Rechargeable interactive toy and charger for same

Abstract

Disclosed herein is an electronic device comprising a rechargeable battery, a coil circuit comprising an electromagnetic coil and a rectifier configured to generate a rectified voltage, the coil circuit being configured for charging of the rechargeable battery. The coil circuit comprises an overvoltage protection circuit configured to short out the electromagnetic coil in response to a first measured voltage or current in the coil circuit exceeding a predetermined protection threshold value. The coil circuit further comprises a detune circuit configured to detune the resonance frequency of the electromagnetic coil in response to a second measured voltage or current in the coil circuit exceeding a predetermined detune threshold value, The coil circuit further comprises a boost circuit configured to boost the rectified voltage in response to the rectified voltage being lower than a charging voltage on the rechargeable battery.

Description

[0001] Rechargeable interactive toy and charger for same

[0002] The present disclosure relates in one aspect to an electronic device that is configured for wireless charging and to an electronic system comprising the electronic device and a wireless charging device.

[0003] BACKGROUND

[0004] Power transmission via magnetic induction is by now well-known, and is utilised widely to charge power receiver devices having one or more receiver coils. When charging of a power receiver device is desired, the device is placed such that at least one of its receiver coils can couple to one or more transmitter coils in a wireless power transmitter device. Such an arrangement allows for wireless power transfer between the power transmitter device and the power receiver device without requiring any wires or physical electrical connections between the transmitter and receiver devices to be made.

[0005] Wireless power transfer arrangements may also be used in toys and toy systems, such as toy construction systems, the latter comprising elements which are designed to be modular and may be configured to be used in the construction of one or more toy construction models; For example, the same toy construction element may in one instance be used as part of the hull of an aircraft toy model and in another instance as part of a leaf of a flower toy model. Advanced toy construction elements comprising wireless power receiver such that the advanced elements can recharge without needing to be physically coupled to a charging source are known. For example, W02020156721 discloses a toy system comprising a contactless charging system.

[0006] Using wireless power transfer for toy systems poses challenges with respect to safety, as one cannot rely on the same measure of impulse control and common sense on the part of the user as systems designed to be used by adults.

[0007] Hence, it is imperative to provide wireless power systems which provide wireless charging to power receivers while providing reasonable safety measures. Further, using wireless power transfer for modular systems, such as modular toy systems, poses challenges for user friendliness as power receivers become part of constructed models.

[0008] Generally, improved operation of a power transfer system would be advantageous, such as an approach allowing increased flexibility, reduced cost, reduced complexity, improved foreign object detection and / or improved performance would be advantageous.

[0009] In systems where a high degree of flexibility and modularity is wanted, such as modular toy systems, it is particularly desirable to have reliable and adaptable wireless power charging.

[0010] Additionally, a power transfer system suitable for use in toy systems may advantageously be user-friendly, even for smaller children, and either require no user involvement at all, or if any, only a user involvement that can be accomplished by smaller children, for example taking into consideration their available cognitive skills and hand control.

[0011] Various aspects of embodiments of a wireless power transfer system disclosed herein address one or more of the above needs and / or other needs that exist in the field of wireless power transfer systems.

[0012] SUMMARY

[0013] According to an aspect, the present disclosure relates to an electronic device that comprises:

[0014] - a rechargeable battery,

[0015] - a coil circuit comprising an electromagnetic coil and a rectifier configured to generate a rectified voltage, the coil circuit being configured for charging of the rechargeable battery, wherein the coil circuit comprises an overvoltage protection circuit configured to short out the electromagnetic coil in response to a first measured voltage or current in the coil circuit exceeding a predetermined protection threshold value, and the coil circuit comprising a detune circuit configured to detune the resonance frequency of the electromagnetic coil in response to a second measured voltage or current in the coil circuit exceeding a predetermined detune threshold value, and the coil circuit comprising a boost circuit configured to boost the rectified voltage in response to the rectified voltage being lower than the charging voltage on the rechargeable battery.

[0016] Thus, the electronic device is capable of wirelessly charging in both relatively low and relatively high charging fields which allows for flexible and opportunistic wireless charging. The electronic device may comprise sensitive components that do not tolerate a voltage beyond a certain value and therefore require an overvoltage protection, but at the same time the device is designed for charging even in relatively high charging fields by detuning the resonance of its electromagnetic coil(s). As the electronic device is also capable of boosting the voltage to a voltage equal to or above the charging voltage, where the charging voltage of a rechargeable battery is the voltage necessary to charge the battery at a given time, it is also able to wirelessly charge in relatively low power charging fields. This provides an advantageous electronic device that is suited for wirelessly charging its battery when subjected to any of a broad range of charging field powers.

[0017] For example, the electronic device may be a wireless interactive toy. In some embodiments, the wireless interactive toy is or comprises a wireless interactive toy construction element. The flexible and opportunistic charging exhibited by the electronic device means that a user, such as a child, has more freedom in positioning of the device for charging, especially when the electronic device is used together with a wireless charging device that has been designed to utilise the flexible charging ability of the electronic device. For example, an electronic device that is or comprises a wireless interactive toy construction element may be part of a constructed toy model made of multiple toy construction elements and possibly the model even comprises multiple electronic devices. In order for each electronic device in the model to be placed directly on a charging surface of a wireless charger as is usually required, the model would likely have to be disassembled. However, the flexible charging ability of the electronic device means that disassembly may not be necessary, and the child may experience that simply placing the toy construction model on the wireless charger will wirelessly charge the electronic device(s) in the model. In other situations, a child may assemble or play with a toy construction model comprising one or more electronic devices, while the model is on or near a wireless charging device, and the one or more electronic devices are able to charge during play. This may allow the child to continue playing without having to stop play while the toy charges. Thus, the play experience of the child is enhanced. To this end, the electronic device and a system comprising the electronic device is configured as described herein.

[0018] The electronic device has an overvoltage protection circuit which acts as a safety system to protect the electronic device. The overvoltage protection circuit may be a voltage clamping circuit. For example, the coil circuit may be configured to measure a received voltage resulting from a wireless power transfer signal being received by the electromagnetic coil, and the overvoltage protection circuit may be configured to short out the electromagnetic coil in response to the received voltage exceeding a predetermined threshold value, the protection threshold value. In this way, sensitive components in the electronic device can be protected from excessive amounts of energy which might cause damage to those components downstream from the coil. The overvoltage protection circuit may comprise one or more comparators to monitor voltage or current signals at one or more points in the coil circuit. The overvoltage protection circuit may comprise a switch, e.g. a thyristor, and be configured to trigger the switch to effectively create a short circuit across the electromagnetic coil if a current or voltage at a point in the circuit exceeds the predetermined protection threshold value.

