Control circuit, electronic device and handwriting input system

Abstract

The embodiment of the present application provides a control circuit, an electronic device and a handwriting input system, wherein the first end of the voltage divider module is connected to the first charging pin, the second end is connected to the second charging pin, and the third end is connected to the control end of the charging control module and the microcontrol module; the first end of the charging control module is connected to the first end of the voltage divider module, and the second end is connected to the charging module; the control end of the communication control module is connected to the microcontrol module, the first end is connected to the first end of the voltage divider module, and the second end is connected to the microcontrol module. When the first charging pin receives the first voltage, the charging control module is turned on to transmit the charging voltage to the charging module through the two charging pins; when the first charging pin receives the second voltage, the communication control module is turned on under the control of the enable signal to transmit the communication information to the microcontrol module through the two charging pins, so that the communication between the host end and the microcontrol module can be realized by reusing the existing two charging pins.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a control circuit, an electronic device and a handwriting input system. Background Art

[0002] Currently, styluses can be charged through a host device (such as a tablet computer or a laptop computer). Charging methods include wireless charging and pin charging. Wireless charging has low charging efficiency, so pin charging is often used.

[0003] However, two pins are only for charging and cannot be used for communication. If communication is required, more pins are needed, but too many pins will affect the appearance of the stylus.

[0004] Therefore, how to achieve charging and communication through two pins is a more important issue. Summary of the invention

[0005] The embodiments of the present application provide a control circuit, an electronic device and a handwriting input system for realizing charging and communication through two pins.

[0006] In a first aspect, an embodiment of the present application provides a control circuit, including a voltage division module, a charging control module and a communication control module;

[0007] The first end of the voltage divider module is connected to the first charging pin, the second end of the voltage divider module is connected to the second charging pin and grounded, and the third end of the voltage divider module is connected to the control end of the charging control module and the microcontroller module;

[0008] The first end of the charging control module is connected to the first end of the voltage dividing module, and the second end of the charging control module is connected to the charging module;

[0009] The control end of the communication control module is connected to the micro control module, the first end of the communication control module is connected to the first end of the voltage divider module, and the second end of the communication control module is connected to the micro control module;

[0010] When the first charging pin receives the first voltage, the charging control module is in a conducting state to transmit the charging voltage to the charging module through the first charging pin and the second charging pin;

[0011] When the first charging pin receives the second voltage, the communication control module is in an on state under the control of an enable signal to transmit communication information to the microcontrol module through the first charging pin and the second charging pin; the enable signal is generated by the microcontrol module based on the voltage of the third terminal of the voltage divider module.

[0012] In a possible implementation, the charging control module includes: a first control submodule and a second control submodule;

[0013] The control end of the first control submodule serves as the control end of the charging control module, the first end of the first control submodule is grounded, and the second end of the first control submodule is connected to the control end of the second control submodule;

[0014] The first end of the second control submodule serves as the first end of the charging control module, and the second end of the second control submodule serves as the second end of the charging control module;

[0015] When the first charging pin receives the first voltage, the first control submodule is in an on state, and pulls down the voltage of the control terminal of the second control submodule to control the second control submodule to be in an on state.

[0016] In a possible implementation manner, the first control submodule includes a transistor, the base of the transistor serves as the control end of the first control submodule, the emitter of the transistor serves as the first end of the first control submodule, and the collector of the transistor serves as the second end of the first control submodule;

[0017] The second control submodule includes a P-type transistor, a gate of the P-type transistor serves as a control terminal of the second control submodule, a source of the P-type transistor serves as a first terminal of the second control submodule, and a drain of the P-type transistor serves as a second terminal of the second control submodule.

[0018] In a possible implementation, the voltage dividing module includes a first resistor R, a second resistor R and a third resistor R;

[0019] The first end of the first resistor R serves as the first end of the voltage divider module, the second end of the first resistor R is connected to the first end of the second resistor R and connected to the second end of the first control submodule, the second end of the second resistor R is connected to the first end of the third resistor R and serves as the third end of the voltage divider module, and the second end of the third resistor R serves as the second end of the voltage divider module.

