NFC module power supply

Abstract

This disclosure relates to power supply for an NFC module. An electronic device includes a near-field communication module and a power supply circuit for transmitting a power supply voltage to the near-field communication module. When the near-field communication module is in a low-power mode, the power supply circuit is configured to operate in an operating mode in which the power supply circuit is periodically activated to provide the power supply voltage.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to French patent application No. 2202283, filed on March 16, 2022, the contents of which are incorporated herein by reference in their entirety to the fullest extent permitted by law. Technical Field

[0003] This disclosure generally relates to power supplies for electronic devices, and more specifically, to near field communication (NFC) modules included in electronic devices. More specifically, this disclosure relates to different power supply modes for NFC modules included in electronic devices. Background Technology

[0004] Currently, power consumption of electronic devices is a significant issue in industry. Reducing device power consumption while ensuring proper operation and performance is one of the main goals of research and development.

[0005] It is hoped that certain aspects of the power supply of electronic devices, including near-field communication modules, can be improved, at least partially.

[0006] Electronic devices that consume less power are needed.

[0007] A near-field communication module that consumes less power is needed.

[0008] It is necessary to overcome all or some of the known shortcomings of electronic devices. Summary of the Invention

[0009] An embodiment addressing all or part of the shortcomings of known near-field communication modules is provided by an electronic device comprising: a near-field communication module; and a power supply circuit for the module, wherein the power supply circuit is configured to periodically activate when the near-field communication module is in a low-power mode.

[0010] Another embodiment provides a method for powering a near-field communication module of an electronic device in a low-power mode, the method further comprising a power supply circuit for the module, wherein the power supply circuit is configured to be periodically activated when the near-field communication module is in a low-power mode.

[0011] According to one embodiment, in the low-power mode of the near-field communication module, the power supply circuit is controlled by a control circuit adapted to periodically activate the power supply circuit.

[0012] According to one embodiment, the control circuit includes a counter.

[0013] According to one embodiment, in the low-power mode of the near-field communication module, a counter is started, and when the value of the counter reaches a threshold, the power supply circuit is started.

[0014] According to one embodiment, in the low-power mode of the near-field communication module, when the value of the counter reaches a limit greater than the threshold, the power supply circuit stops and the value of the counter is reset to zero.

[0015] According to one embodiment, the near-field communication module includes a field detector.

[0016] According to one embodiment, in the low-power mode of the near-field communication module, when the power supply circuit is activated, the near-field communication module is powered on and its field detector is activated.

[0017] According to one embodiment, the near-field communication module further includes circuitry configured to compare the frequency of the electric field detected by the field detector with a reference frequency.

[0018] According to one embodiment, the frequency comparator circuit is a state machine.

[0019] According to one embodiment, during low-power mode, when the circuit determines that the frequency of the field detected by the field detector is equal to the reference frequency with an error margin on the order of 10%, an alarm signal is generated.

[0020] According to one embodiment, the device further includes circuitry for supplying power to a processor adapted to receive the alarm signal.

[0021] According to an embodiment, the circuit for power supply includes a voltage regulator adapted to regulate the internal power supply voltage and to transmit a voltage for powering the near-field communication module.

[0022] According to one embodiment, the circuit for power supply further includes circuitry for a reference voltage transmitted by a bandgap.

[0023] According to one embodiment, the control circuit further includes circuitry for a reference voltage transmitted via a bandgap. Attached Figure Description

[0024] The foregoing features and advantages, as well as other features and advantages, will be described in detail in the remainder of the disclosure of specific embodiments given by way of illustration rather than limitation with reference to the accompanying drawings, in which:

[0025] Figure 1 The boxes illustrate, very schematically, what can be applied to... Figure 3 The electronic device described in connection with the embodiment of FIG5;

[0026] Figures 2A-2B Two block diagrams are shown schematically in the form of boxes, illustrating different power modes for electronic devices and near-field communication modules;

[0027] Figure 3An embodiment of an electronic device is shown very schematically in the form of a box;

[0028] Figure 4 A more detailed embodiment of a portion of an electronic device is shown in box form; and

[0029] Figures 5A-5B Explanation is shown Figure 4 A timing diagram of the operation of an embodiment. Detailed Implementation

[0030] In the various figures, the same features have been designated by the same reference numerals. Specifically, common structural and / or functional features in various embodiments may have the same reference numerals and may be provided with the same structure, dimensions, and material properties.

