Method and device for detecting possible errors on a card in a system fixed on this card

Description

[0001] Implementations and embodiments of the invention relate to the detection of possible defects in the assembly of a system on a card ("board" in English), said card being for example a printed card comprising tracks and intended to receive components, for example soldered thereon.

[0002] The invention applies in particular, but not exclusively, to a system comprising a contactless component coupled to an impedance matching circuit.

[0003] Contactless communication uses electronic components connected to an antenna and configured to exchange information with an external device via said antenna according to a contactless type communication protocol.

[0004] A contactless component is a component capable of exchanging information through an antenna with another contactless device according to a contactless type communication protocol.

[0005] Such contactless components may, for example, be so-called “NFC” components, i.e. components compatible with near-field communication technology, known as NFC (“Near Field Communication”) technology.

[0006] The NFC component can be, for example, an NFC microcontroller.

[0007] The acronym NFC ("Near Field Communication") refers to a short-range, high-frequency wireless communication technology that allows data exchange between two devices without contact over a short distance, for example 10 cm.

[0008] NFC technology is standardized in ISO / IEC 18092 and ISO / IEC 21481 but incorporates a variety of pre-existing standards including the Type A and Type B protocols of ISO / IEC 14443.

[0009] An NFC microcontroller can generally be used either in "reader" mode or in "card" mode, to communicate with another contactless device, for example using a contactless communication protocol such as the Type A protocol of the ISO / IEC 14 443 standard.

[0010] In "reader" mode, the NFC component acts as a reader for the external contactless device, which can be a card or a tag. In reader mode, the NFC component can then read the contents of the external device and write information to the external device.

[0011] In “card” mode, the NFC component behaves like a card or label and communicates with the external device, which this time is a reader.

[0012] An NFC microcontroller can be incorporated into a cellular mobile phone, for example, and the latter can then be used, in addition to its classic telephone function, to exchange information with the external device without contact.

[0013] Many applications are thus possible, such as crossing toll barriers in transport (the mobile phone acts as a transport ticket) or payment applications (the mobile phone acts as a credit card).

[0014] Contactless components, such as NFC components, are usually connected to the antenna via an impedance matching circuit in order to optimize radio frequency communication. And, these external components used in this impedance matching circuit, for example coils and capacitors, are sized to allow good frequency tuning of the antenna, for example on a carrier frequency, (for example 13.56 MHz), and thus ensure maximum performance.

[0015] Generally, the impedance matching circuit incorporates a filter intended to filter electromagnetic interference and commonly referred to by those skilled in the art by the English acronym “EMI” (ElectroMagnetic Interference) filter. More precisely, this EMI filter, which is generally a capacitive inductive filter (LC filter), makes it possible to reduce as much as possible the high harmonic emissions of the transmission signal, typically at 13.56 MHz.

[0016] PCB mounting of a contactless component, particularly an NFC microcontroller, and the impedance matching circuit is complex. It typically requires six pins, plus pins dedicated to ground, plus a dozen discrete components—inductive, resistive, capacitive—and two antenna connections.

[0017] Most defects detected during production testing of devices are due to the assembly process on the printed circuit board.

[0018] It is best to detect these defects early enough in the production chain, for example during electronic board testing.

[0019] Conventional solutions involve testing each node of the impedance matching circuit, which requires test points and a network analyzer, for example, by placing the integrated circuit in different modes.

[0020] It is also possible to make the integrated circuit deliver the radio frequency emission signals and measure the current consumption with an external ammeter and test all the nodes of the impedance matching circuit through the test points with an external oscilloscope.

[0021] Furthermore, the JTAG (Joint Test Action Group) test chains, well known to those skilled in the art, do not allow the connections of radio frequency interfaces to be tested.

[0022] Furthermore, the test points take up space on the printed circuit board and are not accessible when the integrated circuit is covered with a shield, so additional tracks are required.

[0023] In addition, measuring equipment leads to additional costs both in terms of price and testing time.

[0024] Documents EP 2 806 586 A1, KR 2016 0088152 A and EP 2 570 818 A1 describe different approaches for fault detection in systems comprising a non-contact component.

[0025] There is therefore a need to propose a detection of possible defects on the card of a system fixed on the card, comprising for example a contactless component, such as an NFC microcontroller, connected to an impedance matching circuit, which overcomes the drawbacks mentioned above and which offers in particular a simple and easy to implement detection and which can be carried out sufficiently early in production, for example at the level of the test of the printed card, but also possibly at a later stage or even directly in a device incorporating the system, for example a cellular mobile telephone, in particular during a customer return following a fault observed.

[0026] According to one method of implementation and production, an on-board self-test is proposed which uses the contactless component itself, and which makes it possible to diagnose possible faults in the assembly of the system fixed on the card.

[0027] According to one aspect, there is provided a method for on-board detection of possible defects in a system fixed on said board, the system comprising an impedance matching circuit coupled to a contactless component, for example an NFC microcontroller, said detection comprising a first part carried out by the contactless component itself.

[0028] In other words, the contactless component itself is used to carry out at least a first part of said detection, typically measurements of levels of physical quantities such as currents and voltages, which makes it possible to do away with the use of test points and external measuring equipment.