[0020] In a possible implementation, the communication control module includes a first N-type transistor;

[0021] The gate of the first N-type transistor serves as the control end of the communication control module, the source of the first N-type transistor serves as the first end of the communication control module, and the drain of the first N-type transistor serves as the second end of the communication control module.

[0022] In a possible implementation, the communication control module includes a second N-type transistor;

[0023] The gate of the second N-type transistor is connected to the gate of the first N-type transistor, the drain of the second N-type transistor is connected to the drain of the first N-type transistor, and the source of the second N-type transistor serves as the second end of the communication control module.

[0024] In a possible implementation, the circuit includes:

[0025] A transient voltage suppression diode, which is connected between the first end and the second end of the voltage divider module and is used for preventing static electricity;

[0026] and / or, a fourth resistor, the fourth resistor being connected between the control end of the charging control module and the microcontroller module, and being used to control the charging control module to be in a cut-off state when the first charging pin receives the first voltage;

[0027] And / or, a fifth resistor, the fifth resistor is connected to the second end of the charging control module, and is used to pull the communication line between the first charging pin and the microcontroller module to a high level.

[0028] In a second aspect, the present application provides an electronic device, comprising the control circuit described in the first aspect.

[0029] In a possible implementation, it further includes: a microcontroller module, a charging module, and a battery;

[0030] The microcontrol module is connected to the third end of the voltage dividing module, the control end and the second end of the communication control module; the charging module is connected to the second end of the charging control module;

[0031] The microcontrol module is used to generate the enable signal based on the voltage of the third terminal of the voltage divider module to control the charging control module to be in a conducting state;

[0032] The microcontrol module is also used to receive communication information transmitted through the first charging pin and the second charging pin when the communication control module is in a conducting state;

[0033] The charging module is used for receiving the charging voltage transmitted through the first charging pin and the second charging pin when the charging control module is in the on state, and charging the battery based on the charging voltage.

[0034] In a third aspect, the present application provides a handwriting input system, comprising the electronic device as claimed or described in the claims, and a host terminal;

[0035] The host end is used to provide a charging voltage for the electronic device and to communicate with the electronic device.

[0036] The control circuit, electronic device and handwriting input system provided by the embodiment of the present application include a voltage divider module, a charging control module and a communication control module; the first end of the voltage divider module is connected to the first charging pin, the second end of the voltage divider module is connected to the second charging pin and grounded, and the third end of the voltage divider module is connected to the control end of the charging control module and the microcontrol module; the first end of the charging control module is connected to the first end of the voltage divider module, and the second end of the charging control module is connected to the charging module; the control end of the communication control module is connected to the microcontrol module, the first end of the communication module is connected to the first end of the voltage divider module, and the second end of the communication module is connected to the microcontrol module. When the first charging pin receives the first voltage, the charging control module is in a conducting state to transmit the charging voltage to the charging module through the first charging pin and the second charging pin; when the first charging pin receives the second voltage, the communication control module is in a conducting state under the control of an enable signal to transmit communication information to the microcontrol module through the first charging pin and the second charging pin, so that the communication between the host end and the microcontrol module can be realized by multiplexing the existing two charging pins. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0038] Figure 1 A circuit diagram of a control circuit provided for this application;

[0039] Figure 2 A schematic diagram of the structure of the electronic device provided for this application;

[0040] Figure 3 This is a schematic diagram of the structure of the handwriting input system provided in this application.

[0041] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0042] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0043] Currently, the handwriting input function can be realized through communication between the stylus and the host (such as a tablet computer, laptop computer, etc.), which improves the convenience of operation, enhances the user experience, and supports multiple functions and application scenarios.

[0044] For a stylus pen that carries a rechargeable power source, it can be powered by the host when it needs to be charged. The host can charge the stylus by wireless charging and pin charging. Since wireless charging is inefficient and requires an additional wireless charging module, pin charging is often used. Pin charging can be achieved by connecting the USB-C interface of the stylus pen to the USB-C port of the host so that the host can charge the stylus.

[0045] However, the current two pins can only be used for charging but not for communication. If communication through pins is required, more pins are needed, and more pins will affect the appearance of the stylus.

[0046] In the control circuit provided in the present application, when the first charging pin receives the first voltage, the charging control module is in an on state to transmit the charging voltage to the charging module through the first charging pin and the second charging pin; when the first charging pin receives the second voltage, the communication control module is in an on state under the control of an enable signal to transmit communication information to the microcontrol module through the first charging pin and the second charging pin, thereby realizing communication between the host end and the microcontrol module by multiplexing the two existing charging pins.

[0047] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0048] Figure 1 A schematic diagram of the structure of the control circuit provided in the embodiment of the present application is shown in FIG. Figure 1 As shown, the control circuit provided in the embodiment of the present application includes:

[0049] The voltage dividing module 101, the charging control module 102 and the communication control module 103; the voltage dividing module 101 includes a first end, a second end and a third end, the charging control module 102 includes a first end and a second end, and the communication control module 103 includes a control end, a first end and a second end.

[0050] The first end of the voltage divider module 101 is connected to the first charging pin J1, the second end of the voltage divider module 101 is connected to the second charging pin J2 and grounded GND, the third end of the voltage divider module 101 is connected to the control end of the charging control module 102 and the microcontroller unit (MCU); the first end of the charging control module 102 is connected to the first end of the voltage divider module 101, and the second end of the charging control module 102 is connected to the charging module; the control end of the communication control module 103 is connected to the microcontroller module, the first end of the communication control module 103 is connected to the first end of the voltage divider module 101, and the second end of the communication control module 103 is connected to the microcontroller module.

[0051] When the first charging pin J1 receives the first voltage input from the host end, the third end of the voltage divider module 101 has a higher third voltage, so that the charging control module 102 is in a conducting state, so that the charging voltage can be transmitted to the charging module through the first charging pin J1 and the second charging pin J2, and the charging module can charge the battery of the electronic device based on the charging voltage. At the same time, the microcontrol module can detect the voltage of the third end of the voltage divider module 101, and determine whether the first voltage received by the first charging pin J1 is a high voltage or a low voltage based on the voltage of the third end of the voltage divider module 101. When the microcontrol module determines that the first voltage received by the first charging pin J1 is a high voltage, it generates a low-level enable signal UART_EN, and outputs the low-level enable signal UART_EN to the control end of the communication control module 103. The communication control module 103 is in a cut-off state under the control of the low-level enable signal UART_EN. Among them, the specific size of the third voltage is related to the voltage divider module 101.

[0052] When the first charging pin J1 receives the second voltage input from the host end, the third end of the voltage divider module 101 has a lower fourth voltage, so that the charging control module 102 is in a cut-off state. At the same time, the micro-control module can detect the voltage of the third end of the voltage divider module 101, and determine whether the second voltage received by the first charging pin J1 is a high voltage or a low voltage based on the voltage of the third end of the voltage divider module 101. When the micro-control module determines that the second voltage received by the first charging pin J1 is a low voltage, it generates a high-level enable signal UART_EN, and outputs the high-level enable signal UART_EN to the control end of the communication control module 103. The communication control module 103 is in a conducting state under the control of the high-level enable signal UART_EN, so that the communication information can be transmitted to the micro-control module through the first charging pin J1 and the second charging pin J2, so as to realize the single-line communication between the host end and the micro-control module.

[0053] It should be noted that the first voltage is greater than the second voltage, and the third voltage is greater than the fourth voltage. In addition, the above-mentioned high voltage and low voltage are relative. For example, if the first voltage is greater than the second voltage, the first voltage is a high voltage and the second voltage is a low voltage. The first voltage can be any voltage between 3.3V and 5V, such as 3.3V, 4V, 4.5V, 5V, etc., and the second voltage can be a voltage lower than 3.3V, such as 1.7V, 1.8V, 2.5V, etc.

[0054] The control circuit of the embodiment of the present application can reuse the two existing charging pins to realize communication between the host end and the microcontroller module, thereby realizing communication and charging through a minimum number of two pins, improving charging efficiency, and reducing the impact on the appearance of the electronic device.

[0055] For example, the electronic device may be a stylus. The stylus itself is relatively small. If the number of pins is too large, the distance between the pins will be close, which may easily cause a short circuit. The above control circuit only needs to use two charging pins to achieve communication, reducing the impact on the stylus. The electronic device may also be other rechargeable and communicative devices.