[0031] For clarity, only steps and elements useful for understanding the embodiments described herein are illustrated and described in detail. Specifically, near-field communication protocols are not described herein; these protocols are compatible with the embodiments described below.

[0032] Unless otherwise stated, when referring to two elements connected together, it means that there is no direct connection of any intermediate element other than a conductor, and when referring to two elements connected together, it means that the two elements can be connected or they can be connected via one or more other elements.

[0033] In the following disclosure, unless otherwise stated, when referring to absolute position qualifiers, such as the terms “front,” “back,” “up,” “down,” “left,” “right,” etc., or relative position qualifiers, such as the terms “upward,” “downward,” “above,” “below,” etc., or direction qualifiers, such as “horizontal,” “vertical,” etc., refer to the directions shown in the accompanying drawings.

[0034] Unless otherwise stated, the expressions “about,” “approximately,” “substantially,” and “approximately equal to” indicate within 10%, preferably within 5%.

[0035] Figure 1 An example of an electronic device 100 (DEVICE) is shown very schematically in the form of a box, combined with Figure 3 , Figure 4 and Figures 5A-5B The described embodiments can be applied to the electronic device 100 (DEVICE).

[0036] Device 100 is an electronic device, such as a cellular phone or connected device, whose power is at least partially transmitted internally. Therefore, device 100 includes: a processor 101 (CPU); one or more memories 102 (MEM); one or more circuits 103 (FCT) implementing different functions of device 100; a power supply circuit 104 (ALIM); a near field communication module 105 (NFC) or NFC module 105; optionally, a secure element 106 (SE); and one or more computer buses 107 enabling different circuits and components to exchange data and / or power.

[0037] Processor 101 may be a main processor responsible for implementing basic and / or complex functions of, for example, device 100. For example, device 100 may include other processors, such as auxiliary processors linked to specific tasks.

[0038] One or more memories 102 are data storage units of device 100. Memory 102 can be of different types, such as RAM, volatile memory, non-volatile memory, ROM, etc.

[0039] Circuit 103 may include one or more data measurement or processing circuits, one or more display devices, etc.

[0040] The power supply circuit 104 is a circuit for supplying power to the device 100 and each of its circuits and components. The power supply circuit 104 may include power supply circuitry dedicated to specific circuits or components of the device 100. According to an example, the power supply circuit includes at least one circuit for supplying power to the NFC module 105. The power supply circuit 104 may also include an internal power source, such as a battery or voltage source. The power supply circuit 104 may also include circuitry configured to adapt power from an external source (e.g., from a trunk line).

[0041] The NFC module 105 is a near field communication (NFC) module that uses short-range and high-frequency wireless communication technology, allowing data exchange between peripheral devices up to a distance of approximately 10 cm.

[0042] Secure element 106 is a reliable electronic device capable of processing critical or confidential data. Secure element 106 can be used to perform data encryption and / or decryption, manipulation of critical data, and / or storage of critical data. Secure element 106 is optional.

[0043] exist Figure 1 The diagram shows a single bus 107 that couples all the circuitry and components of device 100 to each other, but multiple buses 107 that couple certain circuitry and components to each other are conceivable.

[0044] Figures 2A-2B This is a diagram illustrating examples of different possible power supply modes for electronic devices. Figure 2AIt shows the relationship with Figure 1 Examples of different possible power modes for electronic devices 200 of type 100 described in the related description. Figure 2B Examples of different power modes of a near-field communication module 250 (NFC) or NFC module 250 forming part of device 200 are shown, which near-field communication module 250 (NFC) or NFC module 250 belongs to a combination Figure 1 The type of NFC module 105 described.

[0045] For example, such as Figure 2A The illustrated electronic device 200 includes at least three different power modes during which the electronic device 200 consumes more or less power and / or can perform more or less functionality. The electronic device 200 may include other variations of the power modes besides those described below. The power modes are as follows: "Full Power" mode 201; "Low Power" mode 202; and "Sleep" mode 203.

