Charging case and circuitry thereof, wireless earphone assembly

Abstract

This invention relates to a charging case and its circuit, as well as a wireless earphone assembly. The circuit includes a battery and a charging power supply unit. The charging power supply unit includes a controller, an inductor, multiple switching devices, a voltage input terminal, a battery terminal, and a voltage output terminal. One end of the battery is grounded, and the other end is coupled to the battery terminal. The controller controls the on and off states of the multiple switching devices, enabling the charging power supply unit to operate in a first or second mode. In the first mode, it generates a charging voltage based on the voltage input at the voltage input terminal and the inductor, and outputs it to the battery terminal. Simultaneously, it outputs the voltage input at the voltage input terminal to the wireless earphones through the voltage output terminal. In the second mode, it generates an output voltage based on the battery and the inductor, and outputs it to the wireless earphones through the voltage output terminal. The output voltage provides a charging voltage for the earphone battery. This invention features fast charging speed, low heat generation, eliminates the need for an additional inductor, simplifies the circuit structure, and shortens the earphone charging time.

Description

Technical Field

[0001] This invention relates to the field of headphone technology, and more particularly to a charging case and its circuit, and a wireless headphone assembly. Background Technology

[0002] Compared to wired headphones, wireless headphones offer the advantage of portability and are therefore becoming increasingly popular. Wireless headphones can be categorized as True Wireless Stereo (TWS) headphones. In traditional designs, the charging management unit in the charging case of wireless headphones is typically a linear charging circuit, which suffers from slow charging speeds and significant heat generation. One improvement is to replace it with a switching charging circuit, but this requires an additional inductor, significantly increasing costs and occupying considerable space. Furthermore, when the charging case battery is depleted, it must first charge the case battery before charging the wireless headphones, resulting in longer charging times and a more complex circuit structure. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned technical problems and provide a charging case and its circuit, as well as a wireless earphone assembly, which has fast charging speed, low heat generation, no need to add inductors, and can shorten the earphone charging time when the charging case battery is dead or low on power, while simplifying the circuit structure.

[0004] To achieve the above objectives, the present invention provides a charging case circuit, which includes a charging case battery and a charging power supply unit. The charging power supply unit includes a controller, an inductor, multiple switching devices, a voltage input terminal, a battery terminal, and at least one voltage output terminal. One end of the charging case battery is coupled to a first ground terminal, and the other end is coupled to the battery terminal of the charging power supply unit. The controller is used to control the on and off states of the multiple switching devices, enabling the charging power supply unit to operate in a first mode or a second mode, thereby achieving time-division multiplexing of the inductor. Specifically, when the voltage input to the voltage input terminal is greater than or equal to a first reference voltage, the charging power supply unit operates in the first mode. The charging power supply unit can, based on... The voltage input at the voltage input terminal and the inductor generate a charging voltage, which is output to the charging case battery through the battery terminal to achieve on / off charging. Simultaneously, the charging power supply unit can output the voltage input at the voltage input terminal to the wireless earphones through the voltage output terminal. When the voltage input at the voltage input terminal is less than a first reference voltage and the voltage of the charging case battery is greater than the effective output voltage of the charging case battery, the charging power supply unit operates in the second mode. In this mode, the charging power supply unit can generate an output voltage based on the charging case battery and the inductor, and output it to the wireless earphones through the voltage output terminal. This output voltage provides a charging voltage to the wireless earphone battery, achieving on / off power supply.

[0005] Optionally, the first connection terminal of the inductor is coupled to the battery of the charging box. The charging box circuit further includes a third capacitor, one end of which is coupled to the first connection terminal of the inductor, and the other end is grounded. In the first mode, the controller is used to control the on and off of the plurality of switching devices, such that the second connection terminal of the inductor is alternately coupled to the voltage input terminal and the first ground terminal, and when the second connection terminal of the inductor is coupled to the voltage input terminal, the second connection terminal of the inductor is simultaneously coupled to at least one voltage output terminal. In the second mode, the controller is used to control the on and off of the plurality of switching devices, such that the second connection terminal of the inductor alternately couples with one of the at least one voltage output terminal and with the first ground terminal.

