METHOD TO DELIVER AN INCREASE IN POWER TO THE MICROCIRCUIT IN A SMARTCARD
Original Publication Date: 1999-Sep-01
Included in the Prior Art Database: 2002-Sep-04
In brief, this invention provides a method to deliver an increase in power to the microcircuit in a smartcard for an indeterminate period of time when required by either the card or the reader. This increase in power would typically be used so that a transaction may take place either more rapidly or at a greater distance from the reader (in contactless operation). An energy storage device resident on the card, typically a capacitor or battery, provides this increase in power. Energy is stored in this device through routine operation of the card or, in some circumstances, through the user purposely charging the energy storage device. During a trans- action that involves both card and a card reader, the microcircuit on the card may require more power to conduct the transaction. In this case the micro&r cuit will access the energy stored in the energy stor- age device and convert it to the required power. Alternatively, the card reader may detect a situation in which it requires the card to increase output power or accelerate operation. In this case the card reader may directly, or through the microcircuit, command the energy storage device to supply ener- gy to complete the transaction. To illustrate the operation of this invention, consider several exam- pies In example #l the smartcard is being used in a contractless operation. Contactless is defined as a method for using the card such that a transaction can occur without the card physically contacting the reader. Typically this is done using radio frequency technology, but could be accomplished in other ways, such as infrared technology. In this example the card is brought within the operating range of the reader and a transaction begins. In this example, the card uses the energy being radiated by the reader as its primary energy source. As the transaction pro- ceeds the microcircuit on the card is required to exe- cute a command that will require more power than the card is receiving from the reader. When the microcircuit recognizes this situation, it draws ener- gy from the energy storage device to complete the transaction. Once the microcircuit has drawn the required energy, it begins to recharge the energy storage device using the power radiated from the card reader.