Signal circuit and control method thereof, and wearable device

Abstract

The present application relates to a signal circuit, a control method thereof, and a wearable device, and relates to the technical field of electronic equipment. It is used to solve the problem of low reliability of HBC signal transmission in an HBC communication system in which wearable devices participate. The signal circuit can be applied to a wearable device. The wearable device also includes a first electrode and a second electrode. The first electrode is used to send signals to human skin and / or receive signals transmitted by human skin. The signal circuit includes a first transceiver subcircuit and a compensation subcircuit. The first transceiver subcircuit includes a first signal terminal and a second signal terminal, the first signal terminal is used to couple with the first electrode; the second signal terminal is used to couple with the second electrode and the ground terminal at the same time. The compensation subcircuit includes a third signal terminal and a fourth signal terminal, the third signal terminal is used to couple with the first electrode, and the fourth signal terminal is used to couple with the second electrode.

Description

Technical Field

[0001] The present disclosure relates to the technical field of electronic equipment, and in particular to a signal circuit and a control method thereof, and a wearable device. Background Art

[0002] Wearable devices like smart rings and smartwatches have limited built-in battery capacity. To ensure battery life, they require extremely low-energy communication technologies. Human body communication (HBC), an ultra-low-power communication technology for body-area transmission, uses human tissue as a signal transmission channel. Its advantages include low channel loss and low power consumption, making it a promising technology for future body area networks.

[0003] However, wearable devices are worn on the human body in a variety of wearing scenarios. In some wearing scenarios, the contact or proximity of multiple parts of the human body with the wearable device can cause significant signal attenuation during transmission through the human body, reducing the reliability of HBC signal transmission in HBC communication systems involving wearable devices. Summary of the Invention

[0004] Embodiments of the present application provide a signal circuit, a control method thereof, and a wearable device, for solving the problem of low HBC signal transmission reliability in an HBC communication system in which wearable devices participate.

[0005] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0006] In a first aspect, a wearable device is provided. The wearable device includes a first electrode, a second electrode, an insulator, and a circuit board. The first electrode is used to couple with human skin. The second electrode is spaced apart from the first electrode. The insulator is located between the first electrode and the second electrode to insulate the first electrode and the second electrode from each other. The circuit board is located between the first electrode and the second electrode, a first connection point of the circuit board is coupled to the first electrode, and a second connection point of the circuit board is coupled to the second electrode. The wearable device uses at least the first electrode to send signals to human skin and / or receive signals transmitted by human skin.

[0007] For ease of understanding, the following description uses a smart ring as a wearable device.

[0008] The inner surface of the first electrode may be part of the inner surface of the smart ring. The inner surface of the smart ring is the surface that contacts the finger wearing the smart ring. The inner surface of the smart ring may be cylindrical. The inner surface of the first electrode may serve as part of the inner surface of the smart ring.

[0009] When the smart ring uses capacitive coupling (HBC), the first electrode can serve as a signal electrode. When the smart ring acts as a transmitter of HBC signals, the signal electrode can transmit signals to the human skin; when the smart ring acts as a receiver of HBC signals, the signal electrode can receive signals transmitted by the human skin.

[0010] The insulator may be located outside the first electrode. It is understood that the insulator may be located on the side of the first electrode away from the finger wearing the smart ring. The insulator may cover the outer surface of the first electrode. For example, if the first electrode is entirely curved, the insulator may cover the outer surface of the curved structure. For another example, if part of the first electrode is curved and another part is a flat plate, the insulator may cover both the outer surface of the curved structure and the outer surface of the flat plate.

[0011] The insulator may be an annular structure, wherein the inner ring surface of the insulator covers the outer surface of the first electrode.

[0012] In some examples, the insulator has a recess, and the first electrode can be accommodated within the recess, so that the inner surface of the first electrode and the inner surface of the insulator form a continuous surface. In this way, the inner surface of the first electrode and the inner surface of the insulator can jointly serve as the inner surface of the smart ring. Furthermore, this can avoid the problem of discomfort caused by the step between the first electrode and the inner surface of the insulator, thereby further improving the user's wearing comfort of the smart ring.

[0013] The second electrode is located on a side of the insulator away from the first electrode. In the case where the smart ring adopts capacitive coupling HBC, the second electrode can be used as a ground electrode.

[0014] In some examples, the second electrode may be part of the housing of the smart ring. For example, the housing of the smart ring may include the first electrode and a plastic housing (or a housing made of other materials, which is merely an example and is not limited to the housing material in the embodiments of this application). The plastic housing and the first electrode are interconnected, and the plastic housing may limit the positional movement of the first electrode.

[0015] Illustratively, the first electrode and the second electrode may include a metal material, such as at least one of copper, tungsten, silver, aluminum, etc. The embodiments of the present application do not limit the specific type of the metal material.

[0016] In some feasible implementations of the first aspect, the first electrode includes a first curved surface, and the second electrode includes a second curved surface, wherein a central angle corresponding to the second curved surface is greater than a central angle corresponding to the first curved surface.

[0017] The first electrode can be at least partially curved, so that the inner surface of the first electrode can also serve as a curved surface, adapting to the shape of the finger wearing the smart ring and contacting the finger wearing the smart ring to achieve coupling between the first electrode and human skin. For example, the first electrode can have a partially curved structure and another partially flat structure (or other structures, not limited in the embodiments of this application); alternatively, the first electrode can have an entirely curved structure.

[0018] The inner surface of the first electrode can be referred to as a first curved surface. The central angle corresponding to the first curved surface can be greater than 180°. The second electrode can form a closed shape. The inner surface of the second electrode can be referred to as a second curved surface. The central angle corresponding to the second curved surface is 360°. The central angle corresponding to the second curved surface can be greater than the central angle corresponding to the first curved surface.

[0019] In some feasible implementations of the first aspect, the second electrode serves as a housing of the wearable device, and the housing has a receiving space. The insulator is at least partially located in the receiving space.

[0020] In other examples, the second electrode can also serve as the entire housing of the smart ring. As can be understood, the second electrode forms a closed shape, serving as the housing of the wearable device, with the first electrode and the insulator located inside the second electrode. In this case, the housing is a full metal shell.

[0021] The housing of the smart ring has a storage space inside. This storage space is located between the inner contour of the second electrode and the outer contour of the second electrode. The insulator can be partially or completely located within the storage space. If the insulator is completely located within the storage space, the first electrode can be partially located within the storage space.

[0022] In this way, the insulator is at least partially located in the accommodation space of the second electrode, which can optimize the layout space of the smart ring, facilitate the miniaturized design of the smart ring, and improve the portability of the wearable device.

[0023] In some feasible implementations of the first aspect, the circuit board is located within the accommodation space, and the circuit board is located on a side of the insulator away from the first electrode. The wearable device further includes a conductive structure, one end of the conductive structure being coupled to the first connection point of the circuit board, and the other end of the conductive structure passing through the insulator and coupled to the first electrode.

[0024] The circuit board is located on a side of the insulator away from the first electrode. It is understood that the circuit board is located outside the insulator. The circuit board may be located within the accommodation space. For example, the circuit board may include a first circuit board segment, a second circuit board segment, and a third circuit board segment, wherein the second circuit board segment and the third circuit board segment are respectively connected to opposite ends of the first circuit board segment. The extension direction of the first circuit board segment and the extension direction of the second circuit board segment intersect with each other, and the extension direction of the first circuit board segment and the extension direction of the third circuit board segment intersect with each other.

[0025] Exemplarily, the second circuit board segment and the third circuit board segment are symmetrically arranged along an axis perpendicular to the first circuit board segment.

[0026] In some examples, the same circuit board segment may be coupled to the first electrode and the second electrode. For example, the first circuit board segment is coupled to both the first electrode and the second electrode. In other examples, different circuit board segments may be coupled to the first electrode and the second electrode, respectively. For example, the first circuit board segment is coupled to the second electrode, and the third circuit board segment is coupled to the first electrode.

[0027] The circuit board can be coupled to the second electrode by directly contacting the second electrode through a conductive structure. The circuit board can be coupled to the first electrode by contacting the first electrode through an insulator through a conductive structure.

[0028] The above-mentioned conductive structure can be a metal spring, conductive cloth, conductive glue or metal wire, etc., which can conduct electrical signals, and the embodiments of the present application are not limited to this.

[0029] In this way, by accommodating the circuit board in the accommodating space of the second electrode, it is beneficial to the miniaturized design of the smart ring. At the same time, the first electrode and the second electrode can be coupled to the circuit board through the conductive structure, thereby improving the reliability of the wearable device.

[0030] In some feasible implementations of the first aspect, the insulator includes a flexible material. For example, the flexible material may be a flexible insulating material such as rubber or foam, although this is not a limitation in the embodiments of this application. The insulator can be formed into a closed shape to serve as a buffer between the finger wearing the smart ring and the housing of the smart ring, thereby improving the user's comfort when wearing the smart ring.

[0031] In some feasible implementations of the first aspect, the wearable device includes a finger ring or a ring.

[0032] In a second aspect, a signal circuit is provided. The signal circuit can be applied to a wearable device. The wearable device also includes a first electrode and a second electrode. The first electrode is used to send signals to human skin and / or receive signals transmitted by human skin. The signal circuit includes a first transceiver subcircuit and a compensation subcircuit. The first transceiver subcircuit includes a first signal terminal and a second signal terminal, the first signal terminal is used to couple with the first electrode; the second signal terminal is used to couple with the second electrode and the ground terminal at the same time. The compensation subcircuit includes a third signal terminal and a fourth signal terminal, the third signal terminal is used to couple with the first electrode, and the fourth signal terminal is used to couple with the second electrode.

[0033] The first transceiver subcircuit may be a capacitively coupled HBC signal transceiver subcircuit. The first transceiver subcircuit may include a first signal terminal and a second signal terminal. The first signal terminal may be coupled to the first electrode, such that the first electrode serves as the signal electrode of the smart ring. The second signal terminal may be coupled to the second electrode and to the ground terminal, such that the second electrode serves as the ground electrode of the smart ring.

[0034] The compensation subcircuit may include a third signal terminal and a fourth signal terminal. The third signal terminal may be coupled to the first electrode, and the fourth signal terminal may be coupled to the second electrode. It is understood that the compensation subcircuit and the first transceiver subcircuit are connected in parallel.

[0035] When the second electrode is in contact with human skin (e.g., a finger other than the finger wearing the smart ring), the contact between the second electrode and the human skin can be equivalent to forming a first capacitor. The capacitance value of the first capacitor formed can also vary depending on the degree of contact between the human skin and the second electrode.

[0036] It should be noted that the first capacitor does not belong to the signal circuit. The first capacitor is an electronic device that is equivalent to the contact between the second electrode and the human skin.

[0037] The first capacitor equivalently formed by the contact between the second electrode in the signal circuit and the human skin will increase the transmission loss of the human body channel, thereby resulting in low reliability of HBC signal transmission in the HBC communication system involving the signal circuit and wearable devices.

[0038] The compensation subcircuit is configured to form a parallel resonant network with the first capacitor. The parallel resonant network acts as an open circuit in the signal circuit, thereby disconnecting the first capacitor from the human body channel. This reduces transmission losses in the human body channel and improves the reliability of HBC signal transmission in an HBC communication system involving both the signal circuit and the wearable device.

[0039] In some feasible implementations of the second aspect, when the second electrode is coupled to human skin, a first capacitor is equivalently formed between the second electrode and the human skin. The compensation subcircuit is configured to form a parallel resonant network together with the first capacitor.

[0040] The parallel resonant network can be equivalent to an open circuit in the signal circuit, thereby disconnecting the first capacitor from the human body channel, reducing the transmission loss of the human body channel, and thus improving the reliability of HBC signal transmission in the HBC communication system involving the signal circuit and wearable devices.

[0041] In some feasible implementations of the second aspect, the compensation subcircuit includes a first inductor. A first end of the first inductor is configured to couple to the first electrode, and a second end of the first inductor is configured to couple to the second electrode. The first inductor includes a fixed-value inductor or an adjustable inductor.

[0042] The first end of the first inductor is coupled to the first electrode, and the second end of the first inductor is coupled to the second electrode. The first inductor and the first capacitor are substantially equivalent to a parallel relationship, thereby forming a parallel LC (L represents the first inductor, C represents the first capacitor) resonant network.

[0043] The parallel LC resonant network can be equivalent to an open circuit in the signal circuit, thereby disconnecting the first capacitor from the human body channel, reducing the transmission loss of the human body channel, and thus improving the reliability of HBC signal transmission in the HBC communication system involving the signal circuit and wearable devices.