[0006] Optionally, the first connection terminal of the inductor is coupled to a first node N1, and the second connection terminal of the inductor is coupled to a second node N2. The plurality of switching devices include a third switch and a fourth switch. The third switch is coupled between the voltage input terminal and the second node N2, and the fourth switch is coupled between the second node N2 and the first ground terminal. The at least one voltage output terminal includes: a first voltage output terminal, and the plurality of switching devices further include a first switch coupled between the first voltage output terminal and the second node N2; and / or, a second voltage output terminal, and the plurality of switching devices further include a second switch coupled between the second voltage output terminal and the second node N2.

[0007] Optionally, in the first mode, the controller is configured to control the third switch and the fourth switch to be turned on alternately, wherein when the third switch is turned on, at least one of the first switch and the second switch is turned on; or, in the second mode, the controller is configured to control the third switch to be continuously turned off, and to allow the first sub-mode and the second sub-mode to alternate, wherein in the first sub-mode, the controller is configured to control the fourth switch and the first switch to be turned on alternately, and in the second sub-mode, the controller is configured to control the fourth switch and the second switch to be turned on alternately.

[0008] Optionally, the charging and power supply unit includes a first comparator, a first input terminal of which is coupled to the voltage input terminal, a second input terminal of which receives the first reference voltage, and an output terminal of which is connected to the controller. The controller determines whether the charging and power supply unit can operate in the first mode based on the result output by the first comparator. The charging and power supply unit also includes a second comparator, a first input terminal of which is coupled to the charging case battery, a second input terminal of which receives a second reference voltage, which is greater than or equal to the effective output voltage. The output terminal of the second comparator is connected to the controller, and the controller determines whether the charging and power supply unit can operate in the second mode based on the results output by the first and second comparators.

[0009] Optionally, when the charging case needs to communicate with the wireless earphones, the output voltage can represent data information.

[0010] Optionally, the data information is binary data represented by 1s and 0s, wherein: the output voltage includes a high-level voltage and a low-level voltage, the high-level voltage representing logic 1 and the low-level voltage representing logic 0; or, the output voltage lasting for a first duration represents logic 1 and the output voltage lasting for a second duration represents logic 0; or, the output voltage includes a high-level voltage and a low-level voltage, the period of alternation between the high-level voltage and the low-level voltage being greater than a set duration represents one of logic 1 and 0, and the period of alternation between the high-level voltage and the low-level voltage being less than the set duration represents the other of logic 1 and 0.

[0011] Optionally, in the first mode, the controller is further configured to sample the charging current and control the duty cycle of the multiple switching devices for on and off based on the sampled charging current to achieve constant current charging control of the charging case battery; in the first mode, the controller is further configured to sample the charging voltage and control the duty cycle of the multiple switching devices for on and off based on the sampled charging voltage to achieve constant voltage charging control of the charging case battery; in the second mode, the controller is further configured to sample the output voltage at at least one voltage output terminal and control the output voltage by controlling the duty cycle of the multiple switching devices for on and off based on the sampled output voltage; and / or, the at least one voltage output terminal includes a first voltage output terminal and a second voltage output terminal, wherein a first output capacitor is connected in series between the first voltage output terminal and ground; and a second output capacitor is connected in series between the second voltage output terminal and ground; in the second mode, the controller controls the charging power supply unit to generate an output voltage based on the voltage output by the charging case battery and the inductor, and outputs it alternately through the first voltage output terminal and the second voltage output terminal.

[0012] A second aspect of the present invention provides a charging case, the charging case including the charging case circuit of the first aspect described above.

[0013] A third aspect of the present invention provides a wireless earphone assembly, the wireless earphone assembly comprising: a wireless earphone having a voltage connection terminal and a second ground terminal, and including an earphone battery; and a charging case provided in the second aspect, wherein, during charging, a first ground terminal of the charging case is coupled to the second ground terminal, and a voltage output terminal of the charging case is coupled to the voltage connection terminal, such that the voltage connection terminal can receive the output voltage output by the voltage output terminal, and the output voltage can charge the earphone battery.

[0014] In the above solution, the charging management circuit in the charging case circuit is replaced by a switching charging circuit, and the switching charging circuit and voltage regulation circuit are integrated into a charging power supply unit. The switching charging management circuit and voltage regulation circuit share an inductor. This achieves the advantages of the switching charging circuit when charging the charging case battery, namely fast charging speed and low heat generation, without the need for additional inductors, thus saving space, reducing costs, and facilitating miniaturization. Furthermore, when the charging case battery is depleted or has insufficient power, the voltage input at the voltage input terminal can be used to charge the wireless earphones simultaneously with the charging case battery, shortening the charging time of the wireless earphones. It also simplifies the structure of the charging case circuit, resulting in a smaller chip area that supports the charging case circuit, which is beneficial for miniaturization.

