Patent Description:
The wireless charging technology originates from the wireless power transfer technology, and its principle is that energy is transferred through magnetic fields between a charger and an electric apparatus. Specifically, the charger can generate an electromagnetic signal, and the electric apparatus can sense the electromagnetic signal, so that the electric apparatus can generate current to charge a battery. Wireless charging is widely applied to existing electronic devices because it does not require additional wires and other accessories.

For example, in the field of stylus pens, the charger may be a wireless keyboard or an electronic device, and an electric device may be a stylus. The stylus can be wirelessly charged by using the wireless keyboard or electronic device.

However, existing wireless charging products always have the problem of low charging efficiency.

The object of the present disclosure is to provide a wireless charging circuit and a wireless charging system, so as to shorten a wireless charging link and improve link efficiency According to the invention, this object is achieved with a wireless charging circuit with the technical features of independent claim and with advantageous embodiments defined in dependent claims <NUM> and <NUM>.

According to a first aspect according to the invention, an embodiment of this application provides a wireless charging system, including an electronic device and a stylus. The stylus may also be referred to as a stylus pen or the like.

Specifically, the electronic device is configured to wirelessly charge the stylus; and the stylus includes a wireless charging circuit. The wireless charging circuit includes a first coil, a chip, and a first battery, where the first coil is configured to be coupled to the second coil to obtain an alternating current signal, and the chip is configured to charge the first battery based on the alternating current signal; where a charger unit includes: a voltage-stabilizing charging circuit, a boost charging circuit, or a switched capacitor charging circuit. The chip includes a rectifier, the charger unit, a micro-control unit, and a protocol encoding/decoding unit. The rectifier is configured to rectify an input alternating current signal into a direct current signal; the charger unit is configured to charge the first battery by using the direct current signal from the rectifier; the protocol encoding/decoding unit is configured to communicate with a transmit chip; and the micro-control unit is configured to control the charger unit and the protocol encoding/decoding unit.

In this embodiment of this application, an RX chip and a charger chip of the stylus can be designed as one component. Energy is coupled from the coil in the stylus, passes through the component, and then is directly output to a battery of the stylus, thereby shortening a wireless charging link and improving link efficiency. This can reduce temperature rise of the stylus during charging and improve charging efficiency.

In the invention, the voltage-stabilizing charging circuit includes a first field effect transistor control module, a first field effect transistor, and a second field effect transistor, where a gate terminal of the first field effect transistor and a gate terminal of the second field effect transistor are both connected to the first field effect transistor control module, a source terminal of the first field effect transistor is connected to an output terminal of the rectifier, a drain terminal of the first field effect transistor is connected to a source terminal of the second field effect transistor, and a drain terminal of the second field effect transistor is used to charge a battery of the stylus.

In this way, the chip includes an LDO charger, and the LDO charger includes a relatively small quantity of field effect transistors and has a relatively simple structure.

In a possible design not claimed, the voltage-stabilizing charging circuit includes a second field effect transistor control module, a third field effect transistor, a fourth field effect transistor, and a fifth field effect transistor, where a gate terminal of the third field effect transistor, a gate terminal of the fourth field effect transistor, and a gate terminal of the fifth field effect transistor are all connected to the second field effect transistor control module, a source terminal of the third field effect transistor is connected to an output terminal of the rectifier, a drain terminal of the third field effect transistor is connected to a source terminal of the fourth field effect transistor and one end of an inductor L, a drain terminal of the fourth field effect transistor is connected to a source terminal of the fifth field effect transistor and the other end of the inductor L, and a drain terminal of the fifth field effect transistor is configured to charge a battery of the stylus.

In this way, the chip includes a buck charger, and the buck charger has a larger quantity of field effect transistors than the LDO charger. With the third field effect transistor, the fourth field effect transistor, and the inductor L, flexible and stable voltage conversion can be implemented, achieving relatively high efficiency.

In a possible design not claimed, the voltage-stabilizing charging circuit includes a third field effect transistor control module, a sixth field effect transistor, a seventh field effect transistor, an eighth field effect transistor, a ninth field effect transistor, a tenth field effect transistor, an eleventh field effect transistor, a twelfth field effect transistor, a thirteenth field effect transistor, and a fourteenth field effect transistor.

A gate terminal of each of the sixth field effect transistor, the seventh field effect transistor, the eighth field effect transistor, the ninth field effect transistor, the tenth field effect transistor, the eleventh field effect transistor, the twelfth field effect transistor, the thirteenth field effect transistor, and the fourteenth field effect transistor is connected to the third field effect transistor control module; and a source terminal of the sixth field effect transistor is connected to an output terminal of the rectifier, a drain terminal of the sixth field effect transistor is connected to a source terminal of the seventh field effect transistor and a source terminal of the eleventh field effect transistor, a drain terminal of the seventh field effect transistor is connected to a source terminal of the eighth field effect transistor and one end of a capacitor C1, and a drain terminal of the eighth field effect transistor is connected to a source terminal of the ninth field effect transistor, a drain terminal of the twelfth field effect transistor is connected to a source terminal of the thirteenth field effect transistor, a drain terminal of the ninth field effect transistor is connected to a source terminal of the tenth field effect transistor and the other end of the capacitor C1, a drain terminal of the tenth field effect transistor and a drain terminal of the fourteenth field effect transistor are both grounded, a drain terminal of the eleventh field effect transistor is connected to a source terminal of the twelfth field effect transistor and one end of a capacitor C2, a drain terminal of the twelfth field effect transistor is connected to a source terminal of the thirteenth field effect transistor, and a drain terminal of the thirteenth field effect transistor is connected to a source terminal of the fourteenth field effect transistor and the other end of the capacitor C2, where the drain terminal of the eighth field effect transistor being connected to the drain terminal of the twelfth field effect transistor is used to charge a battery of the stylus.

In a possible design not claimed, the electronic device includes a second battery, a boost chip, a transmit chip, and the second coil, where the second battery is configured to input voltage to the boost chip; the boost chip is configured to boost the voltage to obtain a first direct current signal; the transmit chip is configured to invert the first direct current signal into a first alternating current signal, and transmit the first alternating current signal to the second coil; and the second coil is configured to be coupled to the first coil by using the first alternating current signal. In this way, the electronic device can be used to charge the stylus.

In one possible design, the electronic device is a tablet computer or a wireless keyboard, applied to use scenarios of the stylus.

According to a second aspect not claimed, an embodiment of this application provides a chip, including a rectifier, a charger unit, a micro-control unit, and a protocol encoding/decoding unit. The rectifier is configured to rectify an input alternating current signal into a direct current signal; the charger unit is configured to charge a battery by using the direct current signal from the rectifier, where the charger unit includes a voltage-stabilizing charging circuit, a boost charging circuit, or a switched capacitor charging circuit; the protocol encoding/decoding unit is configured to communicate with a transmit chip; and the micro-control unit is configured to control the charger unit and the protocol encoding/decoding unit.

In a possible design, the voltage-stabilizing charging circuit includes a first field effect transistor control module, a first field effect transistor, and a second field effect transistor, where a gate terminal of the first field effect transistor and a gate terminal of the second field effect transistor are both connected to the first field effect transistor control module, a source terminal of the first field effect transistor is connected to an output terminal of the rectifier, a drain terminal of the first field effect transistor is connected to a source terminal of the second field effect transistor, and a drain terminal of the second field effect transistor is used to charge a battery of the stylus.

In a possible design, the voltage-stabilizing charging circuit includes a second field effect transistor control module, a third field effect transistor, a fourth field effect transistor, and a fifth field effect transistor, where a gate terminal of the third field effect transistor, a gate terminal of the fourth field effect transistor, and a gate terminal of the fifth field effect transistor are all connected to the second field effect transistor control module, a source terminal of the third field effect transistor is connected to an output terminal of the rectifier, a drain terminal of the third field effect transistor is connected to a source terminal of the fourth field effect transistor and one end of an inductor L, a drain terminal of the fourth field effect transistor is connected to a source terminal of the fifth field effect transistor and the other end of the inductor L, and a drain terminal of the fifth field effect transistor is configured to charge a battery of the stylus.

In a possible design, the voltage-stabilizing charging circuit includes a third field effect transistor control module, a sixth field effect transistor, a seventh field effect transistor, an eighth field effect transistor, a ninth field effect transistor, a tenth field effect transistor, an eleventh field effect transistor, a twelfth field effect transistor, a thirteenth field effect transistor, and a fourteenth field effect transistor. A gate terminal of each of the sixth field effect transistor, the seventh field effect transistor, the eighth field effect transistor, the ninth field effect transistor, the tenth field effect transistor, the eleventh field effect transistor, the twelfth field effect transistor, the thirteenth field effect transistor, and the fourteenth field effect transistor is connected to the third field effect transistor control module; and a source terminal of the sixth field effect transistor is connected to an output terminal of the rectifier, a drain terminal of the sixth field effect transistor is connected to a source terminal of the seventh field effect transistor and a source terminal of the eleventh field effect transistor, a drain terminal of the seventh field effect transistor is connected to a source terminal of the eighth field effect transistor and one end of a capacitor C1, and a drain terminal of the eighth field effect transistor is connected to a source terminal of the ninth field effect transistor, a drain terminal of the twelfth field effect transistor is connected to a source terminal of the thirteenth field effect transistor, a drain terminal of the ninth field effect transistor is connected to a source terminal of the tenth field effect transistor and the other end of the capacitor C1, a drain terminal of the tenth field effect transistor and a drain terminal of the fourteenth field effect transistor are both grounded, a drain terminal of the eleventh field effect transistor is connected to a source terminal of the twelfth field effect transistor and one end of a capacitor C2, a drain terminal of the twelfth field effect transistor is connected to a source terminal of the thirteenth field effect transistor, and a drain terminal of the thirteenth field effect transistor is connected to a source terminal of the fourteenth field effect transistor and the other end of the capacitor C2, where the drain terminal of the eighth field effect transistor being connected to the drain terminal of the twelfth field effect transistor is used to charge a battery of the stylus.

According to a third aspect according to the invention, an embodiment of this application provides a wireless charging circuit applied to a stylus. The wireless charging circuit includes a first coil, a chip, and a first battery, where the first coil is configured to be coupled to the second coil to obtain an alternating current signal, and the chip is configured to charge the first battery based on the alternating current signal. The chip includes a rectifier, a charger unit, a micro-control unit, and a protocol encoding/decoding unit. The rectifier is configured to rectify an input alternating current signal into a direct current signal. The charger unit is configured to charge the first battery by using the direct current signal from the rectifier, and the charger unit includes a voltage-stabilizing charging circuit, a boost charging circuit, or a switched capacitor charging circuit. The protocol encoding/decoding unit is configured to communicate with a transmit chip. The micro-control unit is configured to control the charger unit and the protocol encoding/decoding unit.

In a possible design not claimed, the voltage-stabilizing charging circuit includes a third field effect transistor control module, a sixth field effect transistor, a seventh field effect transistor, an eighth field effect transistor, a ninth field effect transistor, a tenth field effect transistor, an eleventh field effect transistor, a twelfth field effect transistor, a thirteenth field effect transistor, and a fourteenth field effect transistor. A gate terminal of each of the sixth field effect transistor, the seventh field effect transistor, the eighth field effect transistor, the ninth field effect transistor, the tenth field effect transistor, the eleventh field effect transistor, the twelfth field effect transistor, the thirteenth field effect transistor, and the fourteenth field effect transistor is connected to the third field effect transistor control module; and a source terminal of the sixth field effect transistor is connected to an output terminal of the rectifier, a drain terminal of the sixth field effect transistor is connected to a source terminal of the seventh field effect transistor and a source terminal of the eleventh field effect transistor, a drain terminal of the seventh field effect transistor is connected to a source terminal of the eighth field effect transistor and one end of a capacitor C1, and a drain terminal of the eighth field effect transistor is connected to a source terminal of the ninth field effect transistor, a drain terminal of the twelfth field effect transistor is connected to a source terminal of the thirteenth field effect transistor, a drain terminal of the ninth field effect transistor is connected to a source terminal of the tenth field effect transistor and the other end of the capacitor C1, a drain terminal of the tenth field effect transistor and a drain terminal of the fourteenth field effect transistor are both grounded, a drain terminal of the eleventh field effect transistor is connected to a source terminal of the twelfth field effect transistor and one end of a capacitor C2, a drain terminal of the twelfth field effect transistor is connected to a source terminal of the thirteenth field effect transistor, and a drain terminal of the thirteenth field effect transistor is connected to a source terminal of the fourteenth field effect transistor and the other end of the capacitor C2, where the drain terminal of the eighth field effect transistor being connected to the drain terminal of the twelfth field effect transistor is used to charge a battery of the stylus.

For beneficial effects in the second aspect, the third aspect, and the possible designs thereof, reference may be made to beneficial effects in the first aspect and the possible implementations of the first aspect, and details are not repeated herein.

Unless otherwise specified, "plurality of" in this specification indicates two or more. The term "and/or" in this specification describes only an association relationship for describing associated objects and represents that three relationships may exist. For example, A and/or B may represent the following three cases: A alone, both A and B, and B alone. In addition, the character "/" in this specification generally represents an "or" relationship between associated objects. In a formula, the character "/" indicates a "division" relationship between the associated objects.

It should be understood that digital numbers in the embodiments of this application are merely for differentiation for ease of description and are not intended to limit the scope of the embodiments of this application.

It should be understood that, in the embodiments of this application, sequence numbers of the foregoing processes do not indicate execution sequences. The execution sequences of the processes should be determined according to functions and internal logic of the processes and should not be construed as any limitation on the implementation processes of the embodiments of this application.

<FIG> is a schematic diagram of a scenario to which the embodiments of this application are applicable. Referring to <FIG>, the scenario includes a stylus (stylus) <NUM>, an electronic device <NUM>, and a wireless keyboard <NUM>. In <FIG>, a tablet computer (tablet) is used as an example of the electronic device <NUM> for description. The stylus <NUM> and the wireless keyboard <NUM> may provide input to the electronic device <NUM>, and in response to the input, the electronic device <NUM> performs an operation based on the input of the stylus <NUM> or the wireless keyboard <NUM>. A touch region may be provided on the wireless keyboard <NUM>, the stylus <NUM> may operate in the touch region of the wireless keyboard <NUM> to provide input to the wireless keyboard <NUM>, and in response to the input, the wireless keyboard <NUM> may perform an operation based on the input of the stylus <NUM>. In an embodiment, the stylus <NUM> and the electronic device <NUM>, the stylus <NUM> and the wireless keyboard <NUM>, and the electronic device <NUM> and the wireless keyboard <NUM> may be interconnected through a communication network to implement wireless signal exchange. The communication network may be, but is not limited to, a Wi-Fi hotspot network, a Wi-Fi peer-to-peer (peer-to-peer, P2P) network, a bluetooth network, a zigbee network, or a near field communication (near field communication, NFC) network, and other near field communication networks.

The stylus <NUM> may be, but is not limited to, an inductive stylus and a capacitive stylus. The electronic device <NUM> has a touchscreen <NUM>. When the stylus <NUM> is an inductive stylus, an electromagnetic induction board needs to be integrated on the touchscreen <NUM> of the electronic device <NUM> that interacts with the stylus <NUM>. Coils are distributed on the electromagnetic induction board, and coils are also integrated in the inductive stylus. Based on the principle of electromagnetic induction, within a range of a magnetic field generated by the electromagnetic induction board, the inductive stylus can accumulate and store electric energy with movement of the inductive stylus. The inductive stylus may transmit the accumulated electric energy to the electromagnetic induction board via the coils in the inductive stylus through free oscillation. The electromagnetic induction board may scan the coils on the electromagnetic induction board based on the electric energy from the inductive stylus to calculate a position of the inductive stylus on the touchscreen <NUM>. The touchscreen <NUM> in the electronic device <NUM> may also be referred to as a touch panel, and the stylus <NUM> may also be referred to as a stylus pen.

The capacitive stylus may include a passive capacitive stylus and an active capacitive stylus. The passive capacitive stylus may be called a passive-type capacitive stylus, and the active capacitive stylus may be called an active-type capacitive stylus.

One or more electrodes may be provided in the active capacitive stylus (for example, in the tip of the stylus), and the active capacitive stylus may transmit a signal through the electrode. When the stylus <NUM> is an active capacitive stylus, an electrode array needs to be integrated on the touchscreen <NUM> of the electronic device <NUM> that interacts with the stylus <NUM>. In an embodiment, the electrode array may be a capacitive electrode array. The electronic device <NUM> may receive a signal from the active capacitive stylus through the electrode array; and when receiving the signal, the electronic device <NUM> further recognizes a position of the active capacitive stylus on the touchscreen and an inclination angle of the active capacitive stylus based on change of a capacitance value on the touchscreen <NUM>.

