WO2005020135A1

WO2005020135A1 - Communication system and method

Info

Publication number: WO2005020135A1
Application number: PCT/IB2004/002695
Authority: WO
Inventors: Joseph Leibenguth; Xavier Soucasse; Benali Khafif
Original assignee: Axalto SA
Current assignee: Axalto SA
Priority date: 2003-08-21
Filing date: 2004-08-19
Publication date: 2005-03-03
Anticipated expiration: 2006-02-21

Abstract

The invention relates to a system comprising a reader (20) and a contactless integrated circuit intended to be connected to an antenna to be incorporated, together with the integrated circuit, in a portable object body, and a method for communicating with such an integrated circuit. The invention is characterised in that the integrated circuit and the reader are electrically connected through conductive lines (25, 26) so that said reader and said integrated circuit are able to communicate according to a contactless communication protocol, without antennas. The invention specifically applies to contactless cards.

Description

COMMUNICATION SYSTEM AND METHOD

The invention relates to a communication system comprising a reader and a contactless integrated circuit or chip, and a corresponding communication method. In particular, it relates to a communication system and method wherein the contactless chip intends to be connected with terminal ends of an antenna to be incorporated, together with said chip, in a card body for a radiofrequency (RF) communication. RF is more and more used as a standard communication channel between two electronic devices. In the smart card industry, there is a trend to replace contact products, where the chip is connected to the reader by means of a contact plate comprising a 6- or a 8-contact connector, by contactless products wherein the communication is done through RF between two antennas, a first antenna being connected to the smart card chip and the other antenna being connected to the reader. Such contactless products may be pure contactless products, which are not capable of communicating via contact, or hybrid or dual interface products, having both capabilities to communicate. During the manufacture of contactless products, the silicon chip is generally mounted onto an intermediate contact plate. This constitutes an electronic micro- module providing a high-quality mechanical behaviour, an easy connection of the chip to the antenna and an excellent protection to the silicon die. In order to test and program contactless modules (pure contactless or hybrid or dual interface modules) , the most common solution according to the state of the art is to position the module on a contact support which connects the module to a reference antenna. A reader antenna is positioned in front of said reference antenna and the test is performed through these two antennas. One possible equivalent electric circuit of the above system is illustrated in Fig. 1. As shown in this figure, the reader is equivalent to a generator of a V_in voltage having a 50 Ohms resistance provided with an antenna characterised by its RLC values R_1# L_x and C^ The chip is equivalent to a RC circuit wherein R = R_ic and C = Cι.c, and the card antenna, is characterised by-* RLC values:

R₂, L₂ and C₂. The quality of the RF communication depends on the following parameters: the card antenna parameters Q (quality factor) and fr (resonance frequency) , and the coupling distance. The quality factor Q is equal to

and the resonance frequency fr is equal to fi - ' Iπ LC If the distance between the two antennas increases, the coupling between the antennas decreases so that it is difficult to detect any communication. Test and programming using such a system of the prior art are of some inconvenience. The reference antennas are designed in order to work with a set of contactless modules. They constitute a best compromise to achieve test and program results. However, such reference antennas do not work with all modules and will not work with most of the future modules. Therefore, the test has a high rejection rate and new designs of references antennas, incurring additional costs, are necessary, when new modules evolutions are tested. Also, in a test environment, typically during cards production, there are a plurality of readers and modules with reference antennas and mutual coupling with the antennas may occur when said antennas are too close. This may disturb the communication signals. Another inconvenient does exist during the use of the contactless products. For some applications of hybrid cards, the contactless and the contact chips should advantageously communicate, for example, in order to permit a secure retrieval of keys or access rights. Today, this is achieved using two different devices, a first device communicating with the contact chip and a second device communicating through RF with the contactless chip using two antennas. Accordingly, there is a need of a straightforward communication in between the contactless chip and the contact chip. Considering this prior art, a problem that the invention intends to solve is to realise a system comprising a reader and a contactless integrated circuit, which offer an innovative and efficient route for communication . In accordance with one aspect, the solution of the invention to the above problem concerns a system comprising a reader and a contactless integrated circuit intended to be electrically connected to an antenna to be incorporated, together with said integrated circuit, in a portable object body, characterised in that the integrated circuit and the reader are electrically connected through conductive lines so that said reader and said integrated circuit are able to communicate according to a contacless communication protocol, without antenna . In accordance with another aspect, the solution of the invention concerns a method for communicating with a contactless integrated circuit intended to be electrically connected to an antenna to be incorporated together with the integrated circuit in a portable object body, characterised in that it comprises the following steps: - providing a reader, two conductive lines and the contactless integrated circuit; - electrically connecting the reader and the integrated circuit through said conductive lines; and - achieving communication between said reader and said integrated circuit through said conductive lines according to a contactless communication protocol, without antenna. Other features and aspects of the invention will be apparent from the following illustrative description and the accompanying drawings, in which: Fig. 1 is a RF link electric equivalent diagram of a system according to the prior art; Figs . 2A and 2B compare a system of the invention with a system of the prior art; Fig. 3 is an electric equivalent diagram of a system according to the invention; Fig. 4 illustrates the contact link influent parameters in a communication system according to the invention; Fig. 5 illustrates a system according to a first embodiment of the invention. The illustration is related to an hybrid module. In case of a dual interface module, it has to be considered that the chips referenced 52 and