[0046] "Full Power" mode 201 is the power mode in which electronic device 200 may consume the most power. All its functions can be used.

[0047] "Low power" mode or "low power mode" 202 is a power mode in which electronic device 200 reduces its power consumption. For this purpose, electronic device 200 may prevent the implementation of certain functions and / or intentionally cause the implementation of some or all of its functions to be slowed down, for example, by slowing down the operation of its processor.

[0048] "Sleep" mode or standby mode 203 is a power mode in which the electronic device 200 significantly reduces its power consumption by authorizing only certain very specific functions. More specifically, in this power mode, most functions of the device 200 are disabled, and only functions that enable "wake up" the device 200 are enabled. These are referred to here as functions that enable the device 200 to switch from "sleep" mode to another power mode, such as "full power" mode or "low power mode." These functions are, for example, the possibility of leaving the mode by pressing a button on the device 200, or, if the device 200 is a telephone, the detection of communication requests, such as near-field communication requests or telephone call requests. Therefore, the NFC module 250 is typically formed as part of the circuitry of the device 200 powered during sleep mode.

[0049] For example, Figure 2BThe NFC module 250 shown in the illustration includes at least two different power modes during which the NFC module 250 consumes more or less power and / or can perform more or less functionality. The NFC module 250 may include other power modes besides those described below. The power modes are: "Full Power" mode 251; and "Low Power" mode 252.

[0050] "Full Power" mode 251 is the power mode in which the NFC module 250 may consume the most power. During this mode, the NFC module 250 may periodically detect the presence of the field, for example, at a frequency on the order of 1 kHz, or even continuously detect the presence of the field.

[0051] The "low power" mode or "low power mode" 252 is a power mode for the NFC module 250 to reduce its power consumption. For this purpose, the NFC module 250 can, for example, slow down its field detection frequency to a frequency on the order of 500 Hz. Figure 3 , Figure 4 and Figures 5A-5B Examples of circuits for powering an NFC module are shown, and more specifically, their implementation in “low power” mode is shown.

[0052] The different power supply modes of device 200 and NFC module 250 are independent of each other. For example, device 200 can be in sleep mode, and NFC module 250 can be in full-power mode. According to another example, if the user of device 200 decides not to use the NFC module, they can set it to "low-power" mode.

[0053] Figure 3 The diagram is shown very schematically in the form of a box. Figure 1 Part 300 of the device of type 100 described in relation to the device 200 described in relation to Figure 2.

[0054] Part 300 includes: a near field communication module 301 (NFC) or NFC module 301; a power supply circuit 302 (ALIM NFC) associated with the NFC module 301; and a control circuit 303 (CMD).

[0055] NFC module 301 is combined with Figure 1The NFC module 301 is of the type described as NFC module 105, or the type described in conjunction with FIG. 2 as NFC module 250. NFC module 301 is configured to transmit and receive electric fields to enable near-field communication. The NFC module includes at least one power terminal ALIM-NFC and one internal communication terminal I / O-NFC. The power terminal ALIM-NFC is coupled (preferably connected) to a power supply circuit 302. The internal communication terminal I / O-NFC enables the NFC module to exchange data and instructions with the rest of the electronic device, such as alarm signals or detection information of fields that could lead to NFC communication. As previously described, NFC module 301 includes several different power modes, for example, at least one “full power” power mode and at least one “low power” power mode. During the “low power” mode, NFC module 301 reduces the frequency at which it attempts to detect electromagnetic fields.

[0056] Power supply circuit 302 is configured to manage the power supply of NFC module 301. For this purpose, circuit 302 includes at least one input terminal IN for receiving a power supply voltage VBAT, an output terminal OUT for transmitting the power supply voltage VSUPP-NFC to NFC module 301, and a control terminal CMD. The power supply voltage VBAT is transmitted to circuit 302, for example, through the internal power supply of an electronic device such as a battery, or through circuitry for converting power supplies coupled to an external device. The control terminal CMD enables the power supply circuit 302 to be turned on or off. Figure 4 A more detailed embodiment of the power supply circuit 302 is described.

