CN217982351U

CN217982351U - Digital electromagnetic pen system

Info

Publication number: CN217982351U
Application number: CN202222115814.2U
Authority: CN
Inventors: 朱少雄
Original assignee: Shenzhen Hezhong Lituo Technology Co ltd; Shenzhen Yike Technology Co ltd
Current assignee: Shenzhen Hezhong Lituo Technology Co ltd; Shenzhen Yike Technology Co ltd
Priority date: 2022-08-11
Filing date: 2022-08-11
Publication date: 2022-12-06
Anticipated expiration: 2032-08-11

Abstract

The utility model relates to a digital electromagnetic pen system. Digital electromagnetic pen system includes the passive electromagnetic pen of electromagnetism several board and digit, and the electromagnetism several board includes: a transmitting circuit module; the analog switch module is electrically connected with the transmitting circuit module; the driving circuit module is electrically connected with the analog switch module; and an antenna module electrically connected with the driving circuit module, the digital passive electromagnetic pen including: an LC resonance module; the power management module is electrically connected with the LC resonance module; the MCU module is electrically connected with the power management module; and the pressure detection module is electrically connected with the MCU module. The digital electromagnetic pen system can improve the pressure measurement precision of the pen point of the digital passive electromagnetic pen.

Description

Digital electromagnetic pen system

Technical Field

The utility model relates to a computer input equipment technical field, more specifically, the utility model relates to a can improve digital electromagnetic pen system of the pressure measurement precision of the nib of digital passive electromagnetic pen.

Background

The electromagnetic pen can be divided into a digital electromagnetic pen and an analog electromagnetic pen in the technical scheme of principle realization. In general, digital electromagnetic pens have better stability than analog electromagnetic pens. At present, digital electromagnetic pens in mass production all adopt a capacitive pressure sensor, which determines the magnitude of pressure applied to a pen point by detecting the charging and discharging time of a pressure variable capacitor. For a digital passive electromagnetic pen, an antenna of the electromagnetic digitizer tablet transmits an electromagnetic signal, and then an LC resonance circuit in the electromagnetic pen receives the electromagnetic signal to extract energy as power supply, so that even if the number of turns of the transmitting antenna is increased, when the electromagnetic pen is at the highest working height, the current which can be stably supplied to the electromagnetic pen by the electromagnetic digitizer tablet is only about 100 uA. However, the low power consumption MCU in the electromagnetic pen generally needs at least 150uA of current when in operation. In order to further reduce power consumption, the MCU of the electromagnetic pen generally operates with a low main frequency. In addition, when the charging and discharging time of the pressure variable capacitor is calculated, the MCU of the electromagnetic pen frequently enters a power saving mode for saving power, only the interrupt controller and the counter are left to work, and a clock signal timed by the counter is provided by the LC resonance circuit. The frequency of the transmission signal of the general electromagnetic digital panel is between 500 and 700KHz, if the transmission frequency is increased, all devices need to adopt high-frequency devices, so that the cost is increased sharply, and the frequency of the transmission signal of the electromagnetic digital panel cannot be increased. The frequency of the transmission signal of the electromagnetic digitizer tablet is consistent with the resonance frequency of the LC resonance circuit, so the LC resonance frequency is lower, thereby making the frequency of the clock signal lower. The frequency of the clock signal and the main frequency of the MCU of the electromagnetic pen are both low, so that the pressure measurement precision is reduced.

In addition, if the pressure of the electromagnetic pen reaches 1024 steps and the resonance frequency of 500KHz, the timing time length required to be changed is 2.048 milliseconds, and if the pressure of 8192 steps is required to be reached, the timing time length required to be changed is more than 16 milliseconds, and the timing time length is longer by adding the basic charging and discharging timing time length when no pressure exists. When the electromagnetic pen draws a line on the electromagnetic digitizer tablet, the moving distance of the electromagnetic pen can reach 10 cm within 16 milliseconds, and the electromagnetic pen is far away from an antenna in a working state, so that the pen dropping phenomenon can be caused, and therefore, when high-order pressure measurement data are sent, an interpolation method is generally adopted, and the pressure measurement value is not very accurate.

On the other hand, if the pressure sensor adopts a resistance type pressure sensor, a resistor with a fixed resistance value and a voltage variable resistor are connected in series between a power supply and the ground, the pressure is measured by measuring the voltage change value on the voltage variable resistor, the A/D converter of the general ultra-low power consumption MCU is 10bit or 12bit, namely, when the voltage changes from GND to VCC (when the reference voltage of the ADC is VCC), the pressure sense only has 1024 steps or 4096 steps, and the voltage divided from the fixed resistor is removed, so that the maximum resolution of the ADC is not reached. Because the power consumption is lower, the resistance value of the voltage variable resistor is generally required to be in the mega ohm level, and the accuracy and consistency of the sensor resistor in the level are difficult to control, so that the mass production is difficult to realize.

Therefore, a technology capable of improving the pressure measurement accuracy of the pen tip of the digital passive electromagnetic pen is required.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information constitutes prior art already known to a person skilled in the art.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problem in the prior art, the utility model provides an embodiment provides a can improve digital electromagnetic pen system of the pressure measurement precision of the nib of digital passive electromagnetic pen.

The technical problem to be solved by the present invention is not limited to the above-mentioned problems, and any other technical problems not mentioned herein will be clearly understood by those skilled in the art from the following description.

