MXPA98006461A - Data exchanging system with communication with or without contact between a terminal and portable objects - Google Patents

Abstract

The portable object (200) comprises a plurality of electric contacts for communicating by galvanic channel with a terminal of a first type itself comprising a plurality of homologous electric contacts, and a coil (102) for communicating without contact with a terminal of a second type (100) transmitting in modulated electromagnetic field transmitting data. The data transmitted by the terminal are timed by a clock signal, and the portable object comprises means for clock detecting (220) to modify the functioning of the portable object depending on the presence or the absence of a clock signal (CLK) in the received signal, in particular the signal picked up by the coil. These means can in particular monitor protocols of communication and/or of signal processing and/or of received data processing, and means for interrupting the connection between the electric contacts and other circuits of the portable object.

Description

SYSTEM OF DATA EXCHANGE BY MEANS OF COMMUNICATION BY 0 NON-CONTACT BETWEEN A TERMINAL AND PORTABLE OBJECTS Field of the Invention The invention refers to the techniques of communication without contact between a portable object and a terminal. BACKGROUND OF THE INVENTION The contactless data exchange is well known; Among the applications of this technique, we find, among others, access control, electronic payment (applications of the "electronic wallet" type) and electronic toll collection, for example for the access and toll of collective means of transport. In this last example, each user is provided with a portable object of the type "contactless card" or "contactless plate", which is an object capable of exchanging information with a fixed (or possibly mobile) terminal bringing the label of the latter closer so as to allow a non-galvanic mutual coupling ("terminal" will be the term used in the present description to designate the transmitting / receiving terminal of data that can cooperate with the portable objects).

More precisely, this coupling is performed by varying the magnetic field produced by an induction coil (a technique known under the name of "induction process"). To this end, the terminal comprises an inductive circuit excited by an alternating signal that produces in the surrounding space, an alternating magnetic field. The portable object that is in this space, detects that field and modulates in return the load of the portable object coupled to the terminal; the terminal detects this variation thus establishing the desired bidirectional communication. On the other hand, there is an important park of electrical contact terminals that communicate galvanically with the existing portable objects, especially those usually referred to as "magnetic strips". For this reason, among others, it is interesting to have portable objects capable of communicating with terminals independently via galvanic (by contacts) or non-galvanically (without contact) EP-A-0 424 726 describes a mixed card of this type capable of establishing communication with or without contact. In this card, the communication is established selectively through the contact terminals or through coils, depending on the presence of an electrical voltage in the terminals or in the coils.

A disadvantage of this system, however, is that piloting according to the presence of a tension becomes difficult to apply in practice. In particular, the appearance of parasites can disturb its functioning. In this way, a parasitic decrease of the supply voltage in the contacts can cause the untimely selection of the communication path by coil and the activation of a bypass regulator in which an excessive current then flows when it is placed in parallel in the power contacts. In any case, this system does not adapt to the selection of the starting and operating conditions of the processing circuit, therefore the disappearance of the contact feed implies a parasitic start. The selection at startup based on information arising from the comparison of the two power supplies presents the difficulty of blocking the selection at the right time in all connection conditions. SUMMARY OF THE INVENTION One of the objectives of the present invention is to propose another way of detecting the communication modality to be used and consequently directing different functions of the portable object.

The portable object of the invention is of the general type set forth in the aforementioned EP-A-0 424 726, which comprises multiple electrical contacts for galvanic communication with a terminal of a first type comprising multiple homologous electrical contacts as well as a coil for contactless communication with a terminal of a second type that emits a modulated electromagnetic field that transmits the data. It is characterized because, since the data transmitted by the terminal are programmed in a regular manner by a clock signal, it comprises clock detector means for modifying the operation of the portable object according to the presence or absence of a clock signal in the signal captured by the coil. Preferably, in the non-contact communication mode, the portable object is powered remotely by the electromagnetic field received by the coil and the clock signal and then comprises rectification and filtering means to obtain a continuous supply voltage for the object in non-contact communication mode from the electromagnetic field picked up by the coil and the detector means receive the input of the signal present between the coil and the rectification and filtering means (where its amplitude is the most important).