[0015] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the charging circuit for a wireless earphone assembly;

[0018] Figure 2 This is a schematic diagram of the charging box circuit provided in an embodiment of this application;

[0019] Figure 3 for Figure 2 A schematic diagram of the circuit structure of the charging and power supply unit in the middle;

[0020] Figure 4 An exemplary waveform of the current in the inductor and a switching control signal waveform when the power supply unit is in a buck charging state;

[0021] Figure 5 An exemplary waveform of the current in the inductor and a switching control signal waveform when the charging power supply unit is in boost power supply mode;

[0022] Figure 6 This is a schematic diagram of the charging circuit of the wireless earphone assembly provided in an embodiment of this application. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Figure 1 This is a schematic diagram of a charging circuit for a wireless earphone assembly. The wireless earphone assembly may include a charging case and wireless earphones. Figure 1 As shown, the charging circuit consists of two parts, namely the first part of the circuit located in the charging case (e.g., Figure 1 (as shown in the dashed box on the left) and the second part of the circuitry located in the wireless earphone (as shown in the dashed box on the left) Figure 1(As shown in the dashed box on the right). The first part of the circuit may include the charging case battery BAT2, a linear charging circuit, and a boost circuit. The second part of the circuit may include the earphone battery BAT1 and a charging management circuit, and may also include a voltage regulation circuit (DCDC), an application processor (AP), and an radio frequency circuit (RF1).

[0025] The linear charging circuit in the charging case charges the charging case battery BAT2. The boost circuit increases the voltage output from the charging case battery BAT2 to 5V before supplying it to the wireless earbuds; that is, the voltage of VCHG is 5V. The charging management circuit in the wireless earbuds charges the earbud battery VBAT1 using this 5V voltage. The voltage regulation circuit DC-DC adjusts the voltage of the earbud battery BAT1 to the voltage required by the application processor AP and the RF circuit RF1, and then outputs it to both. The RF circuit RF1 can communicate with terminal devices such as mobile phones.

[0026] In the above solution, the linear charging circuit in the charging case suffers from slow charging speed and significant heat generation during charging. One improvement is to replace it with a switching charging circuit, but the switching charging circuit requires an additional inductor, which increases cost significantly and occupies a large space. Furthermore, when the charging case battery is depleted, it needs to be charged first before the wireless earbuds can be charged, resulting in longer charging times and a more complex circuit structure.

[0027] In view of this, embodiments of this application provide a charging case and its circuit, and a wireless earphone assembly, which have fast charging speed, low heat generation, no need to add inductors, and can shorten the earphone charging time when the charging case battery is depleted or low on power, while simplifying the circuit structure.

[0028] Figure 2 This is a schematic diagram of the charging box circuit provided in an embodiment of this application. Figure 2 As shown, the charging case circuit includes a charging case battery BAT2 and a charging power supply unit 21. The charging power supply unit 21 may include a voltage input terminal VIN, a battery terminal, and at least one voltage output terminal such as VO1 and / or VO2. One end of the charging case battery BAT2 is coupled to a first ground terminal, and the other end is coupled to the battery terminal of the charging power supply unit 21.

[0029] and Figure 1 compared to, Figure 2 The charging and power supply unit 21 was used instead of Figure 1The invention relates to a linear charging circuit and a boost circuit. In other words, the principle of this invention is to replace the linear charging circuit in the charging box circuit with a switching charging circuit, and to integrate the switching charging circuit and the boost circuit (i.e., voltage regulation circuit) into a charging and power supply unit 21. This allows the switching charging management circuit and the voltage regulation circuit to share an inductor. This achieves the advantages of the switching charging circuit when charging the charging box battery BAT2, namely, fast charging speed and low heat generation, without requiring an additional inductor L1, thus saving space, reducing costs, and facilitating miniaturization.

[0030] Figure 3 for Figure 2 A schematic diagram of the circuit structure of the charging and power supply unit. (See diagram below.) Figure 3 As shown, the charging and power supply unit 21 may also include a controller Ctrl, an inductor L1, and multiple switching devices such as S1-S4. The controller Ctrl is used to control the on and off of the multiple switching devices, so that the charging and power supply unit 21 operates in the first mode or the second mode, realizing time-division multiplexing of the inductor L1.

