Chip card incorporates an autonomous capacitive time measurement component, in which the residual charge is measured after external power is disconnected and related to the time elapsed between successive transactions

摘要

Electronic unit, such as a chip card has means for measuring time elapsed between sequential transactions in the form of a capacitive component (20) with a leak path across its dielectric. The capacitive component is charged from an external power source during a transaction. The residual charge is measured using measurement means (22) when power is available during the subsequent transaction.