[0019] The coil circuit comprises a detune circuit configured to detune the resonance frequency of the electromagnetic coil which will enable the electronic device to control the amount of received power. When the magnetic charging field is relatively weak, the resonance frequency of the electromagnetic coil will be closely matched to that of the transmitter coil for efficient power transfer. However, in a relatively powerful magnetic charging field, the electronic device can detune, i.e. tune the resonance frequency of the coil away from that of the transmitter coil and thereby lower the power transfer efficiency in order to control the amount of power received. The detune circuit will thus allow the electronic device to charge in relatively powerful magnetic charging fields. For example, the coil circuit may be configured to measure the rectified voltage generated by the rectifier, and the detune circuit may be configured to detune the resonance frequency of the electromagnetic coil in response to the rectified voltage exceeding the predetermined detune threshold value. A detune circuit is configured to retune the resonance frequency of the coil when the voltage or current measured again falls below the threshold value. Thus, the detune circuit is configured to retune the resonance frequency of the electromagnetic coil in response to the second measured voltage or current in the coil circuit falling below the predetermined detune threshold value. As the resonance frequency of the electromagnetic coil of the electronic device is detuned due to the detune circuit being triggered, voltages in the coil circuit decrease which may cause the second measured voltage or current to fall to a value that is lower than the predetermined detune threshold value which will cause the detune circuit to retune the resonance frequency of the electromagnetic coil. In this way, the detune circuit may in some circumstances detune and retune successively as the second measured voltage or current rises above and falls below the detune threshold value. The detune circuit may comprise a switch that causes detuning of the resonance frequency of the electromagnetic coil, when it is opened and retuning of the resonance frequency of the electromagnetic coil as it is closes again. Thus, successive detuning and retuning means that the switch opens and closes successively. The detune circuit may be configured for rapid response to facilitate opportunistic charging. For example, the switch may be configured to be able to switch rapidly between a closed and open state. The detune circuit may thus be configured to selectively toggle between two states so as to repeatedly activate the detuning circuit at a rate high enough to allow continued charging of the battery. The electronic device may control the selective activation of the detuning circuit at a rate of between 0.1 kHz and 10 kHz, such as between 0.5 kHz and 5 kHz, such as between 1 kHz and 2 kHz or at another suitable rate.

[0020] In various embodiments, the detune threshold value is smaller than the protection threshold value, thereby allowing charging to be performed as long as the first measured voltage is below the protection threshold value. In particular, the electronic device is capable of charging the battery regardless of whether the second measured voltage is below the detune threshold value or exceeds the detune threshold voltage. If the second measured voltage is above the detune threshold value and the first measured voltage is below the protection threshold value, the electronic device is operable to charge the battery with the detuning circuit performing the detuning operation, thereby reducing the second measured voltage. When activated, the detuning circuit may be controlled to perform pulsewidth modulation of the output voltage of the rectifier, or to otherwise reduce the amount of energy by detuning the electromagnetic coil. The detuning circuit is preferably controlled so as to maximise the harvested power while maintaining the second measured voltage below the protection threshold voltage.

[0021] The boost circuit may operate concurrently with the detuning circuit performing detuning. The boost circuit may be controllable at a rate higher than the rate at which the detune circuit is controlled, e.g. at a rate between 5 and 20 times the rate at which the detune circuit is controlled., thereby allowing the boost circuit to efficiently control the voltage supplied to the battery even while the detuning circuit is active.

[0022] The coil circuit comprises a boost circuit operable to boost the rectified voltage in order to charge the rechargeable battery even when the rectified voltage is lower than the charging voltage of the rechargeable battery at a given time.

[0023] A response by the coil circuit, such as by a circuit in the coil circuit, may be referred to as the coil circuit, or circuit, being “triggered”.

[0024] The second measured voltage or current in the coil circuit may be the same as the first measured voltage or current in the coil circuit. For example, the first measured voltage and / or the second measured voltage may be an output voltage of the rectifier and / or an input voltage of the boost circuit.

[0025] In some embodiments, at least part of the coil circuit is implemented in hardware. In some embodiments, the coil circuit is implemented at least partly in an ASIC (Application-specific integrated circuit). The required hardware may be small enough to fit into electronic devices suitable for being held in the hands of small children. In some embodiments, the electronic device comprises a processing unit that is powered by the rechargeable battery, and the coil circuit comprises a start-up circuit for controlling the activation of the processing unit from a deactivated state, the start-up circuit being configured to activate the processing unit only after determining that the power being delivered by the rectified voltage exceeds a start-up threshold value. The processing unit may be comprised in an ASIC.

[0026] The electronic device may be configured to receive power from a wireless power transfer signal using radio frequencies that are designated for ISM applications, i.e. using an ISM band. The electronic device may be configured to receive, and charge from, a wireless power transfer signal having a centre frequency in the frequency range 100 kHz - 50 MHz. For example, the electronic device may be configured to receive, and charge from, a wireless power transfer signal having a centre frequency in the frequency range 15 - 50 MHz, such as 18 - 45 MHz, such as 21 - 40 MHz, such as 25 - 35 MHz. In some embodiments, the electronic device is configured to receive power from a wireless power transfer signal having a centre frequency in the frequency range 100 kHz - 200 kHz. In some embodiments, the electronic device is configured to receive power from a wireless power transfer signal having a centre frequency in the frequency range 5 MHz - 8.5 MHz. In some embodiments, the electronic device is configured to receive power from a wireless power transfer signal having a centre frequency in the frequency range 12 MHz - 15 MHz. The electronic device may be configured to charge from more than one centre frequency of a wireless power transfer signal, each at a different time. In some embodiments, the electronic device is configured to receive a wireless power transfer signal having a centre frequency in an ISM band comprising 140 kHz, and / or an ISM band comprising 6.78 MHz, and / or an ISM band comprising 13.56 MHz, and / or an ISM band comprising 27.12 MHz, where, for a given centre frequency, the wireless power transfer signal may be configured to comply with a regulated bandwidth of an ISM band comprising the given centre frequency. For example, the electronic device may be configured to receive power from a wireless power transfer signal having a centre frequency centred at or near 140 kHz, and / or centred at or near 6.78 MHz, and / or centred at or near 13.56 MHz, and / or centred at or near 27.12 MHz, where, for a given centre frequency, the wireless power transfer signal may be configured to comply with a regulated bandwidth of an ISM band comprising the given centre frequency. The electronic device may be configured to be able to receive power from a wireless power transfer signal comprising radio frequencies that are higher than those used in the 13.56 MHz RFID band, and the wireless power receiver may further comprise an NFC / RFID tag reader.

