Dual-mode data carrier and circuit for such a data carrier with potential equalizing means for equalizing the potentials of at least two contact terminals
AssigneeU.S. Philips Corporation
InventorsPeter Thuringer, Wolfgang Eber, Dominik J. Berger
Life of this patent
Estimating the term…
Abstract
A data carrier (1) which can be operated in a contact-bound mode and in a contactless mode and a circuit (1A) for such a data carrier (1) has supply voltage generating means (35) for deriving a supply voltage (VDD), for various circuit sections of the data carrier (1) and of the circuit (1A), from a received useful HF signal (HF), and, in addition, potential equalizing circuit (94) by which at least two contact terminals (17A, 19A) each connected to a respective transmission contact (17, 19) can be brought at the same potential (ground).
Claims6
A data carrier (1) which can be operated in a contact-bound mode and in a contactless mode and which includes the means specified hereinafter, namely
- a transmission contact (17) and a further transmission contact (19) which are both mechanically accessible from outside the data carrier (1), and
- at least one transmission coil (31) which is inductively accessible from outside the data carrier (1) and which serves to receive a useful HF signal (HF) in the contactless mode of the data carrier (1), and
- a circuit (1A) which has a contact terminal (17A) connected to the one transmission contact (17) and which has a further contact terminal (19A) connected to the further transmission contact (19) and which includes supply voltage generating means (35) to which a received useful HF signal (HF) can be applied and by which a supply voltage (VDD) for various circuit sections of the circuit (1A) of the data carrier (1) can be derived from an applied useful HF signal (HF),
- characterized in that
- the circuit (1A) includes potential equalizing means (94) by which the contact terminal (17A) connected to the one transmission contact (17) and the further contact terminal (19) connected to the further transmission contact (19) can be brought at substantially the same potential (ground) when a sufficiently powerful useful HF signal (HF) is received, from which a supply voltage (VDD) can be derived by the supply voltage generating means (35).
A circuit (1A) for a data carrier (1A) which can be operated in a contact-bound mode and in a contactless mode and which includes the means specified hereinafter, namely
- a contact terminal (17A) and a further contact terminal (19A) which are both adapted to be connected to transmission contacts (17, 19) which are mechanically accessible from outside the data carrier (1), and
- two coil terminals (32A, 33A) which serve for connection to a transmission coil (31) which is inductively accessible from outside a data carrier (1) and which serves to receive a useful HF signal (HF) in the contactless mode of the circuit (1A), and
- supply voltage generating means (35) to which a received useful HF signal (HF) can be applied and by which a supply voltage (VDD) for various circuit sections of the circuit (1A) can be derived from an applied useful HF signal (HF),
- characterized in that
- the circuit (1A) includes potential equalizing means (94) by which the contact terminal (17A) adapted to be connected to the one transmission contact (17) and the further contact terminal (19) adapted connected to the further transmission contact (19) can be brought at substantially the same potential (ground) when a sufficiently powerful useful HF signal (HF) is received, from which a supply voltage (VDD) can be derived by the supply voltage generating means (35).
Dependencies are inferred from the claim text.