<FIG> is a schematic structural diagram of a stylus according to an embodiment of this application. Referring to <FIG>, the stylus <NUM> may include a tip <NUM>, a barrel <NUM>, and a back cover <NUM>. The barrel <NUM> is hollowed inside, the tip <NUM> and the back cover <NUM> are located at two ends of the barrel <NUM> respectively, and the back cover <NUM> and the barrel <NUM> may be plugged or buckled. For a matching relationship between the tip <NUM> and the barrel <NUM>, refer to the description in <FIG>.

<FIG> is a schematic diagram of a partially disassembled structure of a stylus according to an embodiment of this application. Referring to <FIG>, the stylus <NUM> further includes a mainshaft assembly <NUM>, the mainshaft assembly <NUM> is located in the barrel <NUM>, and the mainshaft assembly <NUM> is slidably disposed in the barrel <NUM>. The mainshaft assembly <NUM> has an external thread <NUM>, and the tip <NUM> includes a writing end <NUM> and a connecting end <NUM>, where the connecting end <NUM> of the tip <NUM> has an internal thread (not shown) matching the external thread <NUM>.

When the mainshaft assembly <NUM> is assembled into the barrel <NUM>, the connecting end <NUM> of the tip <NUM> extends into the barrel <NUM> and is threadedly connected to the external thread <NUM> of the mainshaft assembly <NUM>. In some other examples, the connecting end <NUM> of the tip <NUM> may alternatively be detachably connected to the mainshaft assembly <NUM> through buckling or the like. The connecting end <NUM> of the tip <NUM> being detachably connected to the mainshaft assembly <NUM> can implement replacement of the tip <NUM>.

For detection of a pressure on the writing end <NUM> of the tip <NUM>, as shown in <FIG>, there is a gap 10a between the tip <NUM> and the barrel <NUM>, which can ensure that when the writing end <NUM> of the tip <NUM> is subjected to external force, the tip <NUM> may move toward the barrel <NUM>, and the movement of the tip <NUM> drives the mainshaft assembly <NUM> to move within the barrel <NUM>. For detection of the external force, as shown in <FIG>, the mainshaft assembly <NUM> is provided with a pressure sensitive assembly <NUM>, part of the pressure sensitive assembly <NUM> is fixedly connected to a fixing structure in the barrel <NUM>, and part of the pressure sensitive assembly <NUM> is fixedly connected to the mainshaft assembly <NUM>. In this way, when the mainshaft assembly <NUM> moves with the tip <NUM>, because part of the pressure sensitive assembly <NUM> is fixedly connected to the fixing structure in the barrel <NUM>, movement of the mainshaft assembly <NUM> causes the pressure sensitive assembly <NUM> to deform, and deformation of the pressure sensitive assembly <NUM> is transferred to a circuit board <NUM> (for example, the pressure sensitive assembly <NUM> and the circuit board <NUM> may be electrically connected via a wire or a flexible circuit board), the circuit board <NUM> detects the pressure on the writing end <NUM> of the tip <NUM> based on the deformation of the pressure sensitive assembly <NUM>, so as to control line thickness of the writing end <NUM> based on the pressure on the writing end <NUM> of the tip <NUM>.

It should be noted that the pressure detection of the tip <NUM> includes but is not limited to the foregoing method. For example, a pressure sensor may be provided in the writing end <NUM> of the tip <NUM>, and the pressure on the tip <NUM> may be detected by the pressure sensor.

In this embodiment, as shown in <FIG>, the stylus <NUM> further includes a plurality of electrodes, and the plurality of electrodes may be, for example, a first emission electrode <NUM>, a ground electrode <NUM>, and a second emission electrode <NUM>. The first emission electrode <NUM>, the ground electrode <NUM>, and the second emission electrode <NUM> are all electrically connected to the circuit board <NUM>. The first emission electrode <NUM> may be located within the tip <NUM> and close to the writing end <NUM>, and the circuit board <NUM> may be configured as a control board that can separately provide a signal to the first emission electrode <NUM> and the second emission electrode <NUM>. The first emission electrode <NUM> is configured to emit a first signal, and when the first emission electrode <NUM> is close to the touchscreen <NUM> of the electronic device <NUM>, a coupling capacitor may be formed between the first emission electrode <NUM> and the touchscreen <NUM> of the electronic device <NUM>, so that the electronic device <NUM> can receive the first signal. The second emission electrode <NUM> is configured to emit a second signal, and the electronic device <NUM> may determine an angle of inclination of the stylus <NUM> based on the received second signal. In this embodiment of this application, the second emission electrode <NUM> may be located on an inner wall of the barrel <NUM>. In an example, the second emission electrode <NUM> may alternatively be located on the mainshaft assembly <NUM>.

The ground electrode <NUM> may be located between the first emission electrode <NUM> and the second emission electrode <NUM>, or the ground electrode <NUM> may be located around an outer periphery of the first emission electrode <NUM> and the second emission electrode <NUM>, and the ground electrode <NUM> is configured to reduce coupling between the first emission electrode <NUM> and the second emission electrode <NUM>.

When the electronic device <NUM> receives the first signal from the stylus <NUM>, a capacitance value at a corresponding position of the touchscreen <NUM> changes. Accordingly, the electronic device <NUM> may determine a position of the stylus <NUM> (or the tip of the stylus <NUM>) on the touchscreen <NUM> based on the change of the capacitance value on the touchscreen <NUM>. In addition, the electronic device <NUM> may obtain the angle of inclination of the stylus <NUM> by using a double-tip projection method in an inclination angle detection algorithm. Positions of the first emission electrode <NUM> and the second emission electrode <NUM> in the stylus <NUM> are different. Therefore, when the electronic device <NUM> receives the first signal and the second signal from the stylus <NUM>, capacitance values at the two positions on the touchscreen <NUM> change. The electronic device <NUM> may obtain the angle of inclination of the stylus <NUM> based on a distance between the first emission electrode <NUM> and the second emission electrode <NUM> and a distance between two positions with capacitance values changed on the touchscreen <NUM>. For more details about how the angle of inclination of the stylus <NUM> is obtained, reference may be made to related descriptions of a dual-tip projection method in the prior art.

In this embodiment of this application, as shown in <FIG>, the stylus <NUM> further includes a battery assembly <NUM>, where the battery assembly <NUM> is configured to provide power to the circuit board <NUM>. The battery assembly <NUM> may include a lithium-ion battery, or the battery assembly <NUM> may include a nickel-chromium battery, an alkaline battery, a nickel-metal hydride battery, or the like. In an embodiment, the battery included in the battery assembly <NUM> may be a rechargeable battery or a disposable battery. When the battery included in the battery assembly <NUM> is a rechargeable battery, the stylus <NUM> supports wireless charging for the battery in the battery assembly <NUM>.

When the stylus <NUM> is an active capacitive stylus, referring to <FIG>, after the electronic device <NUM> and the stylus <NUM> are wirelessly connected, the electronic device <NUM> may transmit an uplink signal to the stylus <NUM> through the electrode array integrated on the touchscreen <NUM>. The stylus <NUM> may receive the uplink signal through a receiving electrode, and the stylus <NUM> may transmit a downlink signal through an emission electrode (for example, the first emission electrode <NUM> and the second emission electrode <NUM>). The downlink signal includes the foregoing first signal and second signal. When the tip <NUM> of the stylus <NUM> comes in contact with the touchscreen <NUM>, a capacitance value at a corresponding position of the touchscreen <NUM> changes, and the electronic device <NUM> may determine a position of the tip <NUM> of the stylus <NUM> on the touchscreen <NUM> based on the capacitance value on the touchscreen <NUM>. In an embodiment, the uplink signal and the downlink signal may be square wave signals.

In an embodiment, referring to <FIG>, the wireless keyboard <NUM> may include a first part <NUM> and a second part <NUM>. For example, the wireless keyboard <NUM> may include a keyboard body and a keyboard cover. The first part <NUM> may be the keyboard cover, and the second part <NUM> may be the keyboard body. The first part <NUM> is configured to hold the electronic device <NUM>, and the second part <NUM> may be provided with keys, a touch panel, and the like for user operation.

When the wireless keyboard <NUM> is in use, the first part <NUM> and the second part <NUM> of the wireless keyboard <NUM> need to be opened; and when the wireless keyboard <NUM> is not in use, the first part <NUM> and the second part <NUM> of the wireless keyboard <NUM> can be closed. In an embodiment, the first part <NUM> and the second part <NUM> of the wireless keyboard <NUM> are rotatably connected. For example, the first part <NUM> and the second part <NUM> may be connected through a rotating shaft or a hinge; or in some examples, the first part <NUM> and the second part <NUM> are rotatably connected through a flexible material (for example, a leather material or a cloth material). Alternatively, in some examples, the first part <NUM> and the second part <NUM> may be integrally formed, and a joint between the first part <NUM> and the second part <NUM> is processed by thinning, so that the joint between the first part <NUM> and the second part <NUM> may be bent. The first part <NUM> and the second part <NUM> may be connected in, without limitation to, the foregoing rotatable connection manners.

