Power supply of an electronic device

Abstract

Power supply of an electronic device The present description relates to an electronic device (100) comprising: - at least one universal integrated circuit card (300) or at least one secure element and at least one power supply circuit (301) of said card or said secure element, said power supply circuit (103; 301) being connected to at least one first power supply voltage source of the electronic device and comprising a voltage detector (305) adapted to determine whether said first voltage source provides a first power supply voltage (VCC-UICC-IN) different from a reference voltage; and - at least one near-field communication module adapted to switch to an active mode each time said voltage detector (305) determines that said first power supply voltage (VCC-UICC-IN) is different from the reference voltage. Figure for abstract: Fig. 3

Description

Title of the invention: Power supply for an electronic device Technical field

[0001] The present description relates generally to electronic systems and devices, and the power supply of these systems and devices. The present description relates, more particularly, to electronic devices adapted to near field communication (NFC), and to the adaptation of the power supply means of such electronic devices. Prior art

[0002] Wireless communications are increasingly used nowadays for different applications such as information exchange, banking payments, energy exchanges, etc. There are several types of wireless communication, for example, Near Field Communication (NFC), communications using high frequencies at longer distances such as Bluetooth communications, etc.

[0003] It would be desirable to be able to improve at least in part certain aspects of known devices adapted to near field communication technology. Summary of the invention

[0004] There is a need for devices adapted to higher performance near field communication technology.

[0005] There is a need for devices suitable for near field communication technology that consume less power.

[0006] There is a need for devices suitable for near field communication technology that start up more quickly.

[0007] One embodiment overcomes all or part of the drawbacks of known devices adapted to near-field communication technology.

[0008] One embodiment provides an electronic device comprising: - at least one universal integrated circuit card or at least one secure element and at least one power supply circuit for said card or said secure element, said power supply circuit being connected to at least one first power supply voltage source of the electronic device and comprising a voltage detector adapted to determine whether said first voltage source provides a first power supply voltage different from a reference voltage; and - at least one near-field communication module adapted to switch to an active mode each time said voltage detector determines that said first supply voltage is different from the reference voltage.

[0009] Another embodiment of a method for powering a universal integrated circuit card or a secure element included in an electronic device further comprising: - at least one power supply circuit for said card or said secure element, said power supply circuit being connected to at least one first power supply voltage source of the electronic device and comprising a voltage detector adapted to determine whether said first voltage source provides a first power supply voltage different from a reference voltage; and - at least one near-field communication module adapted to switch to an active mode each time said voltage detector determines that said first supply voltage is different from the reference voltage.

[0010] According to one embodiment, in the power supply circuit of said card or said secure element, the first power supply voltage of said first voltage source is supplied to said card or said secure element via a switch controlled by a first circuit comprising a voltage follower and a first current slope limiter.

[0011] According to one embodiment, each time said voltage detector determines that said first supply voltage is different from the reference voltage, said near-field communication module controls the starting of said first circuit.

[0012] According to one embodiment, each time said voltage detector determines that said first supply voltage is equal to the reference voltage, said near-field communication module commands the stopping of said first circuit.

[0013] According to one embodiment, said power supply circuit is connected to at least one second power supply voltage source of the electronic device.

[0014] According to one embodiment, said at least one second supply voltage source is a battery.

[0015] According to one embodiment, the power supply circuit of said card or said secure element, a second power supply voltage of said second voltage source is supplied to said card or said secure element via a second circuit comprising a linear voltage regulator and a second current slope limiter.

[0016] According to one embodiment, each time said voltage detector determines that said first supply voltage is different from the reference voltage, said near-field communication module deactivates the automatic start-up of said second circuit.

[0017] According to one embodiment, each time said voltage detector determines that said first supply voltage is equal to the reference voltage, said near field communication module activates the automatic start-up of said second circuit.

[0018] According to one embodiment, when the near-field communication module changes from a standby state or an inactive state to an active state, the following successive operations are performed: - the components and circuits of said electronic device are started; - the software of the electronic device and said card are started at the same time.

[0019] According to one embodiment, the starting of said card or said secure element comprises the following successive steps: - the start-up of the power supply circuit of said card or said secure element; and - the software start-up of said card or said secure element.

[0020] According to one embodiment, during the start-up of the power supply circuit, said voltage detector checks whether the first voltage source provides a first supply voltage equal to the reference voltage.

[0021] According to one embodiment, the power supply circuit supplies said card or said secure element with said second power source. Brief description of the drawings

[0022] These characteristics and advantages, as well as others, will be explained in detail in the following description of particular embodiments given without limitation in relation to the attached figures among which:

[0023] [Fig.l] represents, very schematically and in the form of blocks, an embodiment of an electronic device;

[0024] [Fig.2] represents, very schematically and in the form of blocks, an example of near-field communication;

[0025] [Fig. 3] represents, schematically and in block form, an embodiment of a part of a power supply circuit of a part of the electronic device of [Fig. 1];

[0026] [Fig.4] represents timing diagrams illustrating the operation of the embodiment of [Fig.3]; and

[0027] [Fig.5] represents timing diagrams illustrating part of the operation of the embodiment of [Fig.l]. Description of the embodiments

[0028] The same elements have been designated by the same references in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same references and may have identical structural, dimensional and material properties.

[0029] For the sake of clarity, only the steps and elements useful for understanding the described embodiments have been shown and are detailed. In particular, the protocols used during the implementation of near-field communication are not detailed. The embodiments described below adapt to the usual protocols used during the implementation of near-field communication.

[0030] Unless otherwise specified, when referring to two elements connected to each other, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") to each other, this means that these two elements can be connected or be connected by means of one or more other elements.

[0031] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "upper", "lower", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made unless otherwise specified to the orientation of the figures.

[0032] Unless otherwise specified, the expressions "about", "approximately", "substantially", and "of the order of" mean to within 10%, preferably to within 5%.

[0033] [Fig.l] represents, very schematically and in the form of blocks, an embodiment of an electronic device 100.

[0034] The electronic device 100 comprises a processor 101 (CPU) adapted to implement different processing of data stored in memories and / or provided by other circuits of the device 100.

[0035] The electronic device 100 further comprises different types of memories 102 (MEM), including, for example, at least one volatile memory and at least one register, generally several registers. The device 100 may further comprise, according to one example, a non-volatile memory, and a read-only memory. Each memory is adapted to store different types of data.

[0036] The electronic device 100 further comprises power supply circuits 103 (ALIM). The circuits 103 manage the electrical power supply of the various circuits and components of the device 100. The circuits 103 comprise, for example, at least one battery, means for recharging the battery, voltage adaptation circuits, such as voltage regulators, etc. An embodiment of one of the power supply circuits 103 is described in more detail in relation to FIGS. 3 to 5.

[0037] The electronic device 100 further comprises circuits 104 (NFC) adapted to implement near field communication, or near field communication module 104, or NFC module 104. The NFC module 104 comprises, for example, oscillating / resonant circuits, data transmission and reception circuits, data conversion circuits, etc. An example of Near field communication and the various functionalities of the NFC module 104 are described in more detail in relation to [Fig.2].

[0038] The electronic device 100 is further adapted to comprise at least one, or even several, universal integrated circuit card (UICC) cards 105, also called a SIM card (subscriber identification module). A universal integrated circuit card 105 is a card comprising confidential data linked to one or more functions of the electronic device 100. According to a common example, a SIM card of the type of a card 105 can be used in a cellular telephone to enable the use of telephone communications. According to another example, a card 105 can enable the implementation of a banking application by an electronic device, or the implementation of a public transport application. The card(s) 105 can be, in certain cases, secure elements.

[0039] The electronic device 100 further comprises at least one secure element 106 (SE) adapted to implement different functions of the device 100 in a secure manner. The secure element 106 may comprise a secure processor, memories intended to store sensitive data, encryption and / or decryption circuits, circuits allowing secure communication with other electronic devices, etc. According to one embodiment, a part of the NFC module 104 is part of the secure element 106.

[0040] The electronic device 100 may further comprise circuits, not shown in [Fig.l], adapted to implement different functions of the device 100. The circuits are diverse, and may comprise measurement circuits, data analysis circuits, sensors, other circuits enabling communication with other electronic devices, display devices, etc.

[0041] The different circuits and modules of the device 100 are connected to each other, and can communicate, via a communication bus 107.

