Charging circuit with current detection and state indication functions and charging storage box

Abstract

The utility model relates to a charging circuit with current detection and state indication functions and a charging storage box. The charging circuit comprises a charging input port, an input protection circuit, an output protection circuit, a current sampling circuit, an MCU control circuit, a state display circuit and a charging output port. The input protection circuit is used for monitoring an input voltage and is disconnected when the input voltage is greater than a preset voltage; the current sampling circuit is used for collecting a charging current and sending the charging current to the MCU control circuit; and the MCU control circuit is used for controlling the on-off of the output protection circuit and the display condition of the state display circuit according to the magnitude of the charging current. Through the charging input port, the input protection circuit, the output protection circuit, the current sampling circuit, the MCU control circuit, the state display circuit and the charging output port, current detection and state display of the charging circuit of the storage box are realized, and the scheme of the utility model does not need to additionally add metal contacts, so that the cost is saved, and the working efficiency is improved. And the complexity of the interface is also reduced.

Description

Technical Field

[0001] This application relates to the field of charging detection, and in particular to charging circuits and charging storage boxes with current detection and status indication. Background Technology

[0002] Currently available small wearable devices, such as in-ear Bluetooth earphones, wearable Bluetooth ECG patches, and wearable Bluetooth temperature patches, are small in size and powered by small rechargeable batteries. They come with a storage case for storage and charging. To achieve a certain level of waterproofing and dustproofing, the charging interface is small, typically using only two metal contacts for charging voltage input. This means the device and its charging case only connect through these two contacts to complete the charging process. Therefore, the device itself usually doesn't have an LED indicator to show the charging status; or the LED status is invisible to the user because the device is stored in the case. Clearly, existing small wearable devices and their charging cases suffer from a lack of synchronization in charging status indication. That is, how can the user intuitively determine whether the device is charging or has finished charging while it is stored in the case?

[0003] To address these issues, a common solution is to increase the number of communication pins between the device and the charging case, i.e., increase the number of metal contacts. Therefore, existing charging cases, in addition to the two positive and negative metal contacts, include one or two extra contacts and wiring to synchronize the device's charging status information to the case, allowing the case to indicate the charging status via LED indicators. However, this solution not only increases interface complexity, but the extra one or two metal contacts can also easily cause poor physical contact. Furthermore, it requires additional ESD protection circuitry to protect these extra interface contacts, thus increasing material costs. Summary of the Invention

[0004] This application provides a charging circuit and a charging storage box with current detection and status indication, so as to at least solve the problems of high interface complexity and high cost of existing charging storage boxes in related technologies.

[0005] In a first aspect, embodiments of this application provide a charging circuit with current detection and status indication, characterized in that it includes a charging input port, an input protection circuit, an output protection circuit, a current sampling circuit, an MCU control circuit, a status display circuit, and a charging output port;

[0006] The input terminal of the input protection circuit is connected to the charging input port, and the output terminal is connected to the input terminal of the output protection circuit. The output terminal of the output protection circuit is connected to the charging output port. The power supply terminal of the current sampling circuit is connected between the charging input port and the charging output port, and the output terminal is connected to the input terminal of the MCU control circuit. The output terminal of the MCU control circuit is connected to the status display circuit and the output protection circuit respectively.

[0007] The input protection circuit monitors the input voltage and disconnects when the input voltage exceeds a preset voltage. The current sampling circuit collects the charging current of the charging circuit and sends it to the MCU control circuit. The MCU control circuit controls the output current of the output protection circuit and the display status of the status display circuit according to the magnitude of the charging current.

[0008] In one embodiment, the input protection circuit includes a voltage detection unit and an electronic switching unit; wherein,

[0009] The voltage detection unit is connected between the charging input port and the electronic switch unit, and is used to detect the charging voltage of the charging circuit. When the charging voltage is greater than the preset voltage, a switch drive signal is output to the electronic switch unit.

[0010] The electronic switch unit is used to disconnect the connection between the input protection circuit and the output protection circuit after receiving the drive signal.

