Electromagnetic induction input device and electronic equipment

Abstract

The utility model provides an electromagnetic induction input device and electronic equipment, the electronic equipment comprises a resonance circuit, a rectification circuit, a comparator, a voltage division circuit, a potential conversion circuit and a counter, the electromagnetic induction input device receives an electromagnetic induction signal sent by an electromagnetic induction receiving device; the electric potential conversion circuit, the comparator, the counter and the like are used for recognizing the duration time of the electromagnetic induction signal, and input of the electromagnetic induction receiving device can be further achieved based on the recognized duration time of the electromagnetic induction signal. By utilizing the electromagnetic induction receiving device and the electromagnetic induction input device, the electromagnetic induction receiving device and the electromagnetic induction input device can be matched for use only by using a fixed frequency, and wide band pass is not needed, so that the opportunity of noise incoming is reduced, the opportunity of interference is reduced, the design is simplified, and meanwhile, the reliability is also improved.

Description

Technical Field

[0001] The present application relates to the technical field of computer peripheral devices, and in particular to an electromagnetic induction input device and an electronic device using the electromagnetic induction input device. Background Art

[0002] Conventional electromagnetic induction tablets and pens transmit keystroke and pressure information by changing frequency. For example, a prior art method for converting frequency into keystroke and pressure information can eliminate background noise through computational subtraction. However, this method still requires a relatively wide passband (i.e., a wider frequency variation) to achieve a high pressure level. This wider passband also increases the chances of noise entering. If random noise is encountered, such as interference noise at a frequency of 520 kHz but no noise interference at frequencies of 530 kHz or 540 kHz, the frequency calculated using the computational formula will be distorted, resulting in errors in the conversion of pressure or keystroke information. Another prior art method involves digital modulation using different frequencies, f1 and f0, and a demodulation circuit on a passive pen to transmit keystroke and pressure information. While this method can achieve digitalization, it still requires a relatively wide passband (f0-f1), requires a demodulation circuit on the passive pen, and takes additional time to interpret the command, making the design complex and difficult.

[0003] Changing the frequency will cause noise interference. However, the field of electromagnetic induction currently does not provide a solution that avoids changing the signal frequency and instead changes other factors (such as changing the signal duration) to achieve information / command transmission, nor does it have a solution for how to determine the signal duration.

[0004] Therefore, there is an urgent need to provide an electromagnetic induction input device and an electronic device to solve one or more of the above technical problems. Utility Model Content

[0005] Embodiments of the present application provide an electromagnetic induction input device and an electronic device using the electromagnetic induction input device.

[0006] In one aspect, an embodiment of the present application provides an electromagnetic induction input device, comprising a resonance circuit, a rectifier circuit, a comparator, a voltage divider circuit, a potential conversion circuit, and a counter, wherein:

[0007] The output end of the resonant circuit is connected to the input end of the rectifier circuit;

[0008] The output end of the rectifier circuit is connected to the comparator to supply power to the comparator;

[0009] The output end of the rectifier circuit is also connected to the input end of the voltage divider circuit;

[0010] an output terminal of the voltage dividing circuit is connected to a first input terminal of the comparator;

[0011] an input terminal of the potential converting circuit is connected to the output terminal of the voltage dividing circuit and the resonance circuit, and an output terminal of the potential converting circuit is connected to a second input terminal of the comparator; and

[0012] an output terminal of the comparator is connected to the counter.

[0013] In an embodiment, the electromagnetic induction input device further comprises a micro control unit, and the comparator and the counter are integrated in the micro control unit.

[0014] In an embodiment, the electromagnetic induction input device further comprises a user input unit, and the user input unit comprises a switch circuit, and the switch circuit comprises a switch, and the switch is triggered to generate a user input.

[0015] In an embodiment, the resonance circuit is an LC resonance circuit, and the LC resonance circuit comprises an inductor and a first capacitor connected in parallel between an input terminal and an output terminal of the resonance circuit.

[0016] In an embodiment, the potential converting circuit comprises a first resistor and a second capacitor, one end of the first resistor is connected to the output terminal of the resonance circuit, the other end of the first resistor is connected to the second capacitor, one end of the second capacitor away from the first resistor is connected to the input terminal of the resonance circuit, and a connection point between the first resistor and the second capacitor is connected to the second input terminal of the comparator to output the clock signal to the second input terminal of the comparator.

[0017] In an embodiment, the rectifier circuit comprises a first rectifier element and a second rectifier element, the voltage dividing circuit comprises a third capacitor and a fourth capacitor connected in series, an anode of the first rectifier element and a cathode of the second rectifier element are connected to the input terminal of the resonance circuit, the third capacitor and the fourth capacitor are connected in series between a cathode of the first rectifier element and an anode of the second rectifier element in sequence, the fourth capacitor and the anode of the second rectifier element are grounded in common, and a connection point of the third capacitor and the fourth capacitor is connected to the micro control unit to provide the reference voltage to the micro control unit; a connection point of the first rectifier element and the third capacitor is connected to the micro control unit to supply power to the micro control unit.

[0018] In one embodiment, the information sending control circuit includes a control switch circuit, which includes a control end and a first conductive end and a second conductive end. The control end is connected to the micro control unit, and controls the first conductive end and the second conductive end to be connected or disconnected with each other by receiving the control signal. The first conductive end is connected to the input end of the resonant circuit, and the second conductive end is connected to the output end of the resonant circuit.

[0019] In one embodiment, a backflow prevention circuit is connected between the first conducting end of the control switch circuit and the input end of the resonant circuit.

[0020] In one embodiment, the control switch circuit includes an NMOS transistor, and the gate, drain, and source of the NMOS transistor respectively form the control end, the first conduction end, and the second conduction end of the control switch circuit.

[0021] On the other hand, an embodiment of the present application provides an electronic device, which includes the electromagnetic induction input device described above.

[0022] Compared with the prior art, the electromagnetic induction input device and electronic device of the present application use the duration of the electromagnetic induction signal sent by the electromagnetic induction receiving device to the electromagnetic induction input device as a "control instruction". The electromagnetic induction input device can identify the duration of the electromagnetic induction signal through a comparator and a counter. Based on the duration of the identified electromagnetic induction signal, the control instruction can be further identified. Therefore, the present application only needs to use a fixed frequency to achieve the coordinated use between the electromagnetic induction receiving device and the electromagnetic induction input device, and does not require a wide bandpass. In this way, the chance of noise entering is reduced, and the chance of interference is reduced, which not only simplifies the design but also increases reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present application. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which:

[0024] Figure 1 Schematic diagram of the electronic device provided in an embodiment of the present application;

[0025] Figure 2 This is a simplified diagram of the internal structure of the electromagnetic induction receiving device provided in an embodiment of the present application;

[0026] Figure 3 yes Figure 1The circuit block diagram of the electromagnetic induction input device generating and sending information;

[0027] Figure 4 yes Figure 3 The module diagram inside the micro control unit is shown;

[0028] Figure 5A A table showing the correspondence relationship between the preset clock signal quantity interval, port, and control signal ASK used by the microcontroller unit is shown;

[0029] Figure 5B A table showing a correspondence relationship between the preset clock signal quantity interval, information, and control signal ASK used by the microcontroller unit is shown;

[0030] Figure 6 yes Figure 3 Circuit diagram of the electromagnetic induction input device generating and sending information; and

[0031] Figure 7 yes Figure 2 A flow chart of a control method for an electromagnetic induction receiving device is shown;

[0032] Figure 8 yes Figure 7 A detailed flow chart of the control method shown;

[0033] Figure 9 yes Figure 3 A flow chart of a control method for an electromagnetic induction input device is shown;

[0034] Figure 10-12 yes Figure 9 Detailed flow chart of the control method shown. DETAILED DESCRIPTION

[0035] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0036] See also Figure 1The figure shows a schematic diagram of the structure of the electronic device 100 of the present application. The electronic device 100 includes an electromagnetic induction receiving device 1 and an electromagnetic induction input device 2. The electromagnetic induction input device 2 serves as an input device of the electromagnetic induction receiving device 1. The electromagnetic induction receiving device 1 can be a mobile phone, a tablet device, or the like. The electromagnetic induction receiving device 1 is used to control the electromagnetic induction input device 2 to obtain input information from the electromagnetic induction input device 2. In another embodiment, the electromagnetic induction receiving device 1 supplies power to the electromagnetic induction input device 2 and controls the electromagnetic induction input device 2 at the same time to obtain input information from the electromagnetic induction input device 2. In this embodiment, the electromagnetic induction input device 2 is an electromagnetic stylus, which is a passive stylus or an active stylus. The electromagnetic induction input device 2 is provided with a resonant circuit. When the electromagnetic stylus is a passive stylus, the electromagnetic induction receiving device 1 obtains power supply, control instructions, and input information (i.e., feedback) from the electromagnetic induction receiving device 1 through the resonant circuit. When the electromagnetic stylus is an active stylus, the resonant circuit obtains control instructions from the electromagnetic induction receiving device 1 and transmits input information (i.e., feedback) to the electromagnetic induction receiving device 1. The electromagnetic induction receiving device 1 has a transmitting mode and a receiving mode, and switches continuously between the transmitting and receiving modes. In the transmitting mode, the electromagnetic induction receiving device 1 controls the duration of the electromagnetic induction signal it outputs to control the information that the electromagnetic induction input device 2 needs to send in the subsequent receiving mode. In other words, the electromagnetic induction receiving device 1 uses the duration of the electromagnetic induction signal sent to the electromagnetic induction input device 2 as a "control instruction." When the electromagnetic stylus is passive, the electromagnetic induction receiving device 1 simultaneously transmits electromagnetic induction signals to power the electromagnetic induction input device 2. In other words, the duration of the power supply is used as a "control instruction." The electromagnetic induction input device 2 interprets the "control instruction" by determining the duration / duration, and then transmits information that matches the "control instruction." Therefore, the electromagnetic induction input device 2, electromagnetic induction receiving device 1 and electronic device 100 provided in the present application only need to use a fixed frequency to achieve the coordinated use between the electromagnetic induction receiving device 1 and the electromagnetic induction input device 2, and do not require a wide bandpass. In this way, the chance of noise entering is reduced and the chance of interference is reduced, which not only simplifies the design but also increases reliability.

[0037] See also Figure 2Figure 1 shows a simplified schematic diagram of the internal structure of an electromagnetic induction receiving device 1. The electromagnetic induction receiving device 1 includes a processor 11, a memory 13, a signal processing circuit 15, and a resonance circuit 17. The electromagnetic induction receiving device 1 is powered by a power supply 3, which can be an internal or external power supply. The processor 11 controls the electromagnetic induction receiving device 1 to cyclically switch between a transmission mode and a reception mode. It is understood that the electromagnetic induction receiving device 1 cyclically switches between the transmission mode and the reception mode. When the electromagnetic induction receiving device 1 enters the transmission mode from the reception mode, it enters a transmission cycle. When the transmission mode ends and the electromagnetic induction receiving device 1 re-enters the reception mode, the transmission cycle ends. Therefore, a transmission cycle refers to the period from the beginning of the transmission mode to the end of the transmission mode and the switching to the reception mode. It is understood that when the electromagnetic induction receiving device 1 enters the reception mode from the transmission mode, it enters a reception cycle. When the reception mode ends and the electromagnetic induction receiving device 1 re-enters the transmission mode, the reception cycle ends. Therefore, a reception cycle refers to the period from the beginning of the reception mode to the end of the reception mode and the switching to the transmission mode. It is understandable that although the electromagnetic induction receiving device 1 switches between the transmitting cycle and the receiving cycle, in actual process, signal reception and transmission may be performed simultaneously within the same cycle, which is not limited here.

[0038] The processor 11 further controls the electromagnetic induction receiving device 1 to generate and output different control instructions in two or more consecutive (or adjacent) transmission cycles. For example, taking three consecutive transmission cycles as a group, the processor 11 outputs control instruction 1 in the first transmission cycle of each group, outputs control instruction 2 in the second transmission cycle of each group, and outputs control instruction 3 in the third transmission cycle of each group. This cycle continues, and the processor 11 continues to output control instruction 1 in the first transmission cycle of the next group, continues to output control instruction 2 in the second transmission cycle of the next group, and continues to output control instruction 3 in the third transmission cycle of the next group. In this embodiment, the control instruction is related to the time length of the transmission cycle, that is, it is related to the time duration of the corresponding transmission cycle, that is, the duration of the transmission cycle forms the control instruction. The processor 11 outputs the corresponding control instruction to the signal processing circuit 15 according to the difference in the transmission cycle. The signal processing circuit 15 controls the resonance circuit 17 to generate resonance and continue the preset duration according to the control instruction. The preset duration determines the time duration of the transmission cycle. Through the resonant circuit 17 , the electromagnetic induction receiving device 1 sends a control instruction to the electromagnetic induction input device 2 in each transmitting cycle, or supplies power and sends a control instruction at the same time, and receives feedback from the electromagnetic induction input device 2 in each receiving cycle.

[0039] In one embodiment, the electromagnetic induction receiving device 1 further includes a user input unit 19, which includes one or more input units 191. Two input units 191 are shown in the figure. Each input unit 191 is configured to be operated by a user to generate user input. The processor 11 is further configured to receive user input on the electromagnetic induction receiving device 1 and generate the control instruction based on the input. For example, one of the input units 191 is configured to be operated by a user to obtain an identification code pre-stored in the electromagnetic induction input device 2. When the user triggers this input unit 191, the processor 11 generates a matching control instruction based on the state of this input unit 191 and controls the duration of the electromagnetic induction signal emitted by the resonant circuit according to the control instruction. When two or more transmission cycles are bundled into a group, if the user triggers the input unit 191, the processor 11 generates a matching control instruction within the corresponding transmission cycle of a group, and the control instruction causes the electromagnetic induction input device 2 to feedback the pre-stored identification code to the electromagnetic induction receiving device 1; if the user does not trigger the input unit 191, the processor 11 generates another matching control instruction within the corresponding transmission cycle of the group, and the control instruction does not cause the electromagnetic induction input device 2 to feedback the pre-stored identification code.

[0040] See also Figure 3 , which is a circuit block diagram of the electromagnetic induction input device 2 generating and sending input information (and feedback). In this embodiment, the electromagnetic induction input device 2 includes a resonance circuit 21, a potential conversion circuit 22, a voltage divider and rectifier circuit 23, a microcontroller unit 24, a switch circuit 251, a pressure sensing circuit 252, and a feedback transmission control circuit 27. The microcontroller unit 24 includes a comparator 24A and a counter 24B, which are integrated into the microcontroller unit 24. In this embodiment, the switch circuit 251 and the pressure sensing circuit 252, these input units, together constitute the user input unit 25 of the electromagnetic induction input device 2, which generates input signals based on user operations and sends them to the microcontroller unit 24. In other embodiments, the input units in the user input unit 25 can be configured according to actual needs, for example, only including the switch circuit 251 or only including the pressure sensing circuit 252, or may also include other circuits for user input, such as a touch sensing circuit.

[0041] Inside the electromagnetic induction input device 2, the resonance circuit 21 is electrically connected to the potential conversion circuit 22, the voltage division rectification circuit 23 and the feedback transmission control circuit 27 respectively. Outside the electromagnetic induction input device 2, the resonance circuit 21 is coupled with the electromagnetic induction receiving device 1 and configured to receive power supply from the electromagnetic induction receiving device 1. Since the electromagnetic induction signal transmitted by the electromagnetic induction receiving device 1 has a duration as the "control instruction", or the time length of power supply in each transmission cycle when the electromagnetic induction receiving device 1 supplies power to the electromagnetic induction input device at the same time, in the embodiment, the resonance circuit 21 is configured to obtain the control instruction from the electromagnetic induction receiving device 1, or receive power supply and obtain the control instruction.

[0042] The potential conversion circuit 22 is electrically connected to the resonance circuit 21, the voltage division rectification circuit 23 and the micro control unit 24, and is configured to convert the control instruction obtained by the resonance circuit 21 from the resonance signal into an alternating current signal centered on a reference voltage VDD1. In the embodiment, the number of alternating current signals can reflect the duration of the electromagnetic induction signal transmitted by the electromagnetic induction receiving device 1 to the electromagnetic induction input device 2, so the alternating current signal can also be called a clock signal, which is output to the micro control unit 24.

[0043] When the electromagnetic induction input device 2 is a passive input device, the voltage division rectification circuit 23 is configured to rectify and boost the power supplied by the resonance circuit 21 to provide power VDD2 to other power consumption sites, and at the same time generate a reference voltage VDD1 by voltage division to provide to the micro control unit 24 as a reference voltage for the micro control unit 24 to count the number of clock signals. When the electromagnetic induction input device 2 is a passive input device, the voltage division rectification circuit 23 can be replaced by a voltage division circuit to generate a reference voltage VDD1 to provide to the micro control unit 24.

[0044] The micro control unit 24 is configured to work based on the power provided by the voltage division rectification circuit 23, and count the number of clock signals continuously received from the potential conversion circuit 22 based on the reference voltage provided by the voltage division rectification circuit 23. Specifically, the micro control unit 24 counts the number of clock signals continuously received in one transmission cycle of the electromagnetic induction receiving device 1, identifies the control instruction according to the number of received clock signals, and executes the control instruction corresponding to the duration, for example, reads the state of the switch circuit 25 or the pressure data of the pressure sensing circuit 26 connected thereto according to the control instruction, and generates a corresponding control signal to output to the feedback transmission control circuit 27.

[0045] Please refer to Figure 4As shown, it is an internal module diagram of the micro control unit 24, which is internally provided with a first comparison module 241, a counting module 242, a second comparison module 243, a control instruction identification module 244 and a control signal generation module 245. Specifically, in the present embodiment, the first comparison module 241 is a comparator 24A, and a clock signal and a reference voltage VDD1 are provided to the positive and negative input terminals of the comparator 24A respectively. The counting module 242 is a counter 24B, which counts the number of clock signals by counting the output of the comparator 24A. The second comparison module 243 can be a comparison circuit, which compares the number of clock signals counted by the counting module 242 with a preset clock signal number interval, so as to identify the clock signal number interval into which the counted clock signal number falls. The control instruction identification module 244 identifies the control instruction output by the electromagnetic induction receiving device 1 according to the clock signal number interval into which it falls. The control signal generation module 245 reads the state of the switch circuit 25 or the pressure induction circuit 26 connected thereto or the pre-stored data (such as the identification code of the electromagnetic induction input device 2) according to the identified control instruction, and generates a corresponding control signal output to the feedback sending control circuit 27.

[0046] Please refer to Figure 4 and Figure 5A , Figure 5A is an exemplary clock signal number interval-port-control signal ASK correspondence table provided in the micro control unit 24. In the present embodiment, the switch circuit 251 comprises one or more switch branches, Figure 4Two switch branches 2511, 2512 are shown in FIG. 5, each of which is electrically connected with one switch, and each of which is connected with one switch state reading port of the micro control unit 24. Two switch state reading ports K1 and K2 are shown in FIG. 5, and the two switch branches 2511, 2512 are connected with the two switch state reading ports K1, K2 in a one-to-one correspondence. If the number of the continuously received clock signals counted by the micro control unit 24 is located in a certain interval, and the certain interval is set in the micro control unit 24 to correspond to one switch state reading port, then the micro control unit 24 reads the state or data of the corresponding switch state reading port according to the corresponding relationship, and generates a corresponding control signal ASK according to the state or data. In FIG. 5, the switch state reading port K1 corresponds to the certain interval Z1, the certain interval Z1 corresponds to the control signal ASK1, and the switch state reading port K2 corresponds to the certain interval Z2 and the certain interval Z2 corresponds to the control signal ASK2. The pressure sensing circuit 252 is electrically connected with the pressure sensor 2521, and the pressure sensor 2521 is used to sense the magnitude of the pressure applied to a certain position of the electromagnetic induction input device 2. The pressure sensing circuit 251 is connected with the pressure data reading port K3 of the micro control unit 24. If the number of the continuously received clock signals counted by the micro control unit 24 is located in another certain interval Z3, and the other certain interval Z3 is set in the micro control unit 24 to correspond to the pressure data reading port K3, then the micro control unit 24 reads the data of the pressure data reading port K3 according to the corresponding relationship, and generates a corresponding control signal ASK3 according to the data.

[0047] Please refer to Figure 4 and Figure 5B , Figure 5B The table of the clock signal number interval-control signal ASK corresponding relationship set in the micro control unit 24 is shown by way of example. In the present embodiment, if the number of the continuously received clock signals counted by the micro control unit 24 is located in a certain interval Z4, and the certain interval is set in the micro control unit 24 to correspond to the pre-stored information 1 in the electromagnetic induction input device 2, such as the identification code of the electromagnetic induction input device 2, then the micro control unit 24 reads the pre-stored information 1 according to the corresponding relationship, and generates a corresponding control signal ASK4 according to the read identification code. If the number of the continuously received clock signals counted by the micro control unit 24 is located in a certain interval Z5, and the certain interval is set in the micro control unit 24 to correspond to the pre-stored information 2 in the electromagnetic induction input device 2, such as the relevant parameters of the electromagnetic induction input device 2, then the micro control unit 24 reads the pre-stored information 2 according to the corresponding relationship, and generates a corresponding control signal ASK5 according to the read information 2. And so on, which are not listed one by one here.

[0048] The feedback transmission control circuit 27 is configured to control the resonance circuit 21 to transmit electromagnetic wave carrying corresponding information (i.e. feedback) to the electromagnetic induction receiving device 1 according to the control signal ASK generated by the micro control unit 24. It can be understood that the electromagnetic induction receiving device 1 is in the receiving mode at this time. It can be understood that the electromagnetic induction receiving device 1 is switched between the transmitting mode and the receiving mode, in the transmitting mode, the electromagnetic induction receiving device 1 outputs control instruction to the electromagnetic induction input device 2 through its resonance circuit (or antenna), or also provides power supply at the same time. While in the receiving mode, the electromagnetic induction receiving device 1 receives feedback from the electromagnetic induction input device 2, i.e. receives electromagnetic wave transmitted by the electromagnetic induction input device 2, and analyzes the information carried by the electromagnetic wave, which corresponds to the control instruction output by the electromagnetic induction receiving device 1. It can be understood that the electromagnetic induction receiving device can also receive information while transmitting information.

[0049] Please refer to Figure 6 , which is a specific circuit diagram of an embodiment of the present application. In the present embodiment, the voltage dividing and rectifying circuit 23 comprises a rectifying circuit 231 and a voltage dividing circuit 232. The output end of the resonance circuit 21 is connected with the input end of the rectifying circuit 231, the output end of the rectifying circuit 231 is connected with the comparator 24A, which supplies power for the comparator 24A, and the output end of the rectifying circuit 231 is also connected with the input end of the voltage dividing circuit 232. The output end of the voltage dividing circuit 232 is connected with the first input end of the comparator 24A. The input end of the potential converting circuit 22 is connected with the output end of the resonance circuit 21 and the voltage dividing circuit 232, and the output end of the potential converting circuit 22 is connected with the second input end of the comparator 24A. The output end of the comparator 24A is connected with the counter 24B.

[0050] The resonant circuit 21 is an LC resonant circuit comprising an input and an output, and an inductor L1 and a capacitor C1 connected in parallel therebetween. The potential conversion circuit 22 comprises a resistor R1 and a capacitor C2. One end of the resistor R1 (i.e., the input of the potential conversion circuit 22) is connected to the output of the resonant circuit 21, and the other end is connected to the capacitor C2. The end of the capacitor C2, remote from the resistor R1, is connected to the input of the resonant circuit 21. The connection point between the resistor R1 and the capacitor C2 constitutes the output of the potential conversion circuit 22, which is then connected to the microcontroller unit 24. The rectifier circuit 231 comprises rectifier diodes D1 and D2. In this embodiment, the voltage divider circuit 232 is a two-way voltage divider circuit comprising capacitors C3 and C4 connected in series. The anode of the rectifier diode D1 and the cathode of the rectifier diode D2 are connected via a capacitor C5 to form the input of the rectifier circuit 231, which is then connected to the output of the resonant circuit 21. Capacitors C3 and C4 are connected in series between the cathode of rectifier diode D1 and the anode of rectifier diode D2. Capacitor C4 and the anode of rectifier diode D2 are both grounded. The junction of capacitors C3 and C4 forms the output of voltage divider circuit 232. The output of voltage divider circuit 232 is connected to microcontroller unit 24, thereby outputting reference voltage VDD1 generated at this output to microcontroller unit 24. The junction of rectifier diode D1 and capacitor C3 (i.e., the output of rectifier circuit 231 and the input of voltage divider circuit 232) is connected to microcontroller unit 24, thereby providing the voltage generated at this output as power supply VDD2 for microcontroller unit 24. Furthermore, the junction of rectifier diode D1 and capacitor C3 is also grounded via capacitor C6.

[0051] It can be understood that the rectifier circuit 231 is used to convert AC into DC, and can be implemented in other ways, such as a rectifier half-bridge or full-bridge.

[0052] It can be understood that the connection in this application refers to an electrical connection, which can be a direct electrical connection between the two or an electrical connection via a third party.

[0053] The switch circuit 251 is connected with the pressure sensing circuit 252 and the micro control unit 24. In the embodiment, the switch circuit 251 includes two switch branches 2511 and 2512. The switch branch 2511 includes a switch S1, one end of which is connected with the micro control unit 24 and the other end is grounded. The switch branch 2512 includes a switch S2, one end of which is connected with the micro control unit 24 and the other end is grounded. The switches S1 and S2 can be key switches, toggle switches, inductive switches, etc. and are not limited in particular. The pressure sensing circuit 252 includes a pressure sensor 2521, one end of which is connected with the micro control unit 24 and the other end is connected with the power supply VDD2 through a resistor R2. The pressure sensing circuit 252 further includes a resistor R3 and a capacitor C7 connected in series between the micro control unit 24 and the ground. The end of the pressure sensing circuit 252 connected with the micro control unit 24 is further connected to a connection point between the resistor R3 and the capacitor C7.

[0054] The micro control unit 24 is provided with a plurality of ports, including switch state reading ports connected with the switch circuit 251, in the embodiment, switch state reading ports K1 and K2 connected with the switch branches 2511 and 2512 respectively, and a pressure data reading port K3 connected with the pressure sensing circuit 252. In the embodiment, the pressure data reading port K3 includes pressure data reading ports K31 and K32, and the pressure data is obtained through the combination of the two pressure data reading ports K31 and K32. The micro control unit 24 further includes a clock signal receiving port K4 connected with the potential conversion circuit 22, a reference voltage receiving port K5 connected with the voltage dividing and rectifying circuit 23, and a power supply port VDD. In addition, the micro control unit 24 further includes a ground port VSS and a control signal output port K6 outputting a control signal ASK.

[0055] The feedback sending control circuit 27 includes a control switch circuit 271. The control switch circuit 271 includes a control end and two conducting ends, i.e. a first conducting end and a second conducting end. The control end controls the two conducting ends to be conductive or non-conductive to each other by receiving a control signal ASK. The first conducting end is connected to the input end of the resonant circuit 21 through an anti-reverse circuit 272, and the second conducting end is connected to the output end of the resonant circuit 21. In the embodiment, the anti-reverse circuit 272 includes a diode D3, and the control switch circuit 271 includes a switch tube, the control end and the conducting ends of which correspond to the control end and the conducting ends of the control switch circuit 271 respectively. In the embodiment, the switch tube is an NMOS tube, the gate, the drain and the source of which correspond to the control end, the first conducting end and the second conducting end of the control switch circuit 271 respectively. The gate and the source are further connected with a resistor R4. In other embodiments, the switch tube can also be a PMOS, a triode, etc. and is not limited in particular.

[0056] When the electromagnetic induction receiving device 1 transmits an electromagnetic signal, the resonant circuit 21 resonates, drawing electrical energy from the electromagnetic induction receiving device 1. This energy is rectified and boosted by the voltage divider rectifier circuit 23, generating power supply VDD2 at the junction of the rectifier diode D1 and capacitor C3. Power supply VDD2 is supplied to the power port VDD of the microcontroller unit 24 and the pressure sensing circuit 252, serving as the power supply for the internal circuits of the electromagnetic induction input device 2. Simultaneously, a reference voltage VDD1 is generated at the output of the voltage divider circuit 232. In this embodiment, by appropriately matching the capacitance values ​​of C3 and C4, the reference voltage VDD1 can be half the voltage of the power supply VDD2. Of course, in other embodiments, the relationship between the reference voltage VDD1 and the power supply VDD2 can be different, for example, the reference voltage VDD1 being one-third the voltage of the power supply VDD2, and this is not a limitation here.

[0057] At the same time, the resonant circuit 21 resonates and generates electromagnetic waves, which are output to the potential conversion circuit 22 and converted by the potential conversion circuit 22 into an AC signal centered around the reference voltage VDD1, i.e., a clock signal. In this embodiment, by properly matching the resistance value of resistor R1 with the capacitance value of capacitor C2, the resonant signal can be converted into a clock signal centered around the reference voltage VDD1. A clock signal centered around the reference voltage VDD1 is generated at the output of the potential conversion circuit 22 and output to the clock signal receiving port K4 of the microcontroller unit 24. The reference voltage VDD1 is output to the reference voltage receiving port K5 of the microcontroller unit 24. A first comparison module 241 within the microcontroller unit 24 compares the clock signal with the reference voltage VDD1. A counting module 242 counts the number of clock signals by counting the output of the first comparison module 241. Based on the counted number of clock signals, the control instruction issued by the electromagnetic induction receiving device 1 is identified. Based on the control instruction, the corresponding input of the user input unit 25 or pre-stored information, such as a pre-stored identification code, is read. A corresponding control signal ASK is generated based on the corresponding input of the user input unit.

[0058] In this embodiment, the control signal ASK generated by the microcontroller unit 24 varies depending on the input from the user input unit 25. For example, assuming that the microcontroller unit 24 recognizes that the control instruction from the electromagnetic induction receiving device 1 is to transmit pressure data to the electromagnetic induction receiving device 1, the microcontroller unit 24 reads the data from the pressure data reading port K3 and generates a control signal ASK3 based on the pressure data. The switch within the feedback transmission control circuit 27 is turned on or off based on the control signal ASK3, thereby controlling the resonant circuit 21 to transmit information to the electromagnetic induction receiving device 1 in a corresponding manner. For example, the pressure data reflects the pressure level. When the pressure is within a relatively large range, the generated control signal ASK3 remains high for a relatively long time, thereby controlling the switch to be on for a relatively long time. When the pressure is within a relatively small range, the generated control signal ASK3 remains high for a relatively short time, thereby controlling the switch to be on for a relatively short time. If no pressure data is read, for example, when the user pauses writing and the writing area of ​​the electromagnetic induction input device 2 leaves the electromagnetic induction receiving device 1, the pressure sensing circuit 251 does not sense the applied pressure. The generated control signal ASK3 remains low, and the switch is not conducting. For another example, assuming that the microcontroller unit 24 identifies the control instruction from the electromagnetic induction receiving device 1 as sending the state of the switch branch 2511 to the electromagnetic induction receiving device 1, the microcontroller unit 24 reads the state of the switch state reading port K1 and generates a control signal ASK1 based on the read state. The switch within the feedback transmission control circuit 27 is turned on or off based on the control signal ASK1, thereby controlling the resonant circuit 21 to transmit information to the electromagnetic induction receiving device 1 in a corresponding manner. For example, if the switch S1 within the switch branch 2511 is triggered, the transmitted control signal ASK1 is high, and the switch is conducting. If the switch S1 within the switch branch 2511 is not triggered, the transmitted control signal ASK1 remains low, and the switch is not conducting.

[0059] It can be understood that when the microcontroller unit 24 generates the control signal ASK, the resonant circuit 21 generates a resonant electromagnetic wave. Depending on whether the switch tube is turned on or off and the length of time it is turned on, the electromagnetic wave sent by the resonant circuit 21 to the electromagnetic induction receiving device 1 is also different, thereby allowing the electromagnetic induction receiving device 1 to obtain relevant information, such as whether the switch S1 or S2 is triggered or not, whether the pressure sensor 2521 senses pressure, the magnitude of the sensed pressure, and so on, which are not limited here.

[0060] Furthermore, switches S1 and S2 may be associated with different functions in different embodiments. For example, in one embodiment, switch S1 is associated with the identification code (i.e., ID) of the electromagnetic induction input device 2. This identification code is stored in a storage unit 28. The storage unit 28 may be a read-only memory, random access memory, non-volatile memory, or other storage unit manufactured using existing storage technologies, or the storage unit 28 may be composed of a combination of different types of memories. The storage unit 28 may be located inside or outside the microcontroller unit 24. Figure 3 As an example, the storage unit 28 is shown to be located outside the microcontroller unit 24. When triggered, the microcontroller unit 24 reads the identification code from the storage unit 28, and the generated control signal ASK1 carries the identification code. For example, the generated control signal ASK1 carries this identification code through the change of high and low levels. If the identification code is 101101, the level of the control signal ASK1 corresponds to "high-low-high-low-high", where "high" refers to a high level and "low" refers to a low level. The switch S2 is associated with the handwriting color. For example, when the switch S2 is triggered and input is performed using the electromagnetic induction input device 2, the handwriting color is red, and when it is not triggered, the handwriting color is black, and so on. There is no limitation here.

[0061] In addition, the number of switches can be configured as needed, for example, only one switch branch and one switch can be provided, for example, only switch branch 2511 and switch S1 can be provided. More than two switch branches and more than two switches can also be provided.

[0062] It is understood that when the identification code pre-stored in the electromagnetic induction input device 2 needs to be sent to the electromagnetic induction receiving device 1, in one embodiment, the user can trigger the transmission of the identification code pre-stored in the electromagnetic induction input device 2 to the electromagnetic induction receiving device 1 by operating the input unit 191 on the electromagnetic induction receiving device 1. In another embodiment, the user can trigger the transmission of the identification code pre-stored in the electromagnetic induction input device 2 to the electromagnetic induction receiving device 1 by operating a corresponding switch on the electromagnetic induction input device 2.

[0063] In addition, the pressure sensing circuit 252 may be provided or not provided as required.

[0064] See also Figure 7 As shown, a control method for an electromagnetic induction receiving device provided in one embodiment of the present application, the control method for the electromagnetic induction receiving device includes the following operations.

[0065] In operation 701 , a control instruction is generated.

[0066] In operation 703 , an electromagnetic induction signal is generated and a duration of the electromagnetic induction signal is controlled according to the control instruction, so that the electromagnetic induction input device executes the control instruction based on the duration of the electromagnetic induction signal.

[0067] In one embodiment, the control instruction is configured to control the electromagnetic induction input device to send a specific user input or a specific identification code.

[0068] In one embodiment, operation 701 “generating a control instruction” may specifically be receiving an input performed by a user on the electromagnetic induction receiving device and generating the control instruction according to the input.

[0069] See also Figure 8 As shown, in one embodiment, the control method of the electromagnetic induction receiving device further includes the following operations.

[0070] In operation 801, two or more consecutive transmission cycles are grouped together.

[0071] In operation 803 , within each group, the duration of the electromagnetic induction signal in each transmission cycle is set to be different from the duration of the electromagnetic induction signals in other transmission cycles.

[0072] In operation 805 , a control instruction corresponding to the transmission cycle is generated.

[0073] See also Figure 9 As shown, a control method for an electromagnetic induction input device provided in one embodiment of the present application, the control method for the electromagnetic induction input device includes the following operations.

[0074] In operation 901, an electromagnetic induction signal sent by the electromagnetic induction receiving device is received.

[0075] In operation 903 , the duration of the electromagnetic induction signal is determined.

[0076] In operation 905 , a control instruction corresponding to the duration is executed.

[0077] The control instruction is an instruction for feeding back specific information, and the electromagnetic induction input device emits electromagnetic waves containing the specific information based on the instruction.

[0078] In this embodiment, the control instruction is related to the duration of the electromagnetic induction signal in the transmission cycle, that is, the duration of the transmission cycle. In other words, within a transmission cycle, the duration of the electromagnetic induction signal forms or constitutes the control instruction.

[0079] See also Figure 10As shown, in one embodiment, operation 903 further includes the following operations.

[0080] In operation 1001, the electromagnetic induction signal is processed into a clock signal.

[0081] In operation 1002 , the number of the clock signals is counted to determine the duration of the electromagnetic induction signal.

[0082] In one embodiment, operation 1001 further includes: converting the electromagnetic signal into an AC signal centered around a reference voltage, and the clock signal is the AC signal.

[0083] See also Figure 11 As shown, in one embodiment, operation 1002 further includes the following operations.

[0084] In operation 1101 , the electromagnetic signal is converted into an AC signal centered around a reference voltage, and the clock signal is the AC signal.

[0085] In operation 1103 , the comparison results are counted to obtain the number of the clock signals.

[0086] In this embodiment, the clock signal is processed by the potential conversion circuit 22 into an AC signal centered around the reference voltage VDD1 , ie, a clock signal. The clock signal is output to the micro control unit 24 .

[0087] In this embodiment, the first comparison module 241 within the microcontroller unit 24 compares the clock signal with the reference voltage VDD1 and outputs the comparison result to the counting module 242. For each portion of the clock signal that is higher than the reference voltage VDD1, the first comparison module 241 outputs a high level, and for each portion that is equal to or lower than the reference voltage VDD1, the first comparison module 241 outputs a low level. The counting module 242 counts the number of clock signals by counting the number of high levels received.

[0088] See also Figure 12 , in one embodiment, operation 905 further includes the following operations.

[0089] In operation 1201 , it is determined whether the counted number of clock signals falls within a preset clock signal number interval.

[0090] In operation 1203 , the control instruction is identified according to the preset clock signal quantity interval into which the counted number of clock signals falls.

[0091] In this embodiment, the second comparison module 243 of the micro control unit 24 reads the preset clock signal quantity interval from the storage unit 28, compares the counted clock signal quantity with the preset clock signal quantity interval, and determines the clock signal quantity interval into which the clock signal quantity interval falls.

[0092] Specifically, in this embodiment, the second comparison module 243 first determines whether the number of counted clock signals is located in the specific interval Z1. If it is determined that the number of counted clock signals is not located in the specific interval Z1, it continues to determine whether the number of counted clock signals is located in the specific interval Z2. If it is determined that the number of counted clock signals is not located in the specific interval Z2, it continues to determine whether the number of counted clock signals is located in the specific interval Z3.

[0093] The number of specific sections matches the number of input units in the user input unit 25 available for the user to perform input, so in other embodiments, the number of specific sections may be more or less than three.

[0094] In this embodiment, the control instruction recognition module 244 determines the port corresponding to the clock signal quantity interval according to the preset clock signal quantity interval-port-control signal ASK correspondence table, thereby identifying the control instruction output by the electromagnetic induction receiving device 1.

[0095] Specifically, in this embodiment, if it is determined that the number of counted clock signals is in a specific interval Z1, the corresponding port is determined to be the switch status reading port K1 according to the preset clock signal number interval-port-control signal ASK correspondence table, thereby identifying the control instruction as "sending the status of the switch branch 2511 to the electromagnetic induction receiving device 1".

[0096] If it is determined that the number of counted clock signals is in a specific interval Z2, then according to the preset correspondence table of clock signal number interval-port-control signal ASK, the corresponding port is determined to be the switch status reading port K2, thereby identifying the control instruction as "sending the status of switch branch 2512 to the electromagnetic induction receiving device 1".

[0097] If it is determined that the number of counted clock signals is in a specific interval Z3, then according to the preset correspondence table of clock signal number interval-port-control signal ASK, the corresponding port is determined to be the switch state reading port K3, thereby identifying the control instruction as "sending pressure data to the electromagnetic induction receiving device 1".

[0098] In one embodiment, see Figure 12 , operation 905 may further include the following operations.

[0099] In operation 1205, based on the identified control instruction, a specific user input corresponding to the control instruction is obtained, and the specific user input is fed back to the electromagnetic induction receiving device; or, based on the identified control instruction, a pre-stored identification code is obtained, and the identification code is fed back to the electromagnetic induction receiving device.

[0100] In one embodiment, the micro control unit 24 obtains a specific user input corresponding to the control instruction according to the identified control instruction.

[0101] Specifically, the control signal generation module 245 of the micro control unit 24 reads the status or data of the corresponding input unit in the user input unit 25 according to the identified control instruction, and generates a corresponding control signal ASK to output to the feedback transmission control circuit 27 .

[0102] In this embodiment, if the identified control instruction is "sending the status of the switch branch 2511 to the electromagnetic induction receiving device 1", the status of the switch status reading port K1 corresponding to the switch branch 2511 is read, and the corresponding control signal ASK1 is generated according to the status of the switch status reading port K1.

[0103] If the identified control instruction is "send the state of the switch branch 2512 to the electromagnetic induction receiving device 1", the state of the switch state reading port K2 corresponding to the switch branch 2512 is read, and the corresponding control signal ASK2 is generated according to the state of the switch state reading port K2.

[0104] If the identified control instruction is "send pressure data to the electromagnetic induction receiving device 1", the state of the pressure data reading port K3 corresponding to the pressure sensing circuit 252 is read, and a corresponding control signal ASK3 is generated according to the state of the pressure data reading port K3.

[0105] Finally, the feedback transmission control circuit 27 controls the resonance circuit 21 to feed back the specific user input or pre-stored information to the electromagnetic induction receiving device 1 .

[0106] Feedback transmission control circuit 27 controls resonant circuit 21 based on control signal ASK to generate a resonant signal containing relevant information corresponding to the control command, thereby feeding back the specific user input to electromagnetic induction receiving device 1, allowing electromagnetic induction receiving device 1 to obtain the relevant information. In this way, electromagnetic induction input device 2 completes one input to electromagnetic induction receiving device 1.

[0107] In this embodiment, for example, switch S1 is associated with the identification code of electromagnetic induction input device 2. If control signal generation module 245 generates control signal ASK1, control signal ASK1 carries the identification code. For example, if the identification code is 101101, the level of control signal ASK1 corresponds to "high-low-high-high-low-high." Under control of control signal ASK1, feedback transmission control circuit 27 switches its switch on or off accordingly, thereby affecting the resonant signal generated by resonant circuit 21 and causing it to carry the identification code. By transmitting the identification code of electromagnetic induction input device 2 to electromagnetic induction receiving device 1, electromagnetic induction receiving device 1 can associate the identification code of electromagnetic induction input device 2 with one or more specific programs. For example, electromagnetic induction receiving device 1 can associate the identification code of electromagnetic induction input device 2 with a digital signature program, serving as a unique authentication source for the digital signature.

[0108] To sum up, compared with the prior art, the electromagnetic induction input device 2, electromagnetic induction receiving device 1 and electronic device 100 provided by the present application use the duration, i.e., the time length, of the electromagnetic induction signal sent by the electromagnetic induction receiving device 1 to the electromagnetic induction input device 2 as a "control instruction". After the electromagnetic induction input device 2 parses the control instruction, it sends the corresponding input information to the electromagnetic induction receiving device 1. Therefore, the present application only needs to use a fixed frequency to achieve the coordinated use between the electromagnetic induction receiving device 1 and the electromagnetic induction input device 2, and does not require a wide bandpass. In this way, the chance of noise entering is reduced, and the chance of interference is reduced, which not only simplifies the design but also increases reliability.

[0109] The above description is merely an embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An electromagnetic induction input device, characterized in that: It includes a resonance circuit, a rectifier circuit, a comparator, a voltage divider circuit, a potential conversion circuit and a counter, wherein: The output end of the resonant circuit is connected to the input end of the rectifier circuit; The output end of the rectifier circuit is connected to the comparator to supply power to the comparator; The output end of the rectifier circuit is also connected to the input end of the voltage divider circuit; The output end of the voltage divider circuit is connected to the first input end of the comparator; The input end of the potential conversion circuit is connected to the output end of the resonance circuit and the voltage divider circuit, and the output end of the potential conversion circuit is connected to the second input end of the comparator; and The output terminal of the comparator is connected to the counter.

2. The electromagnetic induction input device according to claim 1, wherein: The device further comprises a micro control unit, wherein the comparator and the counter are integrated into the micro control unit.

3. The electromagnetic induction input device according to claim 2, wherein: A user input unit is also included. The user input unit includes a switch circuit. The switch circuit includes a switch. The switch is triggered to generate a user input.

4. The electromagnetic induction input device according to claim 2, wherein: The resonant circuit is an LC resonant circuit including an inductor and a first capacitor connected in parallel between the input end and the output end of the resonant circuit.

5. The electromagnetic induction input device according to claim 4, characterized in that The potential conversion circuit includes a first resistor and a second capacitor, one end of the first resistor is connected to the output end of the resonance circuit, and the other end is connected to the second capacitor, an end of the second capacitor away from the first resistor is connected to the input end of the resonance circuit, and the connection point between the first resistor and the second capacitor is connected to the second input end of the comparator to output the clock signal to the second input end of the comparator.

6. The electromagnetic induction input device according to claim 5, characterized in that The rectifier circuit includes a first rectifier element and a second rectifier element, and the voltage divider circuit includes a third capacitor and a fourth capacitor connected in series. The anode of the first rectifier element and the cathode of the second rectifier element are connected to the input end of the resonant circuit. The third capacitor and the fourth capacitor are connected in series between the cathode of the first rectifier element and the anode of the second rectifier element in sequence. The fourth capacitor and the anode of the second rectifier element are grounded in common. The connection between the third capacitor and the fourth capacitor is connected to the micro control unit to provide the reference voltage to the micro control unit; the connection between the first rectifier element and the third capacitor is connected to the micro control unit to power the micro control unit.

7. The electromagnetic induction input device according to claim 6, characterized in that: It also includes a control switch circuit, which includes a control end and a first conduction end and a second conduction end. The control end is connected to the micro control unit, and controls the first conduction end and the second conduction end to be connected or disconnected with each other by receiving the control signal. The first conduction end is connected to the input end of the resonant circuit, and the second conduction end is connected to the output end of the resonant circuit.

8. The electromagnetic induction input device according to claim 7, characterized in that: A backflow prevention circuit is connected between the first conduction end of the control switch circuit and the input end of the resonance circuit.

9. The electromagnetic induction input device according to claim 8, characterized in that The control switch circuit includes a MOS transistor, and the gate, drain and source of the MOS transistor respectively form the control end, the first conduction end and the second conduction end of the control switch circuit.

10. An electronic device, characterized in that: The electronic device comprises the electromagnetic induction input device according to any one of claims 1-9.

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