[0056] In some embodiments, the charging control module 102 includes a first control submodule and a second control submodule. The control end of the first control submodule serves as the control end of the charging control module 102 and is connected to the third end of the voltage divider module 101; the first end of the first control submodule is grounded GND; the second end of the first control submodule is connected to the control end of the second control submodule. The first end of the second control submodule serves as the first end of the charging control module 102 and is connected to the first end of the voltage divider module 101; the second end of the second control submodule serves as the second end of the charging control module 102 and is connected to the charging module.

[0057] When the first charging pin J1 receives the first voltage, the third end of the voltage divider module 101 has a higher third voltage, so that the first control submodule is in a conductive state. Since the first end of the first control submodule is grounded GND, and the control end of the second control submodule is connected to the second end of the first control submodule, the voltage of the control end of the second control submodule can be lowered, so that the second control submodule is in a conductive state. At this time, the charging voltage can be provided to the charging module through the first charging pin J1 and the second charging pin J2, so that the charging module can charge the battery based on the charging voltage.

[0058] In some examples, the first control submodule includes a transistor Q4, the base of the transistor Q4 serves as the control end of the first control submodule and is connected to the third end of the voltage divider module 101; the emitter of the transistor Q4 serves as the first end of the first control submodule and is grounded GND; the collector of the transistor Q4 serves as the second end of the first control submodule and is connected to the control end of the second control submodule.

[0059] When the voltage at the third terminal of the voltage dividing module 101 is a higher third voltage, the voltage difference between the base and the emitter of the transistor Q4 is greater than the turn-on voltage, and the transistor Q4 is turned on to lower the voltage at the control terminal of the second control submodule.

[0060] For example, transistor Q4 is an NPN transistor.

[0061] In some examples, the second control submodule includes a P-type transistor Q3, the gate of the P-type transistor Q3 serves as the control end of the second control submodule, the source of the P-type transistor Q3 serves as the first end of the second control submodule, connected to the first end of the voltage divider module 101, and the drain of the P-type transistor Q3 serves as the second end of the second control submodule, connected to the charging module.

[0062] When the gate voltage of the P-type transistor Q3 is pulled down to the ground voltage GND, the P-type transistor Q3 is turned on, so that the charging voltage can be transmitted to the charging module through the first charging pin J1 and the second charging pin J2.

[0063] In some examples, the voltage divider module 101 includes a first resistor R1, a second resistor R2, and a third resistor R3. The first end of the first resistor R1 serves as the first end of the voltage divider module 101; the second end of the first resistor R1 is connected to the first end of the second resistor R2, and is connected to the second end of the first control submodule and the control end of the second control submodule; the second end of the second resistor R2 is connected to the first end of the third resistor R3, serving as the third end of the voltage divider module 101, and is connected to the control end of the first control submodule and the microcontroller module; the second end of the third resistor R3 serves as the second end of the voltage divider module 101, and is grounded GND.

[0064] The first resistor R1, the second resistor R2 and the third resistor R3 form a voltage divider network. When the first charging pin J1 receives different voltages, the second end of the second resistor R2 has different voltages. Therefore, the microcontrol module can detect the voltage of the second end of the second resistor R2 (that is, the voltage of the first end of the third resistor R3), and judge whether the first charging pin J1 receives the charging voltage (that is, the first voltage) or the communication voltage (that is, the second voltage) based on the voltage of the second end of the second resistor R2, so as to judge whether the host-side controlled electronic device is in the charging state or the communication state. Accordingly, when the microcontrol module determines that the electronic device is in the charging state, it outputs a low-level enable signal UART_EN to the communication control module 103, so that the communication control module 103 is in the cut-off state; when the microcontrol module determines that the electronic device is in the communication state, it outputs a high-level enable signal UART_EN to the communication control module 103, so that the communication control module 103 is in the on state, so that single-line communication can be realized.

[0065] The first resistor R1 can control the conduction of the second control submodule, for example, to control the voltage difference between the gate and the source of the P-type transistor Q3. The third resistor R3 can control the conduction of the first control submodule, for example, to control the voltage difference between the base and the emitter of the transistor Q4.

