresponding to frequencies emitted by the read/write device; comparing the signal level relative to a detection threshold; when the monitored signal level exceeds the detection threshold, controlling the second oscillator to generate the second clocking signal during a cyclic polling time of a polling cycle; if the monitored signal level reverts to a level below the detection threshold, switching off the second oscillator; supplying the second clocking signal to a data receiver for data reception at a data reception rate during the cyclic polling time; supplying the second clocking signal to a data demodulator during the cyclic polling time, wherein the second clock frequency is sufficiently high relative to the data reception rate to oversample the data being received by the data receiver and, upon a recognition of valid data, performing data demodulation by the demodulator of the received data, wherein the second oscillator is switched on in advance by a predefined time interval relative to the start of the cyclic polling time and prior to performing the demodulation of the received data, wherein power consumption during the cyclic polling time comprise a second power consumption magnitude higher than the first power consumption magnitude, wherein the duration of the cyclic polling time is selected to reduce power consumption and increase an operating life of said at least one depletable energy store; and upon completion of the data demodulation, or a recognition of invalid data, reverting the mobile data memory to the cycle inactive idle mode.