[0057] Control circuit 303 is configured to control power supply circuit 302 and to more precisely control power supply circuit 302 when NFC module 301 is in "low power" mode. Counter 303 includes a power terminal ALIM-CMD for receiving voltage VBAT, an input terminal IN for receiving programming data, and an output terminal OUT. Input terminal IN receives data that informs control circuit 303 of the power mode of NFC module 301 and, for example, the power mode of the device. According to an example, input terminal IN receives this data directly from NFC module 301. Output terminal OUT transmits control voltage to control terminal CMD of power supply circuit 302. Figure 4 A more detailed embodiment of counter 303 is described below.

[0058] The operation of some 300s is as follows.

[0059] During the “full power” mode of NFC module 301, power supply circuit 302 is always activated, enabled and supplies power to NFC module 301.

[0060] During the "low power" mode of NFC module 301, and according to an embodiment, control circuit 303 periodically enables power supply circuit 302, such that power supply circuit 302 consumes power only when NFC module 301 requires power. More precisely, NFC module 301 only periodically performs field search during the "low power" mode, and power supply circuit 302 is periodically enabled by control circuit 301 to supply power only when NFC module 301 attempts to detect a field. If NFC module 301 detects a field, power supply circuit 302 can remain enabled until NFC module 301 has completed the action it must perform, in conjunction with... Figure 4 An example of the action to be performed is described. If the NFC module 301 does not detect a field, the power supply circuit 302 is turned off.

[0061] The advantage of this embodiment is that it can limit the power consumption of the electronic device during the implementation of the "low NFC module power" mode.

[0062] Figure 4 The diagram is shown very schematically in the form of a box. Figure 3 The related description includes part 300 of a device and part 400 of a device of the same type. Part 400 is a more detailed practical example than part 300 described above. The operation of part 400 during the "low power" mode of the NFC module is illustrated with a timing diagram in Figure 5.

[0063] Part 400 includes: Near Field Communication Mode 401 (NFC) or NFC module 401, such as Figure 4 As shown by the dashed line; the power supply circuit 402 (ALIM NFC) associated with the NFC module 401, in Figure 4 The control circuit 403 (CMD) is shown in dashed lines. Figure 4 The components shown by the dashed lines are: main voltage regulator 404 (LDO Main); secondary voltage regulator 405 (LDO LP); and "low power" circuit 406 (LP domain).

[0064] NFC module 401 in Figure 4 The middle portion is shown and includes at least one field detector 4011 (EFD) and state machine 4012 (EFD FSM). Both field detector 4011 and state machine 4012 are powered by voltage VSUPP_NFC provided by power supply circuit 402.

[0065] Field detector 4011 is a circuit configured to detect fields and, more particularly, to find the frequency of the field it detects. Field detector 4011 has other functions commonly used by those skilled in the art, which are not described herein. Field detector 4011 includes a power supply terminal for receiving a voltage VSUPP_NFC, an enable terminal for receiving an enable signal EFD_EN, and a frequency output terminal for transmitting a signal F_EFD representing the frequency of the field detected by field detector 4011. For example, signal F_EFD is a clock signal with a frequency equal to the frequency of the field detected by field detector 4011. In other words, field detector 4011 extracts the frequency of the field it detects and transmits it as a clock signal.

[0066] State machine 4012 is a circuit configured to: enable field detector 4011; verify whether field detector 4011 has detected a field that may transmit near-field communication; and notify the device that near-field communication has been detected.

[0067] For this purpose, state machine 4012 includes: a power supply terminal for receiving voltage VSUPP_NFC; a terminal for providing enable signal EFD_EN to field detector 4011; a terminal for receiving signal F_EFD; a terminal for providing alarm signal FSM_INFO or information signal FSM_INFO to the device; and a terminal for providing signal CNT_RST for resetting counter to control circuit 403.

[0068] The power supply circuit 402 (ALIM NFC) associated with the NFC module 401 includes at least: a reference voltage circuit transmitted by the bandgap circuit 4021 or the reference voltage circuit 4021; a logic "AND" type gate 4022; and a secondary voltage regulator 4023 (EFDLDO).