According to the utility model discloses an embodiment, a digital electromagnetism pen system, it includes: electromagnetism tablet and the passive electromagnetism pen of digit, wherein, electromagnetism tablet includes: a transmit circuit module configured to output a first transmit signal; an analog switch module electrically connected with the transmit circuit module and configured to: when receiving a first transmission signal from the transmission circuit module, turning on a port for outputting the first transmission signal, thereby causing the first transmission signal to be output via the selected port; a driving circuit module electrically connected to the analog switch module and configured to output a second transmission signal based on the first transmission signal received from the analog switch module, wherein the power of the second transmission signal is greater than the power of the first transmission signal; and an antenna module electrically connected to the driving circuit module and configured to transmit a second transmission signal output by the driving circuit module, the digital passive electromagnetic pen including: an LC resonance module configured to receive a second transmission signal transmitted by the antenna module of the electromagnetic digitizer tablet, generate a resonance signal as a first power supply signal, and a power management module electrically connected to the LC resonance module, and configured to output a first control signal and a second control signal based on the resonance signal generated by the LC resonance module, and output a stable second power supply signal; the MCU module is electrically connected with the power management module, is configured to receive the first control signal and the second control signal from the power management module and output a third control signal based on the first control signal and the second control signal; and the pressure detection module is electrically connected with the MCU module and is configured to detect the pressure applied to the pen point based on a third control signal output by the MCU module, so that the detected pressure measurement data of the pen point is transmitted to the electromagnetic digitizer, wherein the MCU module and the pressure detection module supply power by using a second power supply signal output by the power supply management module.

Preferably, the analog switch module comprises a one-out-of-multiple analog switch chip, and the one-out-of-multiple analog switch chipThe analog switch chip comprises a first pin X ₀ To Mth pin X _M-1 And a switch common pin Y.

Preferably, the driving circuit module includes M drivers, and the M drivers are respectively connected to the first pin X ₀ To Mth pin X _M-1 And (4) connecting.

Preferably, the antenna module includes M antennas, and the M antennas are respectively connected to the M drivers.

Preferably, each of the M drivers includes a first resistor, a second resistor, a third resistor, a first NMOS transistor and a PMOS transistor, wherein a first end of the first resistor, a first end of the second resistor and a gate of the first NMOS transistor are respectively connected to the first pin X ₀ To Mth pin X _M-1 The second end of the first resistor and the source electrode of the first NMOS tube are respectively grounded, the second end of the second resistor is respectively connected with the drain electrode of the PMOS tube and the corresponding antenna in the M antennas, the drain electrode of the first NMOS tube is respectively connected with the first end of the third resistor and the grid electrode of the PMOS tube, and the second end of the third resistor and the source electrode of the PMOS tube are respectively connected with the power supply VDD.

Preferably, the LC resonance module includes a first inductor and a first capacitor, the power management module includes a power signal extraction sub-module, the power signal extraction sub-module includes a first diode and a second capacitor, and a part of the resonance signal generated by the LC resonance module is rectified by the first diode and then formed into the first power supply by the second capacitor.

Preferably, the power management module further includes a power supply duration detection sub-module, the power supply duration detection sub-module includes a transmission signal detection circuit, a first not gate, an integration circuit, a second not gate, a fourth resistor and a fifth resistor, another part of the resonance signals generated by the LC resonance module outputs a high level signal via the transmission signal detection circuit, the high level signal output by the transmission signal detection circuit is converted into a low level signal by the first not gate, the low level signal output by the first not gate is output to the MCU module as a first control signal via the fourth resistor, and the low level signal output by the first not gate integrates duration of the signal by the integration circuit, when the duration of the low level signal output by the first not gate is greater than a predetermined threshold time, the second not gate outputs a high level signal, and the high level signal output by the second not gate is output to the MCU module as a second control signal via the fifth resistor.

Preferably, the power management module further includes a power supply voltage stabilization submodule, which includes a low-dropout linear voltage stabilization chip, a sixth resistor, a third capacitor and a second diode, wherein a high level signal output by the power supply time duration detection submodule passes through the sixth resistor and is input into the low-dropout linear voltage stabilization chip through a high level enable pin of the low-dropout linear voltage stabilization chip, a signal output by an output pin of the low-dropout linear voltage stabilization chip is transmitted to the enable pin through the second diode, so that the power supply voltage stabilization submodule outputs a stable second power supply signal, and the second power supply signal is formed into a second power supply by using the third capacitor, thereby providing stable power supply for the MCU module and the pressure detection module.

Preferably, the MCU module includes an MCU chip having an interrupt controller and a counter, the MCU chip is connected to an external high-speed clock source, the external high-speed clock source supplies power by using a second power source, and the counter counts by using the external high-speed clock source.

Preferably, the emission signal detection circuit includes a third diode, a fourth capacitor and a seventh resistor, an input end of the third diode is connected to an output end of the LC resonance module, the fourth capacitor and the seventh resistor are connected in parallel, an output end of the third diode is connected to first ends of the fourth capacitor and the seventh resistor respectively and to an input end of the first not gate, and second ends of the fourth capacitor and the seventh resistor are grounded.

Preferably, the integrating circuit includes a fourth diode, an eighth resistor, and a fifth capacitor, a first end of the fifth capacitor is connected to the output end of the power signal extraction submodule, an output end of the first not gate is connected to an input end of the fourth diode and a first end of the eighth resistor, respectively, and an output end of the fourth diode is connected to a second end of the fifth capacitor, a second end of the eighth resistor, and an input end of the second not gate, respectively.

Preferably, the pressure detection module includes a comparator, a pressure sensor, a second NMOS tube, a ninth resistor and a tenth resistor, a positive phase input terminal of the comparator is connected to the first terminal of the ninth resistor, the first terminal of the pressure sensor and the drain electrode of the second NMOS tube, a negative phase input terminal of the comparator inputs a reference voltage, a gate of the second NMOS tube is connected to the first I/O pin of the MCU chip via the tenth resistor, a second terminal of the ninth resistor is connected to the power supply VCC, a second terminal of the pressure sensor and a source electrode of the second NMOS tube are grounded, an output terminal of the comparator is connected to the MCU module, and the pressure sensor is a capacitive pressure sensor.