[0042] As previously stated, the circuits 103 are adapted to manage the power supply, in voltage and in current, of the different circuits and components of the device 100. According to one embodiment, the circuits 103 comprise at least one circuit particularly adapted to manage the power supply of the cards 105 or the power supply of the secure element 106 by taking into account different power supply modes of the different circuits and components of the device 100. Such a circuit is described in more detail in relation to FIGS. 3 and 4. More particularly, in the embodiment described here, the power supply of the cards 105 or of the secure element 106 depends on the operating mode of the NFC module 104. The different operating modes of the NFC module 104 are described in relation to [Fig.2].

[0043] [Fig.2] schematically represents wireless communication, and more particularly, near-field communication between devices electronics 201 (TERM) and 202 (CARD). The device 202 is a device of the type of the device 100 described in relation to [Fig.l]. According to one example, the device 201 is also a device of the type of the device 100 described in relation to [Fig.l].

[0044] Near Field Communication (NFC) technologies enable high-frequency, short-range communications. Such systems exploit a radiofrequency electromagnetic field emitted by a device (terminal or reader) to communicate with another device (transponder or card).

[0045] In recent systems, the same device can operate in card mode or in reader mode (for example in the case of near-field communication between two mobile phones). It is then common for the devices to be battery-powered and for their functions and circuits to be put on standby so as not to consume energy between periods of use. The devices must then be "waken up" when they are within range of each other.

[0046] We assume the case of the two electronic devices 201 and 202, in which, for example, the device 201 is a terminal, or reader, and the device 202 a transponder, but everything that will be described applies more generally to any system in which a transponder picks up an electromagnetic field radiated by a reader, a terminal or a terminal.

[0047] Depending on the applications, for a communication, one of the devices operates in so-called reader mode while the other operates in so-called card mode, or the two devices communicate in peer-to-peer (P2P) mode. Each device comprises at least one electronic circuit 104 (NFC), or NFC module 104, for generating a radiofrequency signal emitted using an antenna of an oscillating / resonant circuit. The radiofrequency field generated by one of the devices 201 or 202 is picked up by the other device 202 or 201 which is within range and which also comprises an antenna. In certain applications, when a device is not communicating, it is switched to standby mode in order to reduce the energy consumed. This is particularly the case for battery-powered devices.When the first device 201 emits an electromagnetic field to initiate communication with the second device 202, this field is picked up by this second device 202 as soon as it is within range. This field is detected by the circuits 104 of the second device 202 which, if they are on standby, are reactivated. This results in a variation of the charge constituted by the circuits of the second device 202 on the resonant circuit for generating the field of the first device 201. In practice, the corresponding variation in phase or amplitude of the emitted field is detected by the first device 201 which then starts an NFC communication protocol with the second device 202. On the first device 201 side, it is detected in practice whether the amplitude of the . voltage across the resonant circuit falls below a threshold or if the voltage across the resonant circuit has a phase shift greater than a threshold. Once the first device 201 has detected the presence of the second device 202 in its field, it begins a communication establishment procedure, implementing transmissions of requests by the first device 201 and responses by the second device 202.

[0048] During near-field communication, devices 201 and 202 are positioned within range of each other. More specifically, device 202 is positioned within range of device 201 so as to be able to sense the electromagnetic field of device 201. For example, device 202 is positioned at a distance generally less than 10 cm from device 201. According to another example, device 202 is in mechanical contact with device 201.

[0049] The device 201 is a terminal which may be, for example, fixed or mobile. It is the device 201 which is responsible for initiating the communication. For example, the terminal 201 is a payment terminal or a mobile telephone.

[0050] The device 202 is a generally mobile transponder. According to a preferred embodiment, the transponder 202 is a microcircuit card (or smart card), for example a bank card or a transport card. Alternatively, the device 202 could be a mobile telephone or a connected object. According to a preferred embodiment, the device 202 comprises a universal integrated circuit card adapted to implement the functionalities of a bank card or a transport card, and / or a secure element. The various electronic circuits of the device 202 adapted to implement various commands sent by the device 201, such as for example, authentication circuits, cryptography circuits, the cards 105, the secure element 106, etc., are used to receive the data transmitted by the transponder 201.