[0029] According to one embodiment, the possible faults belong to the group comprising possible faults in the components of the impedance matching circuit, possible faults at the level of the connections of these components on said card, and possible faults at the level of the connections of the contactless component on said card.

[0030] In the first part, it is desirable to couple the impedance matching circuit to an antenna. This also allows possible defects at the coupling points with said antenna to be taken into account.

[0031] For example, a possible fault may include a short circuit type fault or an open circuit type fault.

[0032] In other words, it is possible to detect, for example, a short-circuited component of the impedance circuit or a defective component which results in an open circuit.

[0033] Similarly, at the level of a pin or a soldering point, a defect in this soldering can be detected which results in an open circuit or a short circuit with another conductive element.

[0034] The antenna which is advantageously coupled to the impedance matching circuit during the first part may be a device emulating the antenna, for example a resistive inductive circuit or the actual antenna which will be implemented in a device intended to contain said card. This may be useful in particular when the method is implemented in the device itself, for example the telephone, during a customer return due to a malfunction.

[0035] According to one mode of implementation, said detection comprises a second part analyzing results from the first part in order to diagnose any faults.

[0036] This second part can also be done within the contactless component.

[0037] Alternatively, it could be carried out within a processing unit, for example a microprocessor, fixed on the card but separate from the contactless component. It would also be possible for this second part to be carried out within a processing unit not supported by said card, for example within a processing unit of a test bench.

[0038] According to one embodiment, the first part comprises deliveries by the contactless component of test signals in the impedance matching circuit and the results then comprise levels of physical quantities resulting from these deliveries of test signals, the levels being determined by the contactless component.

[0039] Here again, the use of external measuring means is avoided.

[0040] And, the said second part will analyze these levels of physical quantities in relation to reference levels.

[0041] In this regard, the second part advantageously includes the execution of software implementing at least one decision tree.

[0042] Advantageously, said deliveries by the contactless component of the test signals in the first part comprise deliveries in differential and / or single-input / single-ended modes (according to an English expression well known to those skilled in the art).

[0043] More specifically, the contactless component has two output terminals and two input terminals connected to the impedance matching circuit and intended for the delivery and reception of contactless communication signals, for example radio frequency signals.

[0044] The first part then includes: a first delivery on the two output terminals of two first test signals in phase opposition and a reception of two first corresponding signals on the two input terminals.

[0045] So here we have a deliverance in a differential mode.

[0046] The results determined by these deliveries then include the differential level of the current flowing in the impedance matching circuit as well as the differential amplitude of the first two corresponding signals received and / or the phase of one of the first two corresponding signals received.

[0047] Generally speaking, the phase of a received signal is the phase shift of this received signal in relation to the corresponding transmitted signal (or the phase difference between this received signal and the corresponding transmitted signal). This transmitted signal is for example clocked by the local oscillator at the carrier frequency, for example 13.56 MHz.

[0048] In this differential mode, since the phase shift between the first two signals received is 180°, it is sufficient to determine the phase of only one of the first two signals received.

[0049] The first part also includes a second delivery on a first output terminal of a second test signal and a reception on a first input terminal of a second corresponding signal. We are therefore here in a single input / output mode.

[0050] The result determined by this second delivery then includes the amplitude and / or the phase of the corresponding second signal received.

[0051] The first part also comprises a third delivery on a second output terminal of a third test signal and a reception on a second input terminal of a third corresponding signal.

[0052] So we are again in a single input / output mode but this time on the other output terminal and the other input terminal.

[0053] The result determined by this third delivery includes the amplitude and / or phase of the corresponding third signal received.

[0054] Although the terms "first", "second", "third" have been assigned to the word "deliverance", this does not prejudge the order in which these deliveries are made.

[0055] In fact, this is of no importance and one can, for example, perform the two deliveries in single input / output mode before the delivery of the test signals in differential mode or vice versa, or place the delivery in differential mode between the two deliveries in single input / output mode.

[0056] In fact, this first part aims to obtain the levels of the different physical quantities. These levels can then be stored and analyzed later in the second part, for example.

[0057] In this regard, the at least one decision tree used in the second part comprises, for example, three decision levels.

[0058] The second part then includes, according to an implementation method, a first step comprising at the first decision level, a first comparison between said differential current level and at least one reference differential level, then, at the second decision level, second comparisons between said differential amplitude and / or phase and reference differential amplitudes and / or reference phases then, at the third decision level, a determination of the difference between the amplitude and / or phase of the corresponding second received signal and the amplitude and / or phase of the corresponding third received signal and third comparisons between this difference in amplitude and / or phase and reference differences in amplitude and / or phase.

[0059] Depending on the results of these comparisons, we will therefore go through the decision tree to arrive at a diagnosis leading to the detection and identification of certain defects or to a diagnosis conclusive at this stage, to an absence of defects.

[0060] However, some types of defects may not be able to be diagnosed during this first stage.

[0061] This is particularly the case when the contactless component has two additional output terminals connected to the impedance matching circuit and intended to connect the impedance matching circuit to one or more damping resistors.

