Coding voltage regulation circuit and electronic pen

Abstract

The utility model relates to the technical field of electronic pens, and discloses a coding voltage regulation circuit and an electronic pen, the coding voltage regulation circuit comprises a control circuit, a voltage division circuit and a voltage feedback regulation circuit, the control circuit receives the duty ratio of a PWM signal input by a user, regulates the gain of the voltage, regulates the duty ratio of the PWM signal and regulates the amplitude of the voltage, and outputs the voltage feedback regulation circuit. Therefore, the voltage at the feedback end of the DC-DC circuit is only controlled by the change of the duty ratio of the PWM signal or the change of the amplitude of the adjusting voltage, and the purpose of actively adjusting the coding voltage is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to electronic pen technical field, concretely relates to a kind of code voltage regulating circuit and electronic pen. BACKGROUND

[0002] Capacitance pen, especially active capacitance pen is often through stylus to touch screen output code signal to realize the data transmission to touch screen.But code signal is susceptible to environmental noise interference, in order to improve the anti-interference of code signal, generally set relatively high fixed voltage to be the amplitude of code voltage, but the traditional regulating mode such as fixed adjustment DC-DC FB voltage dividing resistor, once hardware production voltage is fixed value, there is poor flexibility in electronic pen application, code voltage cannot be adjusted according to the environmental noise in time behind. SUMMARY

[0003] Therefore, the utility model provides a kind of code voltage regulating circuit and electronic pen to solve how to actively adjust the problem of code voltage.

[0004] Firstly, the utility model provides a kind of code voltage regulating circuit, and the code voltage regulating circuit includes: control circuit, voltage dividing circuit, voltage feedback regulating circuit, wherein the first end of control circuit is connected with the first end of voltage feedback regulating circuit;The second end of voltage feedback regulating circuit is connected with the feedback end of DC-DC circuit in electronic pen, and the third end of voltage feedback regulating circuit is grounded;The first end of voltage dividing circuit is connected with the output end of DC-DC circuit, the second end of voltage dividing circuit is connected with the feedback end of DC-DC circuit, and the third end of voltage dividing circuit is grounded;Control circuit exports PWM signal or regulating voltage to voltage feedback regulating circuit, and voltage feedback regulating circuit feeds back PWM signal or regulating voltage to the feedback end of DC-DC circuit, so that the amplitude of code voltage exported by DC-DC circuit is controlled by the duty ratio of PWM signal or the amplitude of regulating voltage.

[0005] The utility model control circuit receives the duty ratio of PWM signal and the gain of regulating voltage input by user, adjusts the duty ratio of PWM signal and the amplitude of regulating voltage, while voltage dividing voltage is built-in pure resistance, voltage feedback regulating circuit is built-in pure resistance and capacitor, so that the voltage of feedback end of DC-DC circuit is only controlled by the change of duty ratio of PWM signal or the change of amplitude of regulating voltage, to realize the purpose of actively adjusting code voltage.

[0006] In an alternative embodiment, the voltage feedback adjusting circuit comprises a filter circuit, wherein a first end of the filter circuit is connected to the first end of the control circuit, a second end of the filter circuit is grounded, and a third end of the filter circuit is connected to the feedback end of the DC-DC circuit, and the filter circuit is configured to output a direct current voltage after filtering the PWM signal or the adjusting voltage.

[0007] In an alternative embodiment, the filter circuit comprises a first resistor and a first capacitor, wherein a first end of the first resistor is connected to the first end of the control circuit, a second end of the first resistor is connected to a first end of the first capacitor and the feedback end of the DC-DC circuit, and a second end of the first capacitor is grounded.

[0008] In an alternative embodiment, the voltage feedback adjusting circuit further comprises a second resistor, wherein the second end of the first resistor is connected to the feedback end of the DC-DC circuit through the second resistor.

[0009] In an alternative embodiment, the voltage dividing circuit comprises a third resistor and a fourth resistor, wherein a first end of the third resistor is connected to the output end of the DC-DC circuit, and a second end of the third resistor is connected to a first end of the fourth resistor and the feedback end of the DC-DC circuit.

[0010] In an alternative embodiment, the code printing voltage adjusting circuit further comprises an MCU control circuit, wherein the MCU control circuit is connected to the second end of the control circuit, and the MCU control circuit is configured to control the control circuit to adjust the duty cycle of the PWM signal or the amplitude of the adjusting voltage.

[0011] In an alternative embodiment, the code printing voltage adjusting circuit further comprises a wireless communication module, wherein the MCU control circuit receives a duty cycle control instruction or a gain control instruction through the wireless communication module, the duty cycle control instruction is configured to modify the duty cycle of the PWM signal, and the gain control instruction is configured to modify the amplitude of the adjusting voltage.

[0012] The utility model provides a kind of electronic pen, comprising: the voltage adjustment circuit of the first aspect and any optional implementation mode, DC-DC circuit and electronic pen body, wherein the first end of control circuit is connected with the first end of voltage feedback adjustment circuit;The second end of voltage feedback adjustment circuit is connected with the feedback end of DC-DC circuit, and the third end of voltage feedback adjustment circuit is grounded;The first end of voltage dividing circuit is connected with the output end of DC-DC circuit, the second end of voltage dividing circuit is connected with the feedback end of DC-DC circuit, and the third end of voltage dividing circuit is grounded;The output end of DC-DC circuit is connected with the coding part of electronic pen body, and DC-DC circuit is used to output coding voltage to coding part;Control circuit outputs PWM signal or adjustment voltage to voltage feedback adjustment circuit, and voltage feedback adjustment circuit feeds back PWM signal or adjustment voltage to the feedback end of DC-DC circuit, so that the amplitude of coding voltage output by DC-DC circuit is controlled by the duty cycle of PWM signal or the amplitude of adjustment voltage.

[0013] In an alternative embodiment, the DC-DC circuit comprises: a voltage conversion chip, a fifth resistor, a second capacitor, a third capacitor, a fourth capacitor, a first diode and a first inductor, wherein the input end of the voltage conversion chip inputs a supply voltage, the input end of the voltage conversion chip is connected with the first end of the first inductor, the first end of the fifth resistor and the first end of the second capacitor respectively, the enable end of the voltage conversion chip is connected with the second end of the fifth resistor, the output end of the voltage conversion chip is connected with the second end of the first inductor and the anode of the first diode respectively, the feedback end of the voltage conversion chip is connected with the second end of the voltage dividing circuit, the second end of the voltage feedback adjustment circuit and the first end of the third capacitor respectively, and the ground end of the voltage conversion chip is grounded; the second end of the second capacitor is grounded; the second end of the third capacitor is connected with the cathode of the first diode, the first end of the fourth capacitor and the coding part; and the second end of the fourth capacitor is grounