Alternating current charging method for extending the service life of electrical connectors of a smart watch, a charger, and an object

Abstract

The present invention relates to a novel electrical contact charging method for portable electronic objects, in particular smart watches. The method of the invention makes it possible to extend the service life of the electrical connectors of a portable electronic object, and the service life of the object itself, by using square wave alternating current for electrical transfer at the charging port of the object.

Description

[0001] Description

[0002] Title: AC charging method to extend the lifespan of electrical connectors on a smartwatch, charger and device.

[0003] TECHNICAL FIELD OF THE INVENTION

[0004] The present invention relates to a novel charging method for a portable electronic device that extends the lifespan of its electrical connectors, particularly those of a smartwatch. Specifically, the invention proposes supplying an alternating current (AC) signal with a square waveform to mitigate corrosion of electrical connectors during charging in the presence of moisture and / or electrolytes. The invention also relates to a charger and a smart device configured to implement the method of the invention.

[0005] STATE OF THE ART

[0006] Traditional charging methods for smartwatches primarily use direct current (DC) voltage to transfer power to the device. However, prolonged exposure to moisture, perspiration, and other environmental factors can lead to electromigration-induced degradation of the charging connector, resulting in reduced charging efficiency and potential device malfunction. Electromigration occurs when the flow of direct current causes metal atoms to migrate within the conductor, leading to material degradation and corrosion over time.

[0007] This corrosion of the connectors is particularly problematic with male-female pin electrical contacts, known as POGO connectors, commonly integrated into smartwatches and often in contact with or near the user's skin. To mitigate this issue, watch manufacturers recommend cleaning and drying the watch's charging port before connecting the charger. This solution is obviously unsatisfactory and impractical.

[0008] Another solution could be to use a so-called "wireless" inductive charging method. For example, patent application EP1 739 817 A1 suggests a method for charging a wearable device using a charger that generates an alternating current to transfer electrical energy to a wristwatch without direct electrical contact, charging the watch through inductive coupling. However, wireless charging methods are less reliable than charging methods with electrical contact.

[0009] DESCRIPTION OF THE INVENTION

[0010] The present invention aims to propose a new method of alternating current charging to extend the lifespan of portable electronic devices.

[0011] More specifically, the invention proposes a method for charging a portable electronic device using a charger comprising a charging station with electrical contact and a charging port for said device, said portable device operating with a rechargeable DC battery, characterized in that the charger is configured to implement:

[0012] - a step of generating an alternating current “AC” charge signal, said AC charge signal having a square waveform, a preconfigured frequency, and a spread spectrum applied to the preconfigured frequency in order to reduce electromagnetic interference emitted by said charge signal, and

[0013] -a step of transferring said AC charging signal to the electrical connectors of the charging station.

[0014] This charging method is very advantageous because the use of a square wave AC charging signal limits the effects of electromigration at the connectors, thus protecting them from corrosion during charging in a humid environment.

[0015] In particular, this AC charging signal is used only for transfer at the electrical connectors of the charger and the object, and the AC charging signal is intended to be converted to a DC charging signal at the object.

[0016] According to embodiments of the invention, the charging method of the invention comprises at least one of the following features or any technically feasible combination thereof: said AC charging signal, with a square waveform and predefined frequency, is generated by means of a DC / AC converter whose frequency is driven by an oscillator of said charger. Preferably, the DC / AC converter is a driver and H-bridge type.

[0017] - The load signal has a pre-configured frequency between 50 kHz and 300 kHz, and the spectrum spreading is applied at said frequency with an amplitude between ±5% and ±30%. In particular, the spreading amplitude is adjusted progressively for higher frequencies so as to compensate for the increase in electromagnetic emissions generated by the harmonics of the load signal, while preserving the efficiency of the energy transfer. For example, for a pre-configured frequency between 50 kHz and 100 kHz, the spreading amplitude is between ±5% and ±15%; for a frequency between 100 kHz and 200 kHz, the spreading is between ±10% and ±25%; for a frequency between 200 kHz and 300 kHz, the spreading is between ±15% and ±30%.

[0018] - the pre-configured frequency is between 75 kHz and 150 kHz, and the spread spectrum amplitude is between ±10% and ±20%.

[0019] - the charger includes a dedicated jitter circuit to spread a spectrum of said pre-configured frequency.