[0062] In this case, if the first step of the second part reveals no detectable fault, the second part may include a second step intended to detect possible short-circuit type faults at these additional output terminals.

[0063] More specifically, in this regard, it is advantageously provided to re-execute the first part after having configured the two additional output terminals in high impedance and the second step then comprises for example additional comparisons between respectively said differential level of the current, said differential amplitude and / or the phase, said amplitude and / or phase difference and at least one additional reference differential level, at least one additional reference differential amplitude and / or at least one additional reference phase, at least one additional reference amplitude difference and / or at least one additional reference phase difference.

[0064] The different reference levels and / or the different additional reference levels may for example have been developed during a prior part, for example by simulation and / or deliberate creation of faults in the impedance matching circuit for example.

[0065] As mentioned above, the contactless component can be an NFC microcontroller.

[0066] Furthermore, as indicated above, the method can be implemented before inserting the card into a device intended to support a contactless communication function, for example a cellular mobile telephone or a tablet without these examples being limiting.

[0067] Alternatively, the method may be implemented within a device intended to support a contactless communication function and equipped with said card. This may be useful as indicated above for implementing the possible detection of defects during a customer return.

[0068] According to another aspect, there is provided an electronic assembly, comprising a card, a system fixed on said card and comprising an impedance matching circuit coupled to a contactless component, and a detection device configured to carry out a detection on said card of possible defects in the system fixed on said card, the detection device comprising first means incorporated in the contactless component itself and configured to carry out a first part of said detection.

[0069] According to one embodiment, the possible defects belong to the group comprising possible defects in the components of the impedance matching circuit, possible defects at the level of the connections of these components on said card, possible defects at the level of the connections of the contactless component on said card.

[0070] According to one embodiment, the impedance matching circuit is intended to be coupled to an antenna during said first part.

[0071] According to one embodiment, said group further comprises possible defects at the coupling points with said antenna.

[0072] According to one embodiment, a possible defect comprises a short circuit type defect or an open circuit type defect.

[0073] For example, for a component, a short-circuit fault results in an electrical connection between its terminals. For a terminal, a short-circuit fault results, for example, in a connection of this terminal with the circuit ground.

[0074] For a component, an open circuit type fault results, for example, in the component not being functional, and for a terminal, such a fault results, for example, in the signal not passing through this terminal.

[0075] According to one embodiment, the first means are configured to deliver results at the end of the first part, and the detection device further comprises analysis means configured to, during a second part of said detection, analyze said results so as to diagnose any faults.

[0076] According to one embodiment, the analysis means are incorporated within the contactless component, or within a processing unit, fixed on the card but distinct from said contactless component, or within a processing unit not supported by said card.

[0077] According to one embodiment, the first means comprise delivery means configured to deliver test signals in the impedance matching circuit and the results comprise levels of physical quantities resulting from these delivery of test signals, the first means comprising determination means configured to determine said levels.

[0078] According to one embodiment, the analysis means are configured to analyze said levels of physical quantities with respect to reference levels.

[0079] According to one embodiment, the analysis means are configured to execute software implementing at least one decision tree.

[0080] According to one embodiment, the delivery means are configured to deliver the test signals in differential and / or single input / output modes.

[0081] According to one embodiment, the contactless component comprises two output terminals and two input terminals connected to the impedance matching circuit and intended for the delivery and reception of contactless communication signals, and the delivery means are configured to: performing a first delivery on the two output terminals of two first test signals in phase opposition and receiving two first corresponding signals on the two input terminals, and the determination means are configured to determine the differential level of the current flowing in the impedance matching circuit as well as the differential amplitude of the two first corresponding signals received and / or the phase of one of these two first corresponding signals received, performing a second delivery on a first output terminal of a second test signal and receiving on a first input terminal of a second corresponding signal, and the determination means are configured to determine the amplitude and / or the phase of the second corresponding signal received, performing a third delivery on a second output terminal of a third test signal and receiving on a second input terminal of a third corresponding signal,and the determining means are configured to determine the amplitude and / or phase of the third corresponding signal received.

[0082] According to one embodiment, said at least one tree comprises three decision levels and the analysis means are configured to carry out a first step comprising: at the first decision level, a first comparison between said differential current level and at least one reference differential level, then at the second decision level, second comparisons between said differential amplitude and / or phase and reference differential amplitudes and / or reference phases, then at the third decision level, a determination of the difference between the amplitude and / or phase of said corresponding second received signal and the amplitude and / or phase of said corresponding third received signal and third comparisons between this difference in amplitude and / or phase and reference amplitude differences and / or reference phase differences.

[0083] According to one embodiment, the contactless component comprises two additional output terminals connected to the impedance matching circuit and intended to connect the impedance matching circuit to one or more damping resistors, and if the first step of the second part does not reveal any detectable fault, the analysis means are configured to carry out a second step intended to detect possible short-circuit type faults at the additional output terminals.

[0084] According to one embodiment, the two additional output terminals are configured in high impedance, the first means are configured to perform a re-execution of the first part, and the analysis means are configured to perform during the second step, additional comparisons between respectively said differential level of the current, said differential amplitude and / or the phase, said difference in amplitude and / or phase and at least one additional reference differential level, at least one additional reference differential amplitude and / or at least one additional reference phase, at least one additional reference amplitude and / or phase difference.