[0011] In one embodiment, the output protection circuit includes a power switch chip and a current-limiting resistor, wherein,

[0012] The input terminal of the power switch chip is connected to the output terminal of the MCU control circuit to limit the current output by the charging circuit and provide short-circuit protection.

[0013] The current-limiting resistor is connected to the current-limiting terminal of the power switch chip and is used to adjust the limit value of the output current of the charging circuit.

[0014] In one embodiment, the current sampling circuit includes a current amplification chip for amplifying the charging current and outputting it to the MCU control circuit.

[0015] In one embodiment, the MCU control circuit includes a main control chip and a power conversion chip, wherein,

[0016] The input terminal of the power conversion chip is connected to a power source, and the output terminal is connected to the power input terminal of the main control chip. It is used to obtain the power supply voltage and convert it into a voltage suitable for the main control chip to supply power to the main control chip.

[0017] The input terminal of the main control chip is connected to the current sampling circuit to obtain the charging current and control the output protection circuit and the status display circuit according to the charging current.

[0018] In one embodiment, the status display circuit includes a plurality of light-emitting diodes connected in parallel, wherein the trigger voltage and illumination color of the different light-emitting diodes are different.

[0019] In one embodiment, the voltage detection circuit includes a Zener diode and a Zener resistor, wherein,

[0020] The cathode of the Zener diode is connected to the charging input port, the anode of the Zener diode is connected to the first terminal of the Zener resistor, and the second terminal of the Zener resistor is grounded.

[0021] The connection point of the Zener diode and the Zener resistor is connected to the input terminal of the electronic switching unit.

[0022] In one embodiment, the electronic switching unit includes a first MOSFET, a second MOSFET, a transistor, a first resistor, and a second resistor, wherein,

[0023] The gate of the first MOSFET is connected to the voltage detection unit, the source is grounded, and the drain is connected to the base of the transistor; the emitter of the transistor is grounded, and the collector is connected to the gate of the second MOSFET; the source of the second MOSFET is connected to the charging input port, and the drain is connected to the output protection circuit; the connection point between the first MOSFET and the transistor is connected to the charging input port through the first resistor; the connection point between the transistor and the second MOSFET is connected to the charging input port through the second resistor.

[0024] In one embodiment, the input protection circuit further includes a reserved light-emitting diode and a third resistor, the first end of the third resistor being connected to the MCU control circuit and the second end being connected to the cathode of the reserved light-emitting diode; the anode of the light-emitting diode is connected to the charging input port.

[0025] Secondly, embodiments of this application provide a charging storage box, characterized in that it includes a charging circuit with current detection and status indication as described in any of the preceding embodiments.

[0026] The charging circuit and charging storage box with current detection and status indication provided in this application embodiment have at least the following technical effects:

[0027] By using a charging input port, an input protection circuit, an output protection circuit, a current sampling circuit, an MCU control circuit, a status display circuit, and a charging output port, the current detection and status display of the charging circuit of the storage box are realized. Furthermore, the solution of this application does not require additional metal contacts, thereby saving costs and reducing the complexity of the interface.

[0028] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0029] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0030] Figure 1 This is a structural block diagram of a charging circuit with current detection and status indication in one embodiment of this application;

[0031] Figure 2 This is a circuit diagram of an input protection circuit in one embodiment of this application;

[0032] Figure 3 This is a circuit diagram of the output protection circuit in one embodiment of this application;

[0033] Figure 4 This is a circuit diagram of a current sampling circuit in one embodiment of this application;

[0034] Figure 5 This is a circuit schematic diagram of the MCU control circuit in one embodiment of this application;

[0035] Figure 6 This is a circuit schematic diagram of a status display circuit in one embodiment of this application;

[0036] Figure 7 This is a structural diagram of a charging storage box according to one embodiment of this application. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0038] Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0039] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0040] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The terms "first," "second," and "third" used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0041] Based on the above, this Shenzhen-based company provides a device storage box circuit solution specifically designed for small wearable devices, featuring input overvoltage protection, current detection, LED power indication, output overcurrent limiting, and short-circuit protection. It primarily senses the device's charging status by detecting the charging current output from the storage box and indicates the charging status via LEDs. This solution addresses the pain point of devices being difficult for users to observe when charging and storing them in a storage box.

