IC card, IC chip, data assuring method and power supply monitor method
First Claim
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1. An IC card for receiving a power supply or a radio wave from an upper apparatus so as to operate an internal IC chip, comprising:
- a memory element capable of being used as a program memory and a work memory, said memory element for storing electric charges in a capacitor, wherein when a power supply is broken during a writing process so as to not to be supplied inside, the electric charges stored in the capacitor in said memory element are used so that a voltage for time required for completing a unit writing cycle is secured, and the current writing process is continued without interruption, and at a stage that the unit writing cycle is completed, the process is ended.
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Abstract
An IC card of the present invention, which receives a power supply or a radio wave from an upper apparatus so as to operate an internal IC chip, has, for example, an FeRAM which can be used as a program memory and a work memory. When a power supply is broken during a writing process so as not to be supplied to the inside, a ferroelectric capacitor in the FeRAM 4 is used so that a voltage for time required for completing the writing process is secured.
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Citations
8 Claims
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1. An IC card for receiving a power supply or a radio wave from an upper apparatus so as to operate an internal IC chip, comprising:
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a memory element capable of being used as a program memory and a work memory, said memory element for storing electric charges in a capacitor, wherein when a power supply is broken during a writing process so as to not to be supplied inside, the electric charges stored in the capacitor in said memory element are used so that a voltage for time required for completing a unit writing cycle is secured, and the current writing process is continued without interruption, and at a stage that the unit writing cycle is completed, the process is ended. - View Dependent Claims (2, 3)
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4. An IC chip for receiving a power supply or a radio wave from an upper apparatus so as to be operated, comprising:
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a memory element capable of being used as a program memory and a work memory, said memory element for storing electric charges in a capacitor, wherein when a power supply is broken during a writing process so as to not to be supplied inside, the electric charges stored in the capacitor in said memory element are used so that a voltage for time required for completing a unit writing cycle is secured, and the current writing process is continued without interruption, and at a stage that the unit writing cycle is completed, the process is ended. - View Dependent Claims (5, 6)
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7. A data assuring method, wherein when a power supply is broken during a writing process so as not to be supplied into an IC card, electric charges stored in a capacitor in a memory element usable as a program memory and a work memory are used so that a voltage for time required for completing a unit writing cycle is secured, and the current writing process is continued without interruption, and at a stage that the unit writing cycle is completed, the process is ended.
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8. A power-supply monitor method, comprising the steps of:
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monitoring a voltage level of a power supply so as to make a judgment as to whether or not the voltage level is in an operating area showing an operable voltage range, in an operation-forbidden area showing an operation-forbidden voltage range or in an operation waiting area showing an operation waiting voltage range;
when the voltage level is changed from the operating area into the operation waiting area, bringing the on-executing process into the waiting state without ending the process;
when the voltage level is changed from the operation waiting area into the operation-forbidden area, ending the process; and
when the voltage level is changed from the operation waiting area into the operating area, restarting the process in a waiting state.
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Specification