AC charging method to extend the life of electrical connectors of a smart watch, charger and object.

Abstract

The present invention relates to a novel method of electrical contact charging for portable electronic objects, in particular smart watches. The method of the invention makes it possible to extend the life of the electrical connectors of a portable electronic object, and the life of the object itself by using square wave alternating current for electrical transfer at the charging port of the object. Fig. 1

Description

Title of the invention: Alternating current charging method for extending the life of the electrical connectors of a smart watch, charger and object. TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a novel method for charging a portable electronic object making it possible to extend the life of the electrical connectors of said object, in particular a smart watch. In particular, the present invention proposes to supply an alternating current signal "AC" with a square waveform, in order to mitigate corrosion of the electrical connectors during charging in the presence of moisture and / or electrolytes. The invention also relates to a charger and a smart object configured to implement the method of the invention. STATE OF THE ART

[0002] Traditional charging methods for smartwatches primarily use direct current (DC) voltage for power transfer 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 the migration of metal atoms within the conductor, leading to material degradation and corrosion over time.

[0003] This corrosion of connectors is particularly problematic with male-female pin electrical contacts, called POGO, commonly integrated into smart watches and being in contact or close to the user's skin. To overcome this problem, watch manufacturers recommend cleaning and drying the watch's charging port before connecting the charger. This solution is obviously unsatisfactory and impractical.

[0004] Another solution may consist of using a so-called "wireless" induction charging method. Patent application EPI 739 817 A1, for example, suggests a method for charging a portable object using a charger generating an alternating charging current to transfer electrical energy to a wristwatch without direct electrical contact, and charging the watch by inductive coupling. However, wireless charging methods are less reliable than charging methods with electrical contact. Statement of the invention

[0005] The present invention aims to propose a new alternating current charging method making it possible to extend the life of portable electronic objects.

[0006] More particularly, the invention proposes a method for charging an electronic portable object by means of a charger comprising a charging station with electrical contact with a charging port for said object, said portable object operating with a direct current rechargeable battery, characterized in that the charger is configured to implement: - a step of generating an alternating current “AC” charging signal, said AC charging signal comprising a square waveform, as well as a predefined frequency, and - a step of transferring said AC charging signal to the electrical connectors of the charging station.

[0007] This charging method is very advantageous in that the use of a square wave AC charging signal makes it possible to limit the effects of electromigration at the connectors, and thus protect them from corrosion during charging in a humid environment.

[0008] In particular, this AC charging signal is only used for transfer at the electrical connectors of the charger and the object, and the AC charging signal is intended to be converted into a DC charging signal at the object.

[0009] According to embodiments of the invention, the charging method of the invention comprises at least one of the following characteristics or any technically operable combination: - said AC charging signal of square waveform and predefined frequency is generated by means of a DC / AC converter frequency-driven by an oscillator of said charger. Preferably, the DC / AC converter is a driver and H-bridge. - the load signal generation step involves spreading the spectrum of the preconfigured frequency by ± 10%. - the charger includes a dedicated jitter circuit to spread a spectrum of said preconfigured frequency. - said charging signal has a preconfigured frequency between 50kHz and 150 kHz, preferably between 75 kHz and 125 kHz and / or a preconfigured voltage +V7 -V of a value < 10, preferably < 6, and such as approximately +5 V / -5V. - the generation step implements a voltage booster upstream of said DC / AC converter, said voltage booster being configured to increase the charging signal voltage to compensate for a voltage loss during a subsequent AC / DC conversion at the object. - the AC charging signal has a square waveform of +6 V and -6 V. - the object is configured to receive said AC charging signal at the level electrical connectors of the charging port of said object and to implement a step of AC / DC conversion of said charging signal and a step of supplying a direct current to the battery of said object.

[0010] The invention also relates to a charger for a portable electronic object with a “DC” battery and being configured to implement the charging method according to one or any combination of characteristics described above, said charger comprising a charging station with electrical connectors, and comprising a DC / AC converter controlled in frequency by an oscillator to provide an AC charging signal of square wave form and preconfigured frequency.

[0011] Finally, the invention also relates to a portable electronic object such as a smart watch, said object operating with a rechargeable DC battery and comprising a charging circuit configured to receive an AC charging signal provided by means of a charging method according to the invention, said circuit comprising an AC / DC converter being configured to provide 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 as a rectifier bridge, and being accompanied at the output by an electronic discharge protection circuit and a capacitor.

[0012] Other characteristics and advantages of the invention will be apparent from reading the following description of a non-limiting example of embodiment of the invention with reference to the attached drawings. LIST OF FIGURES

[0013] [Fig. 1] schematically represents the AC charging method according to a preferred embodiment of the invention intended for charging a portable electronic object with a DC battery.

