Registers – Records – Conductive
Reexamination Certificate
2001-06-29
2003-06-03
Tremblay, Mark (Department: 2876)
Registers
Records
Conductive
Reexamination Certificate
active
06572023
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to an Integrated Circuit Card in which a semiconductor chip is embedded. Such Integrated Circuit Card is commonly referred to as IC card. More particularly, the present invention relates to a dual mode type IC card that has a contact-free mode and a contact mode. The contact-free mode is a mode where electrical energy is supplied from a reader/writer by an inductive coupling and a data transmission between the IC card and the reader/writer is performed by the inductive coupling. The contact mode is a mode where electrical energy is supplied from the reader/writer via a contact terminal of the IC card and the data transmission is performed via the contact terminal.
This application relies for priority on Japanese patent application, Serial Number 208556/2000, filed Jul. 10, 2000, which is incorporated herein by reference in its entirety.
2. Description of the Related Art
In such this technical field, an IC card of the dual mode type is described in, for example, U.S. Pat. No. 5,206,495 as a related art.
FIG. 2
is a schematic block diagram showing the IC card of the related art.
The IC card has a contact terminal
203
, a coil
204
and a coil
205
. The contact terminal
203
is contacted with a terminal of a reader/writer in the contact mode and receives electrical energy via the contacted terminal of the reader/writer. Bi-directional data transmission between the IC card and the reader/writer is executed via the contact terminal
203
in the contact mode.
The coils
204
and
205
are inductive coupled to a coil of the reader/writer in the contact-free mode and receive electrical energy. The coils
204
and
205
perform the data transmission between the IC card and the reader/writer and receive electrical energy from the reader/writer.
The coils
204
and
205
are connected to a voltage rectification device
211
and a serial/parallel converter
214
in a switching element
210
. The voltage rectification device
211
rectifies an alternating signal (AC signal) induced in the coils
204
and
205
and generates a direct voltage (DC voltage) U
1
. The DC voltage U
1
is applied to an input terminal E
1
of a comparator
212
and a power supply terminal E
4
of the comparator
212
through a diode D
1
. The DC voltage U
1
is also applied to a serial/parallel converter
214
. The serial/parallel converter
214
is connected to a multiplexer
213
.
Signal lines I
1
through I
6
are connected to the multiplexer
213
. The signal line I
6
(it is also referred to as a power supply line I
6
), which receives electrical energy from the contact terminal
203
, is connected to an input terminal E
2
and the power supply terminal E
4
through a diode D
2
.
The comparator
212
compares a voltage at the input terminal E
1
with a voltage at the input terminal E
2
and outputs a select signal as a result of the comparison from an output terminal E
3
. The multiplexer
213
selects the serial/parallel converter
214
in response to the select signal when the voltage at the input terminal E
1
is higher than the voltage at the input terminal E
2
and selects the contact terminal
203
in response to the select signal when the voltage at the input terminal E
1
is lower than the voltage at the input terminal E
2
. A microprocessor
220
is connected to the multiplexer
213
.
When the IC card illustrated in
FIG. 2
operates in the contact mode, the power supply voltage (electrical energy) is supplied from the contact terminal
203
. The power supply voltage is transferred to the input terminal E
2
and the power supply terminal E
4
through the power supply line I
6
. At this time, since AC signal is not induced in the coils
204
and
205
, DC signal U
1
is not generated by the voltage rectification device
211
. Thus, the comparator
212
outputs the select signal so that the multiplexer
213
selects the contact terminal
203
. As a result, the microprocessor
220
is connected to the reader/writer through the contact terminal
203
.
When the IC card illustrated in
FIG. 2
operates in the contact-free mode, the voltage rectification device
211
rectifies AC signal induced in the coils
204
and
205
and generates the DC voltage U
1
. The DC voltage U
1
is transferred to the input terminal El and the power supply terminal E
4
. At this time, since the power supply voltage is not supplied to the power supply line
16
, the comparator
212
outputs the select signal so that the multiplexer
213
selects the serial/parallel converter
214
. Thus, the microprocessor
220
is magnetically coupled to the reader/writer through the coils
204
and
205
.
However, such this conventional IC card has a problem to be solved as explained bellow.
In a case where a strong alternating signal is induced in the coils
204
and
205
due to the noise etc. when the IC card operates in the contact mode (that is, the contact terminal
203
is contacted with the reader/writer), the voltage rectification device
211
rectifies the induced alternating signal and generates DC voltage U
1
. If the generated DC voltage U
1
exceeds the power supply voltage supplied to the power supply line I
6
through the contact terminal
203
, the voltage at the input terminal E
1
of the comparator
212
exceeds the voltage at the input terminal E
2
. At this time, the selection of the multiplexer
213
changes to the other selection. That is, although the IC card operates in the contact mode, the multiplexer
213
selects the serial/parallel converter
214
in response to the selection signal output from the output terminal E
3
. As a result, the microprocessor
220
may not continue to operate in the contact mode.
Consequently, there has been a need for an IC card that can keep an operation of the contact mode even though undesirable AC signal is induced in the coils due to the noise.
SUMMARY OF THE INVENTION
It is an object of the present invention is to provide an integrated circuit card that is seldom influenced by noise.
According to an aspect of the present invention, for achieving one or more of the above objects, there is provided a semiconductor integrated circuit that includes terminals for receiving data, a first control signal and a power supply by mechanical contact to the terminals and a coil for receiving data, a second control signal and a power supply by electromagnetic induction. The integrated circuit card also includes a mode designating circuit for designating a contact mode prior to the second control signal during the first control signal is received therein and for designating a contact-free mode during the second control signal is received therein. The integrated circuit card further includes a processing circuit for operating in the contact mode based on the contact mode designated by the mode designating circuit and for operating in the contact-free mode based on the contact-free mode designated by the mode designating circuit.
The above and further objects and novel features of the invention will more fully appear from the following detailed description, appended claims, and accompanying drawings.
REFERENCES:
patent: 5206495 (1993-04-01), Kreft
patent: 5929414 (1999-07-01), Saitoh
patent: 6105874 (2000-08-01), Berger et al.
patent: 6145749 (2000-11-01), Thuringer et al.
Oki Electric Industry Co. Ltd.
Rabin & Berdo P.C.
Tremblay Mark
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