53 in this figure form a single chip. In case of a pure contactless module, it has to be considered that only the chip 52 does exist; Fig. 6 illustrates a system according to a second embodiment of the invention wherein the contact plates 63 and 64 are connected to the antenna 62; and Figs. 7A and 7B illustrate a system according to a third embodiment of the invention. The invention relates to a system. This system comprises a reader and a contactless chip or integrated circuit (IC) . The reader comprises means for receiving and sending data or instructions from/to the contactless chip. The contactless chip comprises two analogical pins. It is generally incorporated into an electronic micromodule having contact pads, two of said contact pads being electrically connected to the analogical pins through wires (wire bonding) or using bumps (flip-chip). The electronic micro-module may comprise a further chip. In such case, the second chip is a contact chip and this contact chip connected to the contact pads VCC, VPP, I/O, RST and CLK of the module, as defined by the ISO 7816 standard. Referring now to Fig. 2A, a reader 20 of the prior art comprises a first antenna 21. The analogical pins of the contactless IC, incorporated into a contactless card 22 body, are connected to a second antenna 23. The reader 20 and the contactless card 22 communicate using a RF link. According to Fig. 2B, the reader 20 of the invention does not comprise any antenna. The analogical pins of the contactless chip are not only electrically connected to an antenna. They are connected to contact pads of a module 24, which may be a pure contactless, a hybrid or a dual interface module. The reader 20 and the module 24 are electrically connected through two conductive lines 25, 26. It is a contact link. If the module is also connected to an antenna, a switch is added in order to select either a standard RF communication mode through the antenna or the communication according to the invention. Advantageously a matching circuit, well known by the man skilled in the art, which is arranged to improve the communication (not shown on the figure) can be inserted between, for example, the reader 20 and the module 24. One possible equivalent circuit of the contact link between the reader 20 and the module 24 contactless chip is illustrated in Fig. 3. As shown in this figure, the reader is equivalent to a generator of a V_in voltage coupled to a 50 Ohms resistance. The contactless chip is equivalent to a RC circuit having a resistance R_iC and a capacity C_ιc. The output voltage is V_out. According to the invention, all inconvenient of the prior art are avoided because communication is done without antennas. In particular, the choice of a short coupling distance in between antennas is not anymore needed. There is no need to design a particular reference antenna, when the invention is used for testing and programming contactless ICs . The signals exchanged in between the reader and the chip are not perturbed by other signals which are created, for example, by environing machines. However, the reader has to detect the load modulation of the chip and, due to the attenuation of the conductive lines, this detection is more difficult. As illustrated in Fig. 4, the influence of the cables and connectors on the load modulation detection appears more important than the influence of the internal resistance of the reader. The cables and connectors influence is proportional to the conductive lines or cables length and the added capacity of these. Additionally, in order to allow operation and communication with the chip, accurate power supply of the chip and communication in both ways between the reader and the chip has to be achieved. Power supply of the chip is achieved if the voltage of the reader, namely V_r, is higher than V_mιn, the minimal voltage for the chip to function, as disclosed in its electrical characteristics. It is the same thing for the current. Thus, the power conditions are:

The communication in both ways between the reader and the chip is achieved if the reader detects the load modulation of the chip. This is possible if, according to the invention, the length of the conductive lines is short, practically advantageously less than approximately 1 meter and if the voltage of the reader V_r is higher than the minimum supply voltage V_min of the chip. With present chips, Vr can have, for example, a value of 3 volts.

Finally, in order to achieve an impedance matching, all the electrical parameters of the system should be known: the stray capacity due to the test head; the tuning capacity of the chip; the load resistor of the chip and the impedance characteristic of the line. The matching condition, which is valid only for one kind of chip, is:

* 7"* ivtukr =7 c^*hip The following are three illustrative embodiments according to the invention. In the embodiment of Fig. 5, a plurality of modules 50, each comprising a contactless IC, are positioned onto a 35 mm-wide perforated band 51, two modules in front, the pitch in between two modules being equal to 14.25 mm. Such perforated bands are used for the manufacture of the modules . Each module comprises two ICs 52, 53 and eight contact pads 54, 55. The contactless IC 52 and, more specifically, the two analogical pins of said IC, are electrically connected to a first and a second contact pads 55 of the module. The contact IC 53 is connected to the remaining six contact pads 54, namely the GND, VCC, VPP, CLK, I/O and RST contact pads. The reader of the system according to this embodiment of the invention is a tester. It comprises two output conducting lines 56, 57, each conducting line being electrically connected to a contactless pad of a module 50 in order to test and program the contactless chip of said module, prior to incorporation in a card body. For a particular application where the module embedded in a card is used with an external antenna, the same mode can be used to test and program the contactless chip. The tester may be for example a Class 185 or MP300 MICROPROSS™ tester but any other testers as the contact/contactless Ultra-Smart tester of Smartware™ may be used. Communication is achieved in between the tester and the contactless IC 52 without antenna. The two contact pads of the module 50 are connected to a two-pins device 58, said two-pin device being electrically connected to the tester using coaxial cables (the conductive lines 56) . In order to allow operation and communication with the chip, power supply of the chip and communication in both ways in between the tester and the chip are achieved. The power conditions (Vr>Vmin and Ir>Imin) are fulfilled as the Class 185 and MP300 MICROPROSS™ testers are sufficiently powerful. In addition, the tester detects the load modulation of the chip because the link in between the chip and the tester outputs is short and the tester voltage is high enough. The RF without antenna solution of this embodiment allows, for example, testing and programming a bunch of 16 to 32 modules in parallel, without any interference from one chip to the others. There is not an more any problem of footprint of the antenna. In the embodiment of Fig. 6, a module 60 having contact and contactless capabilities is incorporated into a plastic card body 61 of 85.6 mm long, 54 mm wide and 0.76 mm thickness as defined by the 7810 ISO standard. An antenna 62 is embedded into the card body 61, the terminal ends of said antenna being electrically connected to the contact pins of the contactless IC of the module. A reader, not shown in the figure, is electrically connected to the RFU contact pads of the module which are connected to the contactless IC . This connection is done through two conductive lines 63, 64. Such a system allows communication between the reader and the contactless IC, without antennas, and according to a contactless communication protocol like, for example, the ISO 14443 standard, the ISO 15693 standard or the Near Field Communication (NFC) protocol. Other contactless protocols can also be used like, for example, those defined by Radio Frequency Identification (RFID) standard used in the context of RFID chips : 125 KHz, 13,56 MHz or 2,45 GHz. In the embodiment of Figs. 7A and 7B, a module 70, having contact and contactless capabilities, is incorporated into a card body of a SIM plug-in format as mentioned in the 14443 ISO standard. This module comprises two chips, a contactless chip 71 and a contact chip 72. It is positioned into a recess of a mobile phone referenced 73 as a whole, said mobile phone comprising a processor 74 that manages its functioning and a card antenna 75. This antenna 75 is connected to the contacless chip in order to allow communication via RF channel with a contactless reader in the field. As shown in Fig. 7B, the mobile phone 73 comprises a contact reading device 76 and a contactless reading device 77, both devices being connected to the microprocessor 74. The contact reading device is also connected to the contact chip through the VCC, VPP, I/O, RST and CLK contact pads of the contact panel . In addition, the contactless reading device is connected to a directive or directional coupler 78, said coupler being connected to the antenna and to the two RFUs contacts of the contact panel . The electrical connection between the contactless reading device and the directive coupler and between said directive coupler to said RFU contact is achieved via conductive lines, according to the invention. A mobile phone holder may use the mobile phone 23 as follows, for reloading contactless transport access. When instructed, the mobile processor 75 sends useful information and/or orders to the contact reading device 76. The contact reader device 76 retrieves keys and access rights from the contact chip 72. These keys and access rights data are sent to the contactless reading device 77. The contactless reading device communicates with the contactless chip 71 through the directive coupler 78 and the access rights are loaded in this chip 71, thanks to the keys retrieved from the contact chip 72. As the directive coupler is connected to the antenna 75, the mobile holder may use its mobile for transport access through RF communication managed by the contactless chip 77. Communication between the contactless reading device and the contactless chip is achieved through conductive lines and complies with the