[0044] By selecting first inductors with different inductance values, the inductance parameters of the LC resonant network formed by the first capacitor and the first inductor connected in parallel can be adjusted. Alternatively, the first inductor can be an adjustable inductor with an adjustable inductance value. By adjusting the capacitance value of the first inductor, the inductance parameters of the LC resonant network formed by the first capacitor and the first inductor connected in parallel can also be adjusted.

[0045] Exemplarily, the first inductor may include an active inductor. Of course, the first inductor may also adopt other inductor types or circuits to adjust the inductance value, which is not limited in the embodiments of the present application.

[0046] In some feasible implementations of the second aspect, the compensation subcircuit includes an inductor assembly. A first end of the inductor assembly is coupled to the first electrode, and a second end of the inductor assembly is coupled to the second electrode. The inductor assembly includes a plurality of inductor units connected in series. Each inductor unit includes a first switch and a second inductor connected in parallel.

[0047] Multiple second inductors are connected in series with each other. For example, the first end of the first second inductor among the multiple second inductors is coupled to the first electrode as the third signal end, the second end of the first second inductor is coupled to the first end of the second second inductor, the second end of the second second inductor is coupled to the first end of the third second inductor, and so on... until the second end of the last second inductor is coupled to the second electrode as the fourth signal end.

[0048] In addition, each second inductor may be connected in parallel with a first switch. The first end of the second inductor is coupled to the first end of the first switch, and the second end of the second inductor is coupled to the second end of the first switch. When the first switch is in a closed state, the first end of the first switch is connected to the second end of the first switch; when the first switch is in an open state, the first end of the first switch is disconnected from the second end of the first switch.

[0049] The multiple second inductors may be multiple inductors with equal inductance values, or may be multiple inductors with unequal inductance values, which is not limited in the embodiments of the present application.

[0050] In a set of parallel-connected selection units and a second inductor, when the first switch in the selection unit is in the off state, the selection unit is in an open-circuit state. This allows current to flow through the second inductor, causing the second inductor to be effective in the compensation sub-circuit. When the first switch in the selection unit is in the closed state, the selection unit is in a conductive state. This allows current to flow through the selection unit instead of the second inductor, preventing the second inductor from being effective in the compensation sub-circuit.

[0051] By switching the state of the first switch in each set of parallel selection units and second inductors, the effectiveness of the second inductor in the set of parallel selection units and second inductors can be controlled, thereby controlling the effectiveness of the multiple second inductors in the compensation sub-circuit. In other words, by controlling the states of the multiple first switches, the number of the multiple second inductors in the compensation sub-circuit that are effective can be adjusted.

[0052] As previously explained, the multiple second inductors are connected in series. Therefore, by controlling the states of the multiple first switches to control the number of active second inductors, the inductance of the inductor assembly (i.e., the inductance of the compensation subcircuit) can be adjusted. This allows the compensation subcircuit and the first capacitor to form a parallel LC resonant network, which reduces transmission losses in the human body channel, thereby improving the reliability of HBC signal transmission in the HBC communication system involving signal circuits and wearable devices.

[0053] In some feasible implementations of the second aspect, the compensation subcircuit further includes a second capacitor. A first plate of the second capacitor is configured to couple to the first electrode, and a second plate of the second capacitor is configured to couple to the second electrode. The second capacitor includes a fixed-value capacitor or an adjustable capacitor.

[0054] For example, in a compensation subcircuit comprising a second capacitor and a first inductor, the second capacitor and the first inductor are connected in parallel. As previously explained, the first inductor is connected in parallel with the first capacitor, and here the second capacitor is connected in parallel with the first inductor, thus connecting the first capacitor and the second capacitor in parallel.

[0055] By selecting a second capacitor with a different capacitance value, the capacitance value of the first capacitor and the second capacitor connected in parallel can be adjusted. Alternatively, the second capacitor can be an adjustable capacitor with an adjustable capacitance value, and by adjusting the capacitance value of the second capacitor, the capacitance value of the first capacitor and the second capacitor connected in parallel can also be adjusted.

[0056] In this way, the second capacitor in the compensation subcircuit can adjust the capacitance of the parallel LC resonant circuit. This helps the compensation subcircuit and the first capacitor form a parallel LC resonant network, which reduces transmission loss in the human body channel, thereby improving the reliability of HBC signal transmission in the HBC communication system involving signal circuits and wearable devices.

[0057] In some feasible implementations of the second aspect, the compensation subcircuit further includes a capacitor assembly. The capacitor assembly includes a plurality of capacitor units connected in parallel. A first end of each capacitor unit is coupled to a first electrode, and a second end of each capacitor unit is coupled to a second electrode. Each capacitor unit includes a second switch and a third capacitor connected in series.

[0058] The first plate of each third capacitor is coupled to the first electrode, and the second plate of each third capacitor is coupled to the second electrode and the ground. Furthermore, a second switch may be connected in series between each third capacitor and the first electrode. The first end of the second switch is coupled to the first electrode, and the second end of the second switch is coupled to the first plate of the third capacitor. Of course, the second switch may also be connected in series between the third capacitor and the ground.

[0059] When the second switch is in a closed state, the first end of the second switch is connected to the second end of the second switch; when the second switch is in an open state, the first end of the second switch is disconnected from the second end of the second switch.

[0060] The multiple third capacitors may be multiple capacitors with equal capacitance values, or may be multiple capacitors with unequal capacitance values, which is not limited in the embodiments of the present application.

[0061] In a set of a second switch and a third capacitor connected in series, when the second switch is in an open state, the circuit between the third capacitor and the first electrode is open. Thus, current is not conducted to the third capacitor, and the third capacitor does not function in the compensation sub-circuit. When the second switch is in a closed state, a circuit is established between the third capacitor and the first electrode. Thus, current can be conducted to the third capacitor, and the third capacitor functions in the compensation sub-circuit.

[0062] The multiple effective third capacitors are connected in parallel with each other, so the capacitance value of the capacitor assembly can be calculated based on the capacitance values of the multiple effective third capacitors.

[0063] By switching the state of the second switch in each series-connected set of second switches and third capacitors, the effectiveness of the third capacitor in that series-connected set of second switches and third capacitors can be controlled, thereby controlling the effectiveness of the multiple third capacitors in the compensation sub-circuit. In other words, by controlling the states of the multiple second switches, the number of active third capacitors in the capacitor assembly can be adjusted, thereby adjusting the capacitance value of the capacitor assembly.

[0064] The capacitor assembly, similar to the second capacitor, is also connected in parallel with the first capacitor. Therefore, by adjusting the capacitance of the capacitor assembly, the capacitance of the parallel LC resonant circuit can be adjusted. This helps the compensation subcircuit and the first capacitor form a parallel LC resonant network, which reduces transmission losses in the human body channel, thereby improving the reliability of HBC signal transmission in HBC communication systems involving signal circuits and wearable devices.

[0065] In some feasible implementations of the second aspect, the signal circuit further includes a compensation switching subcircuit; the compensation switching subcircuit is connected in series with the compensation subcircuit. For example, the compensation switching subcircuit can be connected in series between the first electrode and the compensation subcircuit, or the compensation switching subcircuit can be connected in series between the second electrode and the compensation subcircuit.

[0066] The compensation switching subcircuit can include a first state and a second state. When the compensation switching subcircuit is in the first state, the first electrode is disconnected from the compensation subcircuit, or the second electrode is disconnected from the compensation subcircuit. Therefore, when the compensation switching subcircuit is in the first state, current does not flow through the compensation subcircuit, rendering the compensation subcircuit ineffective. When the compensation switching subcircuit is in the second state, the first electrode is connected to the compensation subcircuit, and the second electrode is connected to the compensation subcircuit. Therefore, when the compensation switching subcircuit is in the second state, current flows through the compensation subcircuit, rendering the compensation subcircuit effective.

[0067] Therefore, when the second electrode of the smart ring contacts the human skin and a first capacitor is equivalently formed between the human body and the second electrode, resulting in a high human channel transmission loss corresponding to the signal, the compensation switching subcircuit can be adjusted to the second state to make the compensation subcircuit effective. The compensation subcircuit and the first capacitor are used to form a parallel resonant network, thereby reducing the human channel transmission loss corresponding to signals of different frequencies and optimizing the reliability of HBC signal transmission of signals of specific frequencies in the HBC communication system involving signal circuits and wearable devices.

[0068] When the second electrode of the smart ring is not in contact with human skin, no first capacitor is formed between the human body and the second electrode, and the human body channel transmission loss corresponding to the signal is low, the compensation switching subcircuit can be adjusted to the first state, so that the compensation subcircuit is invalid, thereby maintaining the reliability of HBC signal transmission in the HBC communication system involving the signal circuit and the wearable device.

[0069] In some feasible implementations of the second aspect, the signal circuit further includes a second transceiver subcircuit and a switching subcircuit. The second transceiver subcircuit includes a fifth signal terminal and a sixth signal terminal. The switching subcircuit is coupled to the first signal terminal, the second signal terminal, the fifth signal terminal and the sixth signal terminal, respectively. The switching subcircuit is also used to couple to the first electrode and the second electrode. When the switching subcircuit is in the first state, the first electrode is connected to the first signal terminal and disconnected from the fifth signal terminal, and the second electrode is connected to the second signal terminal and disconnected from the sixth signal terminal. When the switching subcircuit is in the second state, the first electrode is connected to the fifth signal terminal and disconnected from the first signal terminal, and the second electrode is connected to the sixth signal terminal and disconnected from the second signal terminal.

[0070] The second transceiver subcircuit can be a current-coupled HBC signal transceiver subcircuit. The second transceiver subcircuit can include a fifth signal terminal and a sixth signal terminal. The fifth signal terminal can be coupled to the first electrode, so that the first electrode serves as the positive signal electrode of the smart ring; the sixth signal terminal can be coupled to the second electrode, so that the second electrode serves as the negative signal electrode of the smart ring.

[0071] The switching subcircuit can be coupled to the first transceiver subcircuit, the second transceiver subcircuit, the first electrode, and the second electrode, respectively. When the switching subcircuit is in a first state, the first electrode and the second electrode are both coupled to the first transceiver subcircuit and disconnected from the second transceiver subcircuit; when the switching subcircuit is in a second state, the first electrode and the second electrode are both coupled to the second transceiver subcircuit and disconnected from the first transceiver subcircuit.

[0072] Exemplarily, when the switching subcircuit is in the first state, the switching subcircuit is used to connect the first signal terminal of the first transceiver subcircuit to the first electrode and disconnect the fifth signal terminal of the second transceiver subcircuit from the first electrode, and connect the second signal terminal of the first transceiver subcircuit to the second electrode and disconnect the sixth signal terminal of the second transceiver subcircuit from the second electrode.

[0073] In this way, when the switching subcircuit is in the first state, the signal transceiver subcircuit as a capacitive coupling type HBC is coupled to the first electrode and the second electrode respectively. At this time, the smart ring can be a signal transceiver device of the capacitive coupling type HBC.

[0074] When the switching subcircuit is in the second state, the switching subcircuit is used to disconnect the first signal terminal of the first transceiver subcircuit from the first electrode, connect the fifth signal terminal of the second transceiver subcircuit to the first electrode, and disconnect the second signal terminal of the first transceiver subcircuit from the second electrode, and connect the sixth signal terminal of the second transceiver subcircuit to the second electrode.

[0075] In this way, when the switching subcircuit is in the second state, the signal transceiver subcircuit as a current-coupled HBC is coupled to the first electrode and the second electrode respectively. At this time, the smart ring can be a signal transceiver device of the current-coupled HBC.

[0076] In this embodiment, by switching the sub-circuits, the smart ring can support capacitive coupling HBC communication and current coupling HBC communication in different time periods, thereby improving the communication diversity of the smart ring.

[0077] In a third aspect, a signal circuit control method is provided. This control method is applicable to the signal circuit described in any one of the second aspects. The method includes: when the second electrode is coupled to human skin to form a first capacitor, the signal circuit and the first capacitor together form a parallel resonant network through a compensation subcircuit.

[0078] In some feasible implementations of the third aspect, the compensation subcircuit includes an inductor component. The signal circuit, through the compensation subcircuit and the first capacitor, forms a parallel resonant network, including: the signal circuit controls the closing or opening of at least one first switch to change the inductance of the inductor component, so that the inductor component with the changed inductance and the first capacitor form a parallel resonant network.

[0079] In some feasible implementations of the third aspect, the compensation subcircuit includes a first inductor, the first inductor including an adjustable inductor. The signal circuit, through the compensation subcircuit and the first capacitor, forms a parallel resonant network, including: the signal circuit adjusts the inductance of the first inductor so that the first inductor, after the changed inductance, and the first capacitor, together form a parallel resonant network.