[0020] - said load signal has a preconfigured +V / -V voltage of a value < 10, preferably < 6, and such that approximately +5 V / -5V.

[0021] - the generation stage implements a voltage booster upstream of said DC / AC converter, said voltage booster being configured to increase the load signal voltage so as to compensate for a voltage loss during a subsequent AC / DC conversion at the object level.

[0022] - the AC load signal has a square waveform of +6 V and -6 V.

[0023] - the object is configured to receive said AC charging signal at the electrical connectors of the charging port of said object and to implement an AC / DC conversion step of said charging signal and a step of supplying a direct current to the battery of said object.

[0024] The invention also relates to a charger for a portable electronic object with a "DC" battery and configured to implement the charging method according to one or any combination of features described above, said charger comprising a charging station with electrical connectors, and comprising a DC / AC converter frequency driven by an oscillator to provide an AC charging signal of square waveform and preconfigured frequency.

[0025] Finally, the invention also relates to a portable electronic device such as a smartwatch, said device operating with a rechargeable DC battery and comprising a charging circuit configured to receive an AC charging signal supplied by means of a charging method according to the invention, said circuit comprising an AC / DC converter configured to supply a DC charging signal of constant polarity and voltage to said battery. In one embodiment, said AC / DC converter comprises a set of rectifier diodes configured in a bridge rectifier, and being accompanied at the output by an electronic discharge protection circuit and a capacitor.

[0026] Other features and advantages of the invention will be apparent from the following description of a non-limiting example of an embodiment of the invention with reference to the attached drawings.

[0027] LIST OF FIGURES

[0028] Figure 1 schematically represents the AC charging method according to a preferred embodiment of the invention for charging a portable electronic object with a DC battery.

[0029] Figure 2 shows the results of a comparative accelerated wear test of electrical connectors under DC or AC load in a humid environment. Method: The contact area of ​​the load pin is immersed in a cotton ball moistened with artificial sweat, and a DC 5V / 100mA or AC +5V / -5V 100mA square wave signal, 50% duty cycle, 100 kHz frequency, is continuously applied for 60 minutes. The positive and negative distances between the product pins are 4.0 mm (ISO 3160-2). Conditions: Temperature 25±3 degrees Celsius, pH 4.7.

[0030] Figure 3 represents the generation step S1 by the charger of a square wave AC charging signal according to the embodiment of the charging method in Figure 1.

[0031] Figure 4 represents a block diagram of a charger configuration for generating the AC signal according to the embodiment of the charging method in Figure 1.

[0032] Figure 5 represents the object-side AC / DC conversion step according to the loading method embodiment of Figure 1. Figure 6 represents a block diagram of an object configuration for performing AC / DC conversion of the loading signal according to the loading method embodiment of Figure 1.

[0033] DETAILED DESCRIPTION OF THE INVENTION

[0034] The present invention relates to a novel electrical contact charging method for portable electronic devices. The method of the invention extends the lifespan of the electrical connectors of a portable electronic device, and the lifespan of the device itself, by using alternating current for electrical transfer at the device's charging port.

[0035] The method is particularly advantageous for charging smartwatches, which are often exposed to moisture and perspiration, and therefore prone to corrosion of their charging ports. Figure 1 schematically illustrates a preferred application of the charging method of the invention, proposing the use of an AC charging signal for electrical transfer between the charger 1 and the wearable electronic device 2, corresponding here to a smartwatch 2 with a DC battery. The charger includes a charging station with an electrical connector with two spring-loaded male pins, known as "POGO" connectors, and the watch 2 has a compatible charging port with a two-pin female POGO electrical connector. Of course, the invention is not limited to this type of connector or to smartwatches, and can be implemented to improve the lifespan of any type of electrical connector in a wearable electronic device 1.

[0036] Figure 2 illustrates in a simplified manner the steps proposed by the charging method of the invention, according to which the charger 1 is configured to implement a first step S1 of generating the AC charging signal, and a second step S2 of transferring said AC charging signal to the intelligent object 2.

[0037] This embodiment aims to charge devices operating with a DC battery and proposes using alternating current only for the electrical transfer between the charger and the device, at the level of the electrical connectors. Device 2 is therefore configured to implement a step S3 for converting this alternating current into direct current ("AC / DC"), and then to power the DC battery in a power supply step S4. Indeed, the inventors have demonstrated that the use of alternating current prevents corrosion of the electrical connectors during charging in a humid environment. This effect was observed in accelerated wear tests of electrical pins immersed in an artificial transpiration solution, to which alternating or direct current was applied.Surprisingly, it was found that alternating current did not generate any visible corrosion of the electrical pins after 24 hours of testing, whereas significant corrosion was obtained when using direct current after 1 hour of charging under equivalent conditions (Fig.2).

[0038] It would therefore appear that the use of alternating current reduces the electromigration effect caused by the movement of metal ions due to the direction of the current flow. This effect could be due to the constant change in direction of the alternating current, distributing the stress more evenly across the conductive materials and thus reducing ion migration in a single direction.

[0039] More specifically, the invention proposes generating an alternating current charging signal with a square waveform and a pre-configured frequency and voltage. This signal shape allows for a clean, instantaneous switching between two voltage levels, further reducing the electromigration effect. This square waveform is also better suited for energy transmission and frequency modulation.

[0040] In a preferred embodiment of the invention, the charger generates said alternating current with a square waveform from a direct current (Fig. 3). The charger 1 therefore includes a DC / AC converter 13 whose frequency is controlled by a local oscillator 11 in order to generate said charging signal (Fig. 4). In one embodiment, said oscillator includes a 74AHC1 G14 type integrated circuit, which is a logic gate with a Schmitt trigger for producing a square waveform. The output of this gate is fed back to the input through a timing network comprising a capacitor and resistors that determine the frequency of the oscillating signal.

[0041] Preferably, the charger uses a driver and H-bridge as a DC / AC converter. This allows for a minimal footprint within the charger and precise control of voltage variations at the desired frequency. The charging signal frequency is pre-configured to a value between 50 kHz and 150 kHz, preferably between 70 kHz and 120 kHz, enabling efficient charging of the device's DC battery and limited emission of unwanted radiation.

[0042] The charging signal has a voltage equal to or close to the voltage of the DC battery to be powered, for example a positive / negative voltage in Volts of a value < 10. In one embodiment the positive voltage and the negative voltage have different values.

[0043] Typically, a load signal of approximately 5 V is desired. However, implementing a square wave signal of approximately +5 V / -5 V at the desired frequency can generate unwanted radiation and high harmonics exceeding the limits established in European radio equipment directives ("RED"), such as the RED EN 300220 or 300328 standards. To overcome this drawback, in addition to limiting the pre-configured frequency, the invention proposes spreading the load signal frequency spectrum by approximately ±10% of the pre-configured frequency. Advantageously, this makes it possible to distribute the power of a narrowband harmonic over a wider bandwidth, limit unwanted radiation, and meet the aforementioned standards.

[0044] In a preferred embodiment, the frequency is spread by means of an oscillator jitter system that varies the preconfigured frequency by ±10%, thus spreading the charging signal energy over a wider spectrum. This jitter system can be implemented in several forms. In one embodiment, a digital oscillator or microcontroller is used to program the desired frequency variation. For example, if the center frequency is 100 kHz, the jitter could vary this frequency by ±10%, resulting in a frequency range of 90 to 110 kHz. In another embodiment, the charger includes a dedicated jitter circuit, based on a Schmitt trigger comparator that modulates the supply voltage of a second charger oscillator, the frequency of which is a function of its supply voltage.

[0045] Figure 4 shows a block diagram of the main components of the charger according to a preferred embodiment of the invention. The charger 1 includes a power boost 10 upstream of a driver and H-bridge 13 acting as a DC / AC converter. The power boost 11 increases the positive voltage of the AC charging signal generated by the H-bridge and compensates for a voltage drop during the AC / DC conversion at the device. The charger also incorporates a current detector 12 with a light-emitting diode (LED) equipped with a resistance RIRI that measures the current flowing through the charger and informs the user when the current is correctly detected. In this non-limiting example, the oscillator 11 is powered by a 5 V DC current from the power boost 10 and provides a clock signal necessary for the H-bridge driver.The H-bridge and driver generate a +6V / -6V square wave AC charging signal, frequency-controlled by the oscillator and powered at the electrical connectors of the charger and the device. Preferably, Pt5 and Pt6 capacitors and resistors are also used to filter and stabilize the output AC charging signal.

[0046] As is known, the charger also incorporates a rectifier and regulators to adapt the alternating current from the electrical network into direct current suitable for powering the various components of the charger, as well as components for protection against overvoltages and overcurrents.

[0047] As schematically represented in Figure 4, the object is configured to convert the AC load signal from a square waveform to direct current in an S3 AC / DC conversion step.

[0048] Figure 5 illustrates a non-limiting example of a device conversion circuit to implement this AC / DC conversion. The circuit includes a pair of POGO inputs, AC1 and AC2, configured to receive the AC load signal at the device's load port. A set of rectifier diodes, D2, D3, and D4, is configured in a bridge rectifier configuration to ensure that the resulting DC current has a constant polarity regardless of the input signal's alternations. Preferably, these rectifier diodes, D2, D3, and D4, are selected from Schottky diodes and rectifiers.

[0049] An ultra-low capacitance ESDI electrostatic discharge protection circuit is connected across the rectifier bridge outputs to protect against potential overvoltages. A capacitor C1 is connected in parallel with the rectifier bridge output to smooth fluctuations in the rectified signal, thus providing a finely stabilized DC voltage for battery charging. This configuration ensures not only efficient AC-to-DC conversion but also protection of sensitive electronic components from unstable or potentially dangerous electrical conditions.

Claims

DEMANDS 1. Method of charging a portable electronic device (2) by means of a charger (1) comprising an electrically contacted charging station with a charging port for said device, said portable device operating with a rechargeable DC battery and comprising an AC / DC converter, characterized in that the charger is configured to implement: - a step (S1) for generating an alternating current “AC” load signal, said AC load signal having a square waveform, a preconfigured frequency, and a spread spectrum applied to the preconfigured frequency in order to reduce electromagnetic interference emitted by said load signal, and -a step (S2) of transferring said AC charging signal to the electrical connectors of the object's charging station.

2. Charging method according to claim 1, wherein said AC charging signal of square waveform and preconfigured frequency is generated by means of a DC / AC converter (13) frequency driven by an oscillator (11) of said charger (1).

3. Charging method according to claim 2, wherein the DC / AC converter (13) is a driver and H-bridge.

4. A charging method according to any one of the preceding claims, wherein said charging signal has a preconfigured frequency between 50 kHz and 300 kHz, and wherein the spread spectrum is applied to said frequency, with an amplitude between ±5% and ±30%.

5. Loading method according to claim 4, wherein the preconfigured frequency is between 75 kHz and 150 kHz, and the spectrum spread amplitude is between ±10% and ±20%.

6. Charging method according to any one of the preceding claims, wherein the charger (1) includes a dedicated jitter circuit for spreading a spectrum of said preconfigured frequency.

7. Charging method according to any one of the preceding claims, said charging signal has a preconfigured +VZ -V voltage of a value < 10, preferably < 6, and such that approximately +5 V / -5V.

8. A charging method according to any one of the preceding claims, wherein the generation step implements a voltage booster (10) upstream of said DC / AC converter (13), said voltage booster (10) being configured to increase the voltage of the charging signal so as to compensate for a voltage loss during a subsequent AC / DC conversion at the object (2).

9. Charging method according to any one of the preceding claims, wherein the AC charging signal has a square waveform of +6 V and -6 V.

10. A charging method according to any one of the preceding claims, wherein the object (2) is configured to receive said AC charging signal at the electrical connectors of the charging port of said object and to implement a step (S3) of AC / DC conversion of said charging signal and a step (S4) of supplying direct current to the battery of said object.

11. A charging method according to any one of the preceding claims, wherein the object is a smartwatch, preferably comprising POGO pin electrical connectors.

12. Charger (1) for portable electronic object (2) with “DC” battery configured to implement the charging method according to any one of claims 1 to 11, said charger comprising a charging station with electrical connectors, characterized in that it comprises a DC / AC converter frequency driven by an oscillator to provide an AC charging signal of square waveform and preconfigured frequency.

13. Portable electronic object such as a smartwatch, said object comprising a rechargeable DC battery and a charging circuit configured to receive an AC charging signal supplied by means of a charging method according to any one of claims 1 to 11 at electrical connectors of said object, said circuit comprising an AC / DC converter configured to supply a constant polarity and voltage DC charging signal to said battery.

14. A portable electronic device according to claim 13, wherein the AC / DC converter comprises a set of rectifier diodes (D2, D3, D4) configured as a rectifier bridge, and being accompanied at the output by a electronic discharge protection circuit (ESDI) and a capacitor (C1).

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