Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Semiconductor Software Co., Ltd

Etsushi Takebayashi

Atsuo Yamaguchi

Shigeru Furuta

A non-contact IC card reader/writer which offers an improved reliability in communication between a non-contact IC card and its reader/writer by reducing malfunction due to data communication error. The reader/writer includes a reader/writer main body electrically connected to a host machine for controlling communications, and an antenna external to and electrically connected to the reader/writer main body for transmitting and receiving electromagnetic waves to and from the non-contact IC card. Since the antenna is L-shaped in cross section, the non-contact IC card is free from right-angle antenna geometry to the antenna and maintains a good communications link with the reader/writer.

Reader/writer for use with non-contact IC card and reader/writer system

An IC card prevents an internal battery from being, rapidly consumed and internal data from being lost due to frequent use or erroneous starts caused by external noise. The number of starts of the card and the number of erroneous starts thereof are respectively counted by registers in a RAM. When one of these start numbers reaches a set value, the receiving circuit selected is switched to another receiving circuit having a higher threshold value and requiring no bias current, or the threshold value of the receiving circuit is increased by an inhibit circuit so that the internal power consumption of the card is suppressed, and the card is not affected by external noise. In addition, when the value of one of the registers reaches a set value, the external device informs the user of the fact that the value has reached a set value, using sound or a visual display.

IC card

A semiconductor integrated circuit for a CMOS microcomputer and others having an analog circuit, in which a gate voltage of a transistor for setting a bias current is generated by arranging a diode formed by two islands in a MOS structure and a transistor in series, so as to decrease also a temperature dependence characteristic of the analog circuit. Thereby, the fluctuation of the characteristic of the analog circuit can be restrained despite of fluctuation not only of a power-supply voltage but also of a temperature.

Growing community of inventors

Itami, Japan

Etsushi Takebayashi