[0080] In some feasible implementations of the third aspect, the compensation subcircuit further includes a capacitor assembly. The signal circuit, through the compensation subcircuit and the first capacitor, forms a parallel resonant network, further comprising: the signal circuit controlling the closing or opening of at least one second switch to change the capacitance of the capacitor assembly to adjust the parallel capacitance of the first capacitor and the capacitor assembly in the parallel resonant network.

[0081] In some feasible implementations of the third aspect, the compensation subcircuit includes a second capacitor, and the first inductor includes an adjustable capacitor. The signal circuit, through the compensation subcircuit and the first capacitor, forms a parallel resonant network, further comprising: the signal circuit adjusting the capacitance value of the second capacitor to adjust the parallel capacitance value of the first and second capacitors in the parallel resonant network.

[0082] In some feasible implementations of the third aspect, the method further includes: the signal circuit acquiring wearing information of the wearable device. The signal circuit determining a target frequency range based on the wearing information. The signal circuit notifies the opposite device to communicate according to the target frequency range. The signal circuit scans the signal within the target frequency range and selects a target frequency having a signal strength greater than a preset strength threshold as the human body communication frequency of the signal circuit; wherein the target frequency is a frequency within the target frequency range.

[0083] In this implementation, the signal circuit can determine a target frequency range for signals that best match the user's current wearing posture based on the wearable device's wearing information, and then determine the human body communication frequency within the target frequency range. This can improve the signal circuit's efficiency in determining the HBC signal frequency.

[0084] The technical effects of the third aspect can be referred to the technical effects of the first or second aspect, and will not be repeated here.

[0085] In a fourth aspect, a circuit board is provided. The circuit board is applied to the wearable device according to any one of the first aspects. The circuit board includes the signal circuit according to any one of the second aspects.

[0086] The technical effects of the fourth aspect can be referred to the technical effects of the first or second aspect, and will not be repeated here.

[0087] In a fifth aspect, a human body communication system is provided. The human body communication system includes a transmitting device and a receiving device that communicate with each other. The transmitting device includes any wearable device as described in the first aspect. And / or the receiving device includes any wearable device as described in the first aspect.

[0088] The technical effects of the fifth aspect can be referred to the technical effects of the first or second aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] Figure 1 A three-dimensional diagram of a smart ring provided for some embodiments of the present application;

[0090] Figure 2 For the Figure 1 The cross-sectional view formed by the line A-A';

[0091] Figure 3 for Figure 1 A schematic structural diagram of the first electrode;

[0092] Figure 4 for Figure 1 Another structural schematic diagram of the first electrode;

[0093] Figure 5 for Figure 1 Another structural schematic diagram of the first electrode;

[0094] Figure 6 for Figure 1 A schematic diagram of another structure of the first electrode;

[0095] Figure 7 It is an equivalent circuit diagram of the HBC communication system;

[0096] Figure 8 A schematic diagram of the structure of a signal circuit provided in some embodiments of the present application;

[0097] Figure 9 is a curve diagram of the human body channel transmission loss between the human body and the second electrode under different conditions;

[0098] Figure 10 for Figure 8 A structural schematic diagram of a signal circuit is provided;

[0099] Figure 11 Schematic diagram of the structure of an active inductor;

[0100] Figure 12 for Figure 8 Another schematic diagram of the structure of the compensation subcircuit in the signal circuit provided;

[0101] Figure 13 for Figure 8 Another structural schematic diagram of the signal circuit provided;

[0102] Figure 14 for Figure 8 A schematic diagram of another structure of a compensation subcircuit in a signal circuit is provided;

[0103] Figure 15 A curve diagram of human body channel transmission loss when human skin is in contact with the second electrode and the capacitor assembly / second capacitor has different capacitance values;

[0104] Figure 16 A schematic structural diagram of a signal circuit provided in some other embodiments of the present application;

[0105] Figure 17 for Figure 16 A structural schematic diagram of a signal circuit is provided;

[0106] Figure 18 A schematic structural diagram of a signal circuit provided in some further embodiments of the present application;

[0107] Figure 19 A schematic structural diagram of a signal circuit provided in some further embodiments of the present application;

[0108] Figure 20 A flowchart of a signal circuit control method provided in some embodiments of the present application;

[0109] Figures 21 to 27 Different wearing scenarios of smart rings on human hands;

[0110] Figure 28 A flowchart of a signal circuit control method provided in some other embodiments of the present application;

[0111] Figure 29 Flowchart of a signal circuit control method provided in some further embodiments of the present application. DETAILED DESCRIPTION

[0112] The following will describe the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments provided in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0113] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of this application, unless otherwise specified, "plurality" means two or more.

[0114] When describing some embodiments, the terms "connected," "connected," and their derivatives may be used. For example, when describing some embodiments, the term "connected" may be used to indicate that two or more components are in direct or indirect physical contact with each other. For example, "A and B are connected" may mean that A and B are connected directly, or that A and B are connected through other components. Furthermore, the term "coupled" may refer to a method of electrical connection for signal transmission.

[0115] “At least one of A, B and C” has the same meaning as “at least one of A, B or C” and both include the following combinations of A, B and C: A only, B only, C only, the combination of A and B, the combination of A and C, the combination of B and C, and the combination of A, B and C.

[0116] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0117] As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of deviation from the particular value as determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0118] HBC is also called intra-body communication (IBC), which can be understood as a short-range wireless communication method that uses human skin as a medium for information transmission (it can be understood as using the human body as a cable). Wearable devices can use signal circuits to achieve bidirectional data transmission. The above-mentioned signal circuit may include a signal transceiver subcircuit. The signal circuit can be connected to multiple electrodes (electrodes). For example, the wearable device may include 2 or more electrodes. The receiving end in the above-mentioned signal transceiver subcircuit can be used as an input device for the wearable device. The signal circuit can receive weak electrical signals transmitted by the human skin through the electrodes, thereby achieving signal reception; the transmitting end in the above-mentioned signal transceiver subcircuit can be used as an output device for the wearable device. The signal circuit can output weak electrical signals to the human skin through the electrodes, thereby achieving signal transmission. The above-mentioned transmitting end and receiving end are respectively coupled to at least one electrode, wherein the coupling method can be a wireless connection or a wired connection.

[0119] Research on the electrical conductivity of human biological tissues shows that as the signal frequency increases, the dielectric constant of most living tissues or organs in the human body usually decreases significantly, while their conductivity increases significantly, which means that HBC should be performed at a higher frequency to reduce signal attenuation during communication.

[0120] However, as the signal frequency increases, the wavelength of the signal becomes shorter. When the signal wavelength approaches a person's height, the human body acts as a radio frequency antenna, radiating electromagnetic waves to the surrounding area, causing signal dissipation. This can even cause the strength of the signal coupled through the air to gradually exceed that of the signal coupled through the human body. Therefore, signals with excessively high frequencies are not suitable for HBC.

[0121] Therefore, when performing HBC, the signal frequency may be selected within a frequency range greater than or equal to 10 KHz and less than or equal to 100 MHz.

[0122] To establish an HBC connection, two or more devices need to be coupled to the human body at the same time (including contacting the human body, or maintaining a certain distance from the human body to enable communication). In addition, different devices can communicate in a simplex or duplex mode.

[0123] Depending on the coupling method, HBC can be categorized into capacitive coupling (also known as electric field coupling) and galvanic coupling (also known as waveguide coupling). Both capacitive and galvanic coupling require electrodes to establish a signal channel with the human body during both signal transmission and reception. The most obvious difference between the two methods is whether the HBC electrodes must be in contact with the human body.

[0124] Capacitive coupling establishes a signal path (communication loop) by capacitively coupling at least two electrodes of the transmitting device and at least two electrodes of the receiving device with the human body and ground, respectively, to achieve signal transmission. In capacitive coupling HBCs, the electrodes of the transmitting and receiving devices can be in contact with the human body, or they can be kept at a certain distance from the human body to achieve capacitive coupling.

[0125] For example, in a capacitively coupled HBC, the distance between the electrode and the human skin can be any value greater than or equal to 0 and less than or equal to 3 mm, such as 0 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.2 mm, 2.8 mm, 3 mm, etc. Of course, in actual applications, the distance between the electrode and the human skin can also be determined based on properties such as the signal frequency in the HBC.

[0126] Galvanic coupling involves injecting a weak current signal into the human body from at least one electrode in the transmitting device. This signal, transmitted through the body, is then received by at least one electrode in the receiving device. In other words, all electrodes in galvanic coupling (HBC) must be attached to and in contact with the human body.

[0127] Among them, for capacitive coupling type HBC, the wearable device needs to have an electrode as a ground electrode coupled to the ground. Taking the wearable device as a smart ring as an example, the metal on the shell of the smart ring is usually used as the ground electrode. However, due to the complex wearing conditions of the smart ring, the ground electrode is easily affected by the proximity or contact of the surrounding fingers, resulting in a large signal attenuation of the signal transmitted by the human body in the capacitive coupling type HBC, which reduces the HBC signal transmission reliability in the HBC communication system in which the wearable device participates. In order to overcome the problem of HBC signal attenuation and improve the reliability of HBC signal transmission, it is necessary to increase the signal transmission power of the wearable device, which will increase the power consumption of the wearable device and reduce the battery life of the wearable device.

[0128] Based on this, embodiments of the present application provide a signal circuit, a control method thereof, and a wearable device.

[0129] The wearable devices provided in the embodiments of the present application may include but are not limited to smart headphones, smart watches, smart bracelets, smart glasses, augmented reality (AR) devices, virtual reality (VR) devices, electronic health monitoring equipment, smart rings, smart belts, smart belts, smart bracelets, smart anklets or smart necklaces and other wearable electronic products.

[0130] For ease of understanding, the following description uses a smart ring as a wearable device. However, this should not be limiting, and it should be understood that the various examples described below can also be applied to other wearable devices such as smart watches and smart glasses.

[0131] Figure 1 Shows a stereoscopic view of a smart ring provided by some embodiments of the present application; Figure 2 Shown along Figure 1 Cross-sectional view formed by line AA'.

[0132] like Figure 1 and Figure 2 As shown, the smart ring 100 may include a first electrode 110, a second electrode 120, an insulator 130 and a circuit board 140. The insulator 130 may be located between the first electrode 110 and the second electrode 120 to insulate the first electrode 110 and the second electrode 120 from each other.

[0133] like Figure 1 and Figure 2 As shown, the inner surface of the first electrode 110 may be part of the inner surface of the smart ring 100. The inner surface of the smart ring 100 is the surface that contacts the finger wearing the smart ring 100. The inner surface of the smart ring 100 may be cylindrical. The inner surface of the first electrode 110 may serve as part of the inner surface of the smart ring 100.

[0134] When the smart ring 100 uses capacitive coupling (HBC), the first electrode 110 can serve as a signal electrode. When the smart ring acts as a transmitter of HBC signals, the signal electrode can transmit signals to the human skin; when the smart ring acts as a receiver of HBC signals, the signal electrode can receive signals transmitted by the human skin.

[0135] The first electrode 110 can be at least partially curved, so that the inner surface of the first electrode 110 can also serve as a curved surface, adapting to the shape of the finger wearing the smart ring 100 and contacting the finger wearing the smart ring 100, thereby coupling the first electrode 110 to the human skin. For example, the first electrode 110 can have a partially curved structure and another partially flat structure (or other structures, not limited in the embodiments of this application); alternatively, the first electrode 110 can have an entirely curved structure.

[0136] The inner surface of the first electrode 110 can be referred to as a first curved surface. Figure 2 As shown, the central angle corresponding to the first arc-shaped surface can be greater than 180°.

[0137] For example, the first electrode 110 may include a metal material, such as at least one of copper, tungsten, silver, aluminum, etc. The embodiments of the present application do not limit the specific type of the metal material.

[0138] The insulator 130 may be located outside the first electrode 110. It is understood that the insulator 130 may be located on the side of the first electrode 110 away from the finger wearing the smart ring 100. The insulator 130 may cover the outer surface of the first electrode 110. For example, if the first electrode 110 is entirely curved, the insulator 130 may cover the outer surface of the curved structure. For another example, if part of the first electrode 110 is curved and the other part is a flat plate, the insulator 130 may cover both the outer surface of the curved structure and the outer surface of the flat plate.

[0139] In some examples, the insulator 130 may include a flexible material. The flexible material may be a flexible insulating material such as rubber or foam, which is not limited in the embodiments of the present application. The insulator 130 may be formed into a closed shape to serve as a buffer layer between the finger wearing the smart ring 100 and the housing 100a of the smart ring 100, thereby improving the user's comfort when wearing the smart ring 100.

[0140] like Figure 2 As shown, the insulator 130 may be a ring structure, and the inner surface of the insulator 130 covers the outer surface of the first electrode 110 .

[0141] In some examples, such as Figure 2 As shown, the insulator 130 is provided with a recess 131, and the first electrode 110 can be accommodated in the recess 131, so that the inner surface of the first electrode 110 and the inner surface of the insulator 130 form a continuous surface. In this way, the inner surface of the first electrode 110 and the inner surface of the insulator 130 can jointly serve as the inner surface of the smart ring 100. In addition, the recess 131 can avoid the problem of a step difference between the first electrode 110 and the inner surface of the insulator 130, which would cause the smart ring 100 to be uncomfortable to wear, thereby further improving the user's wearing comfort of the smart ring 100.

[0142] In some examples, to prevent frictional loss between the first electrode 110 and the finger, the smart ring 100 may further include a protective film (not shown). The protective film may cover the surface of the first electrode 110 that contacts the finger, that is, the surface of the first electrode 110 that is away from the insulator 130.

[0143] In the case where the smart ring 100 includes a protective film, the first electrode 110 does not directly contact the finger, but is indirectly coupled to the finger by being close to the finger.

[0144] The second electrode 120 is located on a side of the insulator 130 away from the first electrode 110. When the smart ring 100 adopts capacitive coupling HBC, the second electrode 120 can be used as a ground electrode.

[0145] In some examples, the second electrode 120 can be part of the housing 100a of the smart ring 100. For example, the housing 100a of the smart ring 100 can include the first electrode 110 and a plastic housing (or a housing made of other materials, which is merely an example and is not limited to the housing material in the embodiments of the present application). The plastic housing and the first electrode 110 are connected to each other, and the plastic housing can limit the positional movement of the first electrode 110.

[0146] In other examples, the second electrode 120 may also serve as the entire housing 100a of the smart ring 100. Figure 2 As shown, the second electrode 120 can be enclosed in a closed shape, serving as the housing 100a of the wearable device 100, with the first electrode 110 and the insulator 130 located inside the second electrode 120. In this case, the housing 100a is a full metal housing. The full metal housing can be an integrally molded structure with no gaps in the housing.

[0147] For example, the second electrode 120 may include a metal material, such as at least one of copper, tungsten, silver, aluminum, etc. The embodiments of the present application do not limit the specific type of the metal material.

[0148] The inner surface of the second electrode 120 can be referred to as a second curved surface. Figure 2 As shown, the central angle of the second arcuate surface is 360°. The central angle of the second arcuate surface may be greater than the central angle of the first arcuate surface.

[0149] The housing 100a of the smart ring 100 can be designed with a flat top 120a. The top 120a can be printed with symbols, patterns, or inlaid with other decorations. The top 120a helps users identify the correct wearing orientation of the smart ring 100, preventing the reliability of HBC signal transmission in the HBC communication system in which the smart ring 100 participates from being compromised due to incorrect wearing orientation.

[0150] The housing 100a of the smart ring 100 has a storage space 100b inside. This storage space 100b is located between the inner and outer contours of the second electrode 120. The insulator 130 can be partially or entirely located within the storage space 100b. If the insulator 130 is entirely located within the storage space 100b, the first electrode 110 can be partially located within the storage space 100b.

[0151] In this way, the insulator 130 is at least partially located in the accommodating space 100b of the second electrode 120, which can optimize the layout space of the smart ring 100, facilitate the miniaturized design of the smart ring 100, and improve the portability of the wearable device.

[0152] The circuit board 140 is located on a side of the insulator 130 away from the first electrode 110. It is understood that the circuit board 140 is located outside the insulator 130. The circuit board 140 can be located within the accommodation space 100b. For example, the circuit board 140 can include a first circuit board segment 141, a second circuit board segment 142, and a third circuit board segment 143. The second circuit board segment 142 and the third circuit board segment 143 are respectively connected to opposite ends of the first circuit board segment 141. The extension direction of the first circuit board segment 141 and the extension direction of the second circuit board segment 142 intersect with each other, and the extension direction of the first circuit board segment 141 and the extension direction of the third circuit board segment 143 intersect with each other.

[0153] Exemplarily, the second circuit board segment 142 and the third circuit board segment 143 are symmetrically arranged along an axis perpendicular to the first circuit board segment 141 .

[0154] In some examples, the same circuit board segment may be coupled to the first electrode 110 and the second electrode 120. For example, the first circuit board segment 141 is coupled to the first electrode 110 and the second electrode 120 at the same time. In other examples, different circuit board segments may be coupled to the first electrode 110 and the second electrode 120 respectively. For example, Figure 2As shown, the first circuit board segment 141 is coupled to the second electrode 120 , and the third circuit board segment 143 is coupled to the first electrode 110 .

[0155] The circuit board 140 can be coupled to the second electrode 120 by directly contacting the second electrode 120 through the conductive structure 144. The circuit board 140 can be coupled to the first electrode 110 by contacting the first electrode 110 through the conductive structure 144 through the insulator 130.

[0156] The conductive structure 144 may be a metal spring, a conductive cloth, a conductive adhesive, a metal wire, or other structure capable of conducting electrical signals, which is not limited in the embodiments of the present application.

[0157] In this way, by accommodating the circuit board 140 in the accommodating space 100b of the second electrode 120, it is beneficial to the miniaturized design of the smart ring 100. The conductive structure 144 can also realize the coupling of the first electrode 110 and the second electrode 120 with the circuit board 140, thereby improving the reliability of the wearable device.

[0158] like Figure 2 As shown, the smart ring 100 may further include a battery 150. The battery 150 may be located in the accommodation space 100b within the housing 100a. The battery 150 may also be arc-shaped. For example, the battery 150 may be located between the top platform 120a and the insulator 130.

[0159] The circuit board 140 is also coupled to a battery 150, which provides an operating voltage to the circuit board 140. The battery 150 can be a dry cell battery (also known as a disposable battery) or a rechargeable battery. If the battery 150 is a rechargeable battery, the housing 100a of the smart ring 100 can also be provided with a charging port for charging the battery 150.

[0160] Figure 3 Shown Figure 1 A schematic structural diagram of the first electrode; Figure 4 Shown Figure 1 Another structural schematic diagram of the first electrode; Figure 5 Shown Figure 1 Another structural schematic diagram of the first electrode; Figure 6 Shown Figure 1 Another structural schematic diagram of the first electrode in .

[0161] In the case where the smart ring 100 does not include other sensors, the shape of the first electrode 110 can be as follows: Figure 3As shown, there is no opening between the first electrodes 110. In the case where the smart ring 100 also includes other sensors (e.g., a light-emitting diode and a photoelectric receiving element for measuring blood oxygen) that need to be in contact with human skin (e.g., the finger wearing the smart ring 100), the first electrodes 110 may be provided with the following openings: Figure 4 The rectangular opening 11a shown, or Figure 5 The circular opening 11b shown, or Figure 6 The specific opening shape may depend on the shape of the sensor, and the embodiments of the present application do not limit this.

[0162] The above-mentioned fracture 11c can divide a first electrode 110 into two sub-electrodes 111, such as Figure 6 As shown, the two sub-electrodes 111 can be coupled through the connecting line 112; alternatively, the two sub-electrodes 111 can also be coupled to the circuit board 140 through a connector respectively, and then coupled through the signal line on the circuit board 140, thereby achieving coupling between the two sub-electrodes 111.

[0163] The number of openings and / or breaks in a first electrode 111 may be one, two, or more, which is not limited in the embodiments of the present application.

[0164] Figure 7 An equivalent circuit diagram of an HBC communication system is shown. Embodiments of the present application also provide an HBC communication system. The transmitting device in the HBC communication system may be a wearable device provided in embodiments of the present application; and / or, the receiving device in the HBC communication system may be a wearable device provided in embodiments of the present application.

[0165] Figure 7 In this example, the HBC communication system uses capacitive coupling. The smart ring 100 can serve as the receiving device of the HBC communication system, the smart watch 300 can serve as the transmitting device of the HBC communication system, and the human body serves as the transmission medium between the transmitting and receiving devices. In other words, the smart watch 300 is the transmitting device, and the smart ring 100 is the receiving device. The smart watch 300 is the counterpart device of the smart ring 100.

[0166] like Figure 7 As shown, the smart watch 300 transmits the HBC signal to the human skin through the electrodes. The HBC signal is transmitted to the smart ring 100 on the human skin. The electrodes of the smart ring 100 collect the HBC signal, thereby completing one HBC signal transmission.

[0167] Among them, since the human body has a lossy effect on the transmission of electrical signals, the human body can be equivalent to multiple electronic devices according to the different positions and functions of the human body. For example, Figure 7 As shown, the HBC communication system may include multiple electronic devices equivalent to the human body, including a first impedance Z1, a second impedance Z2, a third impedance Z3, a fourth impedance Z4, and a fifth impedance Z5. The first impedance Z1 may represent the impedance formed by the contact between the smart watch 300 and human skin; the second impedance Z2 may represent the impedance of human skin on the signal transmission side; the third impedance Z3 may represent the impedance formed by the contact between the smart ring 100 and human skin; the fourth impedance Z4 may represent the impedance of human skin on the signal reception side; and the fifth impedance Z5 may represent the impedance formed between the human subcutaneous tissue and the ground. Exemplarily, the fifth impedance Z5 includes the impedance of the human subcutaneous tissue and the impedance between the subcutaneous tissue and the foot.

[0168] Secondly, the HBC communication system may also include multiple electronic devices equivalent to the contact between the human body and the device. For example, Figure 7 As shown, the HBC communication system may include a first contact capacitor C1 (hereinafter referred to as the first capacitor C1), a second contact capacitor C02, a third contact capacitor C03, and a fourth contact capacitor C04. The first contact capacitor C1 may represent the capacitance between the ground electrode of the smart ring 100 and human skin; the second contact capacitor C02 may represent the capacitance between human skin and the earth on the signal receiving side; the third contact capacitor C03 may represent the capacitance between the ground electrode of the smart watch 300 and human skin; and the fourth contact capacitor C04 may represent the capacitance between human skin and the earth on the signal transmitting side.

[0169] In addition, the HBC communication system may also include electronic devices equivalent to the contact between the human body and the earth, and electronic devices equivalent to the contact between the device and the earth. Figure 7 As shown, the HBC communication system may include a fifth contact capacitor C05, a sixth contact capacitor C06, and a seventh contact capacitor C07. The fifth contact capacitor C05 may represent the capacitance between the ground electrode of the smart watch 300 and the earth; the sixth contact capacitor C06 may represent the capacitance between a human foot and the earth; and the seventh contact capacitor C07 may represent the capacitance between the ground electrode of the smart ring 100 and the earth.

[0170] In some other examples, the receiving device and the sending device in the HBC communication system may both be the smart ring 100 described above.

[0171] Figure 8 shows a schematic structural diagram of a signal circuit provided by some embodiments of the present application; Figure 9A graph showing transmission loss of a human body channel between a human body and a second electrode under different conditions; Figure 10 Shown Figure 8 A structural schematic diagram of a signal circuit is provided; Figure 11 shows a structural schematic diagram of an active inductor; Figure 12 Shown Figure 8 Another structural schematic diagram of the compensation subcircuit in the signal circuit provided.

[0172] like Figure 8 As shown, an embodiment of the present application provides a signal circuit 200. The signal circuit 200 may be located on the circuit board 140 of the wearable device 100. The signal circuit 200 may include a first transceiver sub-circuit 210 and a compensation sub-circuit 220.

[0173] The first transceiver subcircuit 210 can be a capacitively coupled HBC signal transceiver subcircuit. The first transceiver subcircuit 210 can include a first signal terminal X1 and a second signal terminal X2. The first signal terminal X1 can be coupled to the first electrode 110, allowing the first electrode 110 to serve as the signal electrode of the smart ring 100. The second signal terminal X2 can be coupled to the second electrode 120 and to the ground terminal GND, allowing the second electrode 120 to serve as the ground electrode of the smart ring 100.

[0174] The compensation subcircuit 220 may include a third signal terminal X3 and a fourth signal terminal X4. The third signal terminal X3 may be coupled to the first electrode 110, and the fourth signal terminal X4 may be coupled to the second electrode 120. It is understood that the compensation subcircuit 220 and the first transceiver subcircuit 210 are connected in parallel.

[0175] When the second electrode 120 is in contact with human skin (e.g., a finger other than the finger wearing the smart ring 100), it has been previously described that the contact between the second electrode 120 and the human skin can be equivalent to forming a capacitor (i.e., the first capacitor C1 described above). The capacitance value of the first capacitor C1 formed can also vary depending on the degree of contact between the human skin and the second electrode 120.

[0176] It should be noted that the first capacitor C1 does not belong to the signal circuit. The first capacitor C1 is an electronic device equivalent to the contact between the second electrode 120 and the human skin.

