Adaptation of a control voltage

Abstract

Control Voltage Adaptation This description relates to an electronic device comprising: - a battery (201) adapted to provide a supply voltage (Vbat); - a controllable voltage converter circuit (202) adapted to provide a control voltage (Vdd) from said supply voltage (Vbat); - a near-field communication module comprising at least one antenna (207) configured to emit an electromagnetic field whose power is adapted to be controlled by said control voltage (Vdd); and - temperature measurement means, in which said voltage converter (202) is adapted to modify the value of said control voltage (Vdd) as a function of a temperature measurement. Figure for the abbreviation: Fig. 2

Description

Title of the invention: Adaptation of a control voltage Technical field

[0001] The present description relates generally to electronic systems and devices, and in particular to electronic systems and devices adapted to implement wireless communications, such as near field communications (NFC). 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, electronic devices implementing wireless communications, and more particularly, near-field communications. Summary of the invention

[0004] There is a need for electronic devices adapted to modify the characteristics of the wireless communication that they implement as a function of temperature.

[0005] There is a need for electronic devices adapted to modify the characteristics of the near-field communication that they implement as a function of temperature.

[0006] There is a need for electronic devices adapted to modify the electromagnetic field that they emit as a function of temperature.

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

[0008] One embodiment provides an electronic device comprising: - a battery suitable for providing a supply voltage; - a controllable voltage converter circuit adapted to provide a control voltage from said supply voltage; - a near-field communication module comprising at least one antenna configured to emit an electromagnetic field whose power is adapted to be controlled by said control voltage; and - means of measuring temperature, wherein said voltage converter is adapted to modify the value of said control voltage as a function of a temperature measurement.

[0009] Another embodiment provides a method for adapting a control voltage of an electronic device comprising: - a battery suitable for providing a supply voltage; - a controllable voltage converter circuit adapted to provide a control voltage from said supply voltage; - a near-field communication module comprising at least one antenna configured to emit an electromagnetic field whose power is adapted to be controlled by said control voltage; and - means of measuring temperature, wherein said method comprises the following steps: - measure the temperature; and - modify the value of said control voltage.

[0010] According to one embodiment, in an initial state said control voltage is set as a function of the temperature measurement.

[0011] According to one embodiment, said value of said control voltage is chosen using a correspondence table.

[0012] According to one embodiment, in an initial state said control voltage is set to a maximum value.

[0013] According to one embodiment, the maximum value is of the order of 8 V.

[0014] According to one embodiment, in an initial state said control voltage is set to a minimum value.

[0015] According to one embodiment, the minimum value is of the order of 5 V.

[0016] According to one embodiment, after the initial state, if the temperature is greater than a maximum temperature, the value of said control voltage is decreased.

[0017] According to one embodiment, after the initial state, said temperature is compared to the maximum temperature, if the temperature is lower than the maximum temperature, the value of said control voltage is increased.

[0018] According to one embodiment, the temperature is measured periodically.

[0019] According to one embodiment, the temperature measurement period is comprised between 5 s and 1 min.

[0020] According to one embodiment, said antenna is adapted to emit a field after the value of said control voltage has been modified. Brief description of the drawings

[0021] These and other features and advantages will be set forth in detail in the following description of particular embodiments given without limitation in relation with the attached figures among which:

[0022] [Fig.l] represents, very schematically and in the form of blocks, an embodiment of an electronic device;

[0023] [Fig.2] represents, very schematically and in the form of blocks, a part of the electronic device of [Fig.l] capable of implementing the embodiments of figures 3 to 6;

[0024] [Fig.3] represents a block diagram illustrating a first mode of implementation of a method for adapting a voltage;

[0025] [Fig.4] represents a block diagram illustrating a second mode of implementation of a method for adapting a voltage;

[0026] [Fig.5] represents a block diagram illustrating a third mode of implementation of a method for adapting a voltage; and

[0027] [Fig.6] represents a block diagram illustrating a fourth mode of implementation of a method for adapting a voltage. 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 embodiments described have been shown and are detailed. In particular, near-field communication protocols are not described here; the usual near-field communication protocols are compatible with the embodiments described below.

[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 example of a electrical device 100 to which the embodiments described in relation to figures 3 to 6 can be applied.

[0034] The device 100 is an electronic device suitable for implementing wireless communication, and which is particularly suitable for implementing near field communication (NFC).

[0035] The device 100 comprises a processor 101 (CPU) for processing data. According to one example, the device 100 may comprise several processors each adapted to process different types of data. According to a particular example, the device 100 may comprise a main processor and one or more secondary processors.

[0036] The device 100 further comprises a near field communication (NFC) module 102, or NFC module (102). Near field communication (NFC) technologies enable high-frequency, short-range communications. Such systems exploit a radio frequency electromagnetic field emitted by a device (terminal or reader) to communicate with another device (remote module, transponder or card). The NFC module 102 comprises various electronic circuits adapted to emit a radio frequency (RF) signal transmitted using an electromagnetic field emitted by an antenna of an oscillating / resonant circuit. Circuits included in the module 102 are described in more detail in relation to [Fig. 2].

[0037] The device 100 further comprises one or more circuits 103 (ALIM) supporting the power supply of the device 100. According to one example, the circuits 104 may comprise one or more batteries, energy conversion circuits, charging circuits, etc. According to one embodiment, the circuits 103 comprise at least one battery providing a supply voltage used to control the NFC module 102. Circuits included in the circuits 103 are described in more detail in relation to [Fig.2].

[0038] The device 100 further comprises one or more temperature measuring means 104 (TEMP). According to a first example, these means 104 are hardware means, i.e. one or more temperature circuits or sensors. According to a second example, these means 104 are software temperature measuring means. The means 104 are, for example, adapted to measure the ambient temperature surrounding the device 100, and / or adapted to measure the temperature at the level of the elements making up the device 100, such as for example the temperature at the level of the NFC module 102.

[0039] The device 100 further comprises one or more circuits 105 (FCT) implementing one or more functionalities of the device 100. According to one example, the circuits 105 may comprise memories, specific processing circuits data, such as encryption circuits, circuits for performing measurements, input / output circuits of the device 100.

[0040] The device 100 further comprises one or more communication buses 106 allowing all the circuits of the device 100 to communicate. In [Fig.l], a single bus 106 connecting the processor 101, the module 102, and the circuits 103 to 105 is shown, but in practice, the device 100 may comprise several communication buses connecting these different elements.

[0041] [Fig.2] represents, very schematically and in the form of blocks, a part 200 of the device 100 described in relation to [Fig.1].

[0042] The part 200 corresponds to a part of the NFC module 102 of the device 100 and to a part of the power supply circuits 103 of the device 100. More particularly, the part 200 corresponds to the part of the device 100 making it possible to provide an electromagnetic field via an antenna.

[0043] As stated previously, part 200 comprises an ALIM portion of the power supply circuits 102. This ALIM portion comprises: - a 201 battery (BAT); - a voltage converter circuit 202 (DCDC); and - a voltage regulator circuit 203 (LDO).

[0044] The battery 201 is one of the batteries of the device 100. According to one example, the battery 201 is the main battery of the device 100. According to another example, the battery 201 is a battery dedicated to powering the NFC module 102. The battery 201 is adapted to provide a supply voltage Vbat. The supply voltage Vbat is, for example, between 1 and 7 V, for example 2.6 and 5.1 V.

[0045] The voltage converter circuit 202, or converter 202, is adapted to convert a DC voltage into another DC voltage. More particularly, the circuit 202 is a boost converter, that is to say a converter adapted to provide, from a first DC voltage, a second DC voltage whose value is higher than that of the first voltage. The converter 202 is adapted to provide a control voltage Vdd from the supply voltage Vbat provided by the battery 201. In addition, and according to one embodiment, the converter 202 is a controllable converter, that is to say a converter whose value of the output voltage, here the control voltage Vdd, is controllable. More particularly, the converter 202 is adapted to provide at output the control voltage Vdd whose value can vary, depending on the command received, between a minimum value Vddmin and a maximum value Vddmax.According to one example, the converter 202 is adapted to provide an output voltage of between 5 and 10 V, for example between 6 and 8 V.

[0046] The voltage regulator circuit 203, or regulator 203, is a linear regulator of a DC voltage receiving the control voltage Vdd supplied by the converter 202. The regulator 203 provides as output a voltage Vdd_RF corresponding to the difference between the control voltage Vdd and a threshold voltage Vldo. According to one example, the threshold voltage Vldo is of the order of 0.2 V. According to one embodiment, the regulator 203 is optional. The regulator 203 can make it possible to eliminate the noise present on the control voltage Vdd.

[0047] As previously stated, part 200 comprises an NFC portion of the NFC module. This NFC portion comprises: - control circuits 204 (RF Driver) and 205 (RF Driver); - an impedance matching circuit (ANT Matching) 206; and - a 207 antenna (ANT).

[0048] The driving circuits 204 and 205 are driving circuits for the antenna 207. The circuits 204 and 205 receive the output voltage Vdd_RF from the regulator 202, or the control voltage Vdd when the regulator 202 is omitted, and provide a suitable control voltage Vdd_cmd.

[0049] The impedance matching circuit (ANT Matching) 206 receives the matched control voltages Vdd_cmd from the control circuits 204 and 205, and provides as output an antenna control voltage Vdd_Ant whose impedance is matched to the impedance of the antenna 207. The voltage Vdd_Ant is dependent on the matched control voltages Vdd_cmd, the value of which depends on the voltage Vdd_RF, or directly on the voltage Vdd if applicable.

[0050] The antenna 207 is adapted to emit an electromagnetic field making it possible to implement near-field communication. Thus, the antenna 207 is adapted to emit and receive electromagnetic waves whose frequency is included in the radio frequency range, that is to say whose frequency is between 3 kHz and 300 GHz. According to one example, the antenna 207 is adapted to emit and receive electromagnetic waves whose frequency is of the order of 13.56 MHz. The antenna 207 receives the voltage Vdd_Ant, and provides at output an electromagnetic field whose power is dependent on the value of the control voltage Vdd_Ant, and in fact dependent on the value of the control voltage Vdd provided by the converter 202.

[0051] [Fig. 3] is a block diagram illustrating a first mode of implementation of a method for adapting the control voltage Vdd, described in relation to [Fig. 2], of the device 100 described in relation to [Fig. 1].

[0052] At an initial step 301 (Measure T), corresponding to an initial state, the antenna 207 does not emit any electromagnetic field, but receives a request indicating that it must emit one to implement NFC communication. The antenna 207 therefore receiving a command to emit an electromagnetic field, the means 104 of the device 100 are implemented to measure the temperature of the device 100, which corresponds, in this case, to the ambient temperature Tamb around the device 100, since the NFC module is not in operation and therefore does not produce heat.

[0053] At a step 302 (Select Vdd), subsequent to step 301, the value of the control voltage Vdd supplied by the converter 202 is chosen as a function of the value of the measured temperature T, and thus the power of the field to be emitted by the antenna 207 is chosen as a function of the temperature. For this, the device 100 can use a correspondence table indicating the voltage value appropriate to the voltage Vdd supplied. Once the value of the voltage Vdd has been chosen, the converter 202 is controlled to supply the value in question.

[0054] At a step 303 (Field Em.), subsequent to step 302, the voltage value Vdd being fixed, the antenna 207 can start to emit an electromagnetic field whose power is configured using the voltage Vdd as described in relation to [Fig.2],

[0055] An advantage of this embodiment is that it makes it possible to avoid overheating of the device 100. Indeed, emitting an electromagnetic field at full power can cause an increase in the temperature of the circuits and components of the device 100, reducing its power when the temperature is already high makes it possible to avoid increasing this temperature even further.

[0056] [Fig.4] is a block diagram illustrating a second mode of implementation of a method for adapting the control voltage Vdd, described in relation to [Fig.2], of the device 100 described in relation to [Fig.1].

[0057] At an initial step 401 (Vdd=Vddmax), corresponding to an initial state, the antenna 207 does not emit any electromagnetic field, but receives a request indicating that it must emit one to implement NFC communication. The antenna 207 therefore receiving a command to emit an electromagnetic field, the control voltage Vdd is set to its maximum value Vddmax. For this, the converter 202 is controlled to provide the voltage value in question.

[0058] At a step 402 (Field Em.), (Field Em.), subsequent to step 401, the voltage value Vdd being fixed, the antenna 207 can start to emit an electromagnetic field whose power is configured using the voltage Vdd as described in relation to [Fig.2].

[0059] At a step 403 (T>Tmax), subsequent to step 402, the antenna 207 emits an electromagnetic field, and the temperature T of the device 100 is measured by the means 104. This temperature T is compared to a maximum temperature Tmax. According to one embodiment, this step takes place periodically, for example every 5 s to 1 min. If the temperature T is lower than the maximum temperature Tmax (output Y of step 403), then the device continues to operate without modification, and if the temperature T becomes higher than the maximum temperature Tmax (output N of step 403), the next step is a step 404 (Vdd dec.).

[0060] In step 404, the power of the electromagnetic field emitted by the antenna 207 is reduced by reducing the voltage Vdd. For this, a command is sent to the converter circuit 202. According to one example, the control voltage Vdd is reduced in steps, for example in steps of 0.8 V.

[0061] This second mode of implementation has the same advantage as the first mode of implementation described in relation to [Fig.4], but also has the advantage of allowing an adaptation of the power of the electromagnetic field during the emission of said field.

[0062] [Fig.5] is a block diagram illustrating a third mode of implementation of a method for adapting the control voltage Vdd, described in relation to [Fig.2], of the device 100 described in relation to [Fig.1].

[0063] At an initial step 501 (Vdd=Vddmin), corresponding to an initial state, the antenna 207 does not emit any electromagnetic field, but receives a request indicating that it must emit one to implement NFC communication. The antenna 207 therefore receiving a command to emit an electromagnetic field, the control voltage Vdd is set to its minimum value Vddmin. For this, the converter 202 is controlled to provide the voltage value in question.

[0064] At a step 502 (Field Em.), (Field Em.), subsequent to step 501, the voltage value Vdd being fixed, the antenna 207 can begin to emit an electromagnetic field whose power is configured using the voltage Vdd as described in relation to [Fig.2].

[0065] At a step 503 (T / Tmax), subsequent to step 402, the antenna 207 emits an electromagnetic field, and the temperature T of the device 100 is measured by the means 104. This temperature T is compared to a maximum temperature Tmax. According to one embodiment, this step takes place periodically, for example every 5 s to 1 min. If the temperature T is lower than the maximum temperature Tmax (output TcTmax of step 503), then the following step is a step 504 (Vdd inc.), and if the temperature T becomes higher than the maximum temperature Tmax (output T>Tmax of step 503), the following step is a step 505 (Vdd dec.).

[0066] In step 504, the power of the electromagnetic field emitted by the antenna 207 is increased by increasing the voltage Vdd. For this, a command is sent to the converter circuit 202. According to one example, the control voltage Vdd is increased in steps, for example in steps of 0.8 V.

[0067] In step 505, the power of the electromagnetic field emitted by the antenna 207 is reduced by decreasing the voltage Vdd. For this, a command is sent to the converter circuit 202. According to one example, the control voltage Vdd is decreased in steps, for example in steps of 0.8 V.

[0068] This third mode of implementation has the same advantages as the first and second modes of implementation described in relation to figures 4 and 5.

[0069] [Fig.6] is a block diagram illustrating a fourth mode of implementation of a method for adapting the control voltage Vdd, described in relation to [Fig.2], of the device 100 described in relation to [Fig.1].

[0070] At an initial step 601 (Measure T), corresponding to an initial state, the antenna 207 does not emit any electromagnetic field, but receives a request indicating that it must emit one to implement NFC communication. The antenna 207 therefore receiving a command to emit an electromagnetic field, the means 104 of the device 100 are implemented to measure the temperature of the device 100, corresponding here to the ambient temperature as in the implementation mode of [Fig.3].

[0071] At a step 602 (Select Vdd), subsequent to step 601, the value of the control voltage Vdd supplied by the converter 202 is chosen as a function of the value of the measured temperature T. For this, the device 100 can use a correspondence table indicating the voltage value appropriate to the voltage Vdd supplied. Once the value of the voltage Vdd has been chosen, the converter 202 is controlled to supply the value in question.

[0072] At a step 603 (Field Em.), subsequent to step 602, the voltage value Vdd being fixed, the antenna 207 can start to emit an electromagnetic field whose power is configured using the voltage Vdd as described in relation to [Fig.2],

[0073] At a step 604 (T / Tmax), subsequent to step 603, the antenna 207 emits an electromagnetic field, and the temperature T of the device 100 is measured by the means 104. This temperature T is compared to a maximum temperature Tmax. According to one embodiment, this step takes place periodically, for example every 5 s to 1 min. If the temperature T is lower than the maximum temperature Tmax (output TcTmax of step 604), then the following step is a step 605 (Vdd inc.), and if the temperature T becomes higher than the maximum temperature Tmax (output T>Tmax of step 604), the following step is a step 606 (Vdd dec.).

[0074] In step 605, the power of the electromagnetic field emitted by the antenna 207 is increased by increasing the voltage Vdd. For this, a command is sent to the converter circuit 202. According to one example, the control voltage Vdd is increased in steps, for example in steps of 0.8 V.

[0075] In step 606, the power of the electromagnetic field emitted by the antenna 207 is reduced by decreasing the voltage Vdd. For this, a command is sent to the converter circuit 202. According to one example, the control voltage Vdd is decreased in steps, for example in steps of 0.8 V.

[0076] This fourth mode of implementation has the same advantages as the first, second and third modes of implementation described in relation to figures 4 to 6.

[0077] Various embodiments and variants 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. In particular, the embodiment of [Fig. 4] may have a step of decreasing the control voltage Vdd like the embodiment of [Fig. 5].

[0078] 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: - a battery (201) adapted to provide a supply voltage (Vbat); - a controllable voltage converter circuit (202) adapted to provide a control voltage (Vdd) from said supply voltage (Vbat); - a near-field communication module (102) comprising at least one antenna (207) configured to emit an electromagnetic field whose power is adapted to be controlled by said control voltage (Vdd);and - means (104) for measuring the temperature (T), wherein said voltage converter (202) is adapted to modify the value of said control voltage (Vdd) as a function of a measurement of the temperature (T), wherein in an initial state said control voltage (Vdd) is fixed as a function of the measurement of the temperature, wherein, after the initial state, if the temperature (T) is higher than a maximum temperature (Tmax), the value of said control voltage (Vdd) is decreased, wherein, after the initial state, said temperature is compared to the maximum temperature, if the temperature (T) is lower than the maximum temperature (Tmax), the value of said control voltage (Vdd) is increased, and wherein the temperature (T) is measured periodically.;

2. Device according to claim 1, wherein said value of said control voltage (Vdd) is chosen using a look-up table.

3. Device according to claim 1 or 2, wherein in an initial state said control voltage (Vdd) is set to a maximum value (Vddmax).

4. Device according to claim 3, in which the maximum value is of the order of 8 V.

5. Device according to any one of claims 1 to 4, wherein in an initial state said control voltage (Vdd) is set to a minimum value (Vddmin).

6. Device according to claim 5, in which the minimum value is of the order of 5 V.

7. Device according to any one of claims 1 to 6, wherein the temperature measurement period is between 5 s and 1 min.

8. Device according to any one of claims 1 to 7, wherein said antenna is adapted to emit a field after the value of said control voltage (Vdd) has been modified.

9. Method for adapting a control voltage (Vdd) of an electronic device (100) comprising: - a battery (201) adapted to provide a supply voltage (Vbat); - a controllable voltage converter circuit (202) adapted to provide a control voltage (Vdd) from said supply voltage (Vbat); - a near-field communication module (102) comprising at least one antenna (207) configured to emit an electromagnetic field whose power is adapted to be controlled by said control voltage (Vdd); and - means (104) for measuring the temperature (T), wherein said method comprises the following steps: - measuring the temperature (T);and - modifying the value of said control voltage (Vdd), wherein at an initial state said control voltage (Vdd) is set as a function of the temperature measurement, wherein, after the initial state, if the temperature (T) is higher than a maximum temperature (Tmax), the value of said control voltage (Vdd) is decreased, wherein, after the initial state, said temperature is compared to the maximum temperature, if the temperature (T) is lower than the maximum temperature (Tmax), the value of said control voltage (Vdd) is increased, and wherein the temperature (T) is measured periodically.;

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