You can extract the clock signal from the same place. In particular, the clock can be defined by the frequency of the received carrier, divided into the clock extraction means. This authorizes a more sensitive but also more reliable detection of the presence of the clock signal. The data is preferably extracted below the stabilizing and filtering stage, so that the demodulation of the signal is more stable, especially in the case of amplitude modulation. According to the different advantageous subsidiary characteristics of the invention: the means for demodulating the signal captured by the coil, for extracting the communication data, especially from the amplitude demodulator means operating on the signal released at the output of the stabilizing and filtering; downstream of the stabilizing and filtering means, the regulating means for stabilizing the direct voltage, as well as the means for selective inhibition of the regulating means, directed by the clock detector means. means for transmitting data from the portable object to a non-contact terminal, by modulating the load on the terminals of the coil; advantageously, the modulation is then a modulation of a sub-carrier produced by the division of the clock frequency released by the detector means and / or the circuit is susceptible to the two modes of operation, at nominal consumption and with low consumption and means are envisaged to place the circuit in low consumption mode before the data transmission means begin to handle said modulation. The clock detector means can direct the communication and / or processing protocols of received data signals. In this way, the clock presence / absence signal can be exploited in various ways, for example by feeding the inhibition signal with a regulator that stabilizes the DC supply voltage, so that the regulator operates only without contact. The risk of untimely activation of this Shunt regulator is eliminated. Likewise, this signal can be used in the elaboration of the activation signal of the treatment circuit and the selection of its clock signal. Finally, the communication and signal processing protocols may differ from the communication modes with or without contact and the presence / absence of the clock can be used to direct the protocols used. At last, it may be desirable to provide means for interrupting the link between the electrical contacts and other circuits of the portable object, directed by clock detection means so that said link is interrupted as soon as the portable object communicates via a non-contact path. This makes it possible to avoid fraud attempts by capturing or deciphering signals that otherwise appear on the contacts, which are accessible in this form of communication. In a useful way, an analogous switch can be foreseen to interrupt the link in the contact communication mode, being that this makes it possible to avoid interpreting as parasitic data appearing in the input (coil or contacts) not used. In a further advantageous embodiment of a portable object remotely in the non-contact mode, a stabilizing stage is prevented below the rectification and filtering stages which provides a Shunt regulator element mounted in bypass between the supply terminals of the circuit to be powered and associated to a resistive component mounted in series on the circuit power line, the shunt regulator element purged and deriving a variable fraction of feed current from the output circuit that the resistive element and the shunt regulator dissipate the eventual increase in energy not necessary for the operation of the circuit, so that, correlatively, the supply voltage of the terminals of the circuit is stabilized, the voltage excursion to the terminals of the previously agreed element is limited and the variations of current consumed are prevented. do not influence above on the amplitude of the signal ad esmodular In particular, the means may be provided to selectively or temporarily inhibit the operation of the Shunt regulator, especially in response to the detection of a type of contact communication. Finally, the set of electronic circuits of the portable object, with the exception of the winding of the agreed item, is carried out very advantageously with integrated monolithic technology. BRIEF DESCRIPTION OF THE DRAWINGS An exemplary embodiment of the invention is now described in detail, with reference to the accompanying drawings in which the same reference numerals designate identical or functionally similar elements. Figure 1 is a block diagram of a system according to the invention, in its most general aspect, comprising a terminal and a portable object in the field of this terminal. Figure 2 shows a particular embodiment of the portable object of figure 1. Figure 3 details the regulator circuit of the scheme of figure 2. Figures 4 and 5 detail, in two possible variants, the demodulator circuit of the scheme of figure 2 Figure 6 is a detailed example of embodiment of the demodulator circuit of Figure 5. Figure 7 details the clock extractor circuit of the scheme of Figure 2. Figure 8 is a series of chronograms that explain the way in which the object Portable is powered remotely and in which the clock signal is extracted. Figure 9 is a series of schedules that specify the transmission of information from the terminal to the object. Figure 10 is a series of schedules that specify the transmission of information from the object to the terminal. Figure 11 shows the different switches made in a mixed map between the two contact / non-contact operating modes.