[0051] Furthermore, the different power supply modes of certain circuits and components of the device 202 may have an influence on the power supply modes, or on the power supply, of other circuits and components of the device 202. In particular, and according to one embodiment, the NFC module 104 has several power supply modes which influence the power supply mode, and on the power supply, of circuits and components of the device 202, and, in particular, of the cards 105 or a secure element 106 of the device 202 (not shown in [Fig.2]).

[0052] The NFC module 104 includes at least three power modes: an active power mode, a standby power mode, and an inactive power mode. When the NFC module 104 is in the active power mode, i.e., the NFC module 104 is in an active state or is active, the NFC module 104 is available for use at any time. All circuits and components included in the NFC module 104 are likely to be powered, it is in this mode that the NFC module 104 is likely to consume the most energy. When the NFC module 104 is in the standby power mode, in other words when the NFC module is in a standby state or is in standby, the NFC module 104 is expected to be able to provide a service comprising fewer functionalities, and therefore only a portion of the circuits included in the NFC module 104 are likely to be powered. In this mode, the NFC module 104 generally consumes less energy than in the active power mode. When the NFC module 104 is in the inactive power mode, or hibernation mode, in other words when the NFC module 104 is in an inactive state or is inactive, only a minimal portion of the circuits of the NFC module 104 are likely to be powered. It is in this power mode that the NFC module 104 consumes the least energy.

[0053] [Fig. 3] represents, schematically and in block form, a universal integrated circuit card 300 and its power supply circuit 301 of an electronic device of the type of the device 100 described in relation to [Fig. 1]. More particularly, the card 300 is a card 105 of the device 100 of [Fig. 1], and the power supply circuit 301 is adapted to be part of the power supply circuits 103 of the device 100.

[0054] The circuit 301 comprises two input terminals BAT and SUPP-UICC-IN, and one output terminal SUPP-UICC-OUT. The two input terminals BAT and SUPP-UICC-IN are connected, preferably connected, to power sources, and the output terminal SUPP-UICC-OUT is connected, preferably connected, to a power supply terminal VCC of the card 300.

[0055] The input terminal BAT receives a supply voltage VBAT, referenced with respect to a reference voltage, for example ground, from a battery. The supply voltage VBAT is, for example, a direct voltage. According to one example, the battery is part of the power supply circuits of the electronic device of which the card 300 and the power supply circuit 301 are part. The input terminal BAT is connected to the output node SUPP-UICC-OUT via a circuit 302 (LDO + SRL) comprising: - a linear voltage regulator (low-dropout regulator, LDO) adapted to adjust the value of the VBAT voltage so that it corresponds to the value of the VCC-UICC-OUT supply voltage expected by the 300 card; - a pull-down resistor suitable for protecting the linear voltage regulator when it starts up; and - a first current slope limiter (slew rate limiter) adapted to protect the VCC power supply terminal of the 300 card against current peaks.

[0056] The input terminal SUPP-UICC-IN receives a supply voltage VCC-UICC-IN, referenced to the reference voltage, from another source power supply other than the battery. This power source is, for example, a main power source of the device in which the card 300 and the power supply circuit 301 are included, which is switched on when said device is powered on and which is switched off when said device is powered off. According to one example, the supply voltage of this power source is transmitted to the power supply terminal SUPP-UICC-IN via a data transmission line, for example by a modulator-demodulator, or modem. The input terminal SPP-UICC-IN is connected to the output node SUPP-UICC-OUT via a switch 303 controlled by a circuit 304 (Follow + SLR) comprising: - a voltage follower adapted to adapt the impedance of the power source from which the VCC-UICC-IN voltage comes to the input impedance of the card 300; and - a second current slope limiter (slew rate limiter) adapted to protect the VCC power supply terminal of the card 300 against current peaks.

[0057] In addition, and according to one embodiment, the voltage VCC-UICC-IN of the input terminal SUPP-UICC-IN is monitored by a voltage detector 305 (VOLT DET).