[0066] In some examples, the communication control module includes a first N-type transistor Q1, the gate of the first N-type transistor Q1 serves as the control terminal of the communication control module 103, the source of the first N-type transistor Q1 serves as the first terminal of the communication control module 103, and the drain of the first N-type transistor Q1 serves as the second terminal of the communication control module 103. When the gate of the first N-type transistor Q1 receives a high-level enable signal UART_EN, the first N-type transistor Q1 is turned on, so that communication information can be received through the first charging pin J1 and the second charging pin J2. When the gate of the first N-type transistor Q1 receives a low-level enable signal UART_EN, the first N-type transistor Q1 is turned off, and there is no external current and voltage path on the single-line communication.

[0067] In some examples, the communication control module further includes a second N-type transistor Q2, the gate of the second N-type transistor Q2 is connected to the gate of the first N-type transistor Q1, and serves as a control terminal of the communication control module 103; the drain of the second N-type transistor Q2 is connected to the drain of the first N-type transistor Q1, and the source of the second N-type transistor Q2 serves as a second terminal of the communication control module 103, and is connected to the microcontroller module. The first N-type transistor Q1 has a body diode, and when the first charging pin J1 receives the first voltage, the body diode of the first N-type transistor Q1 is turned on, but because the body diode of the second N-type transistor Q2 is turned off and the second N-type transistor Q2 is turned off, current backflow can be prevented, effectively protecting the microcontroller module.

[0068] In a specific implementation, the circuit includes a transient voltage suppression diode FV1 connected between the first end and the second end of the voltage divider module 101. The transient voltage suppression diode FV1 is used to prevent static electricity and surges to protect devices in the control circuit.

[0069] In a specific implementation, the circuit includes a fourth resistor R4, and the fourth resistor R4 is connected between the control end of the charging control module 102 and the microcontroller module. When the first charging pin J1 receives the first voltage, the microcontroller module outputs a low-level enable signal UART_EN, and the voltage of the enable signal UART_EN is divided by the fourth resistor R4, so that the voltage of the control end of the charging control module 102 is pulled down, so that the charging control module 102 is in a cut-off state, protecting the single-line communication line.

[0070] For example, the resistance value of the fourth resistor R4 is 100K, the tolerance is 5%, and the rated voltage is 25 V. In a specific implementation, the circuit includes a fifth resistor R5, which is connected to the second end of the charging control module 102 and is used to pull the communication line between the first charging pin J1 and the microcontroller module to a high level, thereby stabilizing the communication signal transmitted through the communication line and preventing noise interference.

[0071] For example, the first end of the fifth resistor R5 receives the pull-up voltage, and the first end of the fifth resistor R5 is connected to the second end of the charging control module 102 and the microcontroller module. The pull-up voltage may be, for example, 1.7 V. The resistance value of the fifth resistor R5 is 1K, the tolerance is 5%, and the rated voltage is 25 V.

[0072] In actual applications, when the charging pin of the electronic device contacts the charging pin of the host end, the host end preferentially outputs a higher first voltage (for example, a 5V voltage). At this time, the voltage at the second end of the second resistor R2 is a higher third voltage. When the microcontroller module detects that the second end of the second resistor R2 is a higher third voltage, it outputs a low-level enable signal UART_EN to the gate of the first N-type transistor Q1 and the gate of the second N-type transistor Q2. Then, the first N-type transistor Q1 and the second N-type transistor Q2 are cut off. There is no external voltage and current path on the single-line communication, and there is no risk of voltage backflow.

[0073] At the moment when the first charging pin J1 receives the first voltage, the P-type transistor Q3 is in the cut-off state due to the existence of the first resistor R1. Then, due to the voltage division of the first resistor R1, the second resistor R2 and the third resistor R3, the voltage difference between the base and the emitter of the transistor Q4 is greater than the turn-on voltage of the transistor Q4. For example, the first resistor R1 is a resistor of 4.7K, 1%, 25V, the second resistor R2 is a resistor of 82K, 1%, 25V, and the third resistor R3 is a resistor of 20K, 1%, 25V. Then, the voltage difference between the base and the emitter of the transistor Q4 is 0.973V, which is greater than the turn-on voltage of the transistor Q4, 0.7V. At this time, the transistor Q4 is turned on, the gate voltage of the P-type transistor Q3 is pulled down, and the P-type transistor Q3 is turned on. The first voltage can be given to the charging module through the P-type transistor Q3, so that the charging module charges the battery based on the first voltage.