The first part <NUM> may include at least two brackets that are rotatably connected. For example, referring to <FIG>, the first part <NUM> includes a first bracket 301a and a second bracket 301b. The first bracket 301a is rotatably connected to the second bracket 301b. During use of the electronic device <NUM>, both the first bracket 301a and the second bracket 301b may be used to support the electronic device <NUM> (refer to <FIG>). Alternatively, the first bracket 301a supports the second bracket 301b, and the second bracket 301b supports the electronic device <NUM>. Referring to <FIG>, the second bracket 301b and the second part <NUM> are rotatably connected.

Referring to <FIG>, to accommodate the stylus <NUM>, the wireless keyboard <NUM> may be provided with an accommodating portion <NUM> for accommodating the stylus <NUM>. Referring to <FIG>, the accommodating portion <NUM> is a cylindrical chamber. When being accommodated, the stylus <NUM> is inserted into the accommodating chamber in a direction of the arrow in <FIG>. In this embodiment, referring to <FIG>, the second part <NUM> and the second bracket 301b are rotatably connected by using a connecting portion <NUM>, and the connecting portion <NUM> is provided with the accommodating portion <NUM>. The connecting portion <NUM> may be a rotating shaft.

<FIG> is a schematic diagram of a stylus being accommodated in an accommodating portion of a wireless keyboard according to an embodiment of this application; and <FIG> is a schematic side view of a stylus being accommodated in an accommodating portion of a wireless keyboard according to an embodiment of this application. Referring to <FIG>, the accommodating portion <NUM> is a circular chamber, and an inner diameter of the accommodating portion <NUM> is larger than an outer diameter of the stylus <NUM>.

To prevent the stylus <NUM> from dropping from the accommodating portion <NUM>, in an embodiment, a magnetic material may be provided on an inner wall of the accommodating portion <NUM>, and a magnetic material may be provided in the stylus <NUM>. The stylus <NUM> is adsorbed in the accommodating portion <NUM> by magnetic adsorption between the magnetic materials. Certainly, in some examples, the stylus <NUM> may be fastened to the accommodating portion <NUM> by, but not limited to, magnetic adsorption. For example, the stylus <NUM> may alternatively be fastened to the accommodating portion <NUM> by buckling.

To help the stylus <NUM> to be taken out of the accommodating portion <NUM>, an eject structure may be provided in the accommodating portion <NUM>. For example, when one end of the stylus <NUM> is pressed, an eject mechanism may drive that one end of the stylus <NUM> to eject from the accommodating portion <NUM>.

<FIG> is a schematic diagram of a hardware structure of a stylus according to an embodiment of this application. Referring to <FIG>, the stylus <NUM> may have a processor <NUM>. The processor <NUM> may include a storage and processing circuit for supporting an operation of the stylus <NUM>. The storage and processing circuit may include a storage apparatus such as a non-volatile memory (for example, a flash memory or another electrically programmable read-only memory configured as a solid state drive), a volatile memory (for example, a static or dynamic random access memory), and the like. The processing circuit in the processor <NUM> may be configured to control the operation of the stylus <NUM>. The processing circuit may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio chips, application specific integrated circuits, and the like.

The stylus <NUM> may include one or more sensors. For example, the sensor may include a pressure sensor <NUM>. The pressure sensor <NUM> may be disposed on the writing end <NUM> of the stylus <NUM> (as shown in <FIG>). Certainly, the pressure sensor <NUM> may alternatively be disposed in the barrel <NUM> of the stylus <NUM>, so that after one end of the tip <NUM> of the stylus <NUM> is subjected to a force, the other end of the tip <NUM> moves so that the force acts on the pressure sensor <NUM>. In an embodiment, the processor <NUM> may adjust, based on the pressure detected by the pressure sensor <NUM>, the thickness of lines written using the tip <NUM> of the stylus <NUM>.

The sensors may further include an inertial sensor <NUM>. The inertial sensor <NUM> may include a three-axis accelerometer and a three-axis gyroscope, and/or other components for measuring movement of the stylus <NUM>, for example, a three-axis magnetometer may be included in the sensor in a nine-axis inertial sensor structure. The sensors may further include additional sensors, such as a temperature sensor, an ambient light sensor, a light-based proximity sensor, a contact sensor, a magnetic sensor, a pressure sensor, and/or other sensors.

The stylus <NUM> may include a status indicator <NUM> such as a light emitting diode and a button <NUM>. The status indicator <NUM> is configured to inform a user of a status of the stylus <NUM>. The button <NUM> may include a mechanical button and a non-mechanical button, and the button <NUM> may be configured to collect press-button information from a user.

In this embodiment of this application, the stylus <NUM> may include one or more electrodes <NUM> (for details, refer to the descriptions in <FIG>). One of the electrodes <NUM> may be located at the writing end of the stylus <NUM>, and one of the electrodes <NUM> may be located inside the tip <NUM>. Reference may be made to the foregoing related descriptions.

The stylus <NUM> may include a sensing circuit <NUM>. The sensing circuit <NUM> may sense capacitive coupling between the electrodes <NUM> and drive lines of a capacitive touch sensor panel that interacts with the stylus <NUM>. The sensing circuit <NUM> may include an amplifier for receiving a capacitance reading from the capacitive touch sensor panel, a clock for generating a demodulation signal, a phase shifter for generating a phase shifted demodulation signal, a mixer for demodulating a capacitance reading by using an in-phase demodulation frequency component, and a mixer for demodulating a capacitance reading by using a quadrature demodulation frequency component. Results of demodulation by the mixers may be used for determining an amplitude proportional to a capacitance, so that the stylus <NUM> can sense contact with the capacitive touch sensor panel.

It can be understood that, according to an actual need, the stylus <NUM> may include a microphone, a speaker, an audio generator, a vibrator, a camera, a data port, and other devices. A user may use these devices to provide commands to control operations of the stylus <NUM> and the electronic device <NUM> that interacts with the stylus <NUM> and receive status information and other output.

The processor <NUM> may be configured to run software for controlling the operation of the stylus <NUM> in the stylus <NUM>. During the operation of the stylus <NUM>, the software running on the processor <NUM> may process sensor input, button input, and input from other devices to monitor movement of the stylus <NUM> and other user input. The software running on the processor <NUM> may detect a user command and may communicate with the electronic device <NUM>.

To support wireless communication between the stylus <NUM> and the electronic device <NUM>, the stylus <NUM> may include a wireless module. In <FIG>, a bluetooth module <NUM> is used as an example of the wireless module for description. The wireless module may alternatively be a Wi-Fi hotspot module, a Wi-Fi peer-to-peer module, or the like. The bluetooth module <NUM> may include a radio frequency transceiver, such as a transceiver. The bluetooth module <NUM> may further include one or more antennas. The transceiver may transmit and/or receive a wireless signal by using the antenna. The wireless signal may be a bluetooth signal, a wireless local area network signal, a remote signal such as a cellular telephone signal, a near field communication signal, or other wireless signals based on a type of the wireless module.

The stylus <NUM> may further include a charging module <NUM>, and the charging module <NUM> may support charging of the stylus <NUM> and provide power for the stylus <NUM>.

It should be understood that the electronic device <NUM> in this embodiment of this application may be user equipment (user equipment, UE), a terminal (terminal), or the like. For example, the electronic device <NUM> may be a portable android device (portable android device, PAD), a personal digital assistant (personal digital assistant, PDA), a handheld device, a computing device, a vehicle-mounted device, or a wearable device with a wireless communication function, a mobile terminal or fixed terminal with a touchscreen such as a virtual reality (virtual reality, VR) terminal device, an augmented reality (augmented reality, AR) terminal device, a wireless terminal in industrial control (industrial control), a wireless terminal in self driving (self driving), a wireless terminal in remote medical (remote medical), a wireless terminal in a smart grid (smart grid), a wireless terminal in transportation safety (transportation safety), a wireless terminal in a smart city (smart city), or a wireless terminal in a smart home (smart home). The form of the terminal device is not specifically limited in the embodiments of this application.

<FIG> is a schematic diagram of a hardware structure of an electronic device according to an embodiment of this application. Referring to <FIG>, the electronic device <NUM> may include a plurality of subsystems. The subsystems cooperate to perform, coordinate, or monitor one or more operations or functions of the electronic device <NUM>. The electronic device <NUM> includes a processor <NUM>, an input surface <NUM>, a coordination engine <NUM>, a power subsystem <NUM>, a power connector <NUM>, a wireless interface <NUM>, and a display <NUM>.