[0058] The operation of the power supply circuit 301 is as follows. A more detailed mode of operation of the power supply circuit 301 is described in relation to [Fig.4],

[0059] The card 300 can be powered by two different power sources, called the main power source and the battery, the input terminal SUPP-UICC-IN receiving a supply voltage from the main power source, and the input terminal BAT receiving a supply voltage from the battery, as described above. The battery is the default power supply mode of the card 300, and the main power source only powers the card 300 when it is powered on. In addition, the power supply of the card 300 is controlled by the NFC module of the device comprising the card 300, and more particularly by the power supply mode of this NFC module. This aspect is described in more detail in relation to [Fig.4].

[0060] In particular, when the main power source is switched off, for example when the electronic device comprising the card 300 and the circuit 301 is switched off, the circuit 304 controls the opening of the switch 303, and the output node SUPP-UICC-OUT receives a supply voltage coming from the terminal BAT, via the circuit 302. In this case, the voltage VCC-UICC-IN has a value of the order of the value of the reference voltage.

[0061] On the other hand, when the main power source is switched on, for example when said device is switched on or the data transmission line transmitting the supply voltage of said main power source is switched on, the circuit 304 controls the closing of the switch 303 to supply the voltage VCC-UICC-IN to the output terminal SUPP-UICC-OUT. In this case, the voltage VCC-UICC-IN has a value different from the reference voltage and adapted to power the card 300. On the side of the input terminal BAT, the circuit 302 is not activated so as not to have two power sources powering the card 300 at the same time, and more particularly the voltage regulator of the circuit 302 is not activated.

[0062] According to an alternative embodiment, the embodiment of [Fig. 3] could be applied to the power supply of the secure element of an electronic device of the type of device 100 described in relation to [Fig. 1]. More particularly, in this case, the card 300 is replaced by a secure element 106 of the device 100 of [Fig. 1], and the power supply circuit receives the voltage VCC-UICC-IN from a main power source of the electronic device or from a secondary power source dedicated mainly to the power supply of the secure element. The description of [Fig. 4] also applies to this alternative embodiment.

[0063] [Fig.4] represents three timing diagrams illustrating the operation of the circuit 301 described in relation to [Fig.3].

[0064] More particularly, [Fig.4] illustrates timing diagrams: - the VCC-UICC-IN voltage received as input by the SUPP-UICC-IN input terminal; - the voltage VCC-UICC-OUT supplied by the output terminal SUPP-UICC-OUT; and - the states of the NFC module of the device comprising the card 300 and its power supply circuit 301.

[0065] Between an initial state t0 and a time t1, subsequent to time t0, the NFC module is in a state where it does not consume much energy, for example in a standby state or in an inactive state (hatched in [Fig.4]). The main power source does not provide a supply voltage and the supply voltage VCC-UICC-IN is at a low level, i.e. at a voltage value of the order of the reference voltage. In addition, the NFC module controls the power supply of the card 300, and when the NFC module is in a standby state or in an inactive state the card 300 is not powered. Thus the battery is not used to power the card 300, and the voltage VCC-UICC-OUT has a value of the order of the reference voltage.

[0066] Between the instant t1 and an instant t2, subsequent to the instant t1, the voltage VCC-UICC-IN changes from the low state to a high state, that is to say to a state where the value of the voltage VCC-UICC-IN is adapted to supply the card 300. According to one example, the device comprising the card 300 and the power supply circuit 301 is switched on, or the data transmission line supplying the voltage VCC-UICC-IN is activated. According to one embodiment, the voltage detector 305 detects this change in state of the voltage VCC-UICC-IN and informs the NFC module which then changes to an active state. By changing to an active state, the NFC module controls the starting of the circuit 304, and more particularly the starting of the voltage follower and the slope limiter. of current included in circuit 304. The voltage VCC-UICC-OUT then changes from low state to high state, for example, with a slight delay compared to the voltage VCC-UICC-IN. The card 300 is then powered by the main power source. In addition, during this period, the NFC module disables the ability of circuit 302 to start automatically upon detection of a radiofrequency field.

[0067] Between time t2 and a time t3, subsequent to time t2, the NFC module, having commanded the start of the circuit 304, returns to the standby or inactive mode in which it was before time t1. The circuit 304 continues to operate. The voltages VCC-UICC-IN and VCC-UICC-OUT remain in a high state and supply the card 300.