[0031] When the voltage input at the voltage input terminal VIN is greater than or equal to the first reference voltage, the charging power supply unit 21 operates in the first mode. The charging power supply unit 21 can generate a charging voltage based on the voltage input at the voltage input terminal VIN and the inductor L1, and output this voltage to the charging case battery BAT2 through the battery terminal, achieving on / off charging. Simultaneously, the charging power supply unit 21 can output the voltage input at the voltage input terminal VIN to the wireless earphones through voltage output terminals such as VO1 and VO2. Thus, when the charging case battery BAT2 is depleted or has insufficient power, the voltage input at the voltage input terminal VIN can be used to charge the charging case battery BAT2 while simultaneously charging the wireless earphones, shortening the charging time of the wireless earphones. Furthermore, it simplifies the structure of the charging case circuit, resulting in a smaller chip area that facilitates miniaturization.

[0032] When the voltage input at the voltage input terminal VIN is less than the first reference voltage and the voltage of the charging case battery BAT2 is greater than the effective output voltage, the charging power supply unit 21 operates in the second mode. The charging power supply unit 21 can generate an output voltage based on the charging case battery BAT2 and the inductor L1, and output it to the wireless earphones through a voltage output terminal such as VO1 or VO2. The output voltage can provide a charging voltage for the wireless earphone battery, realizing switching power supply.

[0033] Furthermore, when the charging case needs to communicate with the wireless earbuds, the output voltage can represent data information. Because the output voltage can represent data information, the charging case can communicate with the wireless earbuds. Specifically, the communication function can occur simultaneously with power supply, or independently. That is, the output voltage from the charging case circuit can be used solely to power the wireless earbuds, achieving only power supply; or, the output voltage from the charging case circuit can be used solely to represent data information, enabling communication between the charging case and the wireless earbuds, in which case it can be used for communication without charging the earbuds; or, the output voltage from the charging case circuit can be used not only to power the wireless earbuds but also to represent data information, enabling communication between the charging case and the wireless earbuds, i.e., communication is achieved simultaneously with power supply.

[0034] The data information may include the battery level of the charging case (BAT2) and the open / closed status of the charging case lid. The data may be binary data represented by 1s and 0s. The output voltage may include a high-level voltage and a low-level voltage, where a high-level voltage represents logic 1 and a low-level voltage represents logic 0. Alternatively, a continuous output voltage for a first duration may represent logic 1, and a continuous output voltage for a second duration may represent logic 0. Alternatively, the output voltage may include a high-level voltage and a low-level voltage, where the alternation period between the high-level and low-level voltages is greater than the set duration, representing either logic 1 or 0, and the alternation period between the high-level and low-level voltages is less than the set duration, representing the other logic 1 or 0.

[0035] It should be noted that the charging case battery BAT2 usually needs to charge the earphone battery at a voltage higher than a certain voltage threshold. For example, the discharge voltage of a lithium battery is 0 to 4.2V, but the voltage required to charge the earphone battery is usually above 3V. Therefore, the voltage required to charge the earphone battery is defined as the effective output voltage of the charging case battery BAT2.

[0036] like Figure 3As shown, to achieve the first mode of operation, the charging and power supply unit 21 may include a first comparator Com1. The first input terminal of the first comparator Com1 is coupled to the voltage input terminal VIN, the second input terminal of the first comparator Com1 receives the first reference voltage VR1, and the output terminal of the first comparator Com1 is connected to the controller Ctrl. The controller Ctrl determines whether the charging and power supply unit 21 can operate in the first mode based on the output result of the first comparator Com1. Further, in the first mode, the controller Ctrl can also be used to sample the charging current and control the duty cycle of multiple switching devices based on the sampled charging current to achieve constant current charging control for the charging box battery BAT2. In the first mode, the controller Ctrl can also be used to sample the charging voltage and control the duty cycle of multiple switching devices based on the sampled charging voltage to achieve constant voltage charging control for the charging box battery BAT2. In one example, the controller Ctrl can sample the voltage across the third switch S3 and, combined with the resistance of the third switch S3, obtain the charging current. The voltage on one side of the third switch S3 is the voltage at the voltage input terminal VIN. The charging voltage is the voltage VBAT2 at the battery terminal.