[0085] According to one embodiment, the electronic assembly comprises memory means for storing the reference levels and / or the additional reference levels.

[0086] According to one embodiment, the contactless component is an NFC controller.

[0087] According to another aspect, a contactless component is proposed, belonging to the electronic assembly as defined above.

[0088] According to one embodiment, this contactless component comprises first means configured to implement at least the first part of the detection method as defined above.

[0089] According to another aspect, there is provided a device, for example a cellular mobile telephone or a tablet, intended to support a contactless communication function and incorporating an electronic assembly as defined above.

[0090] Other advantages and characteristics of the invention will appear on examining the detailed description of embodiments and implementations, which are in no way limiting, and the appended drawings in which: [ Fig 1 ] illustrates an exemplary embodiment of the invention; [ Fig 2 ] illustrates an exemplary embodiment of the invention; [ Fig 3 ] illustrates an exemplary embodiment of the invention; [ Fig 4 ] illustrates an example of implementation of the invention; [ Fig 5 ] illustrates an example of implementation of the invention; [ Fig 6 ] illustrates an example of implementation of the invention [ Fig 7 ] illustrates an example of implementation of the invention; [ Fig 8 ] illustrates an example of implementation of the invention; [ Fig 9 ] illustrates an example of implementation of the invention.

[0091] On the figure 1 , the APP reference designates a communication device, for example a cellular mobile telephone, in particular of the “smartphone” type, or a tablet, equipped with an ANT3 antenna for establishing telephone communications.

[0092] In this case, the device also includes an NFC system comprising a contactless component CTLR, for example an NFC microcontroller, connected to an impedance adaptation circuit MTC (“Matching Circuit”).

[0093] This CTLR microcontroller system - MTC impedance matching circuit is fixed in a conventional and known way, for example by ball soldering, on a CD printed board.

[0094] The CD card also supports a PROC microprocessor coupled with the CTLR microcontroller.

[0095] The CD card also includes an ALM power supply module intended to power the card, as well as a GEN generator capable of delivering a CLK clock signal to a BCK terminal or pin of the CTLR microcontroller.

[0096] In addition to this BCK pin, the CTLR microcontroller includes six other terminals or pins CDMP1, RFI1, RFO1, RFO2, RFI2 and CDMP2, the functions of which will be detailed in more detail below.

[0097] These pins are connected to the MTC impedance matching circuit.

[0098] Furthermore, an NFC antenna, referenced ANT, is also coupled to the MTC impedance matching circuit via two connection points ANT1, ANT2.

[0099] In the example described here, the ANT antenna is the NFC antenna actually present in the APP device. It can be connected to the CD card via specific connections (for example connections known to those skilled in the art under the Anglo-Saxon term “Pogo pin”).

[0100] To carry out the detection of possible faults in the CTLR-MTC system fixed on the CD card, it is possible, as shown in the figure 1 , to couple the ANT antenna actually present in the phone to the CD card and to carry out this fault detection within the phone itself.

[0101] Alternatively, it is possible to detect possible faults in the CTLR-MTC system mounted on the CD card before inserting the CD card into the APP device. In this case, it is then advantageous to connect a circuit emulating the characteristics of the future antenna to the two terminals ANT1, ANT2. This circuit emulating the antenna can be, for example, a resistive-inductive-capacitive circuit (RLC).

[0102] As illustrated in the figure 2 , in the example described, the CTLR microcontroller has two output terminals RFO1, RFO2 usable in reader mode or for the generation of active or passive load modulation in card mode and two other terminals RFI1 and RFI2 usable in reader mode and in card mode.

[0103] In this regard, the CTRL microcontroller can be equipped with an internal switch allowing the RFO1 and RFO2 terminals to be short-circuited for operation in card mode or not to short-circuit these RFO1 and RFO2 terminals to allow operation in reader mode or when generating active or passive load modulation in card mode.

[0104] The external impedance matching circuit MTC is connected between the two coupling points ANT1, ANT2 and the various terminals RFI1, RFO1, RFO2, RFI2 as well as the additional terminals CDMP1 and CDMP2.

[0105] The structure of such an MTC impedance matching circuit is classical and known per se.

[0106] This impedance matching circuit here includes a filter intended to filter out electromagnetic interference (EMI filter).

[0107] This filter is classically an LC type filter comprising here a coil L1 connected in series between the terminal RFO1 and the ground GND with a capacitor CEMI1.

[0108] The EMI filter also has a coil L2 connected in series between terminal RFO2 and ground with a capacitor CEMI2.

[0109] The MTC impedance matching circuit also includes two capacitors CS1, CS2 connected in series between the coils L1 and L2 and the coupling points ANT1 and ANT2 respectively.

[0110] These capacitors are chosen to maximize the current in the antenna so as to increase the amplitude of the electromagnetic field.

[0111] The MTC impedance matching circuit also includes two resistors R_RFI1 and R_RFI2 respectively connected between terminals RFI1 and RFI2 and the nodes common to coils L1 and L2 and capacitors CS1 and CS2.