For example, the coordination engine <NUM> may be configured to: communicate with other subsystems of the electronic device <NUM> and/or process data; communicate with a stylus <NUM> and/or exchange data; measure and/or obtain output of one or more analog or digital sensors (for example, a touch sensor); measure and/or obtain output of one or more sensor nodes in a sensor node array (for example, a capacitive sensing node array); receive and locate a signal from a tip of the stylus <NUM> and a ring signal; and locate the stylus <NUM> based on a position of an intersection area of the tip signal and a position of an intersection area of the ring signal.

The coordination engine <NUM> of the electronic device <NUM> includes or is otherwise communicatively coupled to a sensor layer located under an input surface <NUM> or integrated with the input surface. The coordination engine <NUM> locates the stylus <NUM> on the input surface <NUM> by using the sensor layer, and estimates an angular position of the stylus <NUM> relative to a plane on which the input surface <NUM> lies, by using the techniques described herein. In an embodiment, the input surface <NUM> may be referred to as a touchscreen <NUM>.

For example, the sensor layer of the coordination engine <NUM> of the electronic device <NUM> is a grid of capacitive sensing nodes arranged in columns and rows. More specifically, an array of column traces is arranged perpendicular to an array of row traces. The sensor layer may be separated from other layers of the electronic device, or the sensor layer may be disposed directly on another layer. The other layers are, for example but not limited to: a display stack layer, a force sensor layer, a digitizer layer, a polarizer layer, a battery layer, and a structural or decorative shell layer.

The sensor layer can operate in various modes. If the sensor layer operates in a mutual capacitance mode, the column traces and the row traces form a single capacitive sensing node at each overlapping point (for example, a "vertical" mutual capacitance). If the sensor layer operates in a self-capacitance mode, the column traces and the row traces form two (vertically aligned) capacitive sensing nodes at each overlapping point. In another embodiment, if the sensor layer operates in a mutual capacitance mode, adjacent column traces and/or adjacent row traces may form a single capacitive sensing node (for example, a "horizontal" mutual capacitance). As described above, the sensor layer may detect presence of the tip <NUM> of the stylus <NUM> and/or touch by a user's finger by monitoring changes in capacitance (for example, mutual capacitance or self-capacitance) presented at each capacitive sensing node. In many cases, the coordination engine <NUM> may be configured to detect, by capacitive coupling, tip and ring signals received from the stylus <NUM> through the sensor layer.

The tip signal and/or the ring signal may include specific information and/or data that may be configured to cause the electronic device <NUM> to recognize the stylus <NUM>. Such information is generally referred to as "stylus identity" information herein. Such information and/or data may be received by the sensor layer, and interpreted, decoded, and/or demodulated by the coordination engine <NUM>.

The processor <NUM> may use the stylus identity information to simultaneously receive input from more than one stylus. Specifically, the coordination engine <NUM> may be configured to transmit a position and/or an angular position of each of the styluses detected by the coordination engine <NUM> to the processor <NUM>. In other cases, the coordination engine <NUM> may also transmit information about relative positions and/or relative angular positions of the plurality of styluses detected by the coordination engine <NUM> to the processor <NUM>. For example, the coordination engine <NUM> may notify the processor <NUM> of a position of a detected first stylus relative to a detected second stylus.

In other cases, the tip signal and/or the ring signal may further include specific information and/or data for enabling the electronic device <NUM> to identify a specific user. Such information is generally referred to as "user identity" information herein.

The coordination engine <NUM> may forward the user identity information (if detected and/or recovered) to the processor <NUM>. If the user identity information cannot be recovered from the tip signal and/or the ring signal, the coordination engine <NUM> may optionally indicate to the processor <NUM> that the user identity information is unavailable. The processor <NUM> can utilize the user identity information (or absence of such information) in any suitable manner, including but not limited to accepting or denying input from the specific user and allowing or denying access to a specific function of the electronic device. The processor <NUM> may use the user identity information to simultaneously receive input from more than one user.

In still other cases, the tip signal and/or ring signal may include specific information and/or data that may be configured to cause the electronic device <NUM> to identify a setting or preference of the user or the stylus <NUM>. Such information is generally referred to as "stylus settings" information herein.

The coordination engine <NUM> may forward the stylus settings information (if detected and/or recovered) to the processor <NUM>. If the stylus settings information cannot be recovered from the tip signal and/or the ring signal, the coordination engine <NUM> may optionally indicate to the processor <NUM> that the stylus settings information is unavailable. The electronic device <NUM> can utilize the stylus settings information (or absence of such information) in any suitable manner, including but not limited to: applying a setting to the electronic device, applying a setting to a program running on the electronic device, changing a line thickness, a color, a pattern presented by a graphics program of the electronic device, and changing a setting of a video game operated on the electronic device.

In general, the processor <NUM> may be configured to perform, coordinate, and/or manage functions of the electronic device <NUM>. Such functions may include but are not limited to: communicating with and/or exchanging data with other subsystems of the electronic device <NUM>; communicating with and/or exchanging data with the stylus <NUM>; performing data communication and/or data exchange over a wireless interface; performing data communication and/or data exchange over a wired interface; facilitating exchange of power through a wireless (for example, inductive or resonant) or wired interface; and receiving position(s) and angular position(s) of one or more styluses.

The processor <NUM> may be implemented as any electronic device capable of processing, receiving, or transmitting data or instructions. For example, the processor may be a microprocessor, a central processing unit, an application specific integrated circuit, a field programmable gate array, a digital signal processor, an analog circuit, a digital circuit, or a combination of these devices. The processor may be a single-threaded or multi-threaded processor. The processor may be a single-core or multi-core processor.

During use, the processor <NUM> may be configured to access a memory in which instructions are stored. The instructions may be configured to cause the processor to perform, coordinate, or monitor one or more operations or functions of the electronic device <NUM>.

The instructions stored in the memory may be configured to control or coordinate operations of other components of the electronic device <NUM>. The components are, for example but not limited to, another processor, an analog or digital circuit, a volatile or nonvolatile memory module, a display, a speaker, a microphone, a rotary input device, a button, or other physical input devices, a biometric authentication sensor and/or system, a force or touch input/output component, a communication module (for example, a wireless interface and/or a power connector), and/or a haptic device or a haptic feedback device.

The memory may further store electronic data for use by the stylus or the processor. For example, the memory may store electronic data or content (for example, a media file, a document, and an application program), a device setting and preference, a timing signal and a control signal, or data, a data structure, or a database for various modules, and a file or configuration related to detecting the tip signal and/or the ring signal. The memory may be configured as any type of memory. For example, the memory may be implemented as a random access memory, a read only memory, a flash memory, a removable memory, other types of storage elements, or a combination of such devices.

The electronic device <NUM> further includes the power subsystem <NUM>. The power subsystem <NUM> may include a battery or other power sources. The power subsystem <NUM> may be configured to provide power to the electronic device <NUM>. The power subsystem <NUM> may also be coupled to the power connector <NUM>. The power connector <NUM> may be any suitable connector or port, and may be configured to receive power from an external power source and/or be configured to provide power to an external load. For example, in some embodiments, the power connector <NUM> may be configured to recharge a battery within the power subsystem <NUM>. In another embodiment, the power connector <NUM> may be configured to transfer power stored in (or available to) the power subsystem <NUM> to the stylus <NUM>.

The electronic device <NUM> further includes the wireless interface <NUM> to facilitate electronic communication between the electronic device <NUM> and the stylus <NUM>. In an embodiment, the electronic device <NUM> may be configured to communicate with the stylus <NUM> via a low-energy bluetooth communication interface or a near field communication interface. In other examples, the communication interface helps implement electronic communication between the electronic device <NUM> and an external communication network, a device, or a platform.

The wireless interface <NUM> (whether the communication interface between the electronic device <NUM> and the stylus <NUM> or another communication interface) may be implemented as one or more wireless interfaces, bluetooth interfaces, near field communication interfaces, magnetic interfaces, universal serial bus interfaces, inductive interfaces, resonant interfaces, capacitive coupling interfaces, Wi-Fi interfaces, TCP/IP interfaces, network communication interfaces, optical interfaces, acoustic interfaces, or any traditional communication interfaces.

The electronic device <NUM> further includes a display <NUM>. The display <NUM> may be located behind the input surface <NUM>, or may be integrated therewith. The display <NUM> may be communicatively coupled to the processor <NUM>. The processor <NUM> may use the display <NUM> to present information to a user. In many cases, the processor <NUM> uses the display <NUM> to present an interface with which a user may interact. In many cases, the user manipulates the stylus <NUM> to interact with the interface.