[0037] To enable the selection of the second mode of operation, the charging and power supply unit 21 may further include a second comparator Com2. The first input terminal of the second comparator Com2 is coupled to the charging box battery BAT2, and the second input terminal of the second comparator Com2 receives a second reference voltage VR2. The second reference voltage VR2 is greater than or equal to the effective output voltage of the charging box battery BAT2. The output terminal of the second comparator Com2 is connected to the controller Ctrl. The controller Ctrl determines whether the charging and power supply unit 21 can operate in the second mode based on the output results of the first comparator Com1 and the second comparator Com2. Furthermore, in the second mode, when power is supplied, the controller Ctrl can also be used to sample the output voltage at at least one voltage output terminal, such as VO1 and / or VO2, and control the output voltage by controlling the duty cycle of the conduction and disconnection of multiple switching devices based on the sampled output voltage.

[0038] In one example, the first reference voltage can be 4.5V. When VIN ≥ 4.5V, the charging power supply unit 21 can both charge the charging box battery BAT2 with VIN as input and generate a bypass voltage output to the voltage output terminals VO1 and VO2, operating in the first mode. When VIN < 4.5V, if the voltage of the charging box battery BAT2 is greater than its effective output voltage, i.e., the second reference voltage VR2, such as 3.2V, then the charging power supply unit 21 can generate an output voltage by boosting VBAT2 as input.

[0039] Continue to refer to Figure 3The first connection terminal of inductor L1 is coupled to the charging box battery BAT2. The charging box circuit also includes a third capacitor CB, one end of which is coupled to the first connection terminal of inductor L1, and the other end is grounded. In the first mode, the controller Ctrl is used to control the on and off of multiple switching devices, so that the second connection terminal of inductor L1 is alternately coupled to the voltage input terminal VIN and the first ground terminal, and when the second connection terminal of inductor L1 is coupled to the voltage input terminal VIN, the second connection terminal of inductor L1 is simultaneously coupled to at least one voltage output terminal.

[0040] In the second mode, the controller Ctrl controls the on and off states of multiple switching devices, causing the second connection terminal of inductor L1 to alternately couple with at least one voltage output terminal and with the first ground terminal. In one example, the at least one voltage output terminal includes a first voltage output terminal VO1 and a second voltage output terminal VO2. In the second mode, the controller Ctrl controls the charging power supply unit 21 to generate an output voltage based on the voltage output from the charging box battery BAT2 and the inductor L1, and alternately outputs VO2 through the first voltage output terminal VO1 and the second voltage output terminal. That is, in the first half-cycle, the second connection terminal of inductor L1 alternately couples with the first voltage output terminal VO1 and with the first ground terminal; in the second half-cycle, the second connection terminal of inductor L1 alternatesly couples with the second voltage output terminal VO2 and with the first ground terminal, and the first half-cycle and the second half-cycle form a complete cycle.

[0041] exist Figure 3In this configuration, the first connection terminal of inductor L1 is coupled to the first node N1, and the second connection terminal of inductor L1 is coupled to the second node N2. Multiple switching devices include a third switch S3 and a fourth switch S4. The third switch S3 is coupled between the voltage input terminal VIN and the second node N2, and the fourth switch S4 is coupled between the second node N2 and the first ground terminal. In one example, at least one voltage output terminal may include a first voltage output terminal VO1, with a first output capacitor C1 connected in series between the first voltage output terminal VO1 and ground. The multiple switching devices also include a first switch S1 coupled between the first voltage output terminal VO1 and the second node N2. In another example, at least one voltage output terminal may include a second voltage output terminal VO2, with a second output capacitor C2 connected in series between the second voltage output terminal VO2 and ground. The multiple switching devices also include a second switch S2 coupled between the second voltage output terminal VO2 and the second node N2. In another example, at least one voltage output terminal may include a first voltage output terminal VO1 and a second voltage output terminal VO2, with a first output capacitor C1 connected in series between the first voltage output terminal VO1 and ground, and a second output capacitor C2 connected in series between the second voltage output terminal VO2 and ground. The plurality of switching devices also include a first switch S1 coupled between the first voltage output terminal VO1 and the second node N2 and a second switch S2 coupled between the second voltage output terminal VO2 and the second node N2.

[0042] In the first mode, the controller Ctrl is configured to control the third switch S3 and the fourth switch S4 to be turned on alternately, and when the third switch S3 is turned on, at least one of the first switch S1 and the second switch S2 is turned on.