[0112] Two other capacitors C_CDMP1 and C_CDMP2 are respectively connected between the additional output terminals CDMP1 and CDMP2 and the coupling points ANT1 and ANT2.

[0113] Another capacitor CP, of lower capacitive value, is connected in parallel to the terminals of the antenna ANT. Similarly, a resistor RP is connected in parallel between the two coupling points ANT1 and ANT2.

[0114] The additional output terminals CDMP1 and CDMP2 allow the MTC impedance matching circuit to be connected to resistors called damping resistors, so as to dampen, in card mode, the resonant circuit formed by the CMP component with the ANT1 antenna and the external MTC impedance matching circuit.

[0115] If we now refer more particularly to the figure 3 , we see that the CTLR microcontroller includes first means FM1 configured to carry out a first part of the detection of possible faults.

[0116] This first part involves obtaining measured levels of physical quantities which will be detailed below.

[0117] These first FM1 means here include a control logic LG receiving the clock signal CLK from the terminal BCK ( figure 1 ).

[0118] This control logic aims in particular to develop test signals which will be delivered to the various output terminals of the CTLR microcontroller connected to the MTC impedance adaptation circuit via a DTX transmission control circuit (“driver”).

[0119] These test signals, which will be detailed in more detail below, will give rise to the reception of corresponding signals on certain terminals of the CTLR microcontroller and will allow the determination of certain levels of physical quantities by ARX reception means.

[0120] These DTX and ARX means are of classic and known structure.

[0121] Furthermore, the first FM1 means also include here a low dropout voltage regulator LDO (“Low Drop Out Voltage”) receiving a supply voltage from the ALM supply means and delivering a regulated voltage VDDRF to the DTX control circuit.

[0122] As illustrated very schematically on the figure 3 , the test signal deliveries by the CTLR contactless component include deliveries in differential and / or single input / output modes.

[0123] More precisely, in a differential mode, two test signals in phase opposition STST10 and STST11 are respectively delivered on the output terminals RFO1 and RFO2 and this results in the reception on the two input terminals RFI1 and RFI2 of two corresponding received signals STSTR10 and STSTR11.

[0124] In a single input / output mode delivery, a test signal STST2 can be delivered on the output terminal RFO1 and a corresponding received signal STSTR2 can be received on the corresponding input terminal RFI1.

[0125] In another single input / output delivery, a test signal STST3 can be delivered on the output terminal RFO2 and the corresponding signal STSTR3 received on the input terminal RFI2.

[0126] As illustrated in the figure 4 , this first part S1 of the detection of possible fault therefore includes the delivery in step S10 of the test signals STST10, STST11, STST2 and STST3 then, in step S11, the determination from the corresponding received signals of the differential level I of the current flowing in the impedance matching circuit, of the differential amplitude AM of the two received differential signals corresponding to the two test signals emitted in the differential mode, as well as the amplitudes SE1 and SE2 of the received test signals STSTR2 and STSTR3 corresponding respectively to the two test signals STST2 and STST3 emitted in the single input / output mode.

[0127] Then, in a second part of the detection process, MAL analysis means housed here in the PROC microprocessor ( figure 1 ) analyze levels I, AM, SE1, SE2 of the corresponding physical quantities with respect to reference levels IR, AMR, (SE1-SE2)R by carrying out in particular S20 comparisons, in order to establish a diagnosis.

[0128] These IR, AMR, (SE1-SE2)R reference levels are stored in an MM memory.

[0129] By way of non-limiting example, the test signals STST10, STST11, STST2 and STST3 are pulses of the order of 100 to 200 microseconds of a carrier signal, for example at 13.56 MHz, having an amplitude of 2.5 volts.

[0130] The differential level I of the current flowing in the impedance matching circuit can for example be measured very simply by measuring the current delivered by the LDO regulator.

[0131] As for the differential amplitudes AM and the amplitudes SE1 and SE2, they are determined in the ARX reception block in a conventional manner.

[0132] That being said, the ARX block also allows phase calculation.

[0133] It would therefore be possible to use phases instead of the differential amplitudes AM and instead of the amplitudes SE1 and SE2.

[0134] In this respect, whether in differential mode or single input / output mode, the phase of a received signal is the phase shift of this received signal relative to the corresponding transmitted signal.

[0135] It would also be possible to use both AM differential amplitudes and phases and both SE1 and SE2 amplitudes and phases.

[0136] As illustrated in the figure 5 , to carry out the second part of the detection, the analysis means, carried out for example in software within the microprocessor, implement an ARB decision tree having several decision levels, here three decision levels LV1, LV2 and LV3.

[0137] At each level, the analysis means carry out comparisons of the different levels of physical quantities obtained in the first part of the detection, with the reference levels IR, AMR, and (SE1-SE2)R.

[0138] More precisely, at the first level LV1 of the ARB tree, the differential current level is compared to four reference differential levels respectively equal to 10, 100, 200 and 300 milliamps.

[0139] At the LV2 level of the ARB tree, the MAL analysis means compare the AM differential amplitude to three reference differential amplitudes respectively equal to -50, -250 and -400.

