Electricity: electrical systems and devices – Safety and protection of systems and devices – With specific quantity comparison means
Reexamination Certificate
1999-12-02
2003-05-06
Jackson, Stephen W. (Department: 2839)
Electricity: electrical systems and devices
Safety and protection of systems and devices
With specific quantity comparison means
C361S082000, C361S115000
Reexamination Certificate
active
06560082
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power source unit and a card-like memory medium, and more particularly, is suitably applied to integrated circuit (IC) cards which are to be used, for example, in a security system.
2. Description of the Related Art
There are security systems in which IC cards are given to users and each person is identified with his IC card. Such security systems uses a reader/writer which exchanges data with an IC card, to identify users by reading/writing the data from/into their IC cards.
As the security systems, there have been proposed and adopted a contact type system which exchanges data between an IC card and a reader/writer by electrically connecting to each other and a non-contact type system which exchanges data between an IC card and a reader/writer via electromagnetic waves.
In the non-contact type security system, a reader/writer first modulates data to be transmitted by a predetermined method and radiates electromagnetic waves (magnetic field) corresponding to the obtained transmission data to an IC card. The IC card receives the electromagnetic waves radiated from the reader/writer and demodulates it by a predetermined method, thereby restoring original data. The IC card generates a response signal by performing predetermined data processing on the restored original data.
The IC card modulates this response signal by a predetermined method and transmits electromagnetic waves corresponding to the obtained transmission data to the reader/writer. The reader/writer receives the electromagnetic waves transmitted from the IC card, restores an original response signal by demodulating the electromagnetic waves and operates in accordance with the response signal. By the way, an IC card which is now used is configured to operate internal circuits by utilizing a magnetic field energy of the received electromagnetic waves without using a battery.
In the contact type security system, on the other hand, the reader/writer is configured to first trigger the IC card via a connection point between the reader/writer and the IC card so that data is transmitted and received between them by the trigger.
Under the present circumstance which is a transition period where the security system is shifting to the non-contact type from the contact type, there is an increasing demand for a system which has functions of both the non-contact type and the contact type, whereby a composite IC card which has functions of both the non-contact type and the contact type has been proposed. A configuration of this composite IC card will be described below with reference to FIG.
1
.
In the following description, a mode where a composite IC card
1
operates as a non-contact type and another mode where it operates as a contact type will be referred to as a remote mode and a contact mode, respectively. In the remote mode, the composite IC card
1
receives electromagnetic waves transmitted from a reader/writer (not shown) with an antenna coil
2
, and sends out the energy of the electromagnetic waves to a power unit
3
, a remote side data input/output unit
4
, a voltage detector
5
and a carrier extraction circuit
6
via an antenna coil connection terminal CP or CM. In the contact mode, on the other hand, the composite IC card
1
supplies to the power unit
3
a source voltage which is sent from the reader/writer (not shown) via a contact side power terminal VDD or a contact side ground terminal VSS.
In the remote mode, the power unit
3
converts the electromagnetic waves energy supplied via the antenna connection terminals CP or CM into a direct voltage with a rectifier
10
and sends out the direct voltage as a service voltage V
sup
to a regulator
11
and the voltage detector
5
by way of a first reverse-flow preventing diode element D
1
. In the contact mode, on the other hand, the power unit
3
supplies a source voltage which is sent via the contact side power terminal VDD as the service voltage V
sup
to the regulator
11
and the voltage detector
5
via a second reverse-flow preventing diode element D
2
.
The regulator
11
is configured to keep the level of the service voltage V
sup
constant and send it out to the voltage detector
5
and a logic circuit
12
, thereby supplying a stable power to the voltage detector
5
and the logic circuit
12
. The voltage detector
5
is configured to generate various kinds of flags for operating the logic circuit
12
.
Concretely, the voltage detector
5
converts the level of the supplied service voltage V
sup
into a voltage level corresponding to an internal source voltage VCC, and in the case where a converted source voltage VCC has a voltage level lower than that which is required to operate the logic circuit
12
, the voltage detector
5
sends out a reset signal VRST having a logical level“H” to the logic circuit
12
, thereby stopping the logic circuit
12
. In the case where the source voltage VCC has a voltage level higher than that which is required to operate the logic circuit
12
, on the other hand, the voltage detector
5
sends out a source voltage monitor flag signal VF
1
having the logical level“H” to the logic circuit
12
, thereby operating the logic circuit
12
. Further, when the service voltage V
sup
has a voltage level higher than a predetermined threshold level, the voltage detector
5
sends out an input voltage detection flag VZ having the logical level “H” to the logic circuit
12
.
When the voltage detector
5
detects the source voltage which is supplied via the antenna connection terminal CM, it generates a remote side source voltage flag VR having the logical level “H” and sends it out to the logic circuit
12
and an operation mode determination circuit
15
, and further when the voltage detector
5
detects the source voltage which is supplied via the contact side power terminal VDD, it generates a contact side source voltage flag VC having the logical level “H” and sends it out to the logic circuit
12
and the operation mode determination circuit
15
.
The remote side data input/output unit
4
generates remote side input data RR
x
by demodulating the electromagnetic waves received by an antenna coil and sends out the data to the logic circuit
12
. The logic circuit
12
generates remote side output data RT
x
by performing predetermined data processing on the remote side input data RR
x
, modulates the remote side output data RT
x
with the remote side data input/output unit
4
and radiates electromagnetic waves corresponding to the remote side output data RT
x
from the antenna coil
2
.
On the basis of the electromagnetic waves received by the antenna coil
2
, the carrier extraction circuit
6
extracts a remote side clock signal RCLK having the same frequency as carrier waves, and sends out the clock signal RCLK to the operation mode determination circuit
15
and a clock generator
16
. In the contact mode, the composite IC card
1
inputs into a level shift circuit
17
a clock signal which is input from the contact side clock input terminal CLK. The level shift circuit
17
converts a signal level of the input clock signal into a signal level corresponding to the internal source voltage VCC, and sends out the obtained contact side clock signal CCLK to the operation mode determination circuit
15
and the clock generator
16
.
On the basis of the remote side source voltage flag VR and the contact side source voltage flag VC, which are supplied from the voltage detector
5
, and the remote side clock signal RCLK and the contact side clock signal CCLK, the operation mode determination circuit
15
determines an operation mode for the composite IC card
1
. When a determined operation mode is the remote mode, the operation mode determination circuit
15
generates an operation mode signal Mode having the logical level “H” and sends it out to the clock generator
16
or when the determined operation mode is the contact mode, the operation mode determination circuit
15
generates an operation mode signal Mode having a logical leve
Bell Boyd & Lloyd LLC
Jackson Stephen W.
Sony Corporation
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