DETAILED DESCRIPTION OF THE PREFERRED MODAL The following is an example of embodiment of the system of the invention with reference to the scheme of Figure 1. In this scheme the reference 100 designates a terminal, which may be coupled with a portable object 200 placed near Of the same. The terminal comprises an emission coil 102 which, together with a capacitor such as 104, forms a tuned circuit 106 designed to generate a modulated magnetic induction field. The tuning frequency of the circuit 106 is, for example, 13.56 MHz, a value which is of course not in any way limiting, this choice being in particular simply due to the fact that it corresponds to a value authorized by the European standards for communication and communication functions. of remote power. In addition, this relatively high value allows to conceive circuits with coils that have few turns, therefore, easy and inexpensive to make. The tuned circuit 106 is fed from an entertained high-frequency wave oscillator 108 and, for modulation, from a mixing stage 108 piloted by the signals to emit TXD emitted by a digital circuit 112. The operation of the circuit 112 and especially the sequencing of the signals TXD is programmed in a regular manner by a circuit 114 which produces a clock signal CLK. The reception stages, which extract the received RXD data from the extracted signal at the terminals of the coil 102, comprise a high frequency demodulator circuit 116 as well as a subcarrier demodulator circuit 118 when it has been chosen, as will be indicated below, use a sub-carrier modulation in the portable object sense - > terminal (this technique, of course is not in any way limiting, modulation can also be done in baseband). As regards the portable object 200, it comprises a coil 202 which is integral with an electronic circuit 204 which, advantageously, is made of fully integrated monolithic technology in order to have a small-sized object, generally of the "card" format "credit": the coil 202 is, for example, a printed coil and the circuit set 204 is made in the form of a specific integrated circuit (ASIC). The coil 202 forms with a capacitor 206 a resonant circuit 208 tuned to a given frequency (for example 13.56 MHz) that allows the bidirectional exchange of data with the terminal by means of the technique called "by induction" as well as the remote feeding by means of the magnetic field captured by the coil 202, that is, the same coil as that used for the exchange of information. The alternating voltage at the terminals of the tuned circuit 208 is applied to a single or double alternating rectifier stage 210, then to a filtering level 212, to give a filtered rectified voltage b. The portable object also comprises a level of numerical processing 214, generally made from a microprocessor of RAM, ROM and EPROM and by interface circuits. Downstream of the rectification 210 and filtering stages 212 several specific steps are mounted in parallel, comprising: a voltage stabilizer 215, which emits a rectified, filtered and stabilized d voltage, applied especially to the terminal of positive power VCC of the numerical circuit 214, whose other power terminal is the mass GND. This stabilizing stage 215 can be a voltage stabilizer of the classic type or, as a variant, among others, a specific circuit which will be described below with reference to FIGS. 2 and 3. a stage of the odometer 218 that receives the signal at the input by emits at the output a demodulated signal applied to the RXD data input of the digital circuit 214. This demodulator can be especially a demodulator for the detection of variations of amplitude and / or variable threshold, as will explain in more detail below, with reference to FIGS. 4, 5 and 6. a clock extraction stage 220, which receives the signal a received at the terminals of the tuned circuit 208 and which emits a signal c applied at the input of the CLK clock of the numerical circuit 214. The clock extractor stage 220 can be placed either above the rectification 210 and filter 212 stages, as illustrated or below these steps, ie operate on the signal b instead of the signal a, however, this variant is less advantageous, insofar as the extractor of the clock must then present a greater sensitivity to compensate the leveling of the introduced signal for the filtering. an odometer stage 222 that functions, in the manner known as "charge modulation", a technique that consists of making a controlled variation of the current consumed by the tuned circuit 208 located in the surrounding magnetic field generated by the terminal. This modulator circuit 222 comprises a resistive element 224 (linked resistance or in monolithic technology, component of MOS type without lattice acting as resistance) in series with a switching element 226 (MOS transistor) controlled by the modulation signal f present at the TXD output of the digital circuit 214. As a variant, the modulator stage 222, instead of being located below the rectification 210 and filtering circuits 212, may also be placed above the circuits as illustrated at 222 'in Figure 1, ie directly at the terminals of the resonant circuit 208. The general structure thus proposed, wherein the demodulator level 218 is located below the rectification 210 and filtering stages. 