[0140] It should be noted here that these reference amplitudes correspond to digital levels at the output of analog-to-digital converters used for measuring these amplitudes and whose maximum level corresponds, for example, to -500.

[0141] The middle value of the converter output scale corresponds to 2 volts, for example.

[0142] At level LV3 of the ARB tree, the analysis means first develop the difference Delta=SE1-SE2 and compare this Delta difference to two reference amplitudes respectively equal to -10 and +10.

[0143] Again, these reference amplitudes correspond to differences in output levels of the analog-to-digital converter.

[0144] At the end of this last level of comparison, we obtain different output states which correspond either to detected faults or in this case to a DGOK state considered as a state without detectable fault detected at the output of the ARB tree.

[0145] More precisely, the letter “O” following the reference of a component or terminal corresponds to a fault at the level of this component or terminal, of the open circuit type.

[0146] The letter "S" following the reference of this component or terminal corresponds to a short-circuit type fault at the level of this component or terminal. For a component, a short circuit connects its 2 terminals together. For a terminal, a short circuit connects it to the circuit ground.

[0147] More precisely, at level LV1, if the differential level I is less than or equal to 10 milliamps, then this means that there is an absence of the CLK signal, that is to say probably a fault at the BCK terminal of the CTLR microcontroller intended to receive this CLK clock signal.

[0148] If the differential level I is greater than 10 milliamperes, then at level LV2, comparisons of the differential amplitude AM with reference differential amplitudes are carried out.

[0149] We then proceed, depending on the result of these comparisons, to different comparisons of the Delta difference with the reference amplitudes -10 and +10.

[0150] Thus, if the differential level I is greater than 10 and less than or equal to 100, and the differential amplitude AM is greater than or equal to -250 and the difference Δ is less than -10, then we conclude that there is an open circuit type fault at the output terminal RFO2 and / or the coil L2.

[0151] If, on the other hand, during the last comparison, the Delta difference is greater than 10, then we can conclude that there is an open circuit type fault at the output terminal RFO1 and / or the coil L1.

[0152] Still assuming that the differential level I is greater than 10 and less than or equal to 100, and assuming that the differential amplitude AM is between -400 and -250, then a Delta difference less than or equal to 10 and greater than or equal to -10 characterizes a short-circuit type fault at the level of the capacitors CS1 and / or CS2 and / or an open-circuit type fault at the level of the coupling points ANT1 and / or ANT2 and / or a short-circuit type fault at the level of the antenna ANT itself.

[0153] For the purpose of simplifying the description, we will not describe in more detail the other paths of the ARB tree leading to the detection of possible faults, the figure 5 being explicit in itself in this regard.

[0154] On the other hand, we see that the ARB tree has a CH path leading to the DGOK state.

[0155] This path CH is traveled when the differential current level I is greater than 200 and less than or equal to 300 milliamperes, when the differential amplitude AM is between -400 and -250 and when the delta difference is less than or equal to 10 and greater than or equal to -10.

[0156] The DGOK state is representative of an absence of fault detected in the majority of components and terminals of the NFC microcontroller-impedance matching circuit system and is also representative of potential but undetectable faults of the short circuit type at the level of the resistors R_RFI1, R_RFI2, at the level of the auxiliary terminals CDMP1 and CDMP2, between these two terminals (such a short circuit between the two terminals CDMP1 and CDMP2 being referenced CDMP S) as well as an open circuit type fault at the level of the capacitor CP.

[0157] Although it is possible to stop the analysis at the output of the ARB tree, because the majority of potential defects have been detected, it is possible, if desired, to continue the analysis once the DGOK state has been reached.

[0158] In this case, as illustrated in the figure 6 , the analysis includes a second step S22 in which the two CDMP terminals are placed in high impedance (step S60) and the first part of the detection is re-executed, i.e. the test signals which were used previously are delivered again.

[0159] Levels I, AM, SE1 and SE2 are then measured again.

[0160] The analysis means then proceed in step S61 to a series of comparisons as illustrated in the figure 6 These comparisons aim to compare the measured levels I, AM, SE1 and SE2 with additional reference levels, also stored in the MM memory.

[0161] More precisely, if the differential level I is greater than 240 milliamps, and if the differential amplitude AM is less than -400 and if the difference SE1-SE2 is positive, then this is representative of a short-circuit fault at the additional terminal CDMP1.

[0162] If the differential level is greater than 240 milliamps, the differential amplitude is less than -400 and the SE1-SE2 difference is negative, then there is a short-circuit fault at terminal CDMP2.

[0163] If level I is greater than 240 milliamps and the differential amplitude greater than -400, then there is a CDMP S short-circuit type fault between the two additional terminals CDMP1 and CDMP2.

[0164] If, on the other hand, level I is less than or equal to 240 milliamps and the differential amplitude AM is less than or equal to -400, then we find ourselves in a DGOK2 state representative of an absence of detected fault knowing that a short-circuit type fault at the level of the resistors R_RFI1 and R_RFI2 is not detectable, nor is an open circuit type fault at the level of the capacitor CP.

[0165] In this case, and if the system is still faulty, then further investigations with other conventional means can be carried out at the level of these resistors and this CP capacitor.