[0042] In a first aspect, embodiments of this application provide a charging circuit with current detection and status indication, including a charging input port, an input protection circuit, an output protection circuit, a current sampling circuit, an MCU control circuit, a status display circuit, and a charging output port.

[0043] For details, please refer to the following: Figure 1 The input protection circuit (i.e., input overvoltage protection circuit) has its input terminal connected to the charging input port and its output terminal connected to the input terminal of the output protection circuit. The output terminal of the output protection circuit (i.e., output current limiting and short-circuit protection circuit) is connected to the charging output port. The power supply terminal of the current sampling circuit is connected between the charging input port and the charging output port, and its output terminal is connected to the input terminal of the MCU control circuit. The output terminal of the MCU control circuit is connected to the status display circuit and the output protection circuit, respectively. In this embodiment, the charging input port is a USB 5V input port, which includes a ground terminal GND and a power supply terminal Vbus. The MCU control current is connected to an LED indicator via an I / O bus. The input protection circuit monitors the input voltage and disconnects when the input voltage exceeds a preset voltage. The current sampling circuit collects the charging current of the charging circuit and sends it to the MCU control circuit. The MCU control circuit controls the output current of the output protection circuit and the display status of the status display circuit based on the magnitude of the charging current. Figure 1 The bolded part in the middle circuit is the main circuit of the charging circuit.

[0044] Specifically, the input overvoltage protection circuit is mainly used to prevent excessively high input voltage from damaging subsequent circuits. The charging output current limiting and short-circuit protection circuit is responsible for overcurrent limiting and short-circuit protection of the current output from the charging case, and can switch the output on and off under the enable control of the MCU main control unit. The charging output current sampling circuit (i.e., the current sampling circuit) mainly monitors the output charging current and outputs the result to the MCU main control unit. The MCU main control unit determines the charging status of the device based on the detected output current (Iout) and the power consumption of the wearable device's charging current. Based on the charging status, it controls the status display circuit to display the corresponding color or pattern. For example, in this embodiment, the status display circuit uses an LED module circuit. Therefore, after determining the charging status, the MCU control circuit controls the LED module circuit to light up the corresponding LED indicator. The display status of the LEDs, etc., is shown in Table 1.

[0045] Table 1: MCU Main Control Unit Charging Output Current Status Judgment Table

[0046]

[0047] In a preferred embodiment, the input protection circuit of this application includes a voltage detection unit and an electronic switching unit. See specifically... Figure 2 The voltage detection unit 10 is connected between the charging input port and the electronic switch unit, and is used to detect the charging voltage of the charging circuit. When the charging voltage is greater than the preset voltage, it outputs a switch drive signal to the electronic switch unit. The electronic switch unit 20 is used to disconnect the connection between the input protection circuit and the output protection circuit after receiving the drive signal.

[0048] Specifically, the voltage detection circuit includes a Zener diode D1 and a Zener resistor R12. The cathode of the Zener diode D1 is connected to the charging input port, the anode of the Zener diode D1 is connected to the first terminal of the Zener resistor R12, and the second terminal of the Zener resistor R12 is grounded. The connection point of the Zener diode D1 and the Zener resistor R12 is connected to the input terminal of the electronic switching unit 20.

[0049] The electronic switching unit 20 includes a first MOSFET Q3, a second MOSFET Q1, a transistor Q2, a first resistor R1, and a second resistor R2. The gate of the first MOSFET Q3 is connected to the voltage detection unit 10, the source is grounded, and the drain is connected to the base of the transistor Q2. The emitter of the transistor Q2 is grounded, and the collector is connected to the gate of the second MOSFET Q1. The source of the second MOSFET Q2 is connected to the charging input port, and the drain is connected to the output protection circuit. The connection point between the first MOSFET Q3 and the transistor Q1 is connected to the charging input port through the first resistor R1. The connection point between the transistor Q2 and the second MOSFET Q1 is connected to the charging input port through the second resistor R2.