212, has the advantage of being less sensitive to instantaneous variations of the signal. In fact, in the case of a portable object powered remotely, the fact of performing the demodulation in a rectified and filtered signal allows to reduce the effects of the instantaneous variations of the power supply in the course of an oscillation cycle. This aspect will be better understood when the detailed operation of the demodulator is explained, with particular reference to the timelines of Figure 8. Next, a particular embodiment of Figure 1 will be described, with reference to Figure 2, which is especially characterized by a particular structure given at the regulator level 216, which is, as will be explained in more detail below, a "bypass regulator" type level with a bypass component 228 that serves to derive the power supply of the digital circuit in a controlled manner 214, then mounted in bypass between the VCC terminals and the ground GND, combined with a series 230 resistive element located in the power supply line VCC above the regulating component 228. The bypass component 228 can advantageously be a Zener diode or, preferably, a component linked or integrated functionally equivalent to a Zener diode, for example a compound The LM185 / LM285 / LM385 series from National Semiconductor Corporation, which is a component that forms a voltage reference (fixed or adjustable voltage depending on the case), with a polarization current of only 20 mA, a very weak dynamic impedance and a range of operating currents ranging from 20 mA to 20 mA. The component 228 can also be a monolithic equivalent, integrated in the SIC, of said voltage reference component. Figure 3 describes a particular embodiment of this circuit 216, with a component of the type described above whose voltage reference input 234 is biased to a predetermined value by a divider bridge 236, 238 mounted between VCC and the ground. The resistive element 230 can be a linked resistor or, advantageously, an integrated monolith component, for example (as for the component 224) a MOS element that acts as a resistor. It is also foreseen, advantageously, a switching component, such as a MOS transistor 240, which is kept in normal operation by means of the application of an INH signal on its lattice. This transistor can be oscillated to the blocked state by means of the application of a simple INH command signal (especially a software command issued by the calculation circuit 214) which has the effect of inhibiting the operation of the bypass regulator, the circuit behaving then as if it had been omitted. This possibility of inhibition of the shunt regulator can be used especially when it is desired to power the microprocessor under a high voltage without risk of destroying the regulating stage. This case is presented especially for the purposes of an examination or when in the presence of a mixed portable object that can be used at choice in the "no contact" mode (with commissioning of the regulator) or in the "with contacts" mode "(with inhibitor of the regulator), applying in this last case the supply voltage regulated directly to one of the contacts of the portable object without the need to proceed to a specific regulation, as in the case of remote power supply. Next, we will describe in more detail the amplitude demodulator level 218, with reference to figures 4 to 6. This amplitude modulator is a circuit capable of processing modulated signals with a low magnitude of modulation. "Low magnitude of modulation" or "low modulation" means a modulation whose index is generally less than or equal to 50%, preferably less than 20%, the "index" being defined as the ratio (Amax-Amln) / (Amax + min) of the maximum levels ^ and minimum min of the considered signal amplitude. In fact, in the particular context of a portable object powered remotely, it is advantageous, taking into account the energy limitations, to use a low modulation index in order to be able to have sufficient energy during the period in which the modulation is in effect. the low state since by the modulation in amplitude, the level of instantaneous energy supplied to the portable object varies directly with the level of the modulation. Figure 4 illustrates a first possible variant of embodiment, in which the demodulator is an adaptive, variable threshold demodulator. The circuit comprises, after an optional low pass filtering level 242, a comparator 244, preferably hysteresis, whose positive input receives the signal b to demodulate (if filtering corresponded by step 242) and whose negative input receives this same signal b, but after the run of a level RC 246, 248 that acts as integrator. The comparison is then made on the one hand, between the instantaneous value of the signal and on the other hand, an average value of that signal, which constitutes the variable comparison threshold.