[0177] In the case where there is no contact between the second electrode 120 and the human skin and no mutual coupling between the ground electrode and the human skin, the human body channel transmission loss is as follows: Figure 9In other words, curve 1 corresponds to the case where the first capacitor C1 does not exist in the HBC communication system. When the second electrode 120 is in contact with the human skin (for example, a finger other than the finger wearing the smart ring 100), and there is mutual coupling between the ground electrode and the human skin, the human body signal transmission loss is as follows: Figure 9 In other words, curve 2 corresponds to the case where the first capacitor C1 exists in the HBC communication system.

[0178] Can be obtained from Figure 9 As can be seen from the graph, the average loss corresponding to curve 1 is less than the average loss corresponding to curve 2. It is understandable that the first capacitor C1 formed by the contact between the second electrode 120 in the signal circuit and human skin increases the transmission loss in the human body channel, thereby resulting in low reliability of HBC signal transmission in the HBC communication system involving the signal circuit 200 and the wearable device 100.

[0179] In the embodiment of the present application, the compensation subcircuit 220 is used to form a parallel resonant network together with the first capacitor C1. The parallel resonant network can be equivalent to an open circuit in the signal circuit 200, thereby disconnecting the first capacitor C1 from the human body channel, thereby reducing the transmission loss of the human body channel and improving the reliability of HBC signal transmission in the HBC communication system involving the signal circuit 200 and the wearable device 100.

[0180] When the second electrode 120 is in contact with the human skin, the ground electrode and the human body are mutually coupled, and the signal circuit 200 includes the compensation subcircuit 220, the human body channel transmission loss is as follows: Figure 9 In other words, curve 3 corresponds to the case where both the first capacitor C1 and the compensation sub-circuit 220 exist in the HBC communication system.

[0181] Can be obtained from Figure 9 As can be seen from the figure, the average loss corresponding to curve 3 is less than the average loss corresponding to curve 2. It can be understood that adding the compensation subcircuit 220 to the signal circuit can reduce the transmission loss of the human body channel, thereby improving the reliability of HBC signal transmission in the HBC communication system involving the signal circuit and the wearable device.

[0182] For example Figure 8 The signal circuit shown in the embodiment of the present application provides a control method for the signal circuit. When the second electrode 120 contacts the human skin and is coupled to form a first capacitor C1, the signal circuit forms a parallel resonant network with the first capacitor C1 through the compensation sub-circuit 220.

[0183] In this way, the parallel resonant network can be equivalent to an open circuit in the signal circuit 200, thereby disconnecting the first capacitor C1 from the human body channel, reducing the transmission loss of the human body channel, and thus improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

[0184] In some examples, such as Figure 10 As shown, the compensation sub-circuit 220 may include an inductor (hereinafter referred to as the first inductor L1 for ease of distinction). A first end of the first inductor L1 is coupled to the first electrode 110, and a second end of the first inductor L1 is coupled to the second electrode 120. The first inductor L1 and the first capacitor C1 are substantially equivalent to a parallel connection, thereby forming a parallel LC (L represents the first inductor, C represents the first capacitor) resonant network.

[0185] The parallel LC resonant network can be equivalent to an open circuit in the signal circuit 200, thereby disconnecting the first capacitor C1 from the human body channel, reducing the transmission loss of the human body channel, and thus improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

[0186] By selecting first inductors L1 with different inductance values, the inductance parameters of the LC resonant network formed by the first capacitor C1 and the first inductor L1 connected in parallel can be adjusted. Alternatively, the first inductor L1 can be an adjustable inductor with an adjustable inductance value. By adjusting the capacitance value of the first inductor L1, the inductance parameters of the LC resonant network formed by the first capacitor C1 and the first inductor L1 connected in parallel can also be adjusted.

[0187] Exemplarily, the signal circuit 200 may further include a controller (not shown) that adjusts the inductance of the first inductor L1 so that the first inductor L1 with the changed inductance and the first capacitor C1 together form a parallel resonant network.

[0188] For example, Figure 11 As shown, the first inductor L1 may include an active inductor. The active inductor may include a transistor Gm1, a transistor Gm2, and a capacitor Cx. Transistors Gm1 and Gm2 may also be referred to as gyrators. By adjusting at least one of transistors Gm1, Gm2, and capacitor Cx, the inductance of the active inductor may be adjusted.

[0189] Of course, the first inductor L1 may also adopt other inductor types or circuits to adjust the inductance value, which is not limited in the embodiments of the present application.

[0190] In some examples, such as Figure 12As shown, the compensation sub-circuit 220 may include a plurality of inductors (for ease of distinction, the plurality of inductors are collectively referred to as an inductor assembly UL, wherein a single inductor is referred to as a second inductor L2). The plurality of second inductors L2 are connected in series with each other. For example, the first end of the first second inductor L2 in the plurality of second inductors L2 is coupled to the first electrode 110 as the third signal terminal X3, the second end of the first second inductor L2 is coupled to the first end of the second second inductor L2, the second end of the second second inductor L2 is coupled to the first end of the third second inductor L2, and so on... until the second end of the last second inductor L2 is coupled to the second electrode 120 as the fourth signal terminal X4.

[0191] In addition, if Figure 12 As shown, each second inductor L2 can be connected in parallel with a first switch K1. The first end of the second inductor L2 is coupled to the first end of the first switch K1, and the second end of the second inductor L2 is coupled to the second end of the first switch K1. When the first switch K1 is in the closed state, the first end of the first switch K1 is connected to the second end of the first switch K1; when the first switch K1 is in the open state, the first end of the first switch K1 is disconnected from the second end of the first switch K1.

[0192] The multiple second inductors L2 may be multiple inductors with equal inductance values, or may be multiple inductors with unequal inductance values, which is not limited in the embodiments of the present application.

[0193] In a set of parallel-connected selection units and the second inductor L2, when the first switch K1 in the selection unit is in the off state, the selection unit is in an open-circuit state. This allows current to flow through the second inductor L2, and the second inductor L2 becomes effective in the compensation sub-circuit 220. When the first switch K1 in the selection unit is in the closed state, the selection unit is in a conductive state. This allows current to flow through the selection unit instead of the second inductor L2, and the second inductor L2 becomes ineffective in the compensation sub-circuit 220.

[0194] By switching the state of the first switch K1 in each set of mutually parallel selection units and second inductors L2, it is possible to control whether the second inductor L2 in the set of mutually parallel selection units and second inductors L2 is effective, thereby controlling whether the multiple second inductors L2 in the compensation sub-circuit 220 are effective. In other words, by controlling the states of the multiple first switches K1, the number of the multiple second inductors L2 in the compensation sub-circuit 220 that are effective can be adjusted.

[0195] For example, the signal circuit 200 may further include a controller (not shown). The controller is coupled to the plurality of first switches K1 and configured to control the state switching of each first switch K1. It is understood that the controller may control each first switch K1 to be in a closed state or an open state.

[0196] As previously explained, the multiple second inductors L2 are connected in series. Therefore, by controlling the states of the multiple first switches K1 to control the number of active second inductors L2, the inductance of the inductor assembly UL (i.e., the inductance of the compensation sub-circuit 220) can be adjusted. This allows the compensation sub-circuit 220 and the first capacitor C1 to form a parallel LC resonant network, which reduces transmission losses through the human body channel, thereby improving the reliability of HBC signal transmission in the HBC communication system involving signal circuits and wearable devices.

[0197] For example Figure 12 In the signal circuit shown, an embodiment of the present application provides a control method for a signal circuit. During the process of the compensation sub-circuit 220 forming a parallel resonant network with the first capacitor C1, the inductance value of the inductor component UL can be changed by controlling at least one first switch K1 to switch from a closed state to an open state, or from an open state to a closed state. This helps the compensation sub-circuit 220 and the first capacitor C1 form a parallel LC resonant network, thereby reducing human body channel transmission loss through the parallel LC resonant network, thereby improving the reliability of HBC signal transmission in an HBC communication system involving the signal circuit and wearable devices.

[0198] Figure 13 Shown Figure 8 Another structural schematic diagram of the signal circuit provided; Figure 14 Shown Figure 8 Another structural schematic diagram of the compensation sub-circuit in the signal circuit is provided.

[0199] In some examples, such as Figure 13 As shown, the compensation sub-circuit 220 may further include a capacitor (hereinafter referred to as the second capacitor C2 for ease of distinction). The first plate of the second capacitor C2 is coupled to the first electrode 110, and the second plate of the second capacitor C2 is coupled to the second electrode 120 and the ground terminal GND.

[0200] For example, the compensation sub-circuit 220 includes a second capacitor C2 and a first inductor L1. In the compensation sub-circuit 220, the second capacitor C2 and the first inductor L1 are connected in parallel. As previously explained, the first inductor L1 is connected in parallel with the first capacitor C1. Here, the second capacitor C2 is also connected in parallel with the first inductor L1. Therefore, the first capacitor C1 and the second capacitor C2 are connected in parallel.

[0201] By selecting a second capacitor C2 with a different capacitance value, the capacitance value of the first capacitor C1 and the second capacitor C2 connected in parallel can be adjusted. Alternatively, the second capacitor C2 can be an adjustable capacitor with an adjustable capacitance value. By adjusting the capacitance value of the second capacitor C2, the capacitance value of the first capacitor C1 and the second capacitor C2 connected in parallel can also be adjusted.

[0202] Exemplarily, the signal circuit 200 further includes a controller that adjusts the capacitance of the second capacitor C2 to adjust the parallel capacitance of the first capacitor C1 and the second capacitor C2 in the parallel resonant network.

[0203] In this way, the compensation sub-circuit 220 can adjust the capacitance of the parallel LC resonant circuit through the second capacitor C2. This helps the compensation sub-circuit 220 and the first capacitor C1 form a parallel LC resonant network, which reduces transmission loss in the human body channel, thereby improving the reliability of HBC signal transmission in the HBC communication system involving the signal circuit 200 and the wearable device 100.

[0204] In some examples, such as Figure 14 As shown, the compensation sub-circuit 220 may further include a plurality of capacitors (for ease of distinction, the plurality of capacitors are collectively referred to as a capacitor assembly UC, wherein a single capacitor is referred to as a third capacitor C3). A first plate of each third capacitor C3 is coupled to the first electrode 110, and a second plate of each third capacitor C3 is coupled to the second electrode 120 and the ground terminal GND.

[0205] In addition, a second switch K2 may be connected in series between each third capacitor C3 and the first electrode 110. A first end of the second switch K2 is coupled to the first electrode 110, and a second end of the second switch K2 is coupled to the first plate of the third capacitor. Alternatively, the second switch may be connected in series between the third capacitor and ground.

[0206] When the second switch K2 is in a closed state, the first end of the second switch K2 is connected to the second end of the second switch K2; when the second switch K2 is in an open state, the first end of the second switch K2 is disconnected from the second end of the second switch K2.

[0207] The multiple third capacitors C3 can be multiple capacitors with equal capacitance values, or can be capacitors with unequal capacitance values, which is not limited in the embodiments of the present application.

[0208] In a set of a second switch K2 and a third capacitor C3 connected in series, when the second switch K2 is in an open state, the circuit between the third capacitor C3 and the first electrode 110 is open. Thus, current is not conducted to the third capacitor C3, and the third capacitor C3 does not take effect in the compensation sub-circuit 220. When the second switch K2 is in a closed state, a circuit is established between the third capacitor C3 and the first electrode 110. Thus, current can be conducted to the third capacitor C3, and the third capacitor C3 takes effect in the compensation sub-circuit 220.

[0209] The multiple effective third capacitors C3 are connected in parallel with each other, so the capacitance value of the capacitor assembly UC can be calculated based on the capacitance values of the multiple effective third capacitors C3.

[0210] By switching the state of the second switch K2 in each series-connected pair of second switches K2 and third capacitors C3, it is possible to control whether the third capacitor C3 in the series-connected pair of second switches K2 and third capacitors C3 is effective, thereby controlling whether the multiple third capacitors C3 in the compensation sub-circuit 220 are effective. In other words, by controlling the states of the multiple second switches K2, it is possible to adjust the number of active third capacitors C3 in the capacitor assembly UC, thereby adjusting the capacitance value of the capacitor assembly UC.

[0211] For example, the signal circuit 200 may further include a controller (not shown). The controller is coupled to the plurality of second switches K2 and is configured to control the state switching of each second switch K2. It is understood that the controller may control each second switch K2 to be in a closed state or an open state.

[0212] Capacitor assembly UC, similar to second capacitor C2, is also connected in parallel with first capacitor C1. Therefore, by adjusting the capacitance of capacitor assembly UC, the capacitance of the parallel LC resonant circuit can be adjusted. This helps the compensation subcircuit 220 and first capacitor C1 form a parallel LC resonant network, which reduces transmission losses in the human body channel, thereby improving the reliability of HBC signal transmission in the HBC communication system involving signal circuit 200 and wearable device 100.

