Texas Instruments Corporation

Texas Instruments Incorporated Deutschland, Gmbh

Konstantin O Aslanidis

Andreas Hagl

Adolf Baumann

Herbert Meier

Thomas J Flaxl

Johann Hoffmann

Alfons Lichtenegger

Wolfgang Ramin

Alain Berthon

Josef H Sch&uuml;rmann

Gerhard Eberth

Helfried Vollbrecht

Heiner Brenninger

Juergen Mayer

Christian Ecker

Simon Atherton

Jürgen Mayer-Zintel

Enn Leong Tan

An RFID tag is provided, which has a transponder part with an antenna coil arranged in the transponder part. A mounting part is also provided for fixing the tag in a mounted position. The mounting part has an elongate portion that is engagable with the transponder part so as to be received in the transponder part when the tag is in the mounted position. Further, the tag comprises a magnetic material arranged in the elongate portion of the mounting part.

RFID tag

A passive entry and immobilizer key for vehicles comprises an integrated front-end circuit () with three battery-supplied receiver channels (), each connected to an associated external antenna circuit with an inductor-capacitor combination (LR, CR) having a resonant frequency in the very low frequency range. The three antennas are arranged in a three-dimensional configuration. An immobilizer transponder () is supplied by energy received from an external transponder antenna circuit and stored in a storage capacitor (CL). The transponder antenna circuit includes an inductor-capacitor combination (LR, CR, CL) having a resonant frequency in the low frequency range. The transponder antenna circuit shares at least one inductive component (LR) with the antenna circuit of one of the three receiver channels. A capacitor in the transponder antenna circuit is selectively disconnected to change the resonant frequency from a frequency in the very low frequency range to a frequency in the low frequency range. Accordingly, one of the three antenna circuits has a dual function. A first function is that in a three-dimensional analog front end of a passive entry system that operates in the very low frequency range. A second function is that in a transponder of an immobilizer system that operates in the much higher low frequency range. As a result, only three antenna coils need to be implemented in the key.

Passive entry and immobilizer at different frequencies using same antenna coil

A method for the authentication of a transceiver unit with respect to a second transceiver unit, located at a distance to it. A first signal is transmitted via an aerial connected to the first unit, when second unit is located within the reception area of the first unit. The first signal is received by means of the second unit via an aerial connected to it, whereby, on the basis of the first signal received, a value is measured that characterizes the strength of the electro-magnetic field generated by the first signal at the location of the second unit. A second signal is transmitted via the aerial connected to the second unit that contains information relating to the magnitude characterizing the field strength; and the second signal is received via the aerial connected to the first unit, where, on the basis of the second signal received, a value is measured that characterizes the strength of the electro-magnetic field generated by the second signal at the location of the first unit. On the basis of the values characterizing the field strengths measured during the transmission of the first and the second signals, a comparison is made as to whether the two magnitudes of coupling corresponding to the field strengths between the two aerials coincide. Only when coincidence is established, a release signal is generated.

Authentication of a first transceiver unit with respect to a second transceiver unit located at a distance

A security system to enable authenticated access of an individual to a protected area, including a remote control unit ( ) with a transponder ( ), carried by the individual, which transmits an identification code group on reception of an interrogation signal. A control unit located within the protected area transmits an interrogation signal when activated by the individual, and verifies the identification code group received from the transponder. Access to the protected area will only be permitted on positive verification of the right to access. The transponder ( ), contained within the remote control unit ( ), is a passive transponder which obtains a supply voltage from the interrogation signal transmitted by the control unit ( ) and then feeds this to a supply voltage rail. The remote control unit ( ) contains a battery ( ) that can be connected to the supply voltage rail ( ) by means of a controllable battery coupling switch ( )via a high-resistance path when the remote control unit ( ) is in its quiescent state, or via a low-resistance path when the remote control ( ) unit is in its active state.

Security system to enable authenticated access of an individual to a protected area

Transponders present in an interrogation zone can be identified by an interrogator by it sending an RF interrogation signal into the interrogation zone, the RF interrogation signal containing a code string prompting the transponders to generate partial addresses. As soon as one transponder &ldquo;sees&rdquo; that the generated partial address agrees with part of its own address, it responds by sending its full address which can then be read by the interrogator. Immediately after having received a full address the interrogator sends a code string characterizing the address of the transponder having responded before so that this transponder is thereby addressable. The signal sent by the interrogator to the transponder with this code string also contains an instruction which prompts the transponder to assume the condition in which it no longer responds to receiving its address or partial address.