It will be apparent to those skilled in the art that some of the specific details presented above with respect to the electronic device <NUM> may not be required to practice particular embodiments or their equivalents. Similarly, other electronic devices may include more subsystems, modules, components, and the like. Some sub-modules may be implemented as software or hardware where appropriate. Therefore, it should be understood that the foregoing descriptions are not intended to be exhaustive or to limit the disclosure to the precise form set forth herein. On the contrary, it will be apparent to those of ordinary skill in the art that many modifications and variations are possible in light of the foregoing teachings.

<FIG> is a schematic diagram of a hardware structure of a wireless keyboard according to an embodiment of this application. Referring to <FIG>, the wireless keyboard <NUM> may include a processor <NUM>, a memory <NUM>, a charging interface <NUM>, a charging management module <NUM>, a wireless charging coil <NUM>, a battery <NUM>, a wireless communication module <NUM>, a touch panel <NUM>, and a keyboard <NUM>.

The processor <NUM>, the memory <NUM>, the charging interface <NUM>, the charging management module <NUM>, the battery <NUM>, the wireless communication module <NUM>, the touch panel <NUM>, the keyboard <NUM>, and the like may all be disposed on a keyboard body of the wireless keyboard <NUM> (that is, the second part <NUM> shown in <FIG>). The wireless charging coil <NUM> may be disposed in a connecting portion <NUM> (as shown in <FIG>) for movably connecting the keyboard body and a bracket. It should be understood that the structure illustrated in this embodiment does not constitute a specific limitation on the wireless keyboard <NUM>. In some other embodiments, the wireless keyboard <NUM> may include components more or fewer than those shown in the figure, or combine some components, or split some components, or have a different component arrangement. The illustrated components may be implemented by hardware, software, or a combination of software and hardware.

The memory <NUM> may be configured to store program code, such as program code for wirelessly charging the stylus <NUM>. The memory <NUM> may further store a bluetooth address that uniquely identifies the wireless keyboard <NUM>. In addition, the memory <NUM> may further store connection data of an electronic device that has been successfully paired with the wireless keyboard <NUM> before. For example, the connection data may be a bluetooth address of the electronic device that has been successfully paired with the wireless keyboard <NUM>. Based on the connection data, the wireless keyboard <NUM> can be automatically paired with the electronic device without having to configure a connection therewith, for example, performing a validity check. The bluetooth address may be a media access control (media access control, MAC) address.

The processor <NUM> may be configured to execute the foregoing application program code and invoke relevant modules to implement the functions of the wireless keyboard <NUM> in the embodiments of this application, for example, to implement a wired charging function, reverse wireless charging function, wireless communication function, and the like of the wireless keyboard <NUM>. The processor <NUM> may include one or more processing units, and different processing units may be separate devices or may be integrated into one or more processors <NUM>. The processor <NUM> may specifically be an integrated control chip or may include a circuit including various active and/or passive components, and the circuit is configured to perform the functions of the processor <NUM> described in the embodiments of this application. The processor of the wireless keyboard <NUM> may be a microprocessor.

The wireless communication module <NUM> may be configured to support data exchange between the wireless keyboard <NUM> and other electronic devices over wireless communication including bluetooth (bluetooth, BT), the global navigation satellite system (global navigation satellite system, GNSS), a wireless local area network (wireless local area networks, WLAN) (for example, a wireless fidelity (wireless fidelity, Wi-Fi) network), frequency modulation (frequency modulation, FM), near field communication (near field communication, NFC), an infrared (infrared, IR) technology, and the like.

In some embodiments, the wireless communication module <NUM> may be a bluetooth chip. The wireless keyboard <NUM> may be a bluetooth keyboard. The wireless keyboard <NUM> may be paired with a bluetooth chip of another electronic device through the bluetooth chip and establish a wireless connection, so as to implement wireless communication between the wireless keyboard <NUM> and the another electronic device through the wireless connection.

In addition, the wireless communication module <NUM> may further include an antenna. The wireless communication module <NUM> receives an electromagnetic wave via the antenna, performs frequency modulation and filtering on an electromagnetic wave signal, and transmits the processed signal to the processor <NUM>. The wireless communication module <NUM> may also receive a to-be-sent signal from the processor <NUM>, perform frequency modulation and amplification on the signal, and radiate the signal as an electromagnetic wave using the antenna.

In some embodiments, the wireless keyboard <NUM> may support wired charging. Specifically, the charging management module <NUM> may receive charging input of a wired charger through the charging interface <NUM>.

In other embodiments, the wireless keyboard <NUM> may support forward wireless charging. The charging management module <NUM> may receive a wireless charging input through the wireless charging coil <NUM> of the wireless keyboard <NUM>. Specifically, the charging management module <NUM> is connected to the wireless charging coil <NUM> through a matching circuit. The wireless charging coil <NUM> may be coupled with a wireless charging coil of a wireless charger and induce an alternating electromagnetic field emitted by the wireless charging coil <NUM> of the wireless charger to generate an alternating current signal. The alternating current signal generated by the wireless charging coil <NUM> is transmitted to the charging management module <NUM> through the matching circuit, so as to charge the battery <NUM> wirelessly.

The charging management module <NUM> may further provide power for the wireless keyboard <NUM> while charging the battery <NUM>. The charging management module <NUM> receives input from the battery <NUM> to provide power for the processor <NUM>, the memory <NUM>, an external memory, the wireless communication module <NUM>, and the like. The charging management module <NUM> may be further configured to monitor parameters such as battery capacity of the battery <NUM>, a cycle count of the battery, and a state of health (leakage and impedance) of the battery. In some other embodiments, the charging management module <NUM> may alternatively be disposed in the processor <NUM>.

In some other embodiments, the wireless keyboard <NUM> may support reverse wireless charging. Specifically, the charging management module <NUM> may further receive input from the charging interface <NUM> or the battery <NUM> and convert a direct current signal input from the charging interface <NUM> or the battery <NUM> into an alternating current signal. The alternating current signal is transmitted to the wireless charging coil <NUM> through the matching circuit. The wireless charging coil <NUM> may generate an alternating electromagnetic field upon receiving the alternating current signal. A wireless charging coil of another mobile terminal may perform wireless charging upon sensing the alternating electromagnetic field. That is, the wireless keyboard <NUM> may further wirelessly charge the another mobile terminal. In an embodiment, the wireless charging coil <NUM> may be disposed in an accommodating portion <NUM> of the wireless keyboard <NUM>, and a wireless charging coil is disposed in the barrel <NUM> of a stylus <NUM>. When the stylus <NUM> is placed in the accommodating portion <NUM>, the wireless keyboard <NUM> may charge the stylus <NUM> through the wireless charging coil <NUM>.

It should be noted that the matching circuit may be integrated in the charging management module <NUM>, or the matching circuit may be independent of the charging management module <NUM>, which is not limited in the embodiments of this application. <FIG> is a schematic diagram of a hardware structure of the wireless keyboard <NUM> by using as an example that the matching circuit may be integrated in the charging management module <NUM>.

The charging interface <NUM> may be configured to provide a wired connection for charging or communication between the wireless keyboard <NUM> and another electronic device (for example, the wired charger of the wireless keyboard <NUM>).

A touch sensor is integrated into the touch panel <NUM>. A laptop may receive a control command of a user for the laptop through the touch panel <NUM> and the keyboard <NUM>.

It should be understood that the structure illustrated in this embodiment of this application does not constitute a specific limitation on the wireless keyboard <NUM>. The wireless keyboard <NUM> may have more or fewer components than those shown in <FIG>, may combine two or more components, or may have a different component configuration. For example, a housing of the wireless keyboard <NUM> may be further provided with an accommodating chamber for accommodating the stylus <NUM>. The wireless charging coil <NUM> is disposed in the accommodating chamber and is configured to wirelessly charge the stylus <NUM> after the stylus <NUM> is accommodated in the accommodating chamber.

For another example, an outer surface of the wireless keyboard <NUM> may further include components such as a key, an indicator light (which may indicate a state such as a battery level, an incoming/outgoing call, or a pairing mode), and a display (which may display prompt information to a user). The key may be a physical key, a touch key (used with the touch sensor), or the like and is configured to trigger operations such as power-on, power-off, start of charging, and end of charging.

For example, <FIG> is a schematic diagram of a possible wireless charging link.