[0050] In another preferred embodiment, the input protection circuit further includes a reserved light-emitting diode LD1 and a third resistor R13. The first end of the third resistor R13 is connected to the MCU control circuit, and the second end is connected to the cathode of the reserved light-emitting diode LD1. The anode of the light-emitting diode LD1 is connected to the charging input port. The reserved light-emitting diode is used for status indication of other circuit conditions. For example, when there are problems such as abnormal charging current, the MCU control circuit can control the reserved light-emitting diode to flash.

[0051] refer to Figure 3 The output protection circuit includes a power switch chip U1 and a current-limiting resistor R17. The input terminal of the power switch chip U1 is connected to the output terminal of the MCU control circuit, used to limit the current output of the charging circuit and provide short-circuit protection. The current-limiting resistor R17 is connected to the current-limiting terminal of the power switch chip, used to adjust the current limit value of the charging circuit output. Preferably, R17 can be set as an adjustable resistor, adjusted by the MCU control circuit, thereby controlling the current limit value.

[0052] refer to Figure 4 The current sampling circuit includes a current amplifier chip U2, which amplifies the charging current and outputs it to the MCU control circuit. In this embodiment, the current amplifier chip U2 employs a low-noise, high-precision CMOS differential amplifier, capable of supporting precise differential signal processing.

[0053] refer to Figure 5The MCU control circuit includes a main control chip U4 and a power conversion chip U3. The input terminal of the power conversion chip U3 is connected to a power supply, and its output terminal is connected to the power input terminal of the main control chip U4. It is used to acquire the supply voltage and convert it into a voltage suitable for the main control chip U4, thus supplying power to the main control chip U4. The input terminal of the main control chip U4 is connected to the current sampling circuit, used to acquire the charging current and control the output protection circuit and the status display circuit based on the charging current.

[0054] refer to Figure 6 The status display circuit includes multiple LEDs (LED1, LED2, LED3, LED4) connected in parallel. Each LED is connected to the MCU main control circuit through a resistor. The trigger voltage and illumination color of different LEDs are different. The control logic can be referred to Table 1. That is, by using different colors and models of different LEDs, this application can achieve different threshold voltages for emitting light, thereby realizing the display of different charging states.

[0055] In summary, the charging circuit with current detection and status indication provided in this application embodiment realizes current detection and status display of the charging circuit of the storage box through a charging input port, an input protection circuit, an output protection circuit, a current sampling circuit, an MCU control circuit, a status display circuit, and a charging output port. Furthermore, the solution of this application does not require additional metal contacts, thereby saving costs and reducing the complexity of the interface.

[0056] Secondly, embodiments of this application provide a charging storage box, which includes a charging circuit with current detection and status indication as described in any of the above embodiments. See details. Figure 7 Wearable devices (such as earphones) are placed in the storage case and connected to a USB socket via two metal contacts for charging. An LED indicator light on the exterior of the storage case tracks the charging status of the wearable device. In this embodiment, the small wearable device is placed in the storage case when not in use. To charge, simply plug a standard USB cable and power adapter into the USB socket. If no power is connected, the storage case indicator light will not illuminate. If power is connected, the device will enter charging mode, and the storage case indicator light will illuminate with a corresponding color. If the device in the storage case is fully charged, the storage case indicator light will illuminate with a different color. If the device is removed from the storage case, the storage case may illuminate with a different color light to indicate that it is powered on, or it may remain off, depending on the product requirements.

[0057] In addition, the charging case also features input overvoltage protection. If the input voltage exceeds the designed voltage, such as 5.6V, the protection circuit automatically cuts off power to protect its own circuitry and the small wearable device inside. The charging output of the charging case also has output overcurrent and short-circuit protection functions, further improving the safety of the device during charging.

[0058] In a preferred embodiment, a chip is added to the charging input terminal of the wearable device and a chip is added to the charging output terminal of the storage box. These two chips are used in pairs. Using two charging lines, without adding interface metal contacts, they are time-division multiplexed as communication lines. Information communication is achieved through modulation or switching signal lines. This also allows the charging status information of the device to be synchronized to the storage box.