[0069] The reference voltage circuit 4021 is powered by the internal power supply voltage VBAT, transmits the reference voltage V-REF, and is therefore configured to transmit the status signal BG_RDY. The reference voltage circuit 4021 also receives an enable signal BG_EN. The power supply voltage VBAT is transmitted to circuit 402, for example, through the internal power supply of an electronic device such as a battery, or through circuitry used to convert the power supply coupled to the device from external sources.

[0070] Logic gate 4022 is an AND gate with two inputs. The first input receives the status signal BG_RDY from the reference voltage circuit 4021, and the second input receives the enable signal ALIM_EN from the control circuit 403. The output of logic gate 4022 is the signal LDO_EN, used to enable the voltage regulator 4023.

[0071] Voltage regulator 4023 is a voltage regulator that, when enabled, enables the transmission of power supply voltage VSUPP_NFC from voltage VBAT to NFC module 401. To this end, voltage regulator 4023 receives voltage VBAT, reference voltage V_REF, and enable signal LDO_EN to output power supply voltage VSUPP_NFC.

[0072] The control circuit 403 (CMD) associated with the power supply circuit 402 includes, for example, a low-frequency oscillator 4031 (LFO) and a counter 4032 (CNT). When the NFC module 401 is in "full power" mode, the control circuit 403 is configured to permanently enable the power supply circuit 402. When the NFC module 401 is in "low power" mode, the control circuit 403 is configured to periodically enable the power supply circuit 402.

[0073] The low-frequency oscillator 4031 is an oscillator that provides a clock signal Clk at a constant frequency. According to the example, the clock signal has a frequency in the range of 60 to 70 kHz, for example, on the order of 64 kHz. For this purpose, the low-frequency oscillator 4031 is powered by a supply voltage VBAT.

[0074] Counter 4032 is a circuit configured to periodically power circuit 402. For this purpose, counter 4032 receives a clock signal Clk, a reset signal RST_CNT, and outputs enable signals BG_EN and ALIM_EN. The value of counter 4032 increments, for example, at each new rising or falling edge of the clock signal Clk. A more detailed description of the operation of counter 4032, and the more general operation of control circuit 403, is provided in conjunction with Figure 5.

[0075] The main voltage regulator 404 (LDO Main) is a voltage regulator configured to transmit the power supply voltage that forms the main power supply for the device. According to the example, regulator 404 transmits the power supply voltage capable of powering the device's main processor and the information signal LDO_INFO to the secondary voltage regulator 405. The regulator receives the voltage VBAT and the information voltage FSM_INFO.

[0076] The secondary voltage regulator 405 (LDO LP) is a voltage regulator configured to transmit the power supply voltage of the secondary power supply of the forming device. According to... Figure 4 For example, regulator 405 provides a power supply voltage that enables all "low-power" circuitry of the device to be powered by voltage VSUPP-LP. Regulator 405 receives voltage VBAT and an information signal LDO_INFO. For instance, the information signal LDO_INFO can enable regulator 404 to indicate its operating status to regulator 405.

[0077] Assembly 406 (LP domain) of the “low power” circuit is an assembly of circuits and components of the device that is powered when the device is in “low power” mode. According to the example, when the device is in “full power” mode, regulators 404 and 405 are both enabled, but when the device is in “low power” mode, regulator 404 is disabled and regulator 405 is enabled.

[0078] According to an alternative embodiment, the reference voltage circuit 4021 may form part of the control circuit 403 instead of the power supply circuit 402.

[0079] Figures 5A-5B The illustration shows the situation when the NFC module 401 is in "low power" mode, combined with... Figure 4 The timing diagram for the operation of part 400 of the described device. Figure 5A The operation of part 400 is shown when the NFC module 401 is in "low power" mode and the field detector 4011 does not detect a field. Figure 5B The operation of part 400 is shown when the NFC module 401 is in "low power" mode and the field detector 4011 detects a field.

[0080] Figure 5A The timing diagram includes the following signals: clock signal Clk; signal EN_BG for enabling reference voltage circuit 4021; status signal BG_RDY for reference voltage circuit 4021; signal EFD_EN for enabling field detector 4011; and signal RST_EN for resetting counter 4032.