[0166] As indicated above and as illustrated in the figure 7 , it is possible to perform the detection of possible faults (parts S1 and S2) by coupling the CD card to an antenna emulating the future antenna, before inserting the CD card into the APP device (step S70).

[0167] Alternatively, as shown in the figure 8 , it is possible to perform the detection of possible faults (parts S1 and S2) when the CD card is inserted into the APP device and coupled to the antenna, for example during a customer return following a fault noted.

[0168] As schematically illustrated on the figure 9 , the different IR, AMR, (SE1-SE2)R reference levels and / or the different additional reference levels may for example have been developed during a prior SPR part.

[0169] This preliminary SPR part uses the same test signal values ​​as those used in the first part S1 of the detection. It can include, for example, simulations and / or deliberate creations of defects in the impedance matching circuit. This preliminary part can also be carried out on several boards equipped with impedance matching circuits in order to take into account possible variations in the manufacturing processes, and then take averages of the different reference levels obtained from these different boards.

Claims

1. Method for detecting possible faults on a board in a system secured to said board, the system including an impedance matching circuit (MTC) coupled to a contactless component (CTLR) including two output terminals (RFO1, RFO2) and two input terminals (RFI1, RFI2) connected to the impedance matching circuit and intended for delivering and receiving contactless communication signals, said detection including a first part (S1) performed by the contactless component itself and a second part (S2) comprising the execution of software implementing at least one decision tree (ARB) and analysing results (I, AM, SE1, SE2) derived from the first part so as to diagnose any faults, - the first part (S1) including deliveries by the contactless component (CTLR) of test signals in the impedance matching circuit (MTC) and the results including levels of physical quantities resulting from these deliveries of test signals, said levels being determined by the contactless component, - said deliveries by the contactless component (CTLR) of the test signals including deliveries in differential and / or single input / output modes, - the first part comprising: - a first delivery on the two output terminals (RFO1, RFO2) of two first test signals in phase opposition and a reception of two first corresponding signals on the two input terminals (RFI1, RFI2), and the results determined by these deliveries include the differential level (I) of the current flowing in the impedance matching circuit as well as the differential amplitude (AM) of the two first corresponding signals received and / or a phase of one of the two first corresponding signals received, - a second delivery on a first output terminal (RFO1) of a second test signal and a reception on a first input terminal (RFI1) of a second corresponding signal, the result determined by this second delivery comprising the amplitude (SE1) and / or the phase of the second corresponding signal received, - a third delivery on a second output terminal (RFO2) of a third test signal and a reception on a second input terminal (RFI2) of a third corresponding signal, the result determined by this third delivery comprising the amplitude (SE2) and / or the phase of the third corresponding signal received.

2. Method according to claim 1, wherein the possible faults belong to the group including possible faults in the components of the impedance matching circuit (MTC), possible faults at the connections of these components on said board, and possible faults at the connections of the contactless component (CTLR) on said board.

3. Method according to claim 1 or 2, wherein during the first part the impedance matching circuit is coupled to an antenna (ANT).

4. Method according to claims 2 and 3, wherein said group furthermore includes possible defects at the points (ANT1, ANT2) of coupling with said antenna.

5. Method according to claim 2 or 4, wherein a possible defect includes a defect of the short-circuit type (S) or of the open circuit type (O).

6. Method according to one of the preceding claims, wherein the second part (S2) is carried out within the contactless component, or within a processing unit, secured on the card but separate from said contactless component, or within a processing unit not supported by said card.

7. Method according to claim 6, wherein said second part (S2) analyses said levels of physical quantities with respect to reference levels.

8. Method according to one of the preceding claims, wherein said at least one tree includes three decision levels (LV1, LV2, LV3) and the second phase (S2) comprises a first step including: - at the first decision level (LV1), a first comparison between said differential current level and at least one reference level, then - at the second decision level (LV2), second comparisons between said differential amplitude and / or the phase and the reference differential amplitudes and / or the reference phases, then - at the third decision level (LV3), determining the difference between the amplitude and / or phase of said corresponding second received signal and the amplitude and / or phase of said corresponding third received signal and third comparisons between this amplitude and / or phase difference and the differences in reference amplitudes and / or phases.

9. Method according to claim 8, wherein the contactless component includes two additional output terminals (CDMP1, CDMP2) connected to the impedance matching circuit and intended to connect the impedance matching circuit to one or more damping resistors, and if the first step of the second part (S2) reveals no detectable defect, the second part includes a second step for detecting possible short-circuit type faults at the additional output terminals (CDMP1, CDMP2).

10. Method according to claim 9, comprising a re-execution of the first part (S1) after configuring the two additional output terminals (CDMP1, CDMP2) in high impedance, and the second step includes additional comparisons between respectively said differential level of the current, said differential amplitude and / or said phase, said difference in amplitude and / or phase and at least one additional reference level, at least one additional reference differential amplitude and / or at least one additional reference phase, at least one additional reference difference in amplitude and / or phase.

11. Method according to claim 10 taken in combination with claim 7 or one of claims 1 to 9 taken in combination with claim 7, comprising a prior part of developing the reference levels and / or additional reference levels.