[0043] In the second mode, the controller Ctrl is configured to keep the third switch S3 continuously off, and to alternate between the first and second sub-modes. In the first sub-mode, the controller Ctrl is configured to alternately turn on the fourth switch S4 and the first switch S1; in the second sub-mode, the controller Ctrl is configured to alternately turn on the fourth switch S4 and the second switch S2. That is, in the first half-cycle, the fourth switch S4 and the first switch S1 alternately turn on; in the second half-cycle, the fourth switch S4 and the second switch S2 alternately turn on, and the first and second half-cycles form a complete cycle. At this time, the charging and power supply unit 21 can generate an output voltage through a boost method. It can be understood that the charging and power supply unit 21 can also directly output the voltage output from the charging box battery BAT2 to the voltage output terminal. In this case, the fourth switch S4 is not turned on, and the first switch S1 and the second switch S2 can alternately turn on.

[0044] The following section uses the charging and power supply unit 21, which includes a first voltage output terminal VO1 and a second voltage output terminal VO2, as an example to introduce the waveform of the current in inductor L1 and the waveform of the switch control signal. Here, the inductor current flowing from the second node N2 to the first node N1 is defined as a positive value.

[0045] like Figure 3 As shown, the charging and power supply unit 21 may include comparators Com1 and Com2, switches S1 to S4, capacitors C1, C2, and CB, a controller Ctrl, and an inductor L1. When VIN is less than the reference voltage VR1 (e.g., 4.5V) and the voltage of the charging box battery BAT2 is less than the reference voltage VR2 (e.g., 3.2V), the controller Ctrl controls switches S1 to S4 to be in an open-circuit state, and the charging and power supply unit 21 stops working.

[0046] When VIN is greater than VR1 (e.g., 4.5V), it indicates that VIN is energized. At this time, the controller Ctrl controls switches S3 and S4 to conduct alternately, charging the charging case battery BAT2 in a step-down manner. Simultaneously, during the period when switch S3 is on, switches S1 and S2 are also on, thus simultaneously supplying power to the first voltage output terminal VO1 and the second voltage output terminal VO2. At this time, the voltage of the first voltage output terminal VO1 and the second voltage output terminal VO2 is close to equal to the VIN voltage, generally slightly lower than the VIN voltage, with the reduced voltage being the voltage drop across switches S3, S1, or S2. When switch S3 is open, switches S1 and S2 are also open. At this time, capacitors C1 and C2 supply power to the wireless earphones, meaning that capacitors C1 and C2 can act as voltage regulators.

[0047] When the charging power supply unit 21 charges the battery BAT2 in a step-down manner, a voltage negative feedback loop is formed with VBAT2 as the input, which can realize constant voltage charging; the controller Ctrl collects the voltage at N2, and combined with the voltage at the voltage input terminal VIN and the resistance of the third switch S3, the current information can be obtained, thereby forming a current negative feedback loop, which can realize constant current charging.

[0048] Figure 4 An exemplary waveform of the current in the inductor and a switching control signal waveform when the charging unit is in a buck charging state. Figure 4As shown, IL represents the inductor current waveform. The dashed line indicates zero current, and a positive inductor current indicates that the inductor current flows from N2 to N1. GS3, GS4, GS1, and GS2 are the control signals for switches S3, S4, S1, and S2, respectively. During time T1, GS3 is high, controlling switch S3 to conduct, causing the inductor current to rise and store energy in inductor L1. At this time, switches S1 and S2 are also turned on. During time T2, GS3 is low and GS4 is high, controlling switch S4 to conduct, causing the inductor current to decrease, and inductor L1 to release energy. At this time, switches S1 and S2 are also turned off.

[0049] When VIN is less than VR1 (e.g., 4.5V), it indicates that VIN is de-energized. Comparator Com2 compares VBAT2 with the reference voltage VR2 (e.g., 3.2V). If the output of comparator Com2 is high (i.e., VBAT2 is greater than 3.2V), it indicates that the battery VBAT2 has power and can support external power supply. During periods T1 and T2, controller Ctrl can control switches S4 and S1 to alternately conduct, generating an output voltage in boost mode, which powers the headphones through the first voltage output terminal VO1. During periods T3 and T4, controller Ctrl can control switches S4 and S2 to alternately conduct, generating an output voltage in boost mode, which powers the headphones through the second voltage output terminal VO2.

