Registers – Records – Conductive
Reexamination Certificate
1998-09-22
2001-03-13
Tremblay, Mark (Department: 2876)
Registers
Records
Conductive
C235S380000
Reexamination Certificate
active
06199763
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a data carrier which can be operated in a contact-bound mode and in a contactless mode and which includes the means specified hereinafter, namely transmission contacts which are mechanically accessible from outside the data carrier and of which a first transmission contact serves to receive a clock signal in the contact-bound mode of the data carrier, and at least one transmission coil which is inductively accessible from outside the data carrier and which serves to receive a useful HF signal in the contactless mode of the data carrier, and a circuit which includes a.c. detection means constructed to detect the presence of a received useful HF signal, by which a.c. detection means the supply of contactless activation information can be initiated upon the detection of the presence of such a useful HF signal in a detection process, which information enables the contactless mode to be activated.
The invention further relates to a circuit for a data carrier which can be operated in a contact-bound mode and in a contactless mode and which includes the means specified hereinafter, namely contact terminals which are adapted to be connected to transmission contacts which are mechanically accessible from outside a data carrier and of which a first contact terminal serves to receive a clock signal in the contact-bound mode of the circuit, and two coil terminals which serve for connection to a transmission coil which is inductively accessible from outside a data carrier and for receiving a useful HF signal in the contactless mode of the circuit, and a.c. detection means constructed to detect the presence of a received useful HF signal, by which a.c. detection means the supply of contactless activation information can be initiated upon the detection of the presence of such a useful HF signal a detection process, which information enables the contactless mode to be activated.
Such a data carrier of the type defined in the first paragraph and such a circuit of the type defined in the second paragraph are known, for example from the document WO 96/38814 A1.
The known data carrier includes only the a.c. detection means, which in this case are realized by an a.c. detection circuit which is connected directly to a transmission coil and which activates the contactless mode and thus a contactless interface when a useful HF signal appears across the transmission coil. A problem encountered with the known data carrier is that in an operating condition in which the data carrier is in the contact-bound mode and powerful spurious signals are received via the transmission coil the received spurious signals fake a received useful HF signal, which is detected as the appearance of a useful HF signal by the a.c. detection circuit, as a result of which in response to the received spurious signal the contactless mode is activated erroneously, although the data carrier has been set to and should remain in the contact-bound mode. Thus, in the case of the known data carrier the operation in the contact-bound mode is interrupted, in response to a spurious signal received by means of the transmission coil, which in the case that a data transmission process is in progress in the contact-bound mode results in this process being disrupted. Such an interruption or disruption of an activated mode of operation as a result of an undesired activation of the other mode of operation is obviously undesirable and inadmissible.
SUMMARY OF THE INVENTION
It is an object of the invention to preclude the afore-mentioned problem and to provide an improved data carrier and an improved circuit for a data carrier in a simple manner and with the aid of simple means.
According to the invention, in order to achieve the afore-mentioned object in a data carrier of the type defined in the first paragraph, the circuit in addition includes clock signal detection means connected to a first contact terminal of the circuit, which contact terminal is connected to the first transmission contact, which clock signal detection means are constructed to detect the presence of a received clock signal and upon the detection of the presence of such a clock signal in a detection process enable the supply of contact-bound activation information to be initiated by means of which the contact-bound mode can be activated, and the circuit includes logic means arranged to receive the contactless activation information and the contact-bound activation information and constructed so as to supply contactless mode-setting information associated with said contactless activation information when solely the contactless activation information occurs and to supply contact-bound mode-setting information associated with said contact-bound activation information when solelely the contact-bound activation information occurs and to give one of the two types of activation information priority over the other one of these two types of activation information when these two types of activation information occur simultaneously and accordingly supply the mode-setting information associated with the activation information having priority, the contact-bound mode-setting information enabling the contact-bound mode and the contactless mode-setting information enabling the contactless mode of the data carrier to be set. In this way it is assured with only a minimal additional expenditure that a data carrier in accordance with the invention is always set to the correct and desired mode and that it can be excluded that while the desired mode is active the other non-desired mode can be activated inadvertently by spurious effects or other negative influences. Thus, a very high reliability is guaranteed as regards the activation of the desired mode of operation in the data carrier in accordance with the invention.
In a data carrier in accordance with the invention having the characteristic features defined in the independent claim
1
the logic means can advantageously be constructed in such a manner that the logic means are advantageously adapted to give the contact-bound activation information priority over the contactless activation information and, accordingly, to supply the associated contact-bound mode-setting information in the case of a simultaneous occurrence of the contactless activation information and the contact-bound activation information, which results in the contactless mode being activated. This guarantees a high reliability of the data carrier as regards the activation and maintenance of the contactless mode. In a data carrier in accordance with the invention having the characteristic features defined in the independent claim
1
it has also proved to be advantageous if, in addition, the measures defined in the dependent claim
2
are taken. This guarantees a high reliability of the data carrier as regards the activation and maintenance of the contact-bound mode.
In a data carrier in accordance with the invention having the characteristic features defined in the independent claim
1
it has also proved to be advantageous if, in addition, the measures defined in the dependent claim
3
are taken. This guarantees a particularly high reliability of the data carrier as regards the activation and maintenance of the contact-bound mode. It is to be noted that the measures defined in the dependent claim
3
can also be applied advantageously to a data carrier in accordance with the invention having the characteristic features defined in the dependent claim
2
.
With regard to a data carrier having supply potential detection means reference is also made to the document EP 0 424 726 B1. Said document discloses a data carrier which includes a discriminator circuit as supply potential detection means, which circuit has a first discriminator input and a second discriminator input, the first discriminator input being arranged to receive a first direct voltage—obtained by rectification and smoothing of an alternating voltage induced in two transmission coils—and the second discriminator input being arranged to receive a second direct v
Berger Dominik J.
Eber Wolfgang
Thuringer Peter
Tremblay Mark
U.S. Philips Corporation
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