12. Method according to one of the preceding claims, wherein the contactless component is a controller (CTLR) compatible with near-field communication technology.

13. Method according to one of the preceding claims, implemented before inserting the card into an apparatus intended to support a contactless communication function.

14. Method according to one of the preceding claims, implemented within an apparatus intended to support a contactless communication function and equipped with said card.

15. Electronic assembly, comprising a board (CD), a system attached to said board and including an impedance matching circuit (MTC) coupled to a contactless component (CTLR) including two output terminals and two input terminals connected to the impedance matching circuit and intended for delivering and receiving contactless communication signals, and a detection device configured to perform a detection on said card of possible faults in the system fixed on said card, the detection device including first means (FM1) incorporated in the contactless component itself (CTLR) and configured to perform a first part of said detection, the first means (FM1) being configured to deliver results at the end of the first part, and the detection device furthermore comprises analysis means (MAL) configured to, during a second part of said detection, execute software implementing at least one decision tree and analyse said results so as to diagnose any defects, - the first means (FM1) include delivery means configured to deliver test signals in the impedance matching circuit and the results include levels of physical quantities resulting from these delivery of test signals, the first means include determination means configured to determine said levels, - the delivery means (DTX) are configured to deliver the test signals in differential and / or single input / output modes, - the delivery means are configured to: -- performing a first delivery on the two output terminals of two first opposed-phase test signals and receiving the two first corresponding signals on the two input terminals, and the determination means are configured to determine the differential level of the current flowing in the impedance matching circuit as well as the differential amplitude of the first two corresponding signals received and / or a phase of one of the first two corresponding signals received, -- performing a second delivery on a first output terminal of a second test signal and receiving on a first input terminal a second corresponding signal, and the determination means are configured to determine the amplitude and / or phase of the second corresponding signal received, -- performing a third delivery on a second output terminal of a third test signal and receiving on a second input terminal a corresponding third signal, and the determination means are configured to determine the amplitude and / or phase of the corresponding third signal received.

16. Electronic assembly according to claim 15, wherein the possible faults belong to the group including possible faults in the components of the impedance matching circuit (MTC), possible faults at the connections of these components on said board, and possible faults at the connections of the contactless component (CTLR) on said board.

17. Electronic assembly according to claim 15 or 16, wherein the impedance matching circuit (MTC) is intended to be coupled to an antenna (ANT) during said first part.

18. Electronic assembly according to claims 16 and 17, wherein said group further includes possible defects at the coupling points (ANT1, ANT2) with said antenna.

19. Electronic assembly according to claim 16 or 18, wherein a possible fault includes a fault of the short-circuit type (S) or of the open circuit type (O).

20. Electronic assembly according to any one of claims 15 to 19, wherein the analysis means (MAL) are incorporated within the contactless component, or within a processing unit, fixed on the card but distinct from said contactless component, or within a processing unit not supported by said card.

21. Electronic assembly according to one of claims 15 to 20, wherein the analysis means (MAL) are configured to analyse said levels of physical quantities with respect to reference levels.

22. Electronic assembly according to one of claims 15 to 21, wherein said at least one tree includes three decision levels (LV1, LV2, LV3) and the analysis means (MAL) are configured to perform a first step comprising: - at the first decision level, a first comparison between said differential current level and at least one reference differential level, then - at the second decision level, second comparisons between said differential amplitude and / or the phase and reference differential amplitudes and / or reference phases, then - at the third decision level, determining the difference between the amplitude and / or phase of said corresponding second received signal and the amplitude and / or phase of said corresponding third received signal and third comparisons between this amplitude and / or phase difference and the differences in reference amplitudes and / or phases.

23. Electronic assembly according to claim 22, wherein the contactless component (CTLR) includes two additional output terminals connected to the impedance matching circuit and intended to connect the impedance matching circuit to one or more damping resistors, and if the first step of the second part reveals no detectable defect, the analysis means (MAL) are configured to perform a second step to detect possible short-circuit type faults at the additional output terminals.

24. Electronic assembly according to claim 23, wherein the two additional output terminals are configured in high impedance, the first means (FM1) are configured to perform a re-execution of the first part, and the analysis means (MAL) are configured to perform, in the second step, additional comparisons between respectively said differential current level, said differential amplitude and / or said phase, said amplitude and / or phase difference and at least one additional reference level, at least one additional reference differential amplitude and / or at least one additional reference phase, at least one additional reference amplitude and / or phase difference.

25. Electronic assembly according to claim 24 taken in combination with claim 19 or one of claims 15 to 23 taken in combination with claim 19, comprising memory means for storing the reference levels and / or additional reference levels.

26. Electronic assembly according to any one of claims 15 to 25, wherein the contactless component is a microcontroller (CTLR) compatible with near-field communication technology.

27. Contactless component belonging to the electronic assembly according to one of claims 15 to 26.

28. Contactless component comprising first means (FM1) configured to implement at least the first part of the detection method according to one of claims 1 to 14.

29. Apparatus intended to support a contactless communication function and incorporating an electronic assembly according to any one of claims 15 to 28.

30. Apparatus according to claim 29, being a cellular mobile phone or a tablet.