Figure 5 illustrates a second possible variant embodiment of the demodulator 218, which in this case is a demodulator sensitive to variations in amplitude. After an optional low pass filtering step 242, signal b is applied to a CR 250, 252 level which acts as a differentiator. The output signal is applied to the positive terminal of the comparator 244 (here again preferably with hysteresis) whose negative input is connected to a fixed potential, for example the ground. In this case, the demodulator is sensitive to variations in amplitude (by the derivative stage), regardless of the average value of the signal; the comparator only detects the variations of this average value. Figure 6 gives a more detailed example of realization of such a demodulator circuit with detection of amplitude variations. In addition to the low-pass filter 242 constituted by the resistor 252 and the capacitor 254, there is the series capacitor 250 which fulfills the function of derivative in combination with the resistors 256 to 264. The signal thus differentiated is applied to two symmetric comparators 244, 266 whose outputs act on two scales 268, 270 mounted on a flip-flop in order to produce two symmetrical signals RXD and RXD / suitably shaped.

Figure 7 illustrates an exemplary embodiment of the clock extractor and detector circuit 220. This circuit receives at the input a signal extracted from the terminals of the resonant circuit 208 and applied to the differential inputs of a compared hysteresis 272 that supplies the signal of the CLK watch. The clock signal also applies to the two inputs of an EXCLUSIVE OR gate 274, directly in one of the inputs and through an RC circuit 276, 278 in the other input. This RC circuit, which introduces a delay in the transmission of the signal captured, is chosen with a constant time url of the order of l / 4fCL? (ICK being the clock frequency generated by circuit 114 of terminal 100). The output signal of gate 274 is then averaged by an RC 280, 282 circuit whose time constant is much greater than l / 2.fCL? (preferably of the order of 1 / ICCL) then it is applied to one of the inputs of a comparator 284 for comparison with a fixed threshold S. The clock signal CLK allows, the appropriate regular programming of the numerical processing circuit 214, in so much that the output of the comparator 284 gives a PRSCLK signal indicative of the presence or not of a clock signal. In the case of a mixed card, able to operate interchangeably in "no contact" mode or in "by contact" mode, the PRSCLK signal of presence / absence of a clock signal is advantageously used to indicate to the digital circuit that the object The laptop is in a "non-contact" environment and to decide the corresponding actions such as the selection of the appropriate communications protocol, the activation of the derivation regulator, using the PRSCLK to produce INH / (see previous description with reference to the figure 3), etc. In this way, Figure 11 shows in detail the different switches that are made between the "non-contact" and "by contact" modalities. The contacts 286 are the contacts CLK (clock), GND (ground), I / O (data), VCC (power supply) and RST / (re-zeroing) of ISO 7816-3, to which we will refer for more details The different switches 288 to 296 are represented in their entirety in the position "by contacts" (referenced "0"), position by default ordering their balancing to the "non-contact" position (referenced as "1") by means of the signal PRSCLK issued by the circuit 220, which reveals the presence of a clock signal emitted by the rectification and filtering means. The extraction of a clock signal is anyway particularly advantageous when it is desired to perform a modulation, not in baseband, but in modulation of sub-carrier, since the sub-carrier can be easily generated by division of the clock frequency. The digital circuit 214 then links the subcarrier thus generated to the data to be transmitted to produce the TXD signal applied to the load modulator circuit 222. The operation of the portable object is described below, with reference to the timings of FIGS. 8 a 10. First, it will be explained, with reference to the timelines of Figure 8, the manner in which the object is fed and in which the clock signal is recovered. The tuned circuit 208 captures a part of the magnetic energy produced by the terminal. The corresponding alternating signal, illustrated in Figure 8, is rectified by block 210 and filtered by means of capacitor 212, to give a filtered rectified voltage b illustrated in Figure 8. For an alternating signal with a peak voltage of 10 V, a rectified and filtered voltage is obtained which has a peak voltage of the order of 8.5 V. Of course, the voltage amplitude a and therefore the voltage b, depends a lot on the distance between object and terminal , being much more important the amplitude and not that the object is near the terminal. The regulator level 216 intervenes to compensate for these variations, by issuing to the digital circuit 214 a stable voltage, generally of the order of 3V (timeline d of FIG. 8). In this way, when we are quite far from the terminal, almost at the limit of the range, the voltage in b will be quite close to the required value of 3V, the voltage drop between b and d will be low, the current that passes through the derivation component 228 will also be very scarce and almost all of the current emitted by the supply circuit will serve to power the digital circuit 214. It will be noted that, in this case, the current through the bypass component 228 may be of only a few micro-amps ( minimum polarization current). Conversely, when the object is very close to the terminal, the voltage at b will rise, the potential difference between by 'd will be equally important (several volts) and the current through the bypass component 228 will be high, dissipating then the resistive element 230 and the bypass component 228, the excess energy. In addition to the purely electrical role of stabilizing the supply of the digital circuit 214, the derivative regulator level achieves several advantages in the context of the circuit described above. First, it allows to limit the voltage variation in b and therefore in a, when the object is close to the terminal, due to the low load that is presented below the tuned circuit 208: by the important current that circulates in the Bypass component 228, the captured power not essential for the operation of the numerical circuit 214 is completely dissipated in the heat. This is particularly interesting when the capacitor 206 of the tuned circuit 208 is an element realized in integrated monolithic technology since the risks of electrical discharges due to excess voltage are thus avoided. By the way, taking into account the geometrical limitations of the integrated circuit, it is not possible to realize capacitors that have high electric voltages. Now, the numerical circuit 214, which is built around a microprocessor, needs a relatively high power for its power, therefore a rather high magnetic field level, which could generate excess voltage in the tuned circuit if not the indicated precautions will be taken.