Preferably, the digital passive electromagnetic pen further comprises a data transmission module, the data transmission module comprises an eleventh resistor and a third NMOS tube, a drain electrode of the third NMOS tube is connected to an output end of the LC resonance module and an input end of the power management module, a gate electrode of the third NMOS tube is connected to the second I/O pin of the MCU chip via the eleventh resistor, a source electrode of the third NMOS tube is grounded, pressure measurement data of the pen tip detected by the pressure detection module is input to the data transmission module via the second I/O pin of the MCU chip, and is transmitted to the electromagnetic digitizer tablet via the LC resonance module.

Preferably, the MCU chip further includes an MCU internal high-speed clock source, and the counter is capable of counting by using the MCU internal high-speed clock source.

Preferably, the one-out-of-multiple analog switch chip comprises a one-out-of-two analog switch chip, a one-out-of-four analog switch chip, an one-out-of-eight analog switch chip and a one-out-of-sixteen analog switch chip.

The utility model adopts the above technical scheme, it has following beneficial effect:

1) The power of the electromagnetic signal transmitted by the antenna of the electromagnetic digitizer tablet is improved, so that the power of the electromagnetic signal received by the LC resonance circuit of the digital passive electromagnetic pen is improved, the power supply of the digital passive electromagnetic pen is enhanced, the MCU of the electromagnetic pen can work under a higher main frequency, and a clock signal timed by the counter of the digital passive electromagnetic pen can be provided by an internal high-speed clock source of the MCU of the electromagnetic pen or an external high-speed clock source connected with the MCU of the electromagnetic pen, so that the pressure measurement precision of the pen point of the digital passive electromagnetic pen can be improved, and the reporting speed of the electromagnetic digitizer tablet can not be reduced;

2) In the process that the electromagnetic digitizer determines the position of the electromagnetic pen, the MCU of the electromagnetic pen is not powered, so that the LC resonance signal intensity of the electromagnetic pen is not greatly reduced, and the signal intensity remained on the LC resonance circuit is stronger, so that the position of the electromagnetic pen can be easily determined by the electromagnetic digitizer, continuous energy supply is kept, and the induction height of the electromagnetic pen is not reduced;

3) The distance between electromagnetic pen and the electromagnetism several board is when near more, the voltage that the electromagnetic pen induction was come out is just higher, the MCU's of electromagnetic pen power supply is just higher, the consumption of electromagnetic pen is just big this moment, in-process in the pressure of nib is applyed in the measurement, utilize the linear steady voltage chip of low dropout to provide stable power supply for MCU and the pressure sensor of electromagnetic pen, thereby the consumption of the electromagnetic pen that leads to when having avoided the distance between electromagnetic pen and the electromagnetism several board near is too big, make holistic consumption control in less scope.

Drawings

Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. For purposes of clarity, the same reference numbers will be used in different drawings to identify the same elements. It is noted that the drawings are merely schematic and are not necessarily drawn to scale. In these drawings:

fig. 1 shows a schematic diagram of a digital electromagnetic pen system according to an embodiment of the present invention.

Fig. 2 shows a block diagram of a circuit of an electromagnetic digitizer in a digital electromagnetic pen system according to an embodiment of the present invention.

Fig. 3 shows a circuit schematic of an electromagnetic digitizer tablet according to an embodiment of the present invention.

Fig. 4 shows a block diagram of a digital passive electromagnetic pen circuit in a digital electromagnetic pen system according to an embodiment of the present invention.

Fig. 5 shows a schematic circuit diagram of a digital passive electromagnetic pen according to an embodiment of the present invention.

Detailed Description

Various modifications and various exemplary embodiments can be made in the present invention, such that certain exemplary embodiments are shown in the drawings and described in detail in the specification. It should be understood, however, that the exemplary embodiments are not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In describing each of the figures, like reference numerals are used for like components. The terms "first," "second," and the like may be used to describe various components, but these components should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first component can be termed a second component, and, similarly, a second component can also be termed a first component, without departing from the scope of the present invention. The term "and/or" includes a combination of a plurality of the associated listed items or any one of the plurality of the associated listed items.

The following is a detailed description of the embodiments of the present invention, which is implemented on the premise of the technical solution of the present invention, and detailed embodiments and specific operation processes are given, but the scope of the present invention is not limited to the following embodiments.

The specific circuit structure and operation principle of the digital electromagnetic pen system according to the present invention will be described with reference to fig. 1 to 5.

Fig. 1 shows a schematic diagram of a digital electromagnetic pen system according to an embodiment of the present invention. Fig. 2 shows a block diagram of a circuit of an electromagnetic digitizer tablet in a digital electromagnetic pen system according to an embodiment of the present invention. Fig. 3 shows a schematic circuit diagram of an electromagnetic digitizer in a digital electromagnetic pen system according to an embodiment of the present invention. Fig. 4 shows a block diagram of a digital passive electromagnetic pen circuit in a digital electromagnetic pen system according to an embodiment of the present invention. Fig. 5 shows a schematic circuit diagram of a digital passive electromagnetic pen according to an embodiment of the present invention.