[0081] At the initial time t0, Figure 5A All signals are in a low state, for example, the voltage level is equal to the reference voltage, such as voltage V_REF or another voltage. The clock signal Clk has regular rising and falling edges.

[0082] At time t1 after time t0, the enable signal EN_BG switches from a low state to a high state, for example, a voltage level higher than the reference voltage level. In other words, counter 4032 initiates the startup of reference voltage circuit 4021. According to the example, counter 4032 initiates the startup of reference voltage circuit because its value has reached a threshold. In parallel, counter 4032 instructs power supply circuit 402 that it requests its startup, for example, via enable signal ALIM_EN, which also switches from a low state to a high state.

[0083] At time t2, following time t1, the status signal BG_RDY transitions from a low state to a high state. Therefore, the reference voltage circuit 4021 indicates that its initial phase has ended and it is ready for use.

[0084] By switching to a high state, the signal BG_RDY allows the voltage regulator 4023 to be activated via the enable signal LDO_EN.

[0085] At time t3, following time t2, the signal EFD_EN, which enables field detector 4011, transitions from a low state to a high state, thus activating field detector 4011. Field detector 4011 then actively searches for the field.

[0086] At time t4, after time t3, the value of counter 4011 reaches a limit greater than the threshold, and its reset signal pulses. Then the value of counter 4011 is set to zero.

[0087] If the value of counter 4011 has reached its limit, it means that during the period it was active, i.e., between time t3 and t4, field detector 4011 did not detect a field that could lead to NFC communication.

[0088] At time t5, following time t4, signals EN_BG, BG_RDY, and EFD_EN transition to a low state due to a peak in signal RST_CNT. The reference voltage circuit, voltage regulator 4023, and NFC module 402 are no longer powered and / or enabled.

[0089] At time t6, following time t5, a new phase of the field detector's activation begins, and as at time t1, the signal EN_BG transitions from a low state to a high state.

[0090] The advantage of this embodiment is that the power supply circuit 402 does not consume power when the field detector is not enabled, because it is not enabled itself.

[0091] Figure 5B The timing diagram includes the following signals: the state of the field RF field that can be detected by the field detector 4011 and may lead to NFC communication; the clock signal Clk; the signal EN_BG for enabling the reference voltage circuit 4021; the state signal BG_RDY for the reference voltage circuit 4021; the signal EFD_EN for enabling the field detector 4011; the internal signal FREQ_CHECK for the state machine 4012; and the information signal FSM_INFO for the state machine 4012.

[0092] At the initial time t10, Figure 5B All signals are in a low state; for example, the voltage level is equal to the reference voltage, such as voltage V_REF or another voltage. The clock signal Clk has regular rising and falling edges. Furthermore, the field detector 4011 cannot detect the RF field.

[0093] At time t11 after time t10, a field RF field that may cause near-field communication may approach the device and be detected by field detector 4011.

[0094] At time t12, following time t11, and as described earlier at time t1, the enable signal EN_BG transitions from low to high. In other words, counter 4032 initiates the startup of reference voltage circuit 4021. In parallel, counter 4032 instructs power supply circuit 402 to request its startup, for example, via enable signal ALIM_EN, which also transitions from low to high.

[0095] At time t13, after time t12, the status signal BG_RDY transitions from a low state to a high state. Therefore, the reference voltage circuit 4021 indicates that its start phase has ended and it is ready to be used.

[0096] By switching to the high state, the signal BG_RDY allows the voltage regulator 4023 to be started via the enable signal LDO_EN.

[0097] At time t14, following time t13, the signal EFD_EN, which enables field detector 4011, transitions from a low state to a high state, thus activating field detector 4011. Field detector 4011 then actively searches for the field.

[0098] Since the field RF field may be detected by the field detector 4011, the latter detects it and determines the frequency of the field RF field. As previously stated, and for this purpose, the field detector 4011 extracts the frequency of the field RF field and transmits a clock signal F_EFD with a frequency equal to that of the field RF field. The state machine 4012 then estimates the frequency by comparing the frequency of the signal F_EFD with a reference clock signal (e.g., the signal Clk). The reference clock signal, for example, has a frequency on the order of 64 kHz.

[0099] To perform this comparison, state machine 4012 can, for example, count the number of cycles of signal F_EFD during the period of a reference clock signal. According to the example, if the reference clock signal is a clock signal Clk and has a frequency on the order of 64 kHz, the state machine verifies that signal F_EFD has 192 to 235 cycles during the period of signal Clk. Therefore, the state machine verifies whether the field frequency is sufficiently close to the reference frequency, typically 13.56 MHz, with an error tolerance of 10%.

[0100] At time t15, following time t14, the internal signal FREQ_CHECK of state machine 4012 transitions from a low state to a high state, thus indicating that the frequency received from field detector 4011 via signal F_EFD is sufficiently close to the reference frequency, i.e., on the order of the reference frequency with an error tolerance of 10%. In other words, the state machine confirms the fact that the field RF field may lead to near-field communication.

[0101] At time t16, following time t15, the information signal FSM_INFO transitions from a low state to a high state. According to one example, the information signal FSM_INFO can enable the device's main power supply circuitry, such as regulator 404, to start. According to another example, the information signal FSM_INFO can therefore indicate that the device should be ready for NFC communication, and if the device is in "sleep" mode, it should switch to an appropriate power consumption mode, such as "full power" or "low power" mode.

[0102] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these different embodiments and variations can be combined, and other variations will occur to those skilled in the art.

[0103] Finally, based on the functional indications given above, the actual implementation of the described embodiments and variations is within the capabilities of those skilled in the art.

Claims

1. An electronic device, comprising: The power supply circuit is configured to provide the power supply voltage; as well as A near-field communication module having a power input and a field detector, the power input being coupled to receive the power supply voltage from the power supply circuit; The near-field communication module can be configured to operate in a full-power mode and a low-power mode. In the full-power mode, the field detector operates at a detection rate at a first frequency or higher to detect the presence of the field for near-field communication. In the low-power mode, the field detector operates at a detection rate at a second frequency lower than the first frequency to detect the presence of the field for near-field communication. and When in the low-power mode, the power supply circuit is configured to periodically supply the power supply voltage to the near-field communication module only when the field detector attempts to detect the presence of the field for near-field communication.

2. The device according to claim 1, further comprising a control circuit coupled to the power supply circuit, wherein, When the near-field communication module is in the low-power mode, the control circuit is configured to periodically activate the power supply circuit.

3. The device according to claim 2, wherein the control circuit includes a counter.

4. The device according to claim 3, wherein, When the near-field communication module enters the low-power mode, the counter is started, and when the value of the counter reaches a threshold, the power supply circuit is started by the control circuit.

5. The device according to claim 4, wherein, When the near-field communication module is in the low-power mode and when the value of the counter reaches a limit greater than the threshold, the power supply circuit is stopped by the control circuit and the value of the counter is reset.

6. The device according to claim 2, wherein the control circuit further includes a reference voltage generation circuit.

7. The device according to claim 6, wherein the reference voltage generation circuit is a bandgap circuit.

8. The device according to claim 1, wherein, When the near-field communication module is in the low-power mode, and wherein the field detector of the near-field communication module is activated when the power supply circuit is activated by the control circuit.

9. The device of claim 1, wherein the near-field communication module further comprises a comparison circuit configured to compare the frequency of the electric field detected by the field detector with a reference frequency.

10. The device of claim 9, wherein the comparison circuit is a state machine.

11. The device according to claim 9, wherein, An alarm signal is generated when the near-field communication module is in the low-power mode and when the comparison circuit determines that the frequency of the field detected by the field detector is substantially equal to the reference frequency.

12. The device according to claim 11, wherein the substantially equalities are satisfied if within an error tolerance of 10%.

13. The device of claim 11, further comprising circuitry for supplying power to a processor configured to receive the alarm signal.

14. The device of claim 13, wherein the circuitry for power supply includes a voltage regulator configured to regulate an internal power supply voltage and transmit the power supply voltage to the near-field communication module.

15. The device of claim 1, wherein the power supply circuit includes a reference voltage generation circuit.

16. The device of claim 15, wherein the reference voltage generation circuit is a bandgap circuit.

Images