Secondly, as will be explained in more detail below, the effect of the derivation regulator is to equate the instantaneous variations of the supply current of the numerical circuit (the consumption of this type of circuits is not constant) and to avoid its repercussions on the operation of the other mechanisms of the circuit, for the communication of both the object to the terminal and the terminal to the object; thus, inconvenient variations of current or voltage could introduce modulation or demodulation errors. Finally, in the case where the object is at the limit of the reach of the terminal and where it receives only a signal from the terminal that is barely enough to power the digital circuit, the conception of the circuit avoids any excessive expenditure of energy since the The current in the branch component 228 is practically zero. In this way, all the available energy captured by the tuned circuit can be used to operate the digital circuit. As far as the clock signal is concerned, the clock extractor circuit 220 allows the alternating signal to be captured at the terminals of the tuned circuit 208 in a series c of perfectly calibrated clock pulses.

Next, the way in which information from the terminal is transmitted to the object is described, with reference to the chronograms of figure 9. In order to transmit information to the object, the terminal modulates in amplitude the magnetic field that it produces. Being binary, the information sent, this modulation is reduced to decrease by a predetermined amount, for example by 10%, the amplitude of the signal. Such a decrease corresponds, for example, to the sending of a logical "0", leaving the maximum amplitude for a logical "1": see in figure 9 the chronogram a of the signal captured by the tuned circuit 208. This is translated after the rectification and the filtering, in b, by a reduction in the rectified and filtered signal amplitude. This decrease in amplitude is detected by the amplitude demodulator 218 which supplies the logic signal applied to the digital circuit to the output. It will be noted that the decrease in amplitude resulting from the modulation of the signal sent by the terminal has no effect on the clock extractor (signal c) and on the supply voltage supplied to the digital circuit (signal d). If other techniques, other than amplitude modulation in the terminal sense - > object, for example a phase modulation of that type is the one described in many documents of the prior art, the type of modulation would have no direct impact on the operation of the regulator circuit of the invention; however, this circuit is particularly advantageous in the case of an amplitude modulation, since, as already explained, it makes it possible to perfectly alleviate the various drawbacks related to the choice of this technique. Next, the manner in which the information is transmitted, back from the object to the terminal, is explained, with reference to the timelines of Figure 10. As indicated above, in the embodiment illustrated, we proceed by variation of load, that is to say, controlled variation of the current consumed by the tuned circuit 208. For this purpose, the resistive element 224 is switched selectively, by means of the component 226, switching, for example, the resistance when the object wants to send a "0". "logical and not switched for a logical" 1". When the resistance is switched, that is to say for a logical "0", the voltage a decreases due to the supplementary load. Of course, the value of the resistance is chosen so that this voltage drop allows, however, to maintain a correct supply of the digital circuit.

