Patent Number: 6,294,980

Title: Transponder with a frequency detector for protection of security-related data during contactless inductive communication, and an integrated circuit therefor

Abstract: A transponder (1) for the contactless communication with a base station (2) comprises an antenna resonant circuit (10) for receiving a modulated HF signal (5), signal processing means (13) for processing the modulated HF signal and for supplying a data signal (DS) and a clock signal (CLK), and data processing means (23) arranged to receive the data signal (DS) and the clock signal (CLK) and to process the data signal (DS), the clock signal (CLK) defining the processing speed of the data processing means (23) and the data processing means (23) being arranged to receive reset information (RI) for terminating the processing of the data signal (DS), the transponder (1) further comprising a frequency detector (31) arranged to receive the clock signal (CLK) and adapted to compare the frequency of the clock signal (CLK) with at least one limit frequency (f.sub.G1) and to supply the reset information (RI) to the data processing means (23).

Inventors: Berger; Dominik J. (Graz, AT), Eber; Wolfgang (Graz, AT)

Assignee: U.S. Philips Corporation

International Classification: G06K 7/00 (20060101); G06K 19/07 (20060101); G05B 019/02 ()

Expiration Date: 09/25/2018