[0068] Between time t3 and a time t4, subsequent to time t3, the voltage VCC-UICC-IN changes from the high state to the low state, and is no longer able to power the card 300. According to one example, the device comprising the card 300 and the power supply circuit 301 is switched off, or the data transmission line supplying the voltage VCC-UICC-IN is deactivated. In the case considered here, that is to say when the NFC module was in an inactive state before being woken up by the change of state of the voltage VCC-UICC-IN, the voltage VCC-UICC-OUT then changes from the high state to the low state, for example, with a slight delay relative to the voltage VCC-UICC-OUT. Indeed, according to one embodiment, the voltage detector 305 detects the change in state of the VCC-UICC-IN voltage and informs the NFC module which then switches to an active state.By switching to an active state, the NFC module controls the shutdown of the circuit 304, and more particularly of the voltage follower and the current slope limiter included in the circuit 304. The card 300 is then no longer powered by the main power source. The NFC module being in a standby or inactive state before time t3, the battery does not take over to power the card 300. In addition, during this period, the NFC module reactivates the possibility of the circuit 302 to start automatically upon detection of a radiofrequency field.

[0069] However, if the NFC module had been in an active state before being woken up by the change in state of the VCC-UICC-IN voltage, the power source of the VCC-UICC-OUT voltage would then have been changed to be the battery. For this, the NFC module would have commanded the activation of the circuit 302, then the opening of the switch 303.

[0070] Between time t4 and a time t5, subsequent to time t4, the NFC module, having commanded the circuit 304 to stop, returns to the standby or inactive mode in which it was before time t3. The voltages VCC-UICC-IN and VCC-UICC-OUT remain in a low state, and the card 300 is not powered.

[0071] At a time t5, subsequent to time t4, the NFC module transitions from the standby or inactive state to the active state. According to one example, the NFC module has sensed a radiofrequency field and is preparing to initiate near-field communication.

[0072] Between a time t6, subsequent to time t5, and a time t7, subsequent to time t6, the NFC module controls the power supply to the card 300. Since the voltage VCC-UICC-IN is still in a low state, power supply by the main power source of the device is not possible, and the battery is used to power the card 300. Thus, the NFC module controls the start-up of the circuit 302 so that it provides the node SUPP-UICC-OUT with a voltage suitable for powering the card 300. The voltage VCC-UICC-OUT then goes to a high state. The NFC module can, for example, transmit data to the card 300 if the near-field communication that it has started concerns the card 300.

[0073] According to one example, starting the circuit 302 comprises, firstly, using the pull-up resistor to ensure that the voltage VCC-UICC-OUT at the output node SUPP-UICC-OUT is at a low level. The pull-up resistor is, for example, used for a duration of the order of 400 ps. The voltage regulator of the circuit 302 is then started.

[0074] An advantage of the embodiment presented in relation to Figures 3 and 4 is that by using the voltage detector 305, the NFC module can activate the circuit 304 and, more particularly, can activate the current slope limiter at each change in the state of the VCC-UICC-IN voltage. This makes it possible to avoid current overconsumption or current peaks that may be generated at these times.

[0075] [Fig. 5] represents a timing diagram and two diagrams illustrating in more detail operations carried out during the startup of the NFC module 104 and the or universal integrated circuit card 105 of the device 100 described in relation to [Fig. 1]. In the example represented here, only one card 105 of the device 100 is considered. [Fig. 5] illustrates more precisely: - an RF-Field chronogram illustrating the appearance of a radiofrequency field; - an NFC-Op timing diagram illustrating the operations implemented for starting the NFC module; and - a UICC-Op timing diagram illustrating the operations implemented for starting card 105.

[0076] The start-up of the NFC module 104 corresponds to the transition from a standby or inactive state to the active state. The start-up of the NFC module takes place, for example, when the NFC module detects a radiofrequency field. It should be noted that when the NFC module is in standby or is inactive, it is capable of detecting a radiofrequency field, and for this the NFC module periodically (alternatively, continuously) performs a radiofrequency field search. According to an exemplary embodiment, when the NFC module is in standby or is inactive, it performs a radiofrequency field search every 0.5 to 5 ms, for example every 1 to 2 ms. And not performing These searches show that periodically, the NFC module lowers its energy consumption.