Method of identifying several transponders

For reading the data stored in a transponder by means of an interrogation device, the interrogation device at first receives the background noise for the purpose of detecting interference frequencies present in this background noise. On the basis of the interference frequencies acquired, coefficients for an adaptive filter are computed by means of which this filter may be tuned in such a way as to suppress the interference frequencies. The response signal from the transponder with the superimposed background noise is received by the interrogation device and routed through the adaptive filter which acts to suppress the interference frequencies. The signal available at the output of the filter can then be demodulated for the purpose of reading the data stored. The transponder system for the execution of the procedure comprises a digital signal processor which computes coefficients for an adaptive filter on the basis of the interference frequencies acquired, and tunes the filter in such a way that the interference frequencies within the RF response signal received from the transponder, carrying the superimposed background noise, are suppressed. The output signal from the adaptive filter may then be used for further processing.

Procedure for reading the data stored in a transponder and a transponder system for the execution of the procedure

A method of tuning the resonance frequency of a transponder to a target frequency is described, wherein a transponder comprises a film antenna with an IC (IC) mounted to the film antenna (L) and an integrated resonance capacitor (C) is part of a IC. During testing of IC at chip probe to determine the pass/fail of the IC, the integrated resonance capacitor (C) is measured and the value is stored with the pass/fail data of the wafer map. Then after mounting a passed IC (IC) to a film antenna (L) with variable inductance, retrieve the integrated resonance capacitance value from the wafer map and calculate the amount of inductance necessary to achieve the target frequency. Tune the film antenna (L) to achieve the necessary inductance, measure the transponder resonance frequency, and compare the transponder resonance frequency to the target frequency.

Method of trimming film type antennas

A corrected digital response signal is generated from a corrupted transponder response signal by receiving the response signal an odd number of times, greater than one, and sampling each received response signal a predetermined number of times. Then, the sample values from each transponder response signal are compared to one another and a majority sample value is obtained. The majority sample value is the value ordained by the majority and therefore represents the corrected response signal value. Alternatively, if time does not permit reception of more than one transponder response signal, additional response signals may be generated from the originally received response signal by shifting the received response by a predetermined number of samples to the right and by shifting the received response by a predetermined number of samples to the left to generate second and third response signals. Then, as similarly described, the first second and third signals are compared sample by sample with the majority sample value yielding the corrected sample value. In this way, a corrected response signal is generated.

Bit error correction algorithm

A novel addressing scheme for an RF-ID system or LAN network is presented in which an interrogator(reader) addresses a set of transponders, each transponder in this set having a common addressing scheme, and the addressed transponders respond only upon the matching of their own address with the received addressing scheme. The addressing scheme comprises a fixed size sub-address and a variable size mask. For example, assuming that the transponder address is 32 bits, the implementation of the addressing scheme can choose 4 bits for the size of the sub-address and 0, 4, 8, 12, 16, 20, 24, 28 bits for the size of the mask. By varying the addressing scheme according to the algorithm in FIG. 4, the reader will in time interrogate all the transponders individually, thus receiving their unique address and achieving the requested exhaustive inventory.

Method for repeating interrogations until failing to receive

Transponder signal collision avoidance system incudes a reader and wireless HDX or FDX type transponders (A, B) are disclosed, interrogated by the reader (R) by alternately powering and then reading through cycles corresponding to a number of possible transponders in the interrogation field. The cycles, which include reader power pulses, signify addresses of respective possible transponders, whether in or out of the field. The transponders for this purpose count reader power pulses by end-of-burst detection, increasing a stored count value with each reader power pulse. The transponder responds to the reader by transmission if and only if a stored count value in a read cycle matches a respective transponder address, preventing the transponders from transmitting telegrams interfering with each other. As a method of reader-transponder operation, the collision avoidance scheme thus cycles the reader interrogating through cycles having power pulses according to possible transponders in the field, not only calling the addresses of each of respective possible transponders but also shortening or lengthening read and power steps dependent upon responses received from the transponders.

Growing community of inventors

Dachau, Germany

Konstantin O Aslanidis