As shown in <FIG>, a portable android device (portable android device, PAD) is used to charge a stylus. The PAD includes a PAD battery, a boost (BOOST) chip, a transmit (transport, TX) chip, and a coil. The stylus includes a coil, a receive (receive, RX) chip, a charger (charger) chip, and a battery.

The following briefly describes a principle of charging the stylus through the PAD in <FIG>.

A voltage of the PAD battery is input to the boost chip, and the boost chip raises the voltage from the PAD battery and uses the raised voltage to power the TX chip. An estimated voltage conversion efficiency in this process is η<NUM>.

The TX chip converts a direct current signal provided by the boost chip into an alternating current signal through inversion and transmits the signal to the coil, so that the coil sends the signal out. An estimated conversion efficiency in this process is η<NUM>.

The coil of the PAD and the coil of the stylus are electromagnetically coupled to transmit energy from the PAD to the stylus. A coupling efficiency is present in the transmission process and an estimated efficiency is η<NUM>.

The RX chip performs rectification and voltage change on an alternating current signal coupled by the coil of the stylus and outputs a stable direct current signal. An estimated efficiency in this process is η<NUM>.

The RX chip outputs the direct current signal, and the direct current signal needs to be processed by the charger chip to charge the battery of the stylus. An estimated efficiency in this process is η<NUM>.

Therefore, an overall link efficiency for charging the stylus by the PAD shown in <FIG> is: <MAT>.

According to project experience, under the premise that the coil of the PAD and the coil of the stylus are completely aligned, ηtotal is about <NUM>%. A link efficiency is relatively low, and the PAD and the stylus overheat severely during charging, resulting in low charging efficiency.

In view of this, in order to improve a charging speed and reduce temperature rise, this embodiment of this application provides a wireless charging circuit to improve overall efficiency of the wireless charging link. Specifically, the RX chip and the charger chip are designed as one component. Energy is coupled from the coil in the stylus, passes through the component, and then is directly output to a battery of the stylus, thereby shortening a wireless charging link and improving link efficiency. This can reduce temperature rise of the stylus during charging and improve charging efficiency.

The RX chip and the charger chip are designed as one component in this embodiment of this application because the RX chip and the charger chip are found to have identical or similar functional components.

For example, <FIG> is a schematic diagram of an internal structure of an RX chip. <FIG> is a schematic diagram of an internal structure of a charger chip.

As shown in <FIG>, the RX chip includes a rectifier <NUM>, a low dropout regulator (low dropout regulator, LDO) <NUM>, a micro-control unit (micro control unit, MCU) <NUM>, and a protocol encoding/decoding unit <NUM>.

The rectifier <NUM> is configured to rectify an alternating current signal coupled by the coil in the stylus to obtain a relatively stable direct current signal, and the direct current signal is used as an input of the LDO <NUM>.

The LDO1002 is configured to convert the direct current signal after rectification into a standard 5V (which may be certainly any other voltage values, where this is not limited in this embodiment of this application) voltage signal as an input signal of the charger chip.

The MCU1003 is configured to execute software code in the stylus and can be controlled by a register.

The protocol encoding/decoding unit <NUM> is configured to communicate with the TX chip. The protocol encoding/decoding unit <NUM> may include an amplitude-shift keying (amplitude-shift keying, ASK) modulation format or a frequency-shift keying (frequency-shift keying, FSK) modulation format, which is not specifically limited in this embodiment of this application.

The LDO <NUM> generally includes a field effect transistor <NUM>, for example, the field effect transistor may include a metal-oxide-semiconductor field-effect transistor (metal-oxide-semiconductor field-effect transistor, MOSFET).

As shown in <FIG>, the charger chip includes a field effect transistor <NUM> (hereinafter referred to as Q1), a field effect transistor <NUM> (hereinafter referred to as Q2), and a control circuit for controlling Q1 and Q2. The control circuit may be implemented by hardware or software, which is not limited in this embodiment of this application.

Q1 may be a MOSFET or the like, and is used as a main LDO to perform voltage stabilization on an input signal VIN from the RX chip and then supply power to a post-stage system.

Q2 may be a MOSFET or the like, and is used to isolate a system power supply from the battery and provides a function of dynamic path management.

Through comparison between <FIG>, it can be found that the LDO in the RX chip may be physically implemented as one MOSFET, and the charger chip may be physically implemented as two MOSFETs, the first MOSFET.

(Q1) in the charger chip having a same function as the LDO. Therefore, in this embodiment of this application, the LDO in the RX chip can be reused as Q1 in the charger chip, and the RX chip and the charger chip are designed as one component. In this way, the component can implement functions of the RX chip and the charger chip and the wireless charging link can be shortened to improve link efficiency, thereby reducing temperature rise of the stylus during charging and improving charging efficiency.

It should be noted that, in a possible implementation, the LDO <NUM> in <FIG> and the field effect transistor <NUM> for implementing the LDO function in <FIG> may alternatively be replaced by a boost circuit (buck) or a switched capacitor (switched capacitor, SC) amplifying circuit for higher power charging. The buck may include two MOSFETs, and the SC may include nine MOSFETs, which are not limited in this embodiment of this application.

For example, <FIG> is a schematic diagram of a chip according to an embodiment of this application, and the chip can implement functions of an RX chip and a charger chip.

As shown in <FIG>, the chip includes a rectifier <NUM>, an LDO/Buck/SC charger <NUM> (which is the foregoing part for implementing functions of LDO/Buck/SC and charger chip, and may be referred to as a charger unit), an MCU1203, and a protocol encoding/decoding unit <NUM>.

The rectifier <NUM> is configured to rectify an alternating current signal coupled by the coil in the stylus to obtain a relatively stable direct current signal, and the direct current signal is used as an input of the LDO/Buck/SC charger <NUM>.

The LDO/Buck/SC charger <NUM> is configured to perform voltage stabilization on a direct current signal obtained through rectification and charge a battery.

The MCU1203 is configured to control wireless communication, the LDO/Buck/SC charger <NUM>, the protocol encoding/decoding unit <NUM>, and the like.

It can be understood that, in this embodiment of this application, because the RX chip and the charger chip are designed as one chip, the functions of the RX chip and the charger chip can be implemented and the wireless charging link can be also shortened to improve link efficiency, thereby reducing temperature rise of the stylus during charging and improving charging efficiency.

For example, <FIG> are schematic diagrams of hardware structures of a chip including an LDO charger, a chip including a buck charger, and a chip including an SC charger respectively.

As shown in <FIG>, the charger unit <NUM> in <FIG> may include an LDO charger <NUM>, and the LDO charger <NUM> includes a first field effect transistor control module <NUM>, a first field effect transistor <NUM>, and a second field effect transistor <NUM>.

A gate terminal of the first field effect transistor <NUM> and a gate terminal of the second field effect transistor <NUM> are both connected to the first field effect transistor control module <NUM>, a source terminal of the first field effect transistor <NUM> is connected to an output terminal of the rectifier <NUM>, a drain terminal of the first field effect transistor <NUM> is connected to a source terminal of the second field effect transistor <NUM>, and a drain terminal of the second field effect transistor <NUM> is used to charge a battery of the stylus.

The first field effect transistor control module <NUM> is configured to control a voltage value of the gate terminal of the first field effect transistor <NUM> and that of the gate terminal of the second field effect transistor <NUM>, so as to control on/off of the first field effect transistor <NUM> and the second field effect transistor <NUM>.

The first field effect transistor <NUM> is configured to stabilize a voltage output by the rectifier <NUM> to reach a charging voltage required by the stylus, and the second field effect transistor <NUM> is configured to isolate a system power supply of the chip from the battery of the stylus.

It can be understood that the drain terminal of the first field effect transistor <NUM> can also be used to provide a voltage output for other devices, for example, the drain terminal of the first field effect transistor <NUM> can output Vsys or the like, which is not specifically limited in this embodiment of this application.

In this embodiment of this application, the chip includes an LDO charger <NUM>, and the LDO charger <NUM> includes a relatively small quantity of field effect transistors and has a relatively simple structure.

As shown in the non-claimed embodiment in <FIG>, the charger unit <NUM> in <FIG> may include a buck charger <NUM>, and the buck charger <NUM> includes a second field effect transistor control module <NUM>, a third field effect transistor <NUM>, a fourth field effect transistor <NUM>, and a fifth field effect transistor <NUM>.

A gate terminal of the third field effect transistor <NUM>, a gate terminal of the fourth field effect transistor <NUM>, and a gate terminal of the fifth field effect transistor <NUM> are all connected to the second field effect transistor control module <NUM>, a source terminal of the third field effect transistor <NUM> is connected to an output terminal of the rectifier <NUM>, a drain terminal of the third field effect transistor <NUM> is connected to a source terminal of the fourth field effect transistor <NUM> and one end of an inductor L, a drain terminal of the fourth field effect transistor <NUM> is connected to a source terminal of the fifth field effect transistor <NUM> and the other end of the inductor L, and a drain terminal of the fifth field effect transistor <NUM> is configured to charge a battery of the stylus.