[0077] In addition, starting the card 104 corresponds to the transition from a switched-off state where the card 104 cannot be used to a powered-on state where the card 104 can use most of its functions.

[0078] Before an initial time t'0, no radiofrequency field is present or can be detected by the NFC module 104, and the RF-Field timing diagram is in a low state. The NFC module 104 is in standby or inactive (HIB). The card 105 is in a switched-off state (UICC OFF).

[0079] Between the initial instant t'0 and an instant fl, subsequent to the instant t'0, a radiofrequency field can be detected by the NFC module 104, and the RF-Field timing diagram goes to a high state. More particularly, it is considered that from the instant t'0 a radiofrequency field is made detectable. The field remains detectable without sending a command for a duration Dmax during which the surrounding devices are supposed to prepare to be able to pick up said field. According to an exemplary embodiment, the duration Dmax is of the order of 5 ms. Once the duration Dmax has passed, the field begins to send instructions and data Data represented by a hatched rectangle in [Fig.5]. In the specific case of [Fig.5], this means that the NFC module 104 of the device must be active before an instant noted t'O+Dmax. The NFC module 104 does not detect the automatic radiofrequency field. The NFC module is therefore always on standby or always inactive.Likewise, card 105 is still off.

[0080] At a time t'2, subsequent to time t'1, the NFC module 104 detects the radiofrequency field. The NFC module 104 begins the various operations comprised by its startup to become active. For this, the NFC module 104 initially controls the startup of certain circuits and components of the electronic device (HW BOOT). The card 105 is always switched off. More particularly, during this startup, the internal power supplies and the power supply circuits of the electronic device are started.

[0081] Between time t'3 and a time t'4, subsequent to time t'3, the NFC module 104 controls, according to one embodiment, the starting of the various software or programs of the electronic device (FW BOOT) and the starting of the card 105.

[0082] The starting of the various software programs of the electronic device 100 is implemented by the processor 101 of the device 100.

[0083] The start-up of the card 105 begins with the start-up of the power supply of the universal integrated circuit card of the electronic device (UICC Alim). More particularly, the NFC module checks the voltage delivered by the power supply circuit of the card 105. The automatic start-up of the power supply voltage regulator of the card causes the device 100 to start a counter. This counter is intended to be read later and its content communicated to the NFC circuit software. This allows it to determine when the universal integrated circuit card (UICC) is powered by the voltage regulator. On this basis, the NFC router software is able to determine when it can initiate communication with the UICC card. In practice, once the power supply circuit is able to power the card 105, i.e. at a time t'4, later than time t'3, the booting of the card 105 (UICC BOOT) can begin, and more particularly the software booting of the card 105 can start.

[0084] At a time t'5, later than time t'3 and, for example, later than time t'4, the software of the device 100 is in operating state. The NFC module can then switch to an active state (NFC FW ACTIVE) and prepare to receive the instructions and data Data provided by the radiofrequency field.

[0085] At a time t'6, later than time t'4 and, for example, later than time t'5, the card 105 is in a state to operate (UICC ON).

[0086] At a time t'7, corresponding to the time t'O+Dmax, the NFC module, the circuits and components of the device 100 controlled by the NFC module, and the card 105 are ready to receive the Data instructions and commands from the radiofrequency field.

[0087] An advantage of this embodiment is that thanks to the presence of the voltage detector 305 of the power supply circuit of the card 105 (described in relation to [Fig. 3]), the NFC module can start said power supply circuit without requiring the software of the device 100 to be started. In certain cases, this makes it possible to start the NFC module and the card 105 in a time less than Dmax, that is to say in an exemplary embodiment in a time less than 5 ms. More generally, this embodiment allows a faster start-up of the NFC module and the circuits and components that it controls.

[0088] Furthermore, this embodiment can be adapted to the power supply of the secure element 106 of the device 100. Indeed, as for the card(s) 105, the NFC module can be adapted to control the start of the power supply of the secure element 106 each time the NFC module detects a radiofrequency field. Thus, according to one embodiment, and similarly to the operation implemented at time t'3, once the NFC module has started certain circuits and components of the device 100 (HW BOOT), the NFC module simultaneously controls: - starting the power supply circuit of the secure element 106; and - starting the various software programs of the device 100.