[0074] When communication is required, the host end stops the output of the first voltage (that is, the output voltage of the host end drops from the first voltage to 0V). At this time, the transistor Q4 is turned off first. When the transistor Q4 is turned off, it cannot pull down the voltage of the gate of the P-type transistor Q3, and the P-type transistor Q3 is also turned off. Correspondingly, the microcontroller module outputs a high-level enable signal UART_EN to the gate of the first N-type transistor Q1 and the gate of the second N-type transistor Q2, so that the first N-type transistor Q1 and the second N-type transistor Q2 are turned on, and because the source of the second N-type transistor Q2 is pulled up by the pull-up voltage, the body diode of the second N-type transistor Q2 is turned on and pulled to the ground (for example, 0V), and the single-wire communication interface 1-WIRE_UART of the electronic device detects a low level.

[0075] Similarly, when the single-wire communication interface 1-WIRE_UART of the electronic device outputs a low level, since the host end originally outputs a high-level first voltage, the body diode of the first N-type transistor Q1 is turned on, and the first N-type transistor Q1 and the second N-type transistor Q2 are turned on under the control of the enable signal UART_EN, then the body diode of the first N-type transistor Q1 is pulled to the ground, and the host end can also detect the low level.

[0076] Then, a handshake can be performed according to the specific communication protocol, and then information can be transmitted, such as transmitting lighting, pairing information, device status, etc.

[0077] It can be understood that the two ends of communication are controlled by switch tubes. As long as the different communication voltages are greater than the minimum voltage for the switch tube to be turned on (for example, greater than 0.7V) and less than the turn-on voltage of the transistor Q4 (for example, less than 3.5V, to avoid misjudgment of charging), the switch tube can be turned on to complete the communication.

[0078] The control circuit provided in the embodiment of the present application is described in detail above. When the first charging pin receives the first voltage, the charging control module is in an on state to transmit the charging voltage to the charging module through the first charging pin and the second charging pin; when the first charging pin receives the second voltage, the communication control module is in an on state under the control of an enable signal to transmit communication information to the microcontrol module through the first charging pin and the second charging pin, so that communication between the host end and the microcontrol module can be achieved by multiplexing the two existing charging pins.

[0079] The present application also provides an electronic device 100, such as Figure 2 As shown, it includes the control circuit 10 mentioned above.

[0080] In some embodiments, Figure 2As shown, the electronic device 100 also includes a microcontroller module 20, a charging module 30 and a battery 40. The microcontroller module 20 is connected to the third end of the voltage divider module, the control end and the second end of the communication control module; the charging module 30 is connected to the second end of the charging control module. The microcontroller module 20 is used to generate an enable signal based on the voltage at the third end of the voltage divider module to control the charging control module to be in a conductive state. The microcontroller module 20 is also used to receive the communication information transmitted by the first charging pin and the second charging pin when the communication control module is in a conductive state; the charging module 30 is used to receive the charging voltage transmitted through the first charging pin and the second charging pin when the charging control module is in a conductive state, and charge the battery 40 based on the charging voltage.

[0081] The embodiment of the present application also provides a handwriting input system, including the above-mentioned electronic device 100 and a host end 200 , wherein the host end 200 is used to provide charging power for the electronic device 100 and communicate with the electronic device 100 .

[0082] Finally, it should be noted that those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention, which follow the general principles of the present invention and include common knowledge or customary technical means in the art not disclosed by the present invention, are not limited to the precise structure described above and shown in the drawings, and may be modified and changed in various ways without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A control circuit, characterized in that: The circuit comprises: Voltage dividing module, charging control module and communication control module; The first end of the voltage divider module is connected to the first charging pin, the second end of the voltage divider module is connected to the second charging pin and grounded, and the third end of the voltage divider module is connected to the control end of the charging control module and the microcontroller module; The first end of the charging control module is connected to the first end of the voltage dividing module, and the second end of the charging control module is connected to the charging module; The control end of the communication control module is connected to the micro control module, the first end of the communication control module is connected to the first end of the voltage divider module, and the second end of the communication control module is connected to the micro control module; When the first charging pin receives the first voltage, the charging control module is in a conducting state to transmit the charging voltage to the charging module through the first charging pin and the second charging pin; When the first charging pin receives the second voltage, the communication control module is in an on state under the control of an enable signal to transmit communication information to the microcontrol module through the first charging pin and the second charging pin; the enable signal is generated by the microcontrol module based on the voltage of the third terminal of the voltage divider module.

2. The circuit according to claim 1, characterized in that The charging control module includes: a first control submodule and a second control submodule; The control end of the first control submodule serves as the control end of the charging control module, the first end of the first control submodule is grounded, and the second end of the first control submodule is connected to the control end of the second control submodule; The first end of the second control submodule serves as the first end of the charging control module, and the second end of the second control submodule serves as the second end of the charging control module; When the first charging pin receives the first voltage, the first control submodule is in an on state, and pulls down the voltage of the control terminal of the second control submodule to control the second control submodule to be in an on state.

3. The circuit according to claim 2, characterized in that The first control submodule comprises a transistor, the base of the transistor serves as the control end of the first control submodule, the emitter of the transistor serves as the first end of the first control submodule, and the collector of the transistor serves as the second end of the first control submodule; The second control submodule includes a P-type transistor, a gate of the P-type transistor serves as a control terminal of the second control submodule, a source of the P-type transistor serves as a first terminal of the second control submodule, and a drain of the P-type transistor serves as a second terminal of the second control submodule.

4. The circuit according to claim 2, characterized in that The voltage dividing module includes a first resistor, a second resistor and a third resistor; The first end of the first resistor serves as the first end of the voltage divider module, the second end of the first resistor is connected to the first end of the second resistor and to the second end of the first control submodule, the second end of the second resistor is connected to the first end of the third resistor and serves as the third end of the voltage divider module, and the second end of the third resistor serves as the second end of the voltage divider module.

5. The circuit according to claim 1, characterized in that The communication control module includes a first N-type transistor; The gate of the first N-type transistor serves as the control end of the communication control module, the source of the first N-type transistor serves as the first end of the communication control module, and the drain of the first N-type transistor serves as the second end of the communication control module.

6. The circuit according to claim 5, characterized in that The communication control module includes a second N-type transistor; The gate of the second N-type transistor is connected to the gate of the first N-type transistor, the drain of the second N-type transistor is connected to the drain of the first N-type transistor, and the source of the second N-type transistor serves as the second end of the communication control module.

7. The circuit according to any one of claims 1 to 6, characterized in that: The circuit comprises: A transient voltage suppression diode, which is connected between the first end and the second end of the voltage divider module and is used for preventing static electricity; and / or a fourth resistor, the fourth resistor being connected between the control end of the charging control module (103) and the microcontroller module, and being used to control the charging control module to be in a cut-off state when the first charging pin receives the first voltage; And / or, a fifth resistor, the fifth resistor is connected to the second end of the charging control module, and is used to pull the communication line between the first charging pin and the microcontroller module to a high level.

8. An electronic device, characterized in that: The control circuit comprises the control circuit described in any one of claims 1 to 7.

9. The electronic device according to claim 8, characterized in that: Also includes: Microcontroller module, charging module and battery; The microcontrol module is connected to the third end of the voltage dividing module, the control end and the second end of the communication control module; the charging module is connected to the second end of the charging control module; The microcontrol module is used to generate the enable signal based on the voltage of the third terminal of the voltage divider module to control the charging control module to be in a conducting state; The microcontrol module is also used to receive communication information transmitted through the first charging pin and the second charging pin when the communication control module is in a conducting state; The charging module is used for receiving the charging voltage transmitted through the first charging pin and the second charging pin when the charging control module is in the on state, and charging the battery based on the charging voltage.

10. A handwriting input system, characterized in that: The electronic device comprising claim 8 or 9, and a host end; The host end is used to provide a charging voltage for the electronic device and to communicate with the electronic device.

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