[0027] In some embodiments, the coil circuit comprises an adjustment circuit for adjusting the resonance frequency of the electromagnetic coil. The adjustment circuit may allow the electromagnetic coil to have a resonance frequency within one of at least two frequency ranges. The electronic device may be configured for performing different tasks using the electromagnetic coil. The electronic device may be configured to receive a wireless charging signal having a frequency within a first frequency range of the at least two frequency ranges, and use the received wireless charging signal to charge the rechargeable battery. For example, the electronic device may be configured to receive a signal from a tag and / or transmit a signal intended for a tag at a time where the electromagnetic coil has a resonance frequency within a resonance frequency range of the at least two resonance frequency ranges different from the first frequency range. A tag may be an RFID / NFC tag. Thus, in some embodiments, the electronic device further comprises a wireless tag reader, such as an RFID / NFC tag reader. The first resonance frequency may be higher than the second resonance frequency, or it may be lower. The coil circuit may be configured such that the default state of the circuit, i.e. the state of the coil circuit when the battery is low on power or without power, is a charging state. Thus, the coil circuit may be configured such that the default resonance frequency of the electromagnetic coil is within the first frequency range. In some embodiments, the coil circuit is configured such the entire coil circuit, or parts thereof, e.g. the detune circuit, is operably independent of available battery power. In this way, the coil circuit, or parts thereof, can operate even when the electronic device is low on battery power, or even with a “dead” battery, i.e. a battery with substantially zero power.

[0028] The present disclosure relates to different aspects including the electronic device described above and in the following, corresponding apparatus, systems, methods, and / or products, each yielding one or more of the benefits and advantages described in connection with one or more of the other aspects, and each having one or more embodiments corresponding to the embodiments described in connection with one or more of the other aspects and / or disclosed in the appended claims.

[0029] According to an aspect, the present disclosure relates to an electronic system that comprises a wireless charging device and at least one electronic device. The wireless charging device comprises a transmitter coil configured to transmit a wireless power transfer signal, and the wireless power transfer signal is transmitted using a magnetic charging field configured for transmission of power. The at least one electronic device is an electronic device as described herein. The wireless charging device is configured for charging of each of the electronic devices.

[0030] In some embodiments, the electronic system is an interactive toy system and the electronic device is a wireless interactive toy. In particular, the interactive toy system may be an interactive toy construction system and the wireless interactive toy is or comprises a wireless interactive toy construction element. For example, the wireless interactive toy, or each wireless interactive toy, may be an individual one of the interactive toy construction elements, or a toy construction model constructed from two or more toy construction elements of the toy construction systems, including at least one interactive toy construction element.

[0031] In the context of an interactive toy system, the user may move the wireless interactive toys around as part of a play experience. The wireless interactive toy may be configured to facilitate the user’s play for example by sensing, communicating, and reacting. A wireless interactive toy may detect the user's interactions with it, for example by sensing the movements of itself or by sensing the movements of other wireless interactive toys in its vicinity. In some systems, multiple wireless interactive toys are communicating and sharing information with each other. A wireless interactive toy may react to any or all of these inputs, for example by providing user-perceptible outputs, such as audible, visual and / or haptic outputs. In embodiments where the wireless interactive toy is a toy construction element of a toy construction system, or is constructed from a plurality of toy construction elements, the user may repeatedly attach and / or detach the wireless interactive toy construction elements to / from one another and / or to / from other toy construction elements of the toy construction system so as to construct and deconstruct different spatial structures. Spatial structures constructed from two or more toy construction elements will also referred to as toy construction models. They may repeatedly be constructed and disassembled without destroying the toy construction elements from which they are constructed.

[0032] As a wireless interactive toy is interacting with its surroundings, e.g. sensing, communicating, and reacting, power is drained from its battery in order to run the various electronic components such as one or more sensors, one or more function devices, one or more processors, etc. It is therefore highly desirable that a wireless interactive toy is able to wirelessly charge opportunistically, i.e. as much as possible whenever possible, in order to optimize its ability to facilitate a user’s play. To this end the electronic system may be configured to facilitate charging of an electronic device even when said electronic device is at a distance from a charging surface of the wireless charging device, for example because the electronic device is a toy construction element that has been used in a toy construction model in such a way that the electronic device is unable to get closer to the charging surface of the wireless charging device without disassembly of the model. The charging surface is a surface of a wireless charging device that is configured for placement of electronic devices thereon, or otherwise at or close to, for wireless charging. Accordingly, in some embodiments, the wireless charging device and each of the at least one electronic devices are configured such that the wireless charging device can charge one or more electronic devices that are connected to one or more other toy construction elements to form a toy construction model, when the toy construction model, including the one or more electronic devices, is positioned on the charging surface of the wireless charging device, or otherwise at or in a proximity of the charging surface of the wireless charging device.

[0033] To this end, in some embodiments, the wireless charging device comprises a charging surface, which may be configured for supporting electronic devices placed thereon for wireless charging, or configured such that the electronic devices may otherwise be positioned in physical contact with or at various distances from the charging surface. The wireless charging device and each of the at least one electronic devices are configured such that the at least one electronic device is able to charge from the wireless charging device regardless of whether it is placed directly at or on the charging surface or whether it is placed at a certain distance from the charging surface, within a certain range from the charging surface, e.g. within a distance of 2 cm, such as within 4 cm, such as within 6 cm, such as within 8 cm, such as within 10 cm, from the charging surface. The wireless charging device may be configured to concurrently charge more than one of the electronic devices.

[0034] In some embodiments, the wireless charging device and each of the at least one electronic device are configured such that: the charging circuit of the at least one electronic device generates a rectified voltage for charging of the rechargeable battery of the at least one electronic device with the detune circuit being active and maintaining the first measured voltage below the protection threshold value, when the wireless charging device is positioned in physical contact with the charging surface or within a first threshold distance from the charging surface, the charging circuit of the at least one electronic device generates a rectified voltage for charging of the rechargeable battery of the at least one electronic device with the detune circuit being inactive and with the second measured voltage being below the detune threshold value, when the wireless charging device is positioned within a second threshold distance range from the charging surface and further removed from the charging surface than the first threshold distance.

[0035] It will be appreciated that the configuration of the wireless charging device and the electronic devices may include a choice of a suitable strength of the power transfer signal transmitted by the wireless charging circuit and a choice of the detune and protection threshold values. For example, the choice of detune and protection threshold values may depend on the sensitivity of the electronic circuits of the electronic device, i.e. they may be chosen to be small enough to avoid damaging the electronic circuits of the electronic device. For example, in an embodiment where the electronic circuitry of the electronic device would get damaged if receiving voltages above a maximum input voltage of 6 V, the protection threshold value may be selected between 4 V and 5 V or another suitable value providing an acceptable safety margin, while the detune threshold value may be selected smaller than the protection threshold value, e.g. between 4 V and 4.5 V and smaller than the selected protection threshold value. It will be appreciated that other embodiments may have a different maximum input voltage and the selected protection threshold values and detune threshold value may be chosen accordingly. For a given choice of the detune and protection threshold values, the strength of the power transfer signal transmitted by the wireless charging device may be selected small enough that, when the electronic device is positioned directly on or at the charging surface during normal operation, the first measured voltage does not exceed the protection threshold value and such that the second voltage exceeds the detune threshold value, if the detune circuit is inactive. Accordingly, when the electronic device is positioned at or in close proximity of the charging circuit, the electronic device can charge its battery with the detune circuit being active so as to ensure that the received voltage remains within an acceptable range. When the electronic device is moved a bit further away from the charging surface, beyond a certain first threshold distance, charging can continue but now with the detune circuit being inactive. Only when the electronic device is removed even further away from the charging surface, beyond a certain second threshold distance, the charging field at the electronic device becomes too weak to allow the electronic device to charge its battery from it. It will be appreciated that the specific values of the first and second threshold distances depend on various factors, including the choice of the strength of the charging signal, the choice of the detune threshold value, the orientation of the electronic device relative to the charging surface, etc. Nevertheless, the electronic device is capable of performing charging at a range of distances from the charging surface while protecting the electronic device from excess voltages.