[0213] For example Figure 14In the signal circuit shown, an embodiment of the present application provides a control method for a signal circuit. During the process of the compensation sub-circuit 220 forming a parallel resonant network with the first capacitor C1, the capacitance value of the capacitor component UC can be changed by controlling at least one second switch K2 to switch from a closed state to an open state, or from an open state to a closed state. This helps the compensation sub-circuit 220 and the first capacitor C1 form a parallel LC resonant network, thereby reducing human body channel transmission loss in the parallel resonant network and improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

[0214] Figure 15 A curve diagram showing the transmission loss of the human body channel when the human skin is in contact with the second electrode and the capacitor assembly / the second capacitor has different capacitance values is shown.

[0215] When the capacitance value of the capacitor component / the second capacitor is 0 pF, the human body channel transmission loss is as follows: Figure 15 As shown in curve 3a in FIG; When the capacitance value of the capacitor component / the second capacitor is 5pF, the human body channel transmission loss is as follows Figure 15 As shown in curve 3b; when the capacitance value of the capacitor component / the second capacitor is 10pF, the human body channel transmission loss is as follows Figure 15 As shown in curve 3c.

[0216] from Figure 15 It can be seen that by changing the capacitance value of the capacitor assembly / the second capacitor, the capacitance value in the parallel LC resonant circuit can be adjusted, so that the compensation sub-circuit 220 and the first capacitor C1 together form a parallel LC resonant network, thereby reducing the human body channel transmission loss corresponding to HBC signals of different frequencies, and optimizing the reliability of HBC signal transmission of specific frequencies in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

[0217] Figure 16 Showing a schematic structural diagram of a signal circuit provided by other embodiments of the present application; Figure 17 Shown Figure 16 A structural schematic diagram of the signal circuit provided.

[0218] In some examples, such as Figure 16 As shown, the signal circuit 200 may further include a compensation switching subcircuit 230. The compensation switching subcircuit 230 is connected in series with the compensation subcircuit 220. For example, the compensation switching subcircuit 230 may be connected in series between the first electrode 110 and the compensation subcircuit 220, or the compensation switching subcircuit 230 may be connected in series between the second electrode 120 and the compensation subcircuit 220 (e.g., Figure 16 shown).

[0219] The compensation switching subcircuit 230 can have a first state and a second state. When the compensation switching subcircuit 230 is in the first state, the first electrode 110 and the compensation subcircuit 220 are disconnected, or the second electrode 120 and the compensation subcircuit 220 are disconnected. Therefore, when the compensation switching subcircuit 230 is in the first state, current does not flow through the compensation subcircuit 220, rendering the compensation subcircuit 220 inoperative. When the compensation switching subcircuit 230 is in the second state, the first electrode 110 and the compensation subcircuit 220 are in communication, and the second electrode 120 and the compensation subcircuit 220 are in communication. Therefore, when the compensation switching subcircuit 230 is in the second state, current flows through the compensation subcircuit 22, rendering the compensation subcircuit 220 operational.

[0220] It can be seen that by adjusting the state of the compensation switching sub-circuit 230 , the compensation sub-circuit 220 in the signal circuit 200 can be enabled or disabled.

[0221] Therefore, when the second electrode of the smart ring 100 is in contact with human skin, a first capacitor is equivalently formed between the human body and the second electrode, resulting in a high human channel transmission loss corresponding to the signal, the compensation switching subcircuit 230 can be adjusted to the second state to make the compensation subcircuit 220 effective. The compensation subcircuit 220 and the first capacitor are used to form a parallel resonant network, thereby reducing the human channel transmission loss corresponding to signals of different frequencies and optimizing the reliability of HBC signal transmission of signals of specific frequencies in the HBC communication system involving signal circuits and wearable devices.

[0222] When the second electrode of the smart ring 100 is not in contact with human skin, no first capacitor is formed between the human body and the second electrode, and the human body channel transmission loss corresponding to the signal is low, the compensation switching subcircuit 230 can be adjusted to the first state, so that the compensation subcircuit 220 is disabled, thereby maintaining the reliability of HBC signal transmission in the HBC communication system involving the signal circuit and the wearable device.

[0223] In some examples, such as Figure 17 As shown, the compensation switching subcircuit 230 may include a third switch K3. When the compensation switching subcircuit 230 is connected in series between the first electrode 110 and the compensation subcircuit 220, a first end of the third switch K3 is coupled to the first electrode 110, and a second end of the third switch K3 is coupled to the compensation subcircuit 220. When the compensation switching subcircuit 230 is connected in series between the second electrode 120 and the compensation subcircuit 220, a first end of the third switch K3 is coupled to the compensation subcircuit 220, and a second end of the third switch K3 is coupled to the second electrode 120 (as shown in FIG. Figure 17 shown).

[0224] When the third switch K3 is closed, the first terminal of the third switch K3 is connected to the second terminal of the third switch K3, placing the compensation switching subcircuit 230 in the second state. This activates the compensation subcircuit 220, which, together with the first capacitor C1, forms a parallel resonant network. This reduces the human body channel transmission loss corresponding to HBC signals of different frequencies, thereby optimizing the reliability of HBC signal transmission for specific frequencies in the HBC communication system involving the signal circuit 200 and the wearable device 100.

[0225] When the third switch K3 is in the off state, the first end of the third switch K3 is disconnected from the second end of the third switch K3, causing the compensation switching sub-circuit 230 to be in the first state. This disables the compensation sub-circuit 220, maintaining the reliability of HBC signal transmission in the HBC communication system involving the signal circuit 200 and the wearable device 100.

[0226] Figure 18 Schematic diagrams showing the structures of signal circuits provided in some further embodiments of the present application; Figure 19 Schematic diagrams of the structures of signal circuits provided in some further embodiments of the present application are shown.

[0227] like Figure 18 As shown, the signal circuit 200 may further include a second transceiver sub-circuit 240 and a switching sub-circuit 250 .

[0228] The second transceiver subcircuit 240 can be a current-coupled HBC signal transceiver subcircuit. The second transceiver subcircuit 240 can include a fifth signal terminal X5 and a sixth signal terminal X6. The fifth signal terminal X5 can be coupled to the first electrode 110, making the first electrode 110 serve as the positive signal electrode of the smart ring 100; the sixth signal terminal X6 can be coupled to the second electrode 120, making the second electrode 120 serve as the negative signal electrode of the smart ring 100.

[0229] The switching subcircuit 250 can be coupled to the first transceiver subcircuit 210, the second transceiver subcircuit 240, the first electrode 110, and the second electrode 120, respectively. When the switching subcircuit 250 is in a first state, the first electrode 110 and the second electrode 120 are both coupled to the first transceiver subcircuit 210 and disconnected from the second transceiver subcircuit 240. When the switching subcircuit 250 is in a second state, the first electrode 110 and the second electrode 120 are both coupled to the second transceiver subcircuit 240 and disconnected from the first transceiver subcircuit 240.

[0230] Illustratively, when the switching subcircuit 250 is in the first state, the switching subcircuit 250 is used to connect the first signal terminal X1 of the first transceiver subcircuit 210 to the first electrode 110, disconnect the fifth signal terminal X5 of the second transceiver subcircuit 240 from the first electrode 110, and connect the second signal terminal X2 of the first transceiver subcircuit 210 to the second electrode 120, and disconnect the sixth signal terminal X6 of the second transceiver subcircuit 240 from the second electrode 120.

[0231] In this way, when the switching subcircuit 250 is in the first state, the signal transceiver subcircuit as a capacitive coupling type HBC is coupled to the first electrode 110 and the second electrode 120 respectively. At this time, the smart ring 100 can be a signal transceiver device of the capacitive coupling type HBC.

[0232] When the switching subcircuit 250 is in the second state, the switching subcircuit 250 is used to disconnect the first signal terminal X1 of the first transceiver subcircuit 210 from the first electrode 110, connect the fifth signal terminal X5 of the second transceiver subcircuit 240 to the first electrode 110, and disconnect the second signal terminal X2 of the first transceiver subcircuit 210 from the second electrode 120, and connect the sixth signal terminal X6 of the second transceiver subcircuit 240 to the second electrode 120.

[0233] In this way, when the switching subcircuit 250 is in the second state, the signal transceiver subcircuit as a current-coupled HBC is coupled to the first electrode 110 and the second electrode 120 respectively. At this time, the smart ring 100 can be a signal transceiver device of the current-coupled HBC.

[0234] In some examples, such as Figure 18 As shown, the switching sub-circuit 250 includes a first terminal D1 , a second terminal D2 , a third terminal D3 , a fourth terminal D4 , a fifth terminal D5 and a sixth terminal D6 .

[0235] The first terminal D1 is coupled to the first signal terminal X1 of the first transceiver sub-circuit 210, the second terminal D2 is coupled to the second signal terminal X2 of the first transceiver sub-circuit 210, the third terminal D3 is coupled to the fifth signal terminal X5 of the second transceiver sub-circuit 240, the fourth terminal D4 is coupled to the sixth signal terminal X6 of the second transceiver sub-circuit 240, the fifth terminal D5 is coupled to the first electrode 110, and the sixth terminal D6 is coupled to the second electrode 120.

[0236] When the switching sub-circuit 250 is in the first state, the fifth terminal D5 is connected to the first terminal D1 and disconnected from the third terminal D3, so that the first signal terminal X1 of the first transceiver sub-circuit 210 is connected to the first electrode 110, and the fifth signal terminal X5 of the second transceiver sub-circuit 240 is disconnected from the first electrode 110. The sixth terminal D6 is connected to the second terminal D2 and disconnected from the fourth terminal D4, so that the second signal terminal X2 of the first transceiver sub-circuit 210 is connected to the second electrode 120, and the sixth signal terminal X6 of the second transceiver sub-circuit 240 is disconnected from the second electrode 120.

[0237] In this way, when the switching subcircuit 250 is in the first state, the signal transceiver subcircuit as a capacitive coupling type HBC is coupled to the first electrode 110 and the second electrode 120 respectively. At this time, the smart ring 100 can be a signal transceiver device of the capacitive coupling type HBC.

[0238] When the switching sub-circuit 250 is in the second state, the fifth terminal D5 is connected to the third terminal D3 and disconnected from the first terminal D1, thereby disconnecting the first signal terminal X1 of the first transceiver sub-circuit 210 from the first electrode 110 and connecting the fifth signal terminal X5 of the second transceiver sub-circuit 240 to the first electrode 110. The sixth terminal D6 is connected to the fourth terminal D4 and disconnected from the second terminal D2, thereby disconnecting the second signal terminal X2 of the first transceiver sub-circuit 210 from the second electrode 120 and connecting the sixth signal terminal X6 of the second transceiver sub-circuit 240 to the second electrode 120.

[0239] In this way, when the switching subcircuit 250 is in the second state, the signal transceiver subcircuit as a current-coupled HBC is coupled to the first electrode 110 and the second electrode 120 respectively. At this time, the smart ring 100 can be a signal transceiver device of the current-coupled HBC.

[0240] In this embodiment, the switching sub-circuit 250 can enable the smart ring 100 to support capacitive coupling HBC communication and current coupling HBC communication in different time periods, thereby improving the communication diversity of the smart ring 100.

[0241] The voltage corresponding to electrostatic stress is very large, and can reach several thousand volts. When electrostatic stress occurs on the first electrode 110 and / or the second electrode 120 , the electrostatic stress with a large voltage can easily damage the electronic devices in the signal circuit 200 .

[0242] So in some examples, like Figure 19 As shown, the signal circuit 200 may further include an electrostatic discharge sub-circuit 260. A first terminal of the electrostatic discharge sub-circuit 260 is coupled to the first electrode 110, and a second terminal of the electrostatic discharge sub-circuit 260 is coupled to the ground terminal GND.

[0243] When the first electrode 110 is subjected to electrostatic stress, the electrostatic discharge sub-circuit 260 can connect the first electrode 110 to the ground terminal GND, and transmit the electrostatic stress to the ground terminal GND, thereby preventing the electrostatic stress with a large pressure value from being transmitted to other electronic devices in the signal circuit 200, preventing the electrostatic stress from damaging the electronic devices and causing failure of the electronic devices, and improving the reliability of the signal circuit and the wearable device.

[0244] In some examples, such as Figure 19 As shown, the signal circuit 200 may further include an electrostatic discharge sub-circuit 260. A first terminal of the electrostatic discharge sub-circuit 260 is coupled to the second electrode 120, and a second terminal of the electrostatic discharge sub-circuit 260 is coupled to the ground terminal GND.

[0245] When the second electrode 120 is subjected to electrostatic stress, the electrostatic discharge sub-circuit 260 can connect the second electrode 120 to the ground terminal GND, and transmit the electrostatic stress to the ground terminal GND, thereby avoiding the electrostatic stress with a large pressure value from being transmitted to other electronic devices in the signal circuit 200, avoiding the electrostatic stress from damaging the electronic devices and causing failure of the electronic devices, and improving the reliability of the signal circuit and the wearable device.