The second field effect transistor control module <NUM> is configured to control voltage values of the gate terminal of the third field effect transistor <NUM>, the gate terminal of the fourth field effect transistor <NUM>, and the gate terminal of the fifth field effect transistor <NUM>, so as to control on/off of the third field effect transistor <NUM>, the fourth field effect transistor <NUM>, and the fifth field effect transistor <NUM>.

The third field effect transistor <NUM>, the fourth field effect transistor <NUM>, and the inductor L can implement flexible and stable conversion of VIN to obtain a charging voltage required by the stylus; and the fifth field effect transistor <NUM> is configured to isolate a system power supply of the chip from the battery of the stylus.

It can be understood that the drain terminal of the fourth field effect transistor <NUM> can also be used to provide a voltage output for other devices, for example, the drain terminal of the fourth field effect transistor <NUM> can output Vsys or the like, which is not specifically limited in this embodiment of this application.

In this embodiment of this application, the chip includes a buck charger <NUM>, and the buck charger <NUM> has a larger quantity of field effect transistors than the LDO charger <NUM>. With the third field effect transistor <NUM>, the fourth field effect transistor <NUM>, and the inductor L, flexible and stable voltage conversion of VIN can be implemented to achieve relatively high efficiency.

As shown in the non-claimed embodiment in <FIG>, the charger unit <NUM> in <FIG> may include an SC charger <NUM>, and the SC charger <NUM> includes a third field effect transistor control module <NUM>, a sixth field effect transistor <NUM>, a seventh field effect transistor <NUM>, an eighth field effect transistor <NUM>, a ninth field effect transistor <NUM>, a tenth field effect transistor <NUM>, an eleventh field effect transistor <NUM>, a twelfth field effect transistor <NUM>, a thirteenth field effect transistor <NUM>, and a fourteenth field effect transistor <NUM>.

A gate terminal of each of the sixth field effect transistor <NUM>, the seventh field effect transistor <NUM>, the eighth field effect transistor <NUM>, the ninth field effect transistor <NUM>, the tenth field effect transistor <NUM>, the eleventh field effect transistor <NUM>, the twelfth field effect transistor <NUM>, the thirteenth field effect transistor <NUM>, and the fourteenth field effect transistor <NUM> is connected to the third field effect transistor control module <NUM>.

A source terminal of the sixth field effect transistor <NUM> is connected to an output terminal of the rectifier <NUM>, a drain terminal of the sixth field effect transistor <NUM> is connected to a source terminal of the seventh field effect transistor <NUM> and a source terminal of the eleventh field effect transistor <NUM>, a drain terminal of the seventh field effect transistor <NUM> is connected to a source terminal of the eighth field effect transistor <NUM> and one end of a capacitor C1, and a drain terminal of the eighth field effect transistor <NUM> is connected to a source terminal of the ninth field effect transistor <NUM>, a drain terminal of the twelfth field effect transistor <NUM> is connected to a source terminal of the thirteenth field effect transistor <NUM>, a drain terminal of the ninth field effect transistor <NUM> is connected to a source terminal of the tenth field effect transistor <NUM> and the other end of the capacitor C1, a drain terminal of the tenth field effect transistor <NUM> and a drain terminal of the fourteenth field effect transistor <NUM> are both grounded, a drain terminal of the eleventh field effect transistor <NUM> is connected to a source terminal of the twelfth field effect transistor <NUM> and one end of a capacitor C2, a drain terminal of the twelfth field effect transistor <NUM> is connected to a source terminal of the thirteenth field effect transistor <NUM>, and a drain terminal of the thirteenth field effect transistor <NUM> is connected to a source terminal of the fourteenth field effect transistor <NUM> and the other end of the capacitor C2, where the drain terminal of the eighth field effect transistor <NUM> being connected to the drain terminal of the twelfth field effect transistor <NUM> is used to charge a battery of the stylus.

The sixth field effect transistor <NUM>, the seventh field effect transistor <NUM>, the eighth field effect transistor <NUM>, the ninth field effect transistor <NUM>, the tenth field effect transistor <NUM>, the eleventh field effect transistor <NUM>, the twelfth field effect transistor <NUM>, the thirteenth field effect transistor <NUM>, the fourteenth field effect transistor <NUM>, the capacitor C1, and the capacitor C2 can implement flexible and stable conversion of VIN and isolate the system power supply of the chip from the battery of the stylus.

It should be noted that the source terminal and the drain terminal of each field effect transistor in the foregoing <FIG> can be used interchangeably, which is not limited in this embodiment of this application.

For example, in response to the chip structures in <FIG>, <FIG> is a schematic diagram of a wireless charging link according to an embodiment of this application.

As shown in <FIG>, a PAD is configured to charge a stylus. The PAD includes a PAD battery, a boost (BOOST) chip, a transmit (transport, TX) chip, and a coil. The stylus includes a coil, a chip <NUM> (for implementing RX and charger functions), and a battery.

The following briefly describes a principle of charging the stylus by using the PAD in <FIG>.

The chip <NUM> performs rectification and voltage change on an alternating current signal coupled by the coil of the stylus, and outputs a stable direct current signal to charge the battery of the stylus. An estimated efficiency in this process is η<NUM>. η<NUM> and η<NUM> described above may be the same or different and are not specifically limited in this embodiment of this application.

It can be learned that, compared with the wireless charging link in <FIG>, the wireless charging link in <FIG> reduces one efficiency-generating step. Therefore, the wireless charging link in <FIG> has higher link efficiency, thereby reducing temperature rise of the stylus during charging and improving charging efficiency.

It should be noted that the chip <NUM> in this embodiment of this application may be an RX chip, a charger chip, or the like. However, functions of the chip <NUM> include both the RX function and the charger function, and a specific name of the chip <NUM> is not limited in this embodiment of this application.

It should be noted that the PAD in this embodiment of this application may be replaced with a wireless keyboard or the like, and then the stylus can be charged by using the wireless keyboard or the like.

It can be understood that the chip and the wireless charging circuit in the embodiments of this application can also be applied to other applicable wireless charging scenarios, and the wireless charging scenarios are not specifically limited in the embodiments of this application.

Claim 1:
A wireless charging circuit applicable
to a stylus (<NUM>), wherein the wireless charging circuit comprises a first coil, a chip (<NUM>, <NUM>), and a first battery, wherein
the first coil is configured to be coupled to a second coil to obtain an alternating current signal;
the chip (<NUM>, <NUM>) comprises a rectifier (<NUM>, <NUM>), a charger unit (<NUM>), a micro-control unit, and a protocol encoding/decoding unit (<NUM>, <NUM>), and is configured to charge the first battery based on the alternating current signal;
the rectifier (<NUM>, <NUM>) is configured to rectify an input alternating current signal into a direct current signal;
the charger unit (<NUM>) comprises a voltage-stabilizing charging circuit (<NUM>) and is configured to charge the first battery by using the direct current signal from the rectifier (<NUM>, <NUM>), wherein the voltage-stabilizing charging circuit (<NUM>) comprises a first field effect transistor control module (<NUM>), a first field effect transistor (<NUM>), and a second field effect transistor (<NUM>),
wherein a gate terminal of the first field effect transistor (<NUM>) and a gate terminal of the second field effect transistor (<NUM>) are both connected to the first field effect transistor control module (<NUM>), and the first field effect transistor control module (<NUM>) is configured to control a voltage value of the gate terminal of the first field effect transistor (<NUM>) and a voltage value of the gate terminal of the second field effect transistor (<NUM>),
a source terminal of the first field effect transistor is connected to an output terminal of the rectifier (<NUM>, <NUM>),
a drain terminal of the first field effect transistor is connected to a source terminal of the second field effect transistor, and
a drain terminal of the second field effect transistor is used to charge a battery (<NUM>) of the stylus (<NUM>),
wherein the first field effect transistor (<NUM>) is a MOSFET and is configured to stabilize a voltage output by the rectifier (<NUM>, <NUM>) and wherein the second field effect transistor (<NUM>) is a MOSFET and is configured to isolate a system power supply of the chip from the first battery;
the protocol encoding/decoding unit (<NUM>, <NUM>) is configured to communicate with a transmit chip; and
the micro-control unit is configured to control the charger unit (<NUM>) and the protocol encoding/decoding unit (<NUM>, <NUM>).