[0059] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A charging circuit with current detection and status indication, characterized in that, It includes a charging input port, an input protection circuit, an output protection circuit, a current sampling circuit, an MCU control circuit, a status display circuit, and a charging output port; The input terminal of the input protection circuit is connected to the charging input port, and the output terminal is connected to the input terminal of the output protection circuit. The output terminal of the output protection circuit is connected to the charging output port. The power supply terminal of the current sampling circuit is connected between the charging input port and the charging output port, and the output terminal is connected to the input terminal of the MCU control circuit. The output terminal of the MCU control circuit is connected to the status display circuit and the output protection circuit respectively. The input protection circuit monitors the input voltage and disconnects when the input voltage exceeds a preset voltage. The current sampling circuit collects the charging current of the charging circuit and sends it to the MCU control circuit. The MCU control circuit controls the output current of the output protection circuit and the display status of the status display circuit according to the magnitude of the charging current.

2. The charging circuit according to claim 1, characterized in that, The input protection circuit includes a voltage detection unit and an electronic switch unit; wherein... The voltage detection unit is connected between the charging input port and the electronic switch unit, and is used to detect the charging voltage of the charging circuit. When the charging voltage is greater than the preset voltage, a switch drive signal is output to the electronic switch unit. The electronic switch unit is used to disconnect the connection between the input protection circuit and the output protection circuit after receiving the drive signal.

3. The charging circuit according to claim 1, characterized in that, The output protection circuit includes a power switch chip and a current-limiting resistor, wherein, The input terminal of the power switch chip is connected to the output terminal of the MCU control circuit to limit the current output by the charging circuit and provide short-circuit protection. The current-limiting resistor is connected to the current-limiting terminal of the power switch chip and is used to adjust the limit value of the output current of the charging circuit.

4. The charging circuit according to claim 1, characterized in that, The current sampling circuit includes a current amplification chip, which amplifies the charging current and outputs it to the MCU control circuit.

5. The charging circuit according to claim 1, characterized in that, The MCU control circuit includes a main control chip and a power conversion chip, wherein... The input terminal of the power conversion chip is connected to a power source, and the output terminal is connected to the power input terminal of the main control chip. It is used to obtain the power supply voltage and convert it into a voltage suitable for the main control chip to supply power to the main control chip. The input terminal of the main control chip is connected to the current sampling circuit to obtain the charging current and control the output protection circuit and the status display circuit according to the charging current.

6. The charging circuit according to claim 1, characterized in that, The status display circuit includes multiple light-emitting diodes connected in parallel, wherein the trigger voltage and illumination color of different light-emitting diodes are different.

7. The charging circuit according to claim 2, characterized in that, The voltage detection circuit includes a Zener diode and a Zener resistor, wherein, The cathode of the Zener diode is connected to the charging input port, the anode of the Zener diode is connected to the first terminal of the Zener resistor, and the second terminal of the Zener resistor is grounded. The connection point of the Zener diode and the Zener resistor is connected to the input terminal of the electronic switching unit.

8. The charging circuit according to claim 2, characterized in that, The electronic switching unit includes a first MOSFET, a second MOSFET, a transistor, a first resistor, and a second resistor, wherein... The gate of the first MOSFET is connected to the voltage detection unit, the source is grounded, and the drain is connected to the base of the transistor; the emitter of the transistor is grounded, and the collector is connected to the gate of the second MOSFET; the source of the second MOSFET is connected to the charging input port, and the drain is connected to the output protection circuit; the connection point between the first MOSFET and the transistor is connected to the charging input port through the first resistor; the connection point between the transistor and the second MOSFET is connected to the charging input port through the second resistor.

9. The charging circuit according to claim 2, characterized in that, The input protection circuit also includes a reserved light-emitting diode and a third resistor. The first end of the third resistor is connected to the MCU control circuit, and the second end is connected to the cathode of the reserved light-emitting diode. The anode of the light-emitting diode is connected to the charging input port.

10. A charging storage box, characterized in that, The charging circuit includes the current detection and status indication as described in any one of claims 1-9.

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