[0246] Among them, when the smart ring 100 is used as a signal transceiver device of a capacitive coupling type HBC and the second electrode 120 is coupled to the ground terminal GND as a ground electrode, the electrostatic discharge sub-circuit 260 coupled to the second electrode 120 can be omitted, saving the cost of the signal circuit 200.

[0247] The electrostatic discharge sub-circuit 260 may include a transient voltage suppressor (TVS) tube, or other suitable electronic components, which is not limited in the present application.

[0248] Figure 20 A flow chart showing a method for controlling a signal circuit provided by some embodiments of the present application is shown; Figures 21 to 27 Shows different wearing scenarios of the smart ring on a person's hand; Figure 28 A flow chart showing a signal circuit control method provided by other embodiments of the present application is shown.

[0249] Embodiments of the present application provide a signal circuit control method. This method enables, after the smart ring 100 is worn on a user's finger, the compensation subcircuit 220 in the signal circuit 200 and the first capacitor C1 equivalent to the human skin and the second electrode 120 to form a parallel resonant network, thereby improving the reliability of HBC signal transmission in an HBC communication system involving the signal circuit and the wearable device.

[0250] In some examples, the frequency of the signal received and transmitted by the first transceiver sub-circuit 210 in the signal circuit 200 is fixed. Figure 20 As shown, taking the smart ring 100 as a receiving device in HBC communication and the signal circuit 200 for signal reception as an example, the control method of the signal circuit may include steps S310 to S380.

[0251] Step S310: The signal circuit obtains the wearing information of the smart ring 100.

[0252] The wearing information may be information indicating different wearing scenarios of the smart ring 100. The wearing information may be set by the user when initially wearing the smart ring 100, or may be determined by the smart ring 100 through its own sensors based on sensing data acquired by various sensors.

[0253] For example, different wearing information of the smart ring 100 may include information such as Figures 21 to 27 The wearing scenarios of multiple smart rings 100 shown in FIG. The wearing information may include at least Figure 21 The information that the second electrode 120 in the smart ring 100 is not in contact with the finger is shown as follows. Figures 22 to 25 The information of the second electrode 120 in the smart ring 100 contacting a finger, and the information indicating that Figure 26 and Figure 27 The information shown is that the second electrode 120 in the smart ring 100 is in contact with two fingers.

[0254] Step S320 : The signal circuit determines target parameters of the compensation sub-circuit 220 corresponding to the wearing information based on the wearing information.

[0255] The circuit structure of compensation subcircuit 220 has been previously described in detail and will not be further elaborated here. If compensation subcircuit 220 includes an inductor, the target parameter may include an inductance value. If compensation subcircuit 220 includes both an inductor and a capacitor, the target parameter may include both an inductance value and a capacitance value.

[0256] For example, Figure 10 As shown, when the compensation sub-circuit 220 includes the first inductor L1, the target parameter may include the inductance value of the first inductor L1. Figure 12 As shown, in the case where the compensation sub-circuit 220 includes the inductor component UL, the target parameter may include the inductance value of the inductor component UL.

[0257] For example, Figure 13 As shown, when the compensation sub-circuit 220 includes the second capacitor C2, the target parameter may include the capacitance value of the second capacitor C2. Figure 14As shown, in the case where the compensation sub-circuit 220 includes a capacitor component UC, the target parameter may include the capacitance value of the capacitor component UC.

[0258] For example, when the compensation sub-circuit 220 includes both an inductor component UL and a capacitor component UC, the target parameter may include the inductance value of the inductor component UL and the capacitance value of the capacitor component UC. For ease of understanding, the following description uses the example of the compensation sub-circuit 220 including both the inductor component UL and the capacitor component UC.

[0259] For each type of wearing information, the compensation sub-circuit 220 can be pre-tested for signal transmission using different parameters. The parameters of the compensation sub-circuit 220 with the best signal transmission results are used as the target parameters corresponding to that wearing information, and a mapping relationship is established. Subsequently, after the wearing information is obtained, the target parameters of the compensation sub-circuit 220 corresponding to each type of wearing information can be directly determined using the mapping relationship.

[0260] After determining the target parameters for the compensation sub-circuit 220, the signal circuit 200 can use a controller to switch the states of the plurality of first switches K1 in the inductor assembly UL according to the target parameters, so that the inductance value of the inductor assembly UL is equal to the inductance value in the target parameters. Similarly, the controller can use a controller to switch the states of the plurality of second switches K2 in the capacitor assembly UC according to the target parameters, so that the capacitance value of the capacitor assembly UC is equal to the capacitance value in the target parameters.

[0261] Step S330: The signal circuit sends a notification to the sending device to enable the sending device to transmit the HBC signal.

[0262] After determining the target parameters, the smart ring 100 can send a notification to the sending device (e.g., a smartwatch). After receiving the notification, the sending device transmits an HBC signal, which is transmitted through the human body to the smart ring (receiving device) 100. The sending device may transmit the HBC signal multiple times. For example, the smart ring 100 may notify the sending device to transmit the HBC signal multiple times. In another example, the smart ring 100 may notify the sending device once, but the sending device may transmit the HBC signal multiple times.

[0263] The smart ring 100 can send notifications to the sending device in a variety of ways. For example, the smart ring 100 can use human skin to send HBC signals to send notifications to the sending device. For another example, the smart ring 100 and the sending device can simultaneously support other communication methods (such as Bluetooth, near field communication (NFC), or other suitable communication methods), and the smart ring 100 can send notifications to the sending device by sending NFC signals.

[0264] Step S340: when the signal circuit 200 receives the HBC signal transmitted by the transmitting device, a judgment result is obtained as to whether the signal strength received by the signal circuit 200 is greater than a preset strength threshold.

[0265] The smart ring 100 can perform Bluetooth communication with the sending device to determine whether the sending device has sent the HBC signal. Alternatively, the smart ring 100 can also determine whether the sending device has sent the HBC signal based on the signal strength received by the first transceiver sub-circuit 110. Of course, the smart ring 100 can also determine whether the sending device has sent the HBC signal through other methods.

[0266] When the smart ring 100 determines that the sending device has sent the HBC signal, it obtains a judgment result of whether the signal strength received by the signal circuit 200 is greater than a preset strength threshold.

[0267] If the result indicates that the signal strength received by the signal circuit 200 under the current parameters is greater than the preset strength threshold, the smart ring 100 determines that the compensation subcircuit 220 has a better reception effect on the HBC signal according to the current parameters. Step S350 is executed: the signal circuit 200 uses the current parameters of the compensation subcircuit 220 as the target parameters.

[0268] If the result indicates that the signal strength received by the signal circuit 200 under the current parameters is less than or equal to the preset strength threshold, the smart ring 100 determines that the compensation sub-circuit 220 is receiving the HBC signal poorly under the current parameters and does not use the current parameters of the compensation sub-circuit 220 as the target parameters. Step S360 is then executed: the signal circuit 200 changes the parameters of the compensation sub-circuit 220.

[0269] Exemplarily, the signal circuit 200 changing the parameters of the compensation sub-circuit 220 may involve the signal circuit 200 changing the inductance of the compensation sub-circuit 220. For example, if the compensation sub-circuit 220 includes an inductor component, step S360 may include the signal circuit 200 changing the inductance of the inductor component. For another example, if the compensation sub-circuit 220 includes both an inductor component and a capacitor component, the signal circuit 200 may change the inductance of the inductor component in the compensation sub-circuit 220, and change the capacitance of the capacitor component in the compensation sub-circuit 220.

[0270] In step S360, the signal circuit 200 changes the parameters of the compensation sub-circuit 220 each time so that the parameters after the change are different from the previous parameters. After completing step S360, step S370 can be performed to determine whether the compensation sub-circuit 220 has traversed the detection results of all parameters of the compensation sub-circuit 220.

[0271] If the detection result indicates that the compensation sub-circuit 220 has not traversed all parameters of the compensation sub-circuit 220, the process returns to step S340. At this point, the signal circuit 200 receives the HBC signal transmitted by the transmitting device according to the parameters changed by the compensation sub-circuit 220. Furthermore, after the signal circuit 200 receives the HBC signal, the signal strength of the HBC signal received by the signal circuit 200 is obtained.

[0272] As can be seen from the previous process, if the compensation sub-circuit 220 receives the HBC signal poorly with the current parameters, the parameters will be changed in step S360. If the HBC signal reception is poor for multiple times, all parameters of the compensation sub-circuit 220 can be traversed in step S360.

[0273] When the detection result indicates that the compensation sub-circuit 220 has not traversed all the parameters of the compensation sub-circuit 220 , returning to step S340 can help find parameters that can have a better reception effect on the HBC signal.

[0274] If the test result indicates that compensation sub-circuit 220 has traversed all parameters of compensation sub-circuit 220, it can be assumed that regardless of the parameters of compensation sub-circuit 220, compensation sub-circuit 220 cannot provide a good reception effect for the HBC signal. In this case, step S380 can be executed: signal circuit 200 determines the parameters of compensation sub-circuit 220 corresponding to the highest signal strength as the target parameters.

[0275] Exemplarily, after traversing all parameters of the compensation subcircuits 220 to receive HBC signals, the compensation subcircuit 220 obtains the signal strengths of the HBC signals received by the multiple signal circuits and determines the target signal strength with the highest signal strength from the signal strengths of the multiple HBC signals.

[0276] The parameters set for the HBC signal reception are determined as target parameters according to the target signal strength.

[0277] It should be noted that Figure 20 The process shown is described by taking step S370 as an example after step S340. In other example processes, such as Figure 28 As shown, step S370 may be performed first, and step S340 may be performed if the detection result in step S370 indicates that the compensation sub-circuit 220 has not traversed all the detection results of the parameters of the compensation sub-circuit 220. After step S360 is completed, the process returns to step S370.

[0278] In this example, when the signal frequency received and transmitted by the first transceiver sub-circuit 210 remains fixed, the parameters of the compensation sub-circuit 220 can be traversed so that the HBC signal strength received by the signal circuit 200 is better or reaches the optimal level, thereby improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

[0279] Furthermore, steps S310 to S380 described above can be considered to be executed after the smart ring 100 is first worn on the user's finger, or each time the wearing information of the smart ring 100 is changed. For example, if the user changes the finger on which the smart ring 100 is worn, the wearing scenario of the smart ring 100 changes from the second electrode 120 contacting one finger to the second electrode 120 contacting two fingers. In this case, steps S310 to S380 can be executed to optimize the parameters of the compensation sub-circuit 220 and improve the reliability of HBC signal transmission in the HBC communication system involving the signal circuit 200 and the wearable device 100.

[0280] Figure 29 A flow chart of a signal circuit control method provided by some further embodiments of the present application is shown.

[0281] In some examples, the frequency of the signal received and transmitted by the first transceiver sub-circuit 210 in the signal circuit 200 is adjustable. Figure 29 As shown, taking the smart ring 100 as a receiving device in HBC communication and the signal circuit 200 for signal reception as an example, the control method of the signal circuit may include steps S410 to S470.

[0282] Step S410: The signal circuit obtains the wearing information of the smart ring 100.

[0283] The wearing information may be set by the user when initially wearing the smart ring 100, and may be information indicating different wearing conditions of the smart ring 100. The wearing information may also be determined by the smart ring 100 through its own sensors based on sensing data acquired by various sensors.

[0284] For example, different wearing conditions of the smart ring 100 may include: Figures 21 to 27 The wearing information of the multiple smart rings 100 shown in FIG. The wearing information may include at least Figure 21 The information that the second electrode 120 in the smart ring 100 is not in contact with the finger is shown as follows. Figures 22 to 25 The information of the second electrode 120 in the smart ring 100 contacting a finger, and the information indicating that Figure 26 and Figure 27 The information shown is that the second electrode 120 in the smart ring 100 is in contact with two fingers.

[0285] Step S420: The signal circuit determines a target frequency range based on the wearing information.

[0286] The human body communication frequency may be within a frequency range greater than or equal to 10 kHz and less than or equal to 100 MHz.

[0287] For each type of wearing information, the compensation sub-circuit 220 can be pre-tested for signal transmission at multiple different frequency intervals within the human body communication frequency range. The frequency interval with the best signal transmission effect is then used as the target frequency interval corresponding to that wearing information, and a mapping relationship is established. Subsequently, after the wearing information is obtained, the target frequency interval of the compensation sub-circuit 220 corresponding to each type of wearing information can be directly determined using this mapping relationship.

[0288] After the wearing information of the smart ring 100 is determined, the controller can be used to adjust the human body communication frequency to the corresponding target frequency range.