[0089] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variants could be combined, and other variants will occur to those skilled in the art.

[0090] Finally, the practical implementation of the embodiments and variants described is within the reach of those skilled in the art from the functional indications given above.

Claims

Claims

1. Electronic device (100) comprising: - at least one universal integrated circuit card (105; 300) or at least one secure element (105) and at least one power supply circuit (103; 301) of said card or said secure element, said power supply circuit (103; 301) being connected to at least one first power supply voltage source of the electronic device (100) and comprising a voltage detector (305) adapted to determine whether said first voltage source provides a first power supply voltage (VCC-UICC-IN) different from a reference voltage;and - at least one near-field communication module (104) adapted to switch to an active mode each time said voltage detector (305) determines that said first supply voltage (VCC-UICC-IN) is different from the reference voltage, wherein, in the supply circuit (301) of said card (105, 300) or said secure element, the first supply voltage of said first voltage source is supplied to said card (300) or said secure element via a switch (303) controlled by a first circuit (304) comprising a voltage follower and a first current slope limiter.;

2. A method for powering a universal integrated circuit card (105; 300) or a secure element included in an electronic device (100) further comprising: - at least one power supply circuit (103; 301) of said card or said secure element, said power supply circuit (103; 301) being connected to at least one first supply voltage source of the electronic device (100) and comprising a voltage detector (305) adapted to determine whether said first voltage source provides a first supply voltage (VCC-UICC-IN) different from a reference voltage; and - at least one near-field communication module (104) adapted to switch to an active mode each time said voltage detector (305) determines that said first supply voltage (VCC-UICC-IN) is different from the reference voltage, the method comprising a step of powering said universal integrated circuit card (105;300) or said secure element; wherein, in the power supply circuit (301) of said card (105, 300) or said secure element, the first supply voltage of said first voltage source is supplied to said card (300) or said secure element via a switch (303) controlled by a first circuit (304) comprising a voltage follower and a first current slope limiter.

3. Device according to claim 1, or method according to claim 2, wherein each time said voltage detector (305) determines that said first supply voltage (VCC-UICC-IN) is different from the reference voltage, said near field communication module (104) commands the start of said first circuit (304).

4. A device according to claim 1 or 3, or a method according to claim 2 or 3, wherein each time said voltage detector (305) determines that said first supply voltage (VCC-UICC-IN) is equal to the reference voltage, said near field communication module (104) commands the shutdown of said first circuit (304).

5. Device according to any one of claims 1, 3 or 4, or method according to any one of claims 2 to 4, wherein said power supply circuit (103; 301) is connected to at least one second supply voltage source of the electronic device (100).

6. A device or method according to claim 5, wherein said at least one second supply voltage source is a battery.

7. Device or method according to claim 5 or 6, wherein, in the power supply circuit (301) of said card (105; 300) or said secure element, a second supply voltage (VBAT) from said second voltage source is supplied to said card (105; 300) or said secure element via a second circuit (302) comprising a linear voltage regulator and a second current slope limiter.

8. The device or method of claim 7, wherein each time said voltage detector (305) determines that said first supply voltage (VCC-UICC-IN) is different from the reference voltage, said field communication module close (104) deactivates the automatic start of said second circuit (302).

9. A device or method according to claim 7 or 8, wherein each time said voltage detector (305) determines that said first supply voltage (VCC-UICC-IN) is equal to the reference voltage, said near field communication module (104) activates the automatic start-up of said second circuit (302).

10. A method of starting an electronic device according to any one of claims 1, 3 to 9, wherein when the near field communication module changes from a standby state or an inactive state to an active state, the following successive operations are carried out: - the components and circuits of said electronic device (100) are started; - the software of the electronic device (100) and said card (105; 300) are started at the same time.

11. Method according to claim 10, wherein the starting of said card or said secure element comprises the following successive steps: - the starting of the power supply circuit (301) of said card (105; 300) or said secure element; and - the software starting of said card (105; 300) or said secure element.

12. A method according to claim 11, wherein during startup of the power supply circuit said voltage detector checks whether the first voltage source provides a first supply voltage equal to the reference voltage.

13. Method according to claim 11 or 12, in their attachment to claim 7, in which the power supply circuit (301) supplies said card or said secure element with said second power source.

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