Patent ID: 6138029
Filing Date: 2000-10-24
Classification: G06K

Abstract:
A smart card reader comprising:a connector intended to be electrically connected to an integrated circuit present on the surface of a smart card inserted into the reader, and of which at least one terminal, called clock terminal, is intended to deliver a clock signal to said integrated circuit,a microcontroller intended to exchange data with the integrated circuit and to manage its power supply and its operating frequency,an interface module inserted between the connector and the microcontroller, comprising a first oscillator, whose output is intended to deliver a first clock signal which has a transition frequency, the interface module further including a processing unit enabling data exchange between the microcontroller and the integrated circuit, anda second oscillator whose output is intended to deliver a second clock signal which has an operational frequency that is higher than the transition frequency,the interface module further including a switching device intended to transport either the first clock signal or the second clock signal to the clock terminal of the connector according to the value of a control signal received from the microcontroller,which smart card reader is characterized in that the switching device of the interface module includes a phase detector which has an output intended to deliver a signal that adopts an active state when the first and the second clock signal feature quasi-simultaneous active edges, the taking into account of the control signal by the switching device being conditioned by said active state.