[0289] Step S430: The signal circuit sends a notification to the sending device, so that the sending device transmits the HBC signal according to the target frequency range.

[0290] After determining the target parameters, the smart ring 100 can send a notification to the sending device (e.g., a smartwatch) via HBC to communicate in the target frequency range. After receiving the notification, the sending device transmits the HBC signal, which is transmitted through the human body to the smart ring (receiving device) 100. The sending device may transmit the HBC signal multiple times. For example, the smart ring 100 may notify the sending device to transmit the HBC signal multiple times. In another example, the smart ring 100 may notify the sending device once, but the sending device may transmit the HBC signal multiple times.

[0291] The signal frequencies of the HBC signals transmitted by the sending device are all within the target frequency range.

[0292] Step S440: the signal circuit scans the HBC signal within the target frequency range to obtain the signal strength of the HBC signal at each frequency.

[0293] The smart ring 100 can perform Bluetooth communication with the sending device to determine whether the sending device has sent the HBC signal. Alternatively, the smart ring 100 can determine whether the sending device has sent the HBC signal based on the signal strength received by the first transceiver subcircuit. Of course, the smart ring 100 can also determine whether the sending device has sent the HBC signal using other methods.

[0294] When determining that the transmitting device has transmitted HBC signals of various frequencies, the smart ring 100 records the signal strength of the HBC signals of each frequency received by the signal circuit during the frequency scanning process.

[0295] Step S450: When the signal circuit receives HBC signals of multiple frequencies, the signal circuit obtains a detection result of whether the signal strength of at least one HBC is greater than a strength threshold.

[0296] If the detection result indicates that the signal strength of at least one HBC signal received by the signal circuit 200 is greater than a preset strength threshold, the smart ring 100 determines that the signal circuit has a better reception effect when receiving HBC signals at the corresponding target frequency. The target frequency is the communication frequency corresponding to the signal strength greater than the preset strength threshold.

[0297] Therefore, when the detection result indicates that the strength of at least one signal received by the signal circuit is greater than the preset strength threshold, step S460 is executed: the signal circuit uses the target frequency as the human body communication frequency of the smart ring 100 .

[0298] In this way, the signal circuit can determine the target frequency range of the signal that best matches the user's current wearing posture based on the wearable device's wearing information, and then determine the human body communication frequency within the target frequency range. This can improve the efficiency of the signal circuit in determining the HBC signal frequency.

[0299] If the detection result indicates that the signal strength of the HBC signal received by the compensation sub-circuit 220 with the current parameters is less than or equal to the preset strength threshold, the smart ring 100 determines that the signal circuit is receiving the HBC signal in the target frequency range poorly and needs to further adjust the parameters of the compensation sub-circuit 220 in the signal circuit. Therefore, step S470 is executed: the signal circuit adjusts the parameters of the compensation sub-circuit 220.

[0300] The specific method of adjusting the parameters of the compensation sub-circuit 220 in step S470 is basically the same as the method of adjusting the compensation sub-circuit 220 in the above-mentioned signal circuit 200 where the signal frequency received and transmitted by the first transceiver sub-circuit 210 is fixed, and will not be repeated here.

[0301] It should be noted that Figure 29 The illustrated process uses the example of first adjusting the human body communication frequency of the signal circuit and then adjusting the compensation parameters of the compensation subcircuit within the signal circuit. In other exemplary processes, the compensation parameters of the compensation subcircuit within the signal circuit may be adjusted first and then the human body communication frequency of the signal circuit. The embodiments of the present application do not limit the order in which the human body communication frequency and the compensation parameters of the compensation subcircuit 220 are controlled.

[0302] By adjusting the parameters of the compensation sub-circuit 220 , the parameters of the compensation sub-circuit 220 can be adjusted so that the HBC signal strength received by the signal circuit 200 is better or reaches the optimum.

[0303] In this example, when the signal frequency received and transmitted by the first transceiver sub-circuit 210 is adjustable, the signal frequency received and transmitted by the first transceiver sub-circuit 210 and the parameters of the traversal compensation sub-circuit 220 can be adjusted in two ways, so that the signal circuit 200 receives the HBC signal with better or optimal strength, thereby improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

[0304] Furthermore, steps S410 to S470 described above can be considered to be executed after the smart ring 100 is first worn on the user's finger, or each time the wearing information of the smart ring 100 is changed. For example, if the user changes the finger on which the smart ring 100 is worn, the wearing scenario of the smart ring 100 changes from the second electrode 120 contacting one finger to the second electrode 120 contacting two fingers. In this case, steps S410 to S470 can be executed to optimize the parameters of the compensation sub-circuit 220 and improve the reliability of HBC signal transmission in the HBC communication system involving the signal circuit 200 and the wearable device 100.

[0305] The above is only a specific embodiment of the present application, but the scope of protection of this application is not limited to this. Any changes or substitutions within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A wearable device, characterized in that: include: A first electrode, configured to couple with human skin; a second electrode, spaced apart from the first electrode; When the second electrode is in contact with human skin, the second electrode and the human skin together form a first capacitor; an insulator, located between the first electrode and the second electrode, so as to insulate the first electrode and the second electrode from each other; a circuit board located between the first electrode and the second electrode, wherein a first connection point of the circuit board is coupled to the first electrode, and a second connection point of the circuit board is coupled to the second electrode; the circuit board further includes a signal circuit, the signal circuit including a compensation subcircuit; the compensation subcircuit and the first capacitor form a parallel resonant network, and the parallel resonant network is equivalent to an open circuit in the signal circuit; The wearable device uses at least the first electrode to send signals to the human skin and / or receive signals transmitted by the human skin.

2. The wearable device according to claim 1, wherein: The first electrode includes a first arcuate surface, and the second electrode includes a second arcuate surface; The central angle of the second arcuate surface is greater than the central angle of the first arcuate surface.

3. The wearable device according to claim 1 or 2, wherein: The second electrode serves as a housing of the wearable device; the housing has a receiving space; The insulator is at least partially located in the accommodating space.

4. The wearable device according to claim 3, wherein: The circuit board is located in the accommodation space, and the circuit board is located on a side of the insulator away from the first electrode; The wearable device further includes a conductive structure, one end of the conductive structure is coupled to the first connection point of the circuit board, and the other end of the conductive structure passes through the insulator and is coupled to the first electrode.

5. The wearable device according to any one of claims 1 to 4, characterized in that: The insulator includes a flexible material.

6. The wearable device according to any one of claims 1 to 5, characterized in that: The wearable device includes a finger ring or a ring.

7. A signal circuit, characterized in that: Applied to a wearable device, the wearable device further comprises a first electrode and a second electrode; the first electrode is used to send signals to human skin and / or receive signals transmitted by the human skin; When the second electrode is in contact with human skin, the second electrode and the human skin together form a first capacitor; The signal circuit includes: The first transceiver sub-circuit includes a first signal terminal and a second signal terminal; the first signal terminal is used to couple with the first electrode; the second signal terminal is used to couple with the second electrode and the ground terminal at the same time; A compensation subcircuit includes a third signal terminal and a fourth signal terminal; the third signal terminal is used to couple with the first electrode, and the fourth signal terminal is used to couple with the second electrode; the compensation subcircuit and the first capacitor form a parallel resonant network, and the parallel resonant network is equivalent to an open circuit in the signal circuit.

8. The signal circuit according to claim 7, characterized in that: When the second electrode is coupled to the human skin, a first capacitor is equivalently formed between the second electrode and the human skin; The compensation sub-circuit is configured to form a parallel resonant network together with the first capacitor.

9. The signal circuit according to claim 7 or 8, characterized in that: The compensation subcircuit includes a first inductor; a first end of the first inductor is used to couple with the first electrode, and a second end of the first inductor is used to couple with the second electrode; The first inductor includes a fixed-value inductor or an adjustable inductor.

10. The signal circuit according to claim 7 or 8, characterized in that: The compensation subcircuit includes an inductor component, a first end of the inductor component is used to couple with the first electrode, and a second end of the inductor component is used to couple with the second electrode; The inductor assembly includes a plurality of inductor units connected in series; each of the inductor units includes a first switch and a second inductor connected in parallel.

11. The signal circuit according to claim 9 or 10, characterized in that: The compensation subcircuit further includes a second capacitor; a first plate of the second capacitor is used to couple to the first electrode, and a second plate of the second capacitor is used to couple to the second electrode; The second capacitor includes a fixed-value capacitor or an adjustable capacitor.

12. The signal circuit according to claim 9 or 10, characterized in that: The compensation subcircuit further includes a capacitor assembly; the capacitor assembly includes a plurality of capacitor units connected in parallel; a first end of each capacitor unit is used to couple to the first electrode, and a second end of each capacitor unit is used to couple to the second electrode; Each of the capacitor units includes a second switch and a third capacitor connected in series.

13. The signal circuit according to any one of claims 7 to 12, characterized in that: The signal circuit further includes a compensation switching subcircuit; the compensation switching subcircuit is connected in series with the compensation subcircuit.

14. The signal circuit according to any one of claims 7 to 13, characterized in that: The signal circuit further includes: The second transceiver sub-circuit includes a fifth signal terminal and a sixth signal terminal; a switching subcircuit, coupled to the first signal terminal, the second signal terminal, the fifth signal terminal, and the sixth signal terminal, respectively; and further configured to couple to the first electrode and the second electrode; When the switching subcircuit is in the first state, the first electrode is connected to the first signal terminal and disconnected from the fifth signal terminal, and the second electrode is connected to the second signal terminal and disconnected from the sixth signal terminal; When the switching subcircuit is in the second state, the first electrode is connected to the fifth signal terminal and disconnected from the first signal terminal, and the second electrode is connected to the sixth signal terminal and disconnected from the second signal terminal.

15. A method for controlling a signal circuit, characterized in that: Applied to the signal circuit according to any one of claims 7 to 14; the method comprising: When the second electrode is coupled to the human skin to form a first capacitor, the signal circuit and the first capacitor together form a parallel resonant network through the compensation subcircuit. The parallel resonant network is equivalent to an open circuit in the signal circuit.

16. The method according to claim 15, characterized in that The compensation subcircuit includes an inductor component, wherein a first end of the inductor component is used to couple to the first electrode, and a second end of the inductor component is used to couple to the second electrode; the inductor component includes a plurality of inductor units connected in series; each of the inductor units includes a first switch and a second inductor connected in parallel; The signal circuit forms a parallel resonant network together with the first capacitor through the compensation sub-circuit, including: The signal circuit controls the closing or opening of at least one of the first switches to change the inductance of the inductor component, so that the inductor component with the changed inductance and the first capacitor together form a parallel resonant network; or, The compensation subcircuit includes a first inductor, wherein the first inductor includes an adjustable inductor; The signal circuit forms a parallel resonant network together with the first capacitor through the compensation sub-circuit, including: The signal circuit adjusts the inductance of the first inductor so that the first inductor with the changed inductance and the first capacitor together form a parallel resonant network.

17. The method according to claim 16, characterized in that The compensation subcircuit further includes a capacitor assembly; the capacitor assembly includes a plurality of capacitor units connected in parallel; a first end of each capacitor unit is configured to be coupled to the first electrode, and a second end of each capacitor unit is configured to be coupled to the second electrode; each capacitor unit includes a second switch and a third capacitor connected in series; The signal circuit forms a parallel resonant network with the first capacitor through the compensation sub-circuit, and further includes: The signal circuit controls the closing or opening of at least one of the second switches to change the capacitance of the capacitor component, so as to adjust the parallel capacitance of the first capacitor and the capacitor component in the parallel resonant network; or, The compensation subcircuit includes a second capacitor, and the first inductor includes an adjustable capacitor; The signal circuit forms a parallel resonant network with the first capacitor through the compensation sub-circuit, and further includes: The signal circuit adjusts the capacitance value of the second capacitor to adjust the parallel capacitance value of the first capacitor and the second capacitor in the parallel resonant network.

18. The method according to any one of claims 15 to 17, characterized in that The method further comprises: The signal circuit obtains wearing information of the wearable device; The signal circuit determines a target frequency range based on the wearing information; The signal circuit notifies the opposite device to communicate according to the target frequency interval; The signal circuit scans the signal in the target frequency range and uses the target frequency with a signal strength greater than a preset strength threshold as the human body communication frequency of the signal circuit; wherein the target frequency is a frequency in the target frequency range.

19. A circuit board, characterized in that: Applicable to the wearable device according to any one of claims 1-6; the circuit board includes the signal circuit according to any one of claims 7-14.

20. A human body communication system, characterized in that: including a sending device and a receiving device that communicate with each other; The sending device comprises a wearable device according to any one of claims 1 to 6; and / or, The receiving device includes the wearable device according to any one of claims 1 to 6.

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