ISO 14443 standard. Communication between the contact reading device and the contact chip is achieved through conductive lines and complies with the ISO 7816 standard. Even if this embodiment specifically concerns GSM applications, other embodiments may concern e-purse or access control applications. In these other embodiments, the information exchanged between the two ICs will not necessary be keys and access rights. It may be any data. More generally, it is to be noted that the previous embodiments of the invention are non limitative and that various modifications and improvements may be made to these embodiments without departing from the scope of the present invention.

Claims

1. A system comprising a reader (20) and a contactless integrated circuit (52, 71) intended to be connected to an antenna (62) to be incorporated, together with the integrated circuit, in a portable object body (61), characterised in that the integrated circuit and the reader are electrically connected through conductive lines (25, 26, 56, 57, 63, 64) so that said reader and said integrated circuit are able to communicate according to a contactless communication protocol, without antennas .

2. The system of claim 1, wherein the contactless integrated circuit (52, 71) is incorporated into a module (24, 50, 60, 70) .

3. The system of claim 2, wherein the module (24, 50, 60, 70) comprises a contact integrated circuit (53, 72) .

4. The system of one of claims 2 or 3 , comprising plurality of modules (50) positioned onto a band (51), for testing, and the reader is a tester.

5. The system of one of the previous claims, wherein the conductive lines are coaxial cables (56, 57).

6. The system of one of the previous claims, wherein the length of the conductive lines (25, 26, 56, 57, 63, 64) is less than approximately 1 meter.

7. The system of one of the previous claims, wherein the reader voltage V_r and the reader output current I_r are such that : I. > I ,„ where Vmm and Imm are the minimal voltag —*e and intensity-_* of the current for the integrated circuit to function.

8. The system of one of the previous claims, wherein the reader is able to detect the load modulation of the contactless integrated circuit.

9. The system of one of the previous claims, wherein the portable object is a smart card.

10. The system of claim 9, wherein the portable object is an hybrid card.

11. The system of claim 9, wherein the portable object is a plug-in card.

12. The system of claim 9, wherein the portable object is a module.

13. The system of one of the previous claims wherein the reader is a reading device included in a mobile phone, together with the contactless integrated circuit.

14. The system of one of the previous claims, wherein the communication protocol is defined by a RFID standard.

15. A method for communicating with a contactless integrated circuit (52, 71) intended to be electrically connected to an antenna (20) to be incorporated together with the integrated circuit in a portable object body, characterised in that it comprises the following steps: providing a reader (20), two conductive lines (25, 26, 56, 57, 63, 64) and the contactless integrated circuit; electrically connecting the reader and the integrated circuit through said conductive lines; and achieving communication between said reader and said integrated circuit through said conductive lines according to a contactless communication protocol, without antenna.