However, it is possible to face a difficulty when you are at the limit of range of the terminal. Indeed, in this case, the current that must be derived in the resistive element 224 to generate the modulation can even be very high so that the digital circuit can continue to function properly. In this case, before the object begins to send information to the terminal, it is advantageously provided to place the numerical circuit in a "low consumption" mode in order to be able to consume more current in the resistive element 224 without threatening the power supply of the device. numerical circuit. This can be done, for example, by the program of the microprocessor of the digital circuit which, before starting to send data to the terminal, will place the transmission routine in RAM (whose access consumes little energy) and disconnect the EPROM memory (whose access it demands a noticeably superior energy). In other words, the numerical circuit is placed in "low consumption" mode to have an important current reserve that will be consumed in the modulation resistance for sending messages to the terminal. In addition, if a more significant modulation current can be passed in the resistive element 224 (by choosing a weaker resistance value) the modulation will be better on the terminal side, which will allow the terminal to be satisfied with less detection means. sophisticated and / or have a better signal-to-noise ratio. Always in the object sense - >; terminal, it is possible to use other types of modulations or variants, for example, as indicated above, the modulation of a sub-carrier that pilots the load variation instead of a modulation of the load directly by means of the signal to be transmitted .

Claims (14)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and therefore the property described in the following claims is claimed as property. 1. A portable object comprises multiple electrical contacts for galvanic communication with a terminal of a first type comprising multiple homologous electrical contacts, as well as a coil for non-contact communication with a terminal of a second type that emits an electromagnetic field modulated transmitting data, characterized in that the data transmitted by the terminal is programmed by a clock signal, comprising clock detector means for modifying the operation of the portable object depending on the presence or absence of a clock signal (CLK) in the signal picked up by the coil. The portable object according to claim 1, characterized in that it comprises the rectification and filtering means for obtaining a direct supply voltage (d) for the object in non-contact communication mode from the electromagnetic field picked up by the coil and in wherein the sensing means receives the input of the signal present between the coil and the rectifying and filtering means. 3. The portable object according to claim 1, characterized in that it comprises the means for demodulating the signal captured by the coil, for extracting the communication data. The portable object according to claims 2 and 3, characterized in that taken in combination with the means for demodulating are the amplitude demodulating means operating on the signal (b) released at the output of the stabilizing and filtering stages. The portable object according to claims 2 to 4, characterized in that it comprises, below the stabilizing and filtering means, the regulating means for stabilizing the direct voltage, as well as the means for selective inhibition of the regulating means, directed by the detector means of a clock The portable object according to claims 1 to 5, characterized in that it comprises the means for transmitting data from the portable object to a non-contact terminal, by modulating the load on the terminals of the coil. The portable object according to claim 6, characterized in that the modulation operated by the data transmission means is a modulation of a sub-carrier produced by the division of the clock frequency released by the detector means. The portable object according to claims 6 or 7, characterized in that the circuit is susceptible to the two modes of operation, in the nominal consumption and with low consumption and means are provided for placing the circuit in low consumption mode before the means of data emission begin to handle this modulation. The portable object according to claims 1 to 8, characterized in that the clock detection means can direct the communication and / or processing protocols of received data signals. The portable object according to claims 1 to 9, characterized in that it also comprises means for interrupting the link between the electrical contacts and other circuits of the portable object, directed by clock detection means so that said link is interrupted as soon as the portable object communicates via a non-contact route. The portable object according to claims 2 to 10, characterized in that it further comprises, below the rectification and filtering stages, a stabilizing stage comprising a Shunt regulator element mounted in a bypass between the supply terminals (VCC, GND) of the circuit to be fed and linked with a resistive component mounted in series on the power line of the circuit, the Shunt regulator element that extracts and derives a variable fraction of the supply current from the circuit so that the resistive element and the shunt regulator dissipate the increase in energy not necessary for the operation of the circuit, in order to stabilize correlatively the supply voltage (d) at the terminals of the circuit, limit the voltage variation (a) at the terminals of the tuned element above and prevent the variations of the current consumed do not influence up on the amplitude of the signal to be demodulated. 12. The portable object according to the claim 11, characterized in that it comprises the means for selectively and temporarily inhibiting the operation of the Shunt regulator. The portable object according to claims 11 and 12, characterized in that means for detecting the type of communication are provided, without contact or by contacts and where the selective and temporary inhibition of the operation of the bypass regulator is performed in response to the detection of a type of communication through contacts. 14. The portable object according to claims 1 to 13, characterized in that the whole of the electronic circuit is realized in integrated monolithic technology, except for the winding of the tuned element.