[0050] Figure 5 An exemplary waveform of the current in the inductor and a switching control signal waveform when the charging power supply unit is in boost power supply mode. Figure 5 As shown, IL represents the inductor current waveform. The dashed line indicates zero current, and a negative inductor current indicates that the inductor current flows from N1 to N2. GS3 is the control signal for switch S3, GS4 is the control signal for switch S4, GS1 is the control signal for switch S1, and GS2 is the control signal for switch S2. During the T1 to T4 period, GS3 is always at a low level, and switch S3 remains in an open circuit state. During time period T1, GS4 is high, controlling switch S4 to conduct, causing the inductor current to decrease, but the absolute value of the inductor current to increase, storing energy in inductor L1; during time period T2, GS1 is high, controlling switch S1 to conduct, causing the inductor current to increase, but the absolute value of the inductor current to decrease, and inductor L1 to release energy, outputting charge to the first voltage output terminal VO1; during time period T3, switch GS4 is high, controlling switch S4 to conduct, causing the inductor current to decrease, but the absolute value of the inductor current to increase, storing energy in inductor L1; during time period T4, GS2 is high, controlling switch S2 to conduct, causing the inductor current to increase, but the absolute value of the inductor current to decrease, and inductor L1 to release energy, outputting charge to the second voltage output terminal VO2.

[0051] In addition, the present invention also provides a charging case, which includes the charging case circuit described above.

[0052] Figure 6 This is a schematic diagram of the charging circuit for a wireless earphone assembly provided in an embodiment of this application. The wireless earphone assembly includes at least one wireless earphone and the aforementioned charging case. Figure 6 As shown, the wireless earphone assembly may include two wireless earphones, namely a first wireless earphone and a second wireless earphone. The first wireless earphone has a voltage connection terminal VCHG1 and a second ground terminal, and includes an earphone battery such as BATR. The second wireless earphone has a voltage connection terminal VCHG2 and a second ground terminal, and includes an earphone battery BATR. During charging, the first ground terminal of the charging case is coupled to the second ground terminal, and the voltage output terminal of the charging case is coupled to the voltage connection terminal, such as VO1 coupled to VCHG1 and VO2 coupled to VCHG2, so that the voltage connection terminal can receive the output voltage output from the voltage output terminal, wherein the output voltage can charge the earphone battery.

[0053] Furthermore, the wireless earphone may also include a communication unit. When the output voltage output by the charging case through voltage output terminals such as VO1 and / or VO2 can characterize data information, the communication unit of the wireless earphone (not shown in the figure) can obtain data information based on the output voltage.

[0054] In addition, wireless headphones can be configured with other functional units as needed. Figure 6 The first wireless earphone also includes a charging management unit (ChargerL), a voltage regulation unit (DCDCL), an application processor (APL), and a radio frequency unit (RFL). The second wireless earphone also includes a charging management unit (ChargerR), a voltage regulation unit (DCDCR), an application processor (APR), and a radio frequency unit (RFR).

[0055] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0056] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A charging box circuit, characterized in that, It includes a charging case battery and a charging power supply unit. The charging power supply unit includes a controller, an inductor, multiple switching devices, a voltage input terminal, a battery terminal, and at least one voltage output terminal. One end of the charging case battery is coupled to a first ground terminal, and the other end is coupled to the battery terminal of the charging power supply unit. The controller is used to control the on and off of the plurality of switching devices, so that the charging and power supply unit operates in a first mode or a second mode, realizing time-division multiplexing of the inductor, wherein: When the voltage input at the voltage input terminal is greater than or equal to the first reference voltage, the charging power supply unit operates in the first mode. The charging power supply unit can generate a charging voltage based on the voltage input at the voltage input terminal and the inductor, and output it to the charging case battery through the battery terminal to realize on / off charging. At the same time, the charging power supply unit can output the voltage input at the voltage input terminal to the wireless earphone through the voltage output terminal. When the voltage input at the voltage input terminal is less than the first reference voltage and the voltage of the charging case battery is greater than the effective output voltage of the charging case battery, the charging power supply unit operates in the second mode. The charging power supply unit can generate an output voltage based on the charging case battery and the inductor, and output it to the wireless earphone through the voltage output terminal. The output voltage can provide a charging voltage to the wireless earphone battery to realize switching power supply. The first connection terminal of the inductor is coupled to the battery of the charging box; the first connection terminal of the inductor is coupled to a first node N1, and the second connection terminal of the inductor is coupled to a second node N2; the plurality of switching devices include a third switch and a fourth switch, the third switch being coupled between the voltage input terminal and the second node N2, and the fourth switch being coupled between the second node N2 and the first ground terminal; the at least one voltage output terminal includes: The first voltage output terminal, the plurality of switching devices further includes a first switch coupled between the first voltage output terminal and the second node N2; and / or, The second voltage output terminal, the plurality of switching devices further includes a second switch coupled between the second voltage output terminal and the second node N2; the charging power supply unit includes a first comparator, the first input terminal of the first comparator is coupled to the voltage input terminal, the second input terminal of the first comparator receives the first reference voltage, and the output terminal of the first comparator is connected to the controller; the charging power supply unit includes a second comparator, the first input terminal of the second comparator is coupled to the charging box battery, the second input terminal of the second comparator receives a second reference voltage, the second reference voltage is greater than or equal to the effective output voltage, and the output terminal of the second comparator is connected to the controller.