Referring to fig. 1 to 5, a digital electromagnetic pen system according to an embodiment of the present invention includes an electromagnetic digitizer 10 and a digital passive electromagnetic pen 20. The electromagnetic digitizer 10 includes a transmitting circuit module 110, an analog switch module 120, a driving circuit module 130, and an antenna module 140, wherein the transmitting circuit module 110 is configured to output a first transmitting signal S1; the analog switch module 120 is electrically connected to the transmission circuit module 110, and is configured to, when receiving the first transmission signal S1 from the transmission circuit module 110, turn on a port for outputting the first transmission signal S1, so that the first transmission signal S1 is output via the selected port; the driving circuit module 130 is electrically connected to the analog switch module 120 and configured to output a second transmission signal S2 based on the first transmission signal S1 received from the analog switch module 120, wherein the power of the second transmission signal S2 is greater than the power of the first transmission signal S1; the antenna module 140 is electrically connected to the driving circuit module 130, and is configured to transmit the second transmitting signal S2 output by the driving circuit module 130. The digital passive electromagnetic pen 20 comprises an LC resonance module 210, a power management module 220, an MCU module 230 and a pressure detection module 240, wherein the LC resonance module 210 is configured to receive a second transmission signal S2 transmitted by the antenna module 140 of the electromagnetic tablet 10 and generate a resonance signal as a first power signal; the power management module 220 is electrically connected to the LC resonance module 210, and is configured to output a first control signal SC1 and a second control signal SC2 based on a resonance signal generated by the LC resonance module 210, and output a stable second power signal; the MCU module 230 is electrically connected to the power management module 220, and is configured to receive the first control signal SC1 and the second control signal SC2 from the power management module 220, and output a third control signal SC3 based on the first control signal SC1 and the second control signal SC 2; the pressure detection module 240 is electrically connected to the MCU module 230 and configured to detect a pressure applied to the pen tip based on a third control signal SC3 output by the MCU module 230, so as to transmit detected pressure measurement data of the pen tip to the electromagnetic digitizer tablet 10, wherein the third control signal SC3 controls discharge of the pressure variable capacitor in the pressure detection module 240, and after the discharge of the pressure variable capacitor is completed, the pressure detection module 240 and the MCU module 230 detect the pressure applied to the pen tip. According to the utility model discloses an embodiment, MCU module 230 and pressure detection module 240 utilize the second power signal of power management module 220 output to supply power.

Referring to fig. 2 and 3, according to an embodiment of the present invention, the transmitting circuit module 110 includes an MCU chip U1. The analog switch module 120 includes a one-out-of-multiple analog switch chip SW1 (e.g., 74HCT4051PW chip), and the one-out-of-multiple analog switch chip SW1 includes a first pin X ₀ To Mth pin X _M-1 And a switch common pin Y, and the one-out-of-multiple analog switch chip SW1 includes at least one of a one-out-of-two analog switch chip, a one-out-of-four analog switch chip, an one-out-of-eight analog switch chip, and a one-out-of-sixteen analog switch chip.

The driving circuit module 130 includes M drivers, and the M drivers are respectively connected to the first pin X ₀ To Mth pin X _M-1 And (4) connecting.

The antenna module 140 includes M antennas ANT, and the M antennas ANT are respectively connected to the M drivers.

Specifically, each of the M drivers includes a first resistor R1, a second resistor R2, a third resistor R3, a first NMOS transistor Q1, and a PMOS transistor Q2. The first end of the first resistor R1, the first end of the second resistor R2 and the grid of the first NMOS transistor Q1 are respectively connected with the first pin X ₀ To Mth pin X _M-1 The second end of the first resistor R1 and the source electrode of the first NMOS tube Q1 are respectively grounded, the second end of the second resistor R2 is respectively connected with the drain electrode of the PMOS tube Q2 and corresponding antennas in the M antennas ANT, the drain electrode of the first NMOS tube Q1 is respectively connected with the first end of the third resistor R3 and the grid electrode of the PMOS tube Q2, and the second end of the third resistor R3 and the source electrode of the PMOS tube Q2 are respectively connected with the power supply VDD.

According to the embodiment of the present invention, referring to fig. 3, the third resistor R3 is a PMOS transistor Q2 gridPulling up the resistor, when the electromagnetic digitizer 10 emits, if one more pin X of the analog switch chip SW1 is selected ₀ And outputting a high-level signal, turning on the first NMOS transistor Q1, and pulling down the gate of the PMOS transistor Q2, so that the PMOS transistor Q2 is turned on, and thus the power supply VDD is directly applied to the antenna ANT. If one selects more first pin X of analog switch chip SW1 ₀ When a low level signal is output, the first NMOS transistor Q1 is turned off, and since the third resistor R3 exists, the gate of the PMOS transistor Q2 is at a high level, and thus the PMOS transistor Q2 is also turned off. In other words, the antenna ANT is directly driven by the power supply VDD. When the electromagnetic digitizer tablet 10 receives, a signal on the antenna ANT is input to the signal amplifying circuit sequentially through the second resistor R2 and the one-out-of-multiple analog switch chip SW 1. The resistance of the first resistor R1 is far smaller than that of the second resistor R2, the driver is an amplifying circuit, the second resistor R2 is equivalent to a positive feedback resistor, the circuit is unstable when no signal is transmitted and can perform self-oscillation, the feedback quantity is reduced because the resistance of the first resistor R1 is far smaller than that of the second resistor R2, the circuit can stably work when no signal exists, and the function of the whole driver cannot be influenced because the PMOS transistor Q2 works in a switching state. Accordingly, the first transmit signal S1 output by the transmit circuit module 110 is amplified by the driver, so that the corresponding antenna ANT connected to the driver transmits the amplified second transmit signal S2.

The utility model discloses an in the embodiment, through add a driver before every antenna in the electromagnetism several board (thereby form the drive circuit module), improved the power of the electromagnetic signal of the antenna transmission via the electromagnetism several board to the power of the electromagnetic signal that the LC resonance circuit of having improved via the passive electromagnetism pen of digit received. Under this condition, the power supply of the passive electromagnetic pen of digit is strengthened, and the MCU of electromagnetic pen need not to get into power saving mode to the MCU of electromagnetic pen can work at higher dominant frequency. At this moment, the clock signal of the counter timing of the passive electromagnetic pen of digit can be provided by the inside high-speed clock source of MCU of electromagnetic pen, or provide through the outside high-speed clock source V1 of being connected with the MCU of electromagnetic pen to can improve the pressure measurement accuracy of the nib of the passive electromagnetic pen of digit.