[0036] In order to provide any significant power to an electronic device at a significant distance from its charging surface, a wireless charging device must output more power than if the system was configured for charging of the electronic device when it is placed on the charging surface. Thus, when an electronic device is positioned directly on the charging surface for charging, and possibly even at some distances from the charging surface, the second measured voltage or current may be higher than the predetermined detune threshold value at some point in time. The detune circuit of the electronic device will then trigger and the resonance frequency of the electromagnetic coil will be detuned thus causing the second measured voltage or current to fall. This will cause the second measured voltage or current to eventually be lower than the predetermined detune threshold value such that the coil circuit retunes. Therefore, the second measured voltage or current is higher than the predetermined detune threshold value only for a time as the detune circuit successively detunes or retunes the resonance frequency of the electromagnetic coil respectively away from or towards the frequency of the wireless power transfer signal. Thus, the detune circuit will generally ensure that the voltage remains below the protection threshold value such that the overvoltage protection circuit only triggers when the detune circuit is unable to sufficiently limit the voltage in the coil circuit. When the electronic system functions as intended, the detune circuit will ensure that the first measured voltage or current will be lower than the predetermined protection threshold value when the electronic device is placed directly on the charging surface.

[0037] The wireless charging device and each of the at least one electronic device may be configured such that the detune circuit triggers even when the electronic device is some distance from the charging surface when the wireless charging device is at its maximum power output. For example, each electronic device may have a housing with a dimension D, e.g. defined as the length of the housing along a direction of the smallest extent of the housing. The wireless charging device and each of the at least one electronic device may be configured such that the at least one electronic device is able to charge from the wireless charging device regardless of whether the electronic device is placed directly at or on the charging surface or is at a distance from the charging surface, the distance being less than a maximum distance. The maximum distance may be larger than the dimension D of the housing of the electronic device, e.g. larger than four times the dimension D, such as larger than five times the dimension D. For example, the maximum distance may be between twice the dimension D and 10 times the dimension D.

[0038] The wireless charging device and each of the at least one electronic device may be configured such that the detune circuit of an electronic device triggers at least if the electronic device is within a distance that is less than the dimension D times a multiplier from a charging surface of the wireless charging device, for example if the electronic device is within a distance that is less than twice, three times, four times, or more, times the dimension D and the wireless charging device is at its maximum power output. In some embodiments, the electronic system is configured such that the detune circuit of an electronic device triggers when the electronic device is within a distance of 1 cm, such as within 2 cm, such as within 3 cm, such as within 4 cm from the charging surface and the wireless charging device is at its maximum power output.

[0039] BRIEF DESCRIPTION OF THE DRAWINGS

[0040] FIG. 1 shows an example of an electronic device in the form of a wireless interactive toy construction element;

[0041] FIG. 2 shows a schematic block diagram of an example of an electronic device formed as a wireless interactive toy construction element;

[0042] FIG. 3 shows a schematic block diagram of a wireless power transmitter according to some embodiments;

[0043] FIG. 4 shows a schematic block diagram of multiple electronic devices, a wireless power transmitter, and a passive repeater according to some embodiments;

[0044] FIG. 5 shows a schematic block diagram of a passive repeater according to some embodiments;

[0045] FIG. 6 shows a schematic block diagram of an electronic device and a wireless power transmitter according to some embodiments; and

[0046] FIG. 7 shows an example of a control loop of an electronic device according to some embodiments.

[0047] DETAILED DESCRIPTION

[0048] Various aspects and embodiments of an interactive toy system comprising a plurality of interactive wireless toys will now be described with reference to toy construction elements in the form of bricks. In this particular and corresponding embodiments, the electronic devices are each formed as a respective wireless interactive toy construction element which each has a housing that is generally shaped as an orthogonal polyhedron with flat side faces and having coupling members extending from its up-per surface and a cavity extending into its bottom surfaces. However, other shapes and sizes of wireless interactive toy construction elements may be used, e.g. box-shaped or tile-shaped toy construction elements of different dimensions and with different numbers of coupling members. Moreover, while the brick-shape has proven to be particularly useful, the various aspects disclosed herein may be applied to other forms of electronic devices, including other forms of toy construction elements for use in play applications educational applications, and / or the like.

[0049] FIG. 1 shows an example of an electronic device in the form of a wireless interactive toy construction element, generally designated 100. On the left-hand side of FIG. 1 the wireless interactive toy construction element is shown with its top surface visible and, on the right-hand side, the wireless interactive toy construction element is shown with its bottom side visible. In particular, the wireless interactive toy construction element comprises a generally box-shaped housing 101 with coupling pegs 104 extending from its top surface and with a cavity extending into the element from the bottom. The cavity is defined by sidewalls 102 and by a central, downwardly extending tube 103. The coupling pegs of another toy construction element can be received in the cavity in a frictional engagement, e.g. as disclosed in US 3 005282. The construction elements shown in the remaining figures have this known type of coupling members in the form of cooperating pegs and cavities. However, other types of coupling members may also be used in addition to, or instead of, the pegs and cavities. The coupling pegs are arranged across the top surface in a square planar grid, i.e. defining orthogonal directions along which sequences of coupling pegs are arranged. The distance between neighbouring coupling pegs is uniform and equal in both directions. This or similar arrangements of coupling members at coupling locations defining a regular planar grid allow the toy construction elements to be inter-connected in a discrete number of positions and orientations relative two each other, in particular at right angles with respect to each other. In an assembled toy construction model, the coupling members of multiple toy construction elements may thus be located on grid points of a three- dimensional grid defined relative to the toy construction model.

[0050] In some embodiments, the housing 101 of the wireless interactive toy construction element is made from plastics material, e.g. thermoplastic polymers, or from another suitable material. The housing may e.g. be made by an injection moulding process or by another suitable manufacturing process.

[0051] The wireless interactive toy construction element 100 may include a function device 105 accommodated within the housing 101 of the wireless interactive toy construction element. Generally, a function device may be any suitable device for performing a function, such as a function that provides a user-perceptible effect, such as a visible and / or audible effect. Examples of function devices may include any suitable mechanical and / or electrical device, arrangement, and / or circuitry adapted to per-form one or more mechanical and / or electrical functions.

[0052] Examples of a mechanical function include driving a rotatable output shaft, winding- up a string or a chain which enables pulling an object closer to a toy module, moving a hinged part of the wireless interactive toy construction element, etc. The mechanical function may thus enable opening or closing a door, ejecting an object, rotating a turntable, moving a linear actuator, etc. Such mechanical motions can be driven by an electric motor.

[0053] Examples of an electrical function include emitting constant or blinking light, activating several lamps in a predetermined sequence, emitting audible sound such as beep, alarm, bell, siren, voice message, music, synthetic sound, natural or imitated sound simulating and / or stimulating play activities, playback of a sound, and / or other audio content, etc.

[0054] Accordingly, the function device may be selected from a motor, a light source (e.g. one or more LEDs), a sound source (e.g. a loudspeaker). The function wireless toy construction element may include more than one function device. In some embodiments, the system includes different types of wireless interactive toy construction elements comprising respective, different types of function devices.

[0055] The wireless interactive toy construction element 100 includes a sensor system 108 comprising one or more sensors accommodated within the housing 101 of the wireless interactive toy construction element. The sensor system 108 may include one or more sensors, e.g. including the position and / or orientation sensor described herein and / or one or more other sensors, e.g. a linear or rotary encoder, a light detector, and a sound detector (e.g. a microphone), an accelerometer, and / or the like.

[0056] FIG. 2 shows a schematic block diagram of an example of an electronic device formed as a wireless interactive toy construction element, generally designated 100, e.g. of the wireless interactive toy construction element shown in FIG. 1.

[0057] The wireless interactive toy construction element 100 comprises a housing 101 defining a top face which is provided with coupling members 104, all as described above with reference to FIG.1. The wireless interactive toy construction element 100 further comprises one or more electromagnetic coils 207 and a control unit 209 which may comprise one or more processing units, all accommodated with the housing 101. The wireless interactive toy construction element may further comprise, also accommodated with the housing 101 , one or more additional sensors 108 and / or one or more function devices 105, e.g. as described in connection with the sensor system and function device of the embodiment of FIG. 1 above. The wireless interactive toy construction element 100 further comprises a rechargeable battery 210, and a wireless communications interface 211 , also accommodated with the housing 101.

[0058] The wireless interactive toy construction element is configured to receive electrical energy via one or more of the electromagnetic coils 207 for charging the battery 210 which in turn powers electrical components such as the control unit 209, for example a processing unit within the control unit, the function device 105 and the wireless communications interface 211 . The one or more of the electromagnetic coils 207 are part of a coil circuit configured for charging of the rechargeable battery. The coil circuit comprises an overvoltage protection circuit configured to short out the electromagnetic coil in response to a first measured voltage or current in the coil circuit exceeding a predetermined protection threshold value. Further, the coil circuit comprises a detune circuit configured to detune the resonance frequency of the electromagnetic coil in response to a second measured voltage or current in the coil circuit exceeding a predetermined detune threshold value. Even further, the coil circuit comprises a boost circuit configured to boost the rectified voltage in response to the rectified voltage being lower than the charging voltage of the rechargeable battery. As described herein, in particular in connection with figs. 4 and 6, the wireless interactive toy construction element is configured for flexible and opportunistic wireless charging which has a number of advantages such as facilitating charging during and after construction of a toy model using one or more of the wireless interactive toy construction elements.

[0059] Each electromagnetic coil 207 defines a coil axis around which the electromagnetic coil extends. In this example, the electromagnetic coils 207 are arranged such that one coil is arranged with its coil axis extending out of the top face of the housing while another other coil is arranged with its coil axis extending out of one of the side faces of the housing. A third electromagnetic coil (not explicitly shown in FIG. 2) may be arranged with its coil axis extending out of another side face of the housing, e.g. such that the axes of all three coils are oriented orthogonal to each other or at least linearly independent from each other. It will be appreciated, however, that other arrangements of coils are possible. It may be that only one electromagnetic coil is configured for wireless charging, while any other electromagnetic coils are used for performing other functions. In some embodiments, the wireless interactive toy may use one or more of the electromagnetic coils to perform additional functions, e.g. to detect, identify and / or capture data from a wireless tag. For example, one electromagnetic coil may be used for wireless charging, while all electromagnetic coils are used for performing other functions. The single electromagnetic coil used for wireless charging may be arranged with its coil axis extending out of the top face of the housing. In this way the more efficient charging will primarily be achieved by positioning the wireless interactive toy construction element 100 with its top face being parallel to an induction coil of a wireless charging device which will usually also be parallel with a charging surface of said wireless charging device. This will allow a user to easily distinguish a more efficient positioning of the wireless interactive toy construction element for charging.

[0060] The one or more function devices 105 may include a light source, e.g. an LED, a loudspeaker, a motor, and / or another function device operable to perform a user- perceivable function. The one or more sensors 108 may include a light sensor, a sound sensor, a rotational encoder, an accelerometer, a gyro, and / or any other suitable sensor, e.g. as described in connection with FIG. 1.

[0061] The wireless communications interface 211 may comprise a radio-frequency transceiver and an associated antenna. In some embodiments, the wireless communications interface may comprise a Bluetooth chip or circuit or another form of radio-frequency transceiver adapted for communication via a wireless communications network, e.g. using known low-power, short-range wireless networking technology, such as Bluetooth / Bluetooth Low Energy, ZigBee, Z-Wave, or a similar wireless technology for low-power personal area data networking in compliance with a standardized protocol. The wireless communications interface 211 may be operable for two-way communication with other wireless interactive toy construction elements of the system. Accordingly, the wireless interactive toy construction element may be operable to communicate its identity and / or operational characteristics, scheduling information, position information and / or the like.

[0062] The control unit 209 may comprise one or more microcontrollers, one or more microprocessors, one or more ASICs, and / or one or more other suitable processing units, or combinations thereof and be configured to control the functional behaviour of the wireless interactive toy construction element. The wireless interactive toy construction element may be provided, e.g. pre-programmed, with a default behaviour, e.g. with default executable instructions stored in a memory of the wireless interactive toy construction element and executable by a processing unit of the wireless interactive toy construction element. The default executable instructions may define a set of predetermined rules for reacting to external stimuli as sensed by the sensor system, in particular for reacting to detected positions and / or orientations relative to other interactive toy construction elements or to detected changes in such positions and / or orientations. In some embodiments, the behaviour of the wireless interactive toy construction element may be programmed or configured by the user, e.g. by receiving program data and / or configuration parameters. To this end, the wireless interactive toy construction element may receive program and / or control data and / or configuration parameters from a computer or from another external electronic device, e.g. directly or via another toy module of the system. An external electronic device may e.g. a desktop computer, a tablet computer, a smartphone, a laptop computer, or another programmable computing device. Alternatively or additionally, the wireless interactive toy construction element may capture program and / or control data and / or configuration parameters from a wireless tag, e.g. from an RFID tag, or from other data storage devices. For example, the wireless interactive toy construction element may be operable to read out such wireless tag or other data storage device in a contactless manner.

[0063] FIG. 3 shows a schematic block diagram of a wireless power transmitter 300, also referred to as a wireless charger or wireless charging device, according to some embodiments. The wireless power transmitter comprises a transmitter coil 301 which is connected electrically to inductive charging circuitry 302, a power adapter 303 for connecting the wireless power transmitter to a power grid or other power supply, a transmitter control unit 304, a transmitter communication unit 305, and a user interface 306. The user interface may comprise buttons with which a user can interact with the wireless power transmitter, and / or it may comprise visible and / or tactile elements by which the wireless power transmitter can relay information to a user. The wireless power transmitter is configured to transmit a wireless power transfer signal using a magnetic charging field configured for transmission of power. The wireless power transfer signal can be utilised by a suitably configured wireless power receiver for wireless charging of the wireless power receiver. A wireless power receiver may be the electronic device shown in figs. 1 and 2.

[0064] The wireless power transmitter 300 may comprise an encasing 307, i.e. a housing, configured for facilitating charging of one or more electronic devices by placement of the one or more electronic devices on or near a charging surface 308 of the wireless power transmitter. The charging surface 308 may comprise one or more substantially horizontal surfaces to allow one or more objects, such as an electronic device, placed on it to be supported at rest by the wireless power transmitter, when the transmitter itself is positioned substantially horizontally. The charging surface may be a surface of the transmitter encasing 307 which is closest to the transmitter coil. The charging surface 308 may comprise a visible and / or tactile marking. The visible and / or tactile marking may be configured to aid a user in placement of electronic devices on or near the charging surface. The wireless power transmitter may advantageously be configured to produce a charging field that is powerful enough and which extends far enough away from the charging surface 308 that an electronic device is able to harvest energy from it even while at a distance from the charging surface 308.

[0065] The wireless power transmitter 300 may be configured to work in an advantageous manner together with the electronic devices described herein, such as those described in connection with fig. 2. For example, the wireless power transmitter may be configured to produce a charging field that is more powerful than needed for an electronic device to charge, when the electronic device placed on the charging surface of the wireless power transmitter. As the power of the charging field decreases with distance from the transmitter coil 301 , the powerful charging field extends relatively far away from the charger and provides charging power to electronic devices at a distance from the charging surface as described further in connection with figs. 4 and 6.

[0066] In some cases, the wireless power transmitter 300 is configured for charging of a single electronic device, while in other embodiments, the wireless power transmitter 300 is configured to allow charging of multiple electronic devices simultaneously. For example, the wireless power transmitter may be configured for charging one or more electronic devices similar to the electronic device 100 shown in fig. 2. The wireless power transmitter may be configured to support charging of electronic devices having one or more of a plurality of supported electromagnetic coil sizes, i.e. receiver coil sizes. The wireless power transmitter may be configured to support charging of an electronic device that comprises more than one receiver coil, where each receiver coil may be a different size and / or shape, and / or to support charging of various electronic devices that each comprise a coil that may be a different size and / or shape to that of the other electronic devices.

[0067] The transmitter control unit 304 may comprise one or more microcontrollers, one or more microprocessors, one or more ASICs, and / or one or more other suitable processing units, or combinations thereof and be configured to control the functional behaviour of the wireless interactive toy construction element. The transmitter control unit 304 may be configured to handle numerous control functions related to the wireless power transmitter. For example, the transmitter control unit 304 may control the functioning of the transmitter coil 308, the transmitter communications unit 305, etc. At least some functions of the transmitter control unit 304 may be implemented in hardware.

[0068] FIG. 4 shows a schematic block diagram of multiple electronic devices 100A, 100B, 100C, a wireless power transmitter 300, and a passive repeater 402 according to some embodiments.

[0069] In fig. 4 is shown three electronic devices 100A, 100B, 100C that are wireless interactive toy construction elements which may be used in a construction toy set together with other toy construction elements. The wireless interactive toy construction elements have been assembled together with multiple passive toy construction elements 400, shown as hatched, into a toy construction model 401. The passive toy construction elements 400 are toy construction elements which do not comprise any electronic components. All of the construction elements shown in fig. 4 may be shaped as described above in connection with fig. 1. For example, each of the three wireless interactive toy construction elements 100A, 100B, 100C and all of the passive toy construction elements 400 may be shaped as a construction element with a 2-by-4 planar grid of coupling members 104 on what may be referred to as the top of the element. Some of the coupling pegs 104 are visible in fig. 4 as they have not been used for coupling to other elements in the construction of the toy model 401 , while others are unseen in fig. 4 are they partake in the coupling to other elements. The toy construction model is illustrated without any visible depth, but is to be imagined as having depth in the direction into or out of the illustration.

[0070] The three wireless interactive toy construction elements 100A, 100B, 100C are electronic devices as described herein, each comprising a rechargeable battery and a coil circuit, and are configured to be able to wirelessly charge their batteries when in the charging field of a wireless charging device 300. The toy construction model 401 has been placed on a wireless charging device 300 that may be configured as described above in connection with fig. 3. The wireless charging device 300 is configured to produce a charging field that is more powerful than needed for a wireless interactive toy construction elements to charge were it is placed on the charging surface 308 of the wireless power transmitter, and the wireless charging device is able to charge a wireless interactive toy construction element at a distance from the charging surface 308.

[0071] A first wireless interactive toy construction element 100A is at the bottom of the toy construction model 401 and is positioned directly on the charging surface 308 of the charger 300. The charging field produced by the wireless charging device is so powerful that the detune circuit comprised in the first wireless interactive toy construction element 100A detunes and retunes constantly in order to lower the effective received voltage in the coil circuit of the wireless interactive toy construction element. By detuning of the coil resonance frequency, the voltage in the coil circuit is kept low enough that the overvoltage protection circuit which acts to prevent excessive voltages from affecting sensitive electronics within the first wireless interactive toy construction element, such as e.g. an ASIC, is not triggered. The boost circuit of the first wireless interactive toy construction element will likely not trigger as the rectified voltage in the charging first wireless interactive toy construction element is likely high enough that it is equal to or higher than the charging voltage of the rechargeable battery.

[0072] A second wireless interactive toy construction element 100B is positioned in the middle of the toy construction model 401 and at a distance of four times the height of a toy construction element from the charging surface 308 of the charger 300, assuming that all the toy construction elements are of equal height. The charging field produced by the wireless charging device is powerful enough that the second wireless interactive toy construction element 100B is able to wirelessly charge even at this distance from the charging surface. The detune circuit of the second wireless interactive toy construction element may or may not trigger, depending on whether the power of the charging field at this distance is high enough to cause the circuit to trigger. The boost circuit of the second wireless interactive toy construction element may trigger as the rectified voltage in the second wireless interactive toy construction element may be lower than the charging voltage of the rechargeable battery. A third wireless interactive toy construction element 100C is positioned at the top of the toy construction model 401 and at a distance of more than six times the height of a toy construction element from the charging surface 308 of the charger 300, assuming that all the toy construction elements are of equal height. The charging field produced by the wireless charging device 300 may be powerful enough that the third wireless interactive toy construction element 100C is able to wirelessly charge even at this distance from the charging surface, although the charging may be slow.

[0073] In order to improve the charging of the third wireless interactive toy construction element 100C, a passive repeater 402 has been positioned in the toy model 401 so as to be positioned in-between the electronic device 100 and the wireless power transmitter 300. The passive repeater 402 is also a construction element with coupling members suitable for coupling it to the passive construction elements 400 and / or to the electronic device 100. The passive repeater 402 is configured to extend the charging range of the wireless power transmitter 300 via near field magnetic resonant coupling. The charging field of the wireless power transmitter energizes the passive repeater 550 via near field magnetic resonant coupling and the passive repeater 402 “repeats” the charging field of the wireless power transmitter. More than one passive repeater 402 may be used and any additional passive repeaters may also receive energy from the wireless power transmitter 300 or optionally from another passive repeater 402 via near field magnetic resonant coupling. The use of one or more passive repeaters may provide an extension of the charging field and thereby allow an electronic device that is relatively far away from a wireless power transmitter 300 to harvest energy from the wireless power transmitter, or to harvest more energy from the wireless power transmitter.

[0074] Depending on the strength of the charging field at the third wireless interactive toy construction element, its detune circuit may or may not trigger. The boost circuit of the third wireless interactive toy construction element will trigger if the rectified voltage in the third wireless interactive toy construction element is lower than the charging voltage on the rechargeable battery.

[0075] Thus, all three wireless interactive toy construction elements 100A, 100B, 100C are able to wireless charge while remaining part of the toy construction model 401 in the advantageous electronic system comprising the wireless charger 300 and the three wireless interactive toy construction elements. If the toy construction model 401 is assembled on or near the charging surface of the wireless charging device 300, while the device is producing a charging field, the wireless interactive toy construction elements 100A, 100B, 100C may also be able to charge during assembly of the model.

[0076] FIG. 5 shows a schematic block diagram of a passive repeater according to some embodiments. As an example, a passive repeater 402 shaped as a square ring is shown in fig. 5. The passive repeater 402 has eighteen coupling pegs 104 on one side and cooperating cavities on the opposing side (not shown). The passive repeater shown is ring shaped, but other shapes may be suitable as well.

[0077] FIG. 6 shows a schematic block diagram of an electronic device and a wireless power transmitter according to some embodiments. The wireless power transmitter, also referred to as a wireless charger or a wireless charging device, is configured as the wireless power transmitter described in connection with fig. 5. The electronic device 100 is a wireless interactive toy construction element, also as described in connection with fig. 5.

[0078] In fig. 6 the wireless interactive toy construction element 100 is illustrated in three positions as it is moved towards the charging surface 308 of a wireless charging device 300, the three positions being designated with one, two, or three prime symbols (‘), respectively. A user is holding the wireless interactive toy construction element 100 in their hand 600 and moving it in such a way that the wireless interactive toy construction element is in the charging field of the wireless charging device in all three positions.

[0079] In the first position, the wireless interactive toy construction element 100’ is relatively far away from the wireless charger 300 and the charging field from the charger is weak at its position. The wireless interactive toy construction element is however configured for charging even in a weak charging field. A boost circuit in the wireless interactive toy construction element will act to boost the rectified voltage such that the rechargeable battery is able to charge despite the charging field being weak.

[0080] The wireless interactive toy construction element may be configured to inform the user on the strength of the charging field detected by the wireless interactive toy construction element, for example by providing a user-perceptible output, such as an audible, visual and / or haptic output.

[0081] In the second position, the wireless interactive toy construction element 100” has moved closer to the charging surface and may be close enough that the detune circuit in the wireless interactive toy construction element has triggered due to the increased strength of the charging field at the second position compared to the first position. Even with the stronger charging field, the boost circuit may still need to boost the rectified voltage for the wireless interactive toy construction element to be able to charge.

[0082] In the third position, the wireless interactive toy construction element 100”’ is almost at the charging surface 208 of the wireless charging device, and the detune circuit is actively ensuring that the voltages in the coil circuit are controlled and optimized for charging by successively detuning and retuning the resonance frequency of the electromagnetic coil in the wireless interactive toy construction element.

[0083] Thus, the wireless interactive toy construction element 100 is able to charge, while being moved about in the charging field of the wireless charging device, i.e. during variable charging field conditions. The wireless interactive toy construction element 100 of fig. 6 may be the first wireless interactive toy construction element 100A of fig. 5, and fig. 6 also illustrates how a wireless interactive toy construction element may be able to charge during construction of a toy construction model.

[0084] FIG. 7 shows an example of a control loop of an electronic device according to some embodiments. The electronic device comprises an overvoltage protection circuit, a detune circuit, and a boost circuit as described herein. The electronic device may be a wireless interactive toy construction element as described herein.

[0085] In state S1, the electronic device is in an initialisation state in which it is ready to start charging. When detecting a charging field, the electronic device may use a dummy load to check whether the charging field at the electromagnetic coil is powerful enough that the power supply can stay up if connected to the coil circuit. If this is the case, the dummy load is disconnected and the electronic device may move on to state S2 wherein it is charging, possibly trickle charging from a weak charging field. This process acts to prevent a fast power drain from the battery shortly after it begins receiving power. Otherwise, the electronic device could, in some instances, be “stuck” in a process loop in a weak charging field, where the battery is drained as fast as it is charged.

[0086] In state S2, the electronic device begins normal charging operation in which the battery is charging, possibly with the boost circuit increasing the rectified voltage. If the charging field is strong enough to trigger the detune circuit, the electronic device moves to state S3.

[0087] The electronic device may further comprise a processing unit which is active when there is enough power in the battery to operate it and which is usually only deactivated due to low battery. A processing unit requires significant amounts of power to operate, and an electronic device initialising from a low battery condition may not be able to operate the processing unit. Therefore, the electronic device may have a start-up circuit for controlling the activation of the processing unit from a deactivated state. The start-up circuit activates the processing unit from an inactive state if it determines that the power being delivered by the rectified voltage exceeds a start-up threshold value. To this end, electronic device may use a dummy load that it intermittently switched on to determine whether the strength of the charging field is strong enough to support switching on the processing unit.

[0088] In state S3, the detune circuit detunes the resonance frequency of the electromagnetic coil which in turn reduces the received power from the charging field. As the received power is reduced, it will eventually be low enough that it falls below the threshold which triggers the detune circuit and the resonance frequency of the coil is retuned, whereby the electronic device moves back to state S2. The electronic device may alternate between states S2 and S3 for extended periods of time. The boost circuit may act to increase the rectified voltage, while the electronic device is in state S3.

[0089] In state S4, the overvoltage protection circuit has triggered due to an excessive voltage or current being detected in the coil circuit and the electromagnetic coil has been shorted out in order to protect the electronic device. This state is also referred to as a shunt state. Entering state S4 may start a timer in the electronic device which keeps the electronic device in state S4 for a predetermined time period.

[0090] In state S5, the electronic device resets, possibly after a predetermined time period, following a shunt state. After the reset of state S4, the electronic device returns to the initialisation state S1.

[0091] LIST OF REFERENCES

[0092] 100 a wireless interactive toy construction element

[0093] 101 housing

[0094] 102 sidewalls

[0095] 103 tube

[0096] 104 coupling members / pegs

[0097] 105 function device

[0098] 108 sensor system

[0099] 207 electromagnetic coil

[0100] 209 control unit

[0101] 210 rechargeable battery

[0102] 211 wireless communications interface

[0103] 300 wireless power transmitter

[0104] 301 transmitter coil

[0105] 302 inductive charging circuitry

[0106] 303 power adapter

[0107] 304 transmitter control unit

[0108] 305 transmitter communications unit

[0109] 306 user interface

[0110] 307 charger encasing 308 charging surface

[0111] 400 passive toy construction element

[0112] 401 toy construction model

[0113] 402 passive repeater 600 user’s hand

Claims

CLAIMS1. An electronic device comprising: a rechargeable battery, a coil circuit comprising an electromagnetic coil and a rectifier configured to generate a rectified voltage, the coil circuit being configured for charging of the rechargeable battery, wherein the coil circuit comprises an overvoltage protection circuit configured to short out the electromagnetic coil in response to a first measured voltage or current in the coil circuit exceeding a predetermined protection threshold value, and the coil circuit comprises a detune circuit configured to detune the resonance frequency of the electromagnetic coil in response to a second measured voltage or current in the coil circuit exceeding a predetermined detune threshold value, and the coil circuit comprises a boost circuit configured to boost the rectified voltage in response to the rectified voltage being lower than the charging voltage on the rechargeable battery.

2. The electronic device according to claim 1, wherein the coil circuit may be configured to measure a received voltage resulting from a wireless power transfer signal being received by the electromagnetic coil, and the overvoltage protection circuit may be configured to short out the electromagnetic coil in response to the received voltage exceeding the predetermined protection threshold value.

3. The electronic device according to any of the previous claims, wherein the coil circuit is configured to measure the rectified voltage generated by the rectifier, and the detune circuit is configured to detune the resonance frequency of the electromagnetic coil in response to the rectified voltage exceeding the predetermined detune threshold value.

4. The electronic device according to any of the previous claims, wherein at least part of the coil circuit is implemented in hardware.

5. The electronic device according to any of the previous claims, wherein the coil circuit is implemented at least partly in an ASIC.

6. The electronic device according to any of the previous claims, wherein the coil circuit is configured to receive, and charge from, a wireless power transfer signal having a centre frequency in an ISM band comprising 140 kHz, and / or an ISM band comprising 6.78 MHz, and / or an ISM band comprising 13.56 MHz, and / or an ISM band comprising 27.12 MHz, where, for a given centre frequency, the wireless power transfer signal may be configured to comply with a regulated bandwidth of an ISM band comprising the given centre frequency.

7. The electronic device according to any of the previous claims, wherein the electronic device comprises a processing unit that is powered by the rechargeable battery, and the coil circuit comprises a start-up circuit for controlling the activation of the processing unit from a deactivated state, the start-up circuit being configured to activate the processing unit only after determining that the power being delivered by the rectified voltage exceeds a start-up threshold value.

8. The electronic device according to any of the previous claims, wherein the electronic device further comprises a wireless tag reader, such as an RFID / NFC tag reader.

9. The electronic device according to any of the previous claims, wherein the coil circuit further comprises an adjustment circuit for adjusting the resonance frequency of the electromagnetic coil, and wherein the adjustment circuit allows the electromagnetic coil to have a resonance frequency within one of at least two frequency ranges.

10. The electronic device according to claim 9, wherein the electronic device is configured to:- receive a wireless charging signal having a frequency within a first frequency range of the at least two frequency ranges, and- use the received wireless charging signal to charge the rechargeable battery, and wherein the coil circuit is configured such that the default resonance frequency of the electromagnetic coil is within the first frequency range.

11. The electronic device according to any of the previous claims, wherein the electronic device is a wireless interactive toy.

12. The electronic device according to claim 11 , wherein the wireless interactive toy is or comprises a wireless interactive toy construction element.

13. An electronic system comprising a wireless charging device and at least one electronic device, the wireless charging device comprising a transmitter coil configured to transmit a wireless power transfer signal, the wireless power transfer signal being transmitted using a magnetic charging field configured for transmission of power, and each of the at least one electronic devices being an electronic device according to any of claims 1 - 12.

14. The electronic system according to claim 13, wherein the wireless charging device comprises a charging surface, and wherein the wireless charging device and each of the at least one electronic device are configured such that: the charging circuit of the at least one electronic device generates a rectified voltage for charging of the rechargeable battery of the at least one electronic device with the detune circuit being active and maintaining the first measured voltage below the protection threshold value, when the wireless charging device is positioned in physical contact with the charging surface or within a first threshold distance from the charging surface, the charging circuit of the at least one electronic device generates a rectified voltage for charging of the rechargeable battery of the at least one electronicdevice with the detune circuit being inactive and with the second measured voltage being below the detune threshold value, when the wireless charging device is positioned within a second threshold distance range from the charging surface and further removed from the charging surface than the first threshold distance.

15. The electronic system according to claim 13 or 14, wherein the wireless charging device comprises a charging surface configured for supporting electronic devices placed thereon for wireless charging, and wherein the wireless charging device and each of the at least one electronic devices are configured such that the at least one electronic device is able to charge from the wireless charging device whether it is placed directly on the charging surface or is at a distance within 2 cm, such as within 4 cm, such as within 6 cm, such as within 8 cm, such as within 10 cm, from the charging surface.

16. The electronic system according to any of claims 13 through 15, wherein the electronic system is part of a toy set, such as part of a toy construction set.

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