2. The charging box circuit according to claim 1, characterized in that, The charging box circuit also includes a third capacitor, one end of which is coupled to the first connection terminal of the inductor, and the other end is grounded. In the first mode, the controller is used to control the on and off of the plurality of switching devices, such that the second connection terminal of the inductor is alternately coupled to the voltage input terminal and the first ground terminal, and when the second connection terminal of the inductor is coupled to the voltage input terminal, the second connection terminal of the inductor is simultaneously coupled to the at least one voltage output terminal. In the second mode, the controller controls the on and off of the plurality of switching devices, such that the second connection terminal of the inductor alternately couples with one of the at least one voltage output terminal and with the first ground terminal.

3. The charging box circuit as described in claim 1, characterized in that: In the first mode, the controller is configured to control the third switch and the fourth switch to be turned on alternately, and when the third switch is turned on, at least one of the first switch and the second switch is turned on; or, In the second mode, the controller is configured to keep the third switch continuously off and to alternate between the first sub-mode and the second sub-mode. In the first sub-mode, the controller is configured to alternately turn the fourth switch on and the first switch on. In the second sub-mode, the controller is configured to alternately turn the fourth switch on and the second switch on.

4. The charging box circuit as described in claim 1, characterized in that: The controller determines whether the charging and power supply unit can work in the first mode based on the result output from the output terminal of the first comparator. The controller determines whether the charging and power supply unit can operate in the second mode based on the results output from the first comparator and the second comparator.

5. The charging box circuit as described in any one of claims 1-4, characterized in that, When the charging case needs to communicate with the wireless earphones, the output voltage can represent data information.

6. The charging box circuit as described in claim 5, characterized in that, The data information is binary data represented by 1s and 0s, wherein: The output voltage includes a high-level voltage and a low-level voltage, where the high-level voltage represents logic 1 and the low-level voltage represents logic 0; or... The output voltage lasting for a first duration represents logic 1, and the output voltage lasting for a second duration represents logic 0; or... The output voltage includes a high-level voltage and a low-level voltage. The period of alternation between the high-level voltage and the low-level voltage is greater than a set duration, representing one of logic 1 and 0. The period of alternation between the high-level voltage and the low-level voltage is less than the set duration, representing the other of logic 1 and 0.

7. The charging box circuit as described in any one of claims 1-4, characterized in that: In the first mode, the controller is also used to sample the charging current and control the duty cycle of the multiple switching devices to achieve constant current charging control of the charging box battery according to the sampled charging current; in the first mode, the controller is also used to sample the charging voltage and control the duty cycle of the multiple switching devices to achieve constant voltage charging control of the charging box battery according to the sampled charging voltage. In the second mode, the controller is also used to sample the output voltage at the at least one voltage output terminal, and control the output voltage by controlling the duty cycle of the multiple switching devices based on the sampled output voltage; And / or, The at least one voltage output terminal includes a first voltage output terminal and a second voltage output terminal, wherein a first output capacitor is connected in series between the first voltage output terminal and ground; and a second output capacitor is connected in series between the second voltage output terminal and ground. In the second mode, the controller controls the charging power supply unit to generate an output voltage based on the voltage output by the charging box battery and the inductor, and outputs the voltage alternately through the first voltage output terminal and the second voltage output terminal.

8. A charging case, characterized in that, Includes the charging box circuit according to any one of claims 1-7.

9. A wireless earphone assembly, characterized in that, include: A wireless earphone, having a voltage connection terminal and a second ground terminal, and including an earphone battery; According to claim 8, during charging, the first grounding terminal of the charging box is coupled to the second grounding terminal, and the voltage output terminal of the charging box is coupled to the voltage connection terminal, so that the voltage connection terminal can receive the output voltage output by the voltage output terminal, and the output voltage can charge the earphone battery.

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