Referring to fig. 4 and 5, the LC resonance module 210 of the digital passive electromagnetic pen 20 according to an embodiment of the present invention includes a first inductance L1 and a first capacitance C1.

The power management module 220 of the digital passive electromagnetic pen 20 comprises a power signal extraction submodule 221, wherein the power signal extraction submodule 221 comprises a first diode D1 and a second capacitor C2, and a part of resonance signals generated by the LC resonance module 210 are rectified by the first diode D1 and then formed into a first power supply by the second capacitor C2.

According to the related art, when the electromagnetic digitizer tablet works, the antenna is selected to transmit the electromagnetic signal in the transmitting state, and then the residual resonant electromagnetic signal on the electromagnetic pen is received through the selected antenna in the receiving state. When the position of the electromagnetic pen is determined, the electromagnetic digitizer transmits an electromagnetic signal on the antenna opposite to the electromagnetic pen, then receives a resonant electromagnetic signal, and at the moment, the energy supplied to the electromagnetic pen is continuous, and the electromagnetic pen can work normally. However, when the position of the electromagnetic pen is not determined, that is, in the process of determining the position of the electromagnetic pen by the electromagnetic digitizer, the electromagnetic digitizer scans each antenna in sequence or scans a part of the antennas at intervals, at this time, most of the time cannot provide energy for the electromagnetic pen, and when the antenna at the position of the electromagnetic pen is scanned, the power supply time is short. At this moment, if directly make all work of the device of the circuit on the electromagnetism pen, because the electric capacity needs the energy storage in addition on the electromagnetism pen, the MCU of electromagnetism pen also needs the electric current to move, whole circuit can draw down the intensity of the LC resonance signal on the passive electromagnetism pen, and the electromagnetism digit board stops the transmission back, and the last residual signal of LC resonance circuit is also extremely low, leads to the electromagnetism digit board can not find the electromagnetism pen. In addition, when the electromagnetic pen is higher than the electromagnetic digital board, the electromagnetic digital board can not find the electromagnetic pen, so that the electromagnetic pen does not have continuous energy supply and can not work normally, or the electromagnetic pen is forced to reduce the induction height. If the amplification times of the signals on the electromagnetic digital plate are increased, the noise signals are amplified, so that the signal-to-noise ratio of the electromagnetic digital plate is reduced, and the work is unstable.

In order to solve the above problem, according to the embodiment of the present invention, the power management module 220 further includes a power supply duration detection submodule 222, the power supply duration detection submodule 222 includes a transmission signal detection circuit, a first not gate U2, an integration circuit, a second not gate U3, a fourth resistor R4 and a fifth resistor R5, another part of the resonance signal generated by the LC resonance module 210 outputs a high level signal via the transmission signal detection circuit, the high level signal output by the transmission signal detection circuit is converted into a low level signal by the first not gate U2, the low level signal output by the first not gate U2 is output to the MCU module 230 via the fourth resistor R4 as a first control signal SC1, and the low level signal output by the first not gate U2 is integrated by the integration circuit for a duration of the signal, when the duration of the low level signal output by the first not gate U2 is greater than a predetermined threshold time, the second not gate U3 outputs a high level signal, and the high level signal output by the second not gate is output to the MCU module via the fifth resistor R5 as a second control signal SC 2. In the embodiment of the present invention, the first control signal SC1 is a transmission signal detection signal, and when the first control signal SC1 is at a low level, the digital passive electromagnetic pen 20 is instructed to receive the electromagnetic signal transmitted by the electromagnetic digitizer 10. The second control signal SC2 is a sync signal detection signal, and when the second control signal SC2 is at a high level, the digital passive electromagnetic pen 20 is instructed to receive the sync signal transmitted by the electromagnetic digitizer 10. When the MCU module 230 receives the first control signal SC1 and the second control signal SC2, the MCU module 230 outputs a high-level third control signal SC3 to the pressure detecting module 240, the third control signal SC3 controls the discharge of the pressure variable capacitor in the pressure detecting module 240, and the pressure detecting module 240 starts to detect the pressure applied to the pen tip after the discharge of the pressure variable capacitor is completed.

Further, according to the utility model discloses an embodiment, power management module 220 includes power regulator module 223, power regulator module 223 includes low dropout linear regulator chip (LDO) U4, sixth resistance R6, third electric capacity C3 and second diode D2, the high level signal of detecting submodule 222 output during by the power supply passes through sixth resistance R6, the high level via low dropout linear regulator chip U4 enables the pin input low dropout linear regulator chip U4, the signal via low dropout linear regulator chip U4's output pin transmits to enabling the pin through second diode D2, make power regulator module 223 output stable second power signal, second power signal utilizes third electric capacity C3 to form the second power supply, thereby provide stable power supply for MCU module 230 and pressure detection module 240.

According to the utility model discloses an embodiment, MCU module 230 includes the MCU chip, the MCU chip has interrupt controller and counter.

According to the utility model discloses an embodiment, the MCU chip is connected with outside high-speed clock source V1, outside high-speed clock source V1 utilizes the second power to supply power, and the counter utilizes outside high-speed clock source V1 to count. According to the utility model discloses a further embodiment, the MCU chip further includes the inside high-speed clock source of MCU, the counter utilizes the inside high-speed clock source of MCU to count. The clock frequency of the external high-speed clock source V1 is, for example, 4MHz, but is not limited thereto.

According to the utility model discloses an embodiment, the transmission signal detection circuitry includes third diode D3, fourth electric capacity C4 and seventh resistance R7, and third diode D3's input is connected with LC resonance module 210's output, fourth electric capacity C4 and seventh resistance R7 parallel connection, and third diode D3's output is connected and is connected to first not gate U2's input, fourth electric capacity C4 and seventh resistance R7's second end ground connection with fourth electric capacity C4 and seventh resistance R7's first end respectively.

According to the utility model discloses an embodiment, integrating circuit includes fourth diode D4, eighth resistance R8 and fifth electric capacity C5, and fifth electric capacity C5's first end is connected with the output of power signal extraction submodule 221, and first NOT gate U2's output is connected with fourth diode D4's input and eighth resistance R8's first end respectively, and fourth diode D4's output is connected with fifth electric capacity C5's second end, eighth resistance R8's second end and second NOT gate U3's input respectively.

According to an embodiment of the present invention, the pressure detection module 240 comprises a ratioThe comparator U5, the pressure sensor C6, the second NMOS tube Q3, the ninth resistor R9 and the tenth resistor R10, wherein the positive phase input end of the comparator U5 is respectively connected with the first end of the ninth resistor R9, the first end of the pressure sensor C6 and the drain electrode of the second NMOS tube Q3, and the negative phase input end of the comparator U5 inputs a reference voltage V _REF The grid electrode of the second NMOS tube Q3 is connected to a first I/O pin of the MCU chip through a tenth resistor R10, the second end of a ninth resistor R9 is connected with a power supply VCC, and the second end of the pressure sensor C6 and the source electrode of the second NMOS tube Q3 are grounded respectively. The pressure sensor C6 is a capacitive pressure sensor. The comparator U5 is, for example, but not limited to, a TS882 ultra-low power comparator chip.

According to the utility model discloses an embodiment, digital passive electromagnetic pen 20 further includes data transmission module 250, data transmission module 250 includes eleventh resistance R11 and third NMOS pipe Q4, and the drain electrode of third NMOS pipe Q4 is connected with LC resonance module 210's output and power management module 220's input respectively, and third NMOS pipe Q4's grid is connected to the second IO pin of MCU chip, third NMOS pipe Q4's source ground connection via eleventh resistance R11. The pressure measurement data of the pen tip detected by the pressure detection module 240 is input to the data transmission module 250 via the second I/O pin of the MCU chip, and is transmitted to the electromagnetic tablet 10 via the LC resonance module 210.

The operation of the digital electromagnetic pen system according to the present invention will be described in detail with reference to fig. 3 and 5. According to the embodiment of the present invention, the transmitting circuit module 110 outputs the first transmitting signal S1 containing the synchronization signal, the pressure detection communication signal and the coordinate scanning signal, and the first transmitting signal S1 passes through the analog switch module 120, is amplified into the second transmitting signal S2 by the driving circuit module 130, and is transmitted by the antenna module 140. The synchronization signal, the pressure detection communication signal and the coordinate scanning signal are all a series of square wave signals, and the signal duration of the synchronization signal is longer than the signal duration of the pressure detection communication signal and the coordinate scanning signal. Preferably, in order to clearly distinguish the synchronization signal from the pressure detection communication signal and the coordinate scanning signal, the duration of the synchronization signal is set to 10 times the duration of the pressure detection communication signal and the coordinate scanning signal, and the durations of the pressure detection communication signal and the coordinate scanning signal are substantially the same. The predetermined threshold time is set to be greater than the signal duration of both the pressure detection communication signal and the coordinate scanning signal and less than the signal duration of the synchronization signal.

According to the embodiment of the present invention, in the process of determining the position of the digital passive electromagnetic pen 20 by the electromagnetic digitizer 10, the electromagnetic digitizer 10 only transmits the coordinate scanning signal. Thus, in the process that the electromagnetic digitizer 10 determines the position of the passive digital electromagnetic pen 20, when the electromagnetic digitizer 10 transmits, the first inductor L1 and the first capacitor C1 in the LC resonance module 210 will resonate after receiving the transmission signal, and part of the energy is rectified by the first diode D1 and then stored in the second capacitor C2. Since the electromagnetic digitizer 10 only transmits the coordinate scanning signal at this time, when the transmission signal detection circuit composed of the third diode D3, the fourth capacitor C4 and the seventh resistor R7 receives the coordinate scanning signal, the transmission signal detection circuit outputs a high level signal, the high level signal is converted into a low level signal through the first not gate U2, the integration circuit composed of the fourth diode D4, the eighth resistor R8 and the fifth capacitor C5 integrates the low level signal, and since the duration of the received coordinate scanning signal is less than the predetermined threshold time, the second not gate U3 outputs a low level signal, that is, the synchronization signal is not detected. At this time, the enable pin of the low dropout linear regulator chip U4 inputs a low level signal, so that the low dropout linear regulator chip U4 enabled by a high level does not operate, and power is not supplied to the MCU module 230, the pressure detection module 240, and the like. In this case, the LC resonance signal strength will not be greatly reduced, and the signal strength remaining on the LC resonance module 210 will be stronger, so that the electromagnetic digitizer tablet 10 can easily determine the position of the digital passive electromagnetic pen 20, thereby maintaining continuous power supply, and not reducing the inductive height of the digital passive electromagnetic pen 20.

Then, after the electromagnetic digitizer board 10 determines the position of the digital passive electromagnetic pen 20, the electromagnetic digitizer board 10 sequentially transmits the synchronization signal, the pressure detection communication signal, and the coordinate scanning signal. At this time, when the transmitting signal detection circuit composed of the third diode D3, the fourth capacitor C4 and the seventh resistor R7 receives the synchronizing signal for the first time, the transmitting signal detection circuit outputs a high level signal, the high level signal is converted into a low level signal through the first not gate U2, the integrating circuit composed of the fourth diode D4, the eighth resistor R8 and the fifth capacitor C5 integrates the low level signal, and the second not gate U3 outputs the high level signal to the MCU module 230 because the duration of the received synchronizing signal is greater than the predetermined threshold time, that is, the MCU module 230 detects the synchronizing signal. At this time, the enable pin of the low dropout regulator U4 inputs a high level signal, so that the low dropout regulator U4 enabled at a high level operates. The high level signal output by the low dropout linear regulator chip U4 is transmitted to the enable pin via the second diode D2, so that the enable pin always keeps high level input, the power regulator module 223 outputs a stable second power signal, the second power signal is formed into a second power source by using the third capacitor C3, and stable power supply is provided for the MCU module 230, the pressure detection module 240, and the external high-speed clock source V1. When the distance between the digital passive electromagnetic pen 20 and the electromagnetic digitizer 10 changes, the intensity of the resonant signal of the LC resonance module 210 changes, and the closer the digital passive electromagnetic pen 20 is to the electromagnetic digitizer 10, the higher the energy received by the digital passive electromagnetic pen 20 is, the higher the intensity of the resonant signal of the LC resonance module 210 is, and the higher the voltage on the second capacitor C2 is. As is known, the power consumption of the MCU of the electromagnetic pen is related to the supply voltage, in addition to the main frequency of the operation, and when the supply voltage is higher, the operating current of the MCU of the electromagnetic pen is higher, so the power consumption is higher. The utility model provides a low dropout linear voltage regulation chip can avoid the electromagnetic pen to be too near from the electromagnetism several boards when, and supply voltage risees the work unstability that MCU and the follow-up circuit consumption that arouses the electromagnetic pen too big and lead to, makes the whole consumption control of electromagnetic pen in a less within range.

Meanwhile, after the MCU module 230 detects the sync signal, a high level signal is output via the I/O pin connected to the tenth resistor R10, the second NMOS transistor Q3 is turned on, the pressure sensor C6 (i.e., the pressure variable capacitor) starts to discharge, the second NMOS transistor Q3 is turned off immediately after the discharge is completed, and the counter is turned on to start counting, thereby starting to detect the pressure applied to the pen tip. When the signal level of the output end of the comparator U5 is inverted from low level to high level, the counting is stopped. When the tip pressure of the digital passive electromagnetic pen 20 changes, the capacitance value of the pressure sensor C6 also changes, the count value also changes, and pressure measurement data can be obtained by detecting the change in the count value. The pressure detection process is performed for the duration of the synchronization signal.

When the electromagnetic tablet 10 transmits a pressure detection communication signal to the digital passive electromagnetic pen 20, pressure measurement data of the pen tip detected by the pressure detection module 240 is input to the data transmission module 250 via the second I/O pin of the MCU chip, and is thus transmitted to the electromagnetic tablet 10 via the LC resonance module 210.

The utility model discloses a basis that above-mentioned embodiment is disclosed the utility model discloses a digital electromagnetic pen system of embodiment adds a driver before through every antenna in the electromagnetism several board, the power of the electromagnetic signal of the antenna emission via the electromagnetism several board has been improved, thereby the power of the electromagnetic signal that the LC resonant circuit received via the passive electromagnetic pen of digit received has been improved, make the power supply of the passive electromagnetic pen of digit strengthened, thereby make the MCU of electromagnetic pen can work at higher dominant frequency, and the clock signal of the counter timing of the passive electromagnetic pen of digit can be provided by the inside high-speed clock source of MCU of electromagnetic pen, or provide through the outside high-speed clock source of being connected with the MCU of electromagnetic pen, thereby can improve the pressure measurement precision of the nib of the passive electromagnetic pen of digit. If the clock frequency of the timing of the counter is 4MHz, the counter can count about 4000 times within 1 millisecond, if the resistance value of the ninth resistor R9 is increased, the counting time of the counter is prolonged, the pressure measurement precision of the electromagnetic pen can be greatly improved, and meanwhile, the point reporting speed of the electromagnetic digitizer tablet cannot be reduced. For example, as the clock frequency of the timing is increased from the frequency of the LC resonance signal (500 KHz) to 4MHz, the pressure measurement accuracy can be improved by about 8 times.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. The foregoing description is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously, many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application, to thereby enable others skilled in the art to utilize and implement the invention in various exemplary embodiments and various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the following claims and their equivalents.

Claims

1. A digital electromagnetic pen system comprises an electromagnetic digitizer and a digital passive electromagnetic pen, and is characterized in that,

the electromagnetic digitizer tablet includes:

a transmit circuit module configured to output a first transmit signal;

an analog switch module electrically connected with the transmit circuit module and configured to: when receiving a first transmission signal from the transmission circuit module, turning on a port for outputting the first transmission signal, thereby causing the first transmission signal to be output via the selected port;

a driving circuit module electrically connected to the analog switch module and configured to output a second transmission signal based on the first transmission signal received from the analog switch module, wherein the power of the second transmission signal is greater than the power of the first transmission signal; and

an antenna module electrically connected with the driving circuit module and configured to transmit a second transmission signal output by the driving circuit module,

the digital passive electromagnetic pen includes:

an LC resonance module configured to receive a second transmission signal transmitted by the antenna module of the electromagnetic digitizer pad, generate a resonance signal as a first power supply signal,

a power management module electrically connected to the LC resonance module and configured to output a first control signal and a second control signal based on a resonance signal generated by the LC resonance module and output a stable second power signal;

the MCU module is electrically connected with the power management module, is configured to receive the first control signal and the second control signal from the power management module and output a third control signal based on the first control signal and the second control signal;

a pressure detection module electrically connected with the MCU module and configured to detect a pressure applied to the pen tip based on a third control signal output from the MCU module, thereby transmitting detected pressure measurement data of the pen tip to the electromagnetic digitizer,

the MCU module and the pressure detection module supply power by using a second power supply signal output by the power supply management module.

2. The digital electromagnetic pen system of claim 1, wherein the analog switch module comprises a one-out-of-many analog switch chip comprising a first pin X ₀ To Mth pin X _M-1 And a switch common pin Y.

3. The digital electromagnetic pen system of claim 2, wherein the driving circuit module comprises M drivers, and the M drivers are respectively connected with the first pin X ₀ To Mth pin X _M-1 And (4) connecting.

4. The digital electromagnetic pen system of claim 3, wherein the antenna module comprises M antennas, and the M antennas are respectively connected with the M drivers.

5. The digital electromagnetic pen system of claim 4, wherein each of the M drivers comprises a first resistor, a second resistor, a third resistor, a first NMOS transistor, and a PMOS transistor, wherein,

the first end of the first resistor, the first end of the second resistor and the grid of the first NMOS tube are respectively connected with the first pin X ₀ To Mth pin X _M-1 The second end of the first resistor and the source electrode of the first NMOS tube are respectively grounded, and the second end of the second resistor and the PMOS tube are respectively connected with corresponding pinsThe drain electrode of the first NMOS tube is connected with the first end of the third resistor and the grid electrode of the PMOS tube respectively, and the second end of the third resistor and the source electrode of the PMOS tube are connected with a power supply VDD respectively.

6. The digital electromagnetic pen system of claim 1, wherein the LC resonance module comprises a first inductance and a first capacitance,

the power management module comprises a power signal extraction submodule which comprises a first diode and a second capacitor, and a part of resonance signals generated by the LC resonance module are rectified by the first diode and then form a first power supply by the second capacitor.

7. The digital electromagnetic pen system of claim 6, wherein the power management module further comprises a power supply duration detection submodule including a transmission signal detection circuit, a first not gate, an integration circuit, a second not gate, a fourth resistor and a fifth resistor, wherein another part of the resonance signals generated by the LC resonance module outputs a high level signal via the transmission signal detection circuit, the high level signal output by the transmission signal detection circuit is converted into a low level signal by the first not gate, the low level signal output by the first not gate is output to the MCU module as a first control signal via the fourth resistor, and the low level signal output by the first not gate integrates a duration of the signal by the integration circuit, and when the duration of the low level signal output by the first not gate is greater than a predetermined threshold time, the second not gate outputs a high level signal, and the high level signal output by the second not gate is output to the MCU module as a second control signal via the fifth resistor.

8. The digital electromagnetic pen system of claim 7, wherein the power management module further comprises a power supply voltage stabilization sub-module, the power supply voltage stabilization sub-module comprises a low dropout linear voltage stabilization chip, a sixth resistor, a third capacitor and a second diode, a high level signal output by the power supply time length detection sub-module is input to the low dropout linear voltage stabilization chip through the sixth resistor and a high level enable pin of the low dropout linear voltage stabilization chip, a signal output through an output pin of the low dropout linear voltage stabilization chip is transmitted to the enable pin through the second diode, the power supply voltage stabilization sub-module is enabled to output a stable second power supply signal, and the second power supply signal is formed as a second power supply by the third capacitor, so as to provide stable power supply for the MCU module and the pressure detection module.

9. The digital electromagnetic pen system of claim 8, wherein the MCU module comprises an MCU chip having an interrupt controller and a counter,

the MCU chip is connected with an external high-speed clock source, the external high-speed clock source supplies power by using a second power supply, and the counter counts by using the external high-speed clock source.

10. The digital electromagnetic pen system of claim 9, wherein the emission signal detection circuit comprises a third diode, a fourth capacitor and a seventh resistor, an input terminal of the third diode is connected to an output terminal of the LC resonance module, the fourth capacitor and the seventh resistor are connected in parallel, an output terminal of the third diode is connected to first terminals of the fourth capacitor and the seventh resistor, respectively, and to an input terminal of the first not gate, and second terminals of the fourth capacitor and the seventh resistor are grounded.

11. The digital electromagnetic pen system of claim 10, wherein the integration circuit comprises a fourth diode, an eighth resistor and a fifth capacitor, a first terminal of the fifth capacitor is connected to the output terminal of the power signal extraction submodule, an output terminal of the first not gate is connected to an input terminal of the fourth diode and a first terminal of the eighth resistor, respectively, and an output terminal of the fourth diode is connected to a second terminal of the fifth capacitor, a second terminal of the eighth resistor and an input terminal of the second not gate, respectively.

12. The digital electromagnetic pen system of claim 9, wherein the pressure detection module comprises a comparator, a pressure sensor, a second NMOS transistor, a ninth resistor and a tenth resistor, wherein a positive input terminal of the comparator is connected to a first terminal of the ninth resistor, a first terminal of the pressure sensor and a drain of the second NMOS transistor, respectively, a negative input terminal of the comparator inputs a reference voltage, a gate of the second NMOS transistor is connected to a first I/O pin of the MCU chip via the tenth resistor, a second terminal of the ninth resistor is connected to a power supply VCC, a second terminal of the pressure sensor and a source of the second NMOS transistor are grounded, respectively, an output terminal of the comparator is connected to the MCU module,

the pressure sensor is a capacitive pressure sensor.

13. The digital electromagnetic pen system of claim 12, wherein the digital passive electromagnetic pen further comprises a data transmission module, the data transmission module comprises an eleventh resistor and a third NMOS transistor, a drain electrode of the third NMOS transistor is respectively connected with an output end of the LC resonance module and an input end of the power management module, a gate electrode of the third NMOS transistor is connected to the second I/O pin of the MCU chip via the eleventh resistor, a source electrode of the third NMOS transistor is grounded,

pressure measurement data of the pen point detected by the pressure detection module are input into the data transmission module through a second I/O pin of the MCU chip, and are transmitted to the electromagnetic digitizer tablet through the LC resonance module.

14. The digital electromagnetic pen system of claim 9, wherein the MCU chip further comprises an MCU internal high-speed clock source, the counter capable of counting with the MCU internal high-speed clock source.

15. The digital electromagnetic pen system of claim 2, wherein the one-out-of-multiple analog switch chip comprises a one-out-of-two analog switch chip, a one-out-of-four analog switch chip, an one-out-of-eight analog switch chip, and a one-out-of-sixteen analog switch chip.