[0014] [Fig.2] shows the results of a comparative accelerated wear test of electrical connectors during DC or AC charging in a humid environment. Method: The contact area of ​​the charging pin is immersed in a cotton ball moistened with artificial sweat, and the electricity DC 5V / 100mA or AC square wave signal +5V / -5V 100mA, duty cycle 50%, frequency 100 kHz is transmitted continuously for 60 minutes, the positive and negative distance of the product pin is 4.0mm (ISO IS 3160-2 standard). Conditions: temperature 25+3 degrees, pH 4.7.

[0015] [Fig.3] shows the step of generating SI by the charger of a square wave AC charging signal according to the embodiment of the charging method of [Fig.l].

[0016] [Fig.4] shows a block diagram of a charger configuration for generating the AC signal according to the embodiment of the charging method of [Fig.l].

[0017] [Fig.5] shows the AC / DC conversion step on the object side according to the embodiment of the charging method of [Fig.l].

[0018] [[Fig.6] represents a block diagram of a configuration of the object for performing AC / DC conversion of the charging signal according to the embodiment of the charging method of [Fig.l]. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention relates to a novel method of electrical contact charging for portable electronic objects. The method of the invention makes it possible to extend the life of the electrical connectors of a portable electronic object, and the life of the object itself by using alternating current for electrical transfer at the charging port of the object.

[0020] The method is particularly advantageous for recharging smart watches, which are often exposed to humidity and perspiration, and are therefore prone to corrosion of their charging port. [Fig. 1] schematically illustrates a preferred application of the charging method of the invention proposing the use of an AC alternating current charging signal for an electrical transfer between the charger 1 and the portable electronic object 2, corresponding here to a smart watch 2 with a DC battery. The charger comprises a charging station comprising an electrical connector with two spring-loaded male pins called "POGO", and the watch 2 comprises a compatible charging port comprising an electrical connector with two female POGO pins. Of course, the invention is not limited to this type of connector or to smart watches, and can be implemented to improve the lifespan of any type of electrical connector of a portable electronic object 1..

[0021] [Fig.2] illustrates in a simplified manner the steps proposed by the method of charging 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 smart object 2.

[0022] This embodiment aims at charging objects operating with a DC battery and proposes to use the alternating current only for the electrical transfer between the charger and the object, at the level of the electrical connectors. The object 2 is therefore configured to implement a step S3 of conversion of this alternating current in direct current “AC / DC”, and then supply the DC battery in a power supply step S4.

[0023] Indeed, the inventors have demonstrated that the use of alternating current makes it possible to prevent corrosion of electrical connectors during charging in a humid environment. This effect was observed in accelerated wear tests of electrical pins immersed in an artificial perspiration solution, and to which an alternating current or a direct current is applied. Surprisingly, it was observed that the alternating current did not generate any visible corrosion of the electrical pins after 24 hours of testing, whereas significant corrosion is obtained when using a direct current after 1 hour of charging under equivalent conditions ([Fig.2]).

[0024] It would therefore appear that the use of alternating current has the effect of reducing the electromigration effect caused by the movement of metal ions due to the direction of flow. This effect could be due to the constant change in direction of the alternating current, distributing the stress more evenly on the conductive materials, and thus reducing the migration of ions in a single direction.

[0025] More particularly, the invention proposes to generate an alternating current charging signal of square wave form, and of preconfigured frequency and voltage. This signal form allows a clean switching between two voltage levels instantaneously, further reducing the electromigration effect. This square wave form is also more suitable for the transmission of energy and its frequency modulation.

[0026] In a preferred embodiment of the invention, the charger generates said alternating current of square wave form from a direct current ([Fig. 3]). The charger 1 therefore comprises a DC / AC converter 13 frequency-controlled by a local oscillator 11 in order to generate said charging signal ([Fig. 4]). In one embodiment, said oscillator comprises an integrated circuit of type 74AHC1G14, which is a logic gate with a Schmitt trigger making it possible to produce a square wave form. The output of this gate is fed back to the input through a timing network comprising a capacitor and resistors determining the frequency of the oscillating signal.

[0027] Preferably, the charger uses a driver and H-bridge as a DC / AC converter. The latter allows for minimal bulk in the charger and fine control of voltage variations at the desired frequency.

[0028] The frequency of the charging signal is preconfigured to a value between 50 kHz and 150 kHz, preferably between 70 kHz and 120 kHz allowing efficient charging of the DC battery of the object, and limited emission of parasitic radiation.

[0029] The charging signal has a voltage equal to or close to the voltage of the DC battery to be supplied, 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.

[0030] Typically, it is desired to provide a charging signal of approximately 5 V. However, implementing a square waveform signal of approximately +5V / -5V at the desired frequency may generate spurious radiation and high harmonics exceeding the thresholds established in the directives relating to “RED” radio equipment in Europe, such as the RED standards EN 300220 or 300328. In order to overcome this drawback, in addition to limiting the preconfigured frequency, the invention proposes to spread a frequency spectrum of the charging signal by approximately ±10% relative to the preconfigured frequency. Advantageously, it is thus possible to distribute the power of a narrowband harmonic over a larger bandwidth, limit spurious radiation and satisfy the standards mentioned.

[0031] In a preferred embodiment, the frequency is spread by means of an oscillator jitter system varying the preconfigured frequency by ±10%, the energy of the charging signal is thus spread over a wider spectrum band. This jitter system, called "jitter" in English, can be implemented in several forms. In one embodiment, a digital oscillator or a 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%, giving a frequency range of 90 to 110 kHz. In another embodiment, the charger includes a dedicated jitter circuit, and this circuit is based on a Schmitt trigger comparator which modulates the supply voltage of a second oscillator of the charger, the frequency of the latter being a function of its supply voltage.

[0032] [Fig. 4] represents a block diagram with the main components of the charger according to a preferred embodiment of the invention. The charger 1 here comprises a power booster 10 upstream of a driver and H-bridge 13 acting as a DC / AC converter. The power booster 11 makes it possible to increase a positive voltage of the AC charging signal generated by said H-bridge and to compensate for a voltage loss during the AC / DC conversion at the object. The charger also implements a current detector 12 with a light-emitting diode "LED" provided with a resistor RIRI measuring the current flowing through the charger and informing the user when the current is correctly detected. In the non-limiting example, the oscillator 11 is powered by a DC current of 5 V from the power booster 10, and provides a clock signal necessary for the driver of the H-bridge.The driver and H-bridge 13 are used to generate a +6V / -6V square wave AC charging signal, frequency driven by the oscillator and fed at the . electrical connectors of the charger and the object. Preferably, capacitors and resistors Pt5, Pt6 are also implemented to filter and stabilize the output AC charging signal.

[0033] In a known manner, the charger also integrates a rectifier and regulators making it possible to adapt the alternating current of the electrical network into direct current capable of supplying the various components of the charger, as well as components for protection against overvoltages and overcurrents.

[0034] As schematically shown in [Fig.4], the object is configured to convert the square waveform AC load signal into direct current in an AC / DC conversion step S3.

[0035] [Fig.5] illustrates a non-limiting example of a conversion circuit of the object to implement this AC / DC conversion. The circuit comprises a pair of inputs POGO AC1, POGO AC2 configured to receive the AC charging signal at the charging port of the object. A set of rectifier diodes D2, D3, D4 is configured as a rectifier bridge to ensure that the direct current produced is of constant polarity regardless of the alternations of the input signal. Preferably, these rectifier diodes D2, D3, D4 are chosen from Schottky diodes and rectifiers.

[0036] An ultra-low capacitance ESDI electrostatic discharge protection circuit is connected across the rectifier bridge outputs to protect against possible overvoltages. A capacitor Cl is connected in parallel with the rectifier bridge output to smooth out fluctuations in the rectified signal, thus providing a finely stabilized DC voltage for battery charging. This configuration not only ensures efficient conversion of AC to DC, but also protects delicate electronic components from unstable or potentially dangerous electrical conditions.

Claims

Claims

1. Method for charging an electronic portable object (2) by means of a charger (1) comprising an electrical contact charging station with a charging port for said object, said portable object operating with a direct current “DC” rechargeable battery and comprising an AC / DC converter, characterized in that the charger is configured to implement: - a step (S1) of generating an alternating current “AC” charging signal, said AC charging signal comprising a square waveform, as well as a predefined frequency, and - a step (S2) of transferring said AC charging signal to the electrical connectors of the charging station of the object.

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

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

4. A charging method according to one of the preceding claims, wherein the step of generating the charging signal comprises spreading the spectrum of the preconfigured frequency by ± 10%.

5. A charging method according to claim 4, wherein the charger (1) comprises a dedicated jitter circuit for spreading a spectrum of said preconfigured frequency.

6. Charging method according to one of the preceding claims, wherein said charging signal has a preconfigured frequency between 50kHz and 150 kHz, preferably between 75 kHz and 125 kHz and / or a preconfigured voltage +V / -V of a value < 10, preferably < 6, and such as approximately +5 V / -5V.

7. Charging method according to one of claims 2 to 6, wherein the generating 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).

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

9. Charging method according to 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 a direct current to the battery of said object.

10. A charging method according to one of the preceding claims, wherein the object is a smart watch, preferably comprising POGO pin electrical connectors.

11. Charger (1) for a portable electronic object (2) with a “DC” battery configured to implement the charging method according to one of claims 1 to 8, said charger comprising a charging station with electrical connectors, characterized in that it comprises a DC / AC converter controlled in frequency by an oscillator to provide an AC charging signal of square wave form and preconfigured frequency.

12. A portable electronic object such as a smart watch, said object comprising a DC rechargeable battery and a charging circuit configured to receive an AC charging signal provided by means of a charging method according to one of claims 1 to 10 at electrical connectors of said object, said circuit comprising an AC / DC converter configured to provide a DC charging signal of constant polarity and voltage to said battery.

13. Portable electronic object according to claim 12, in which 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 an electronic discharge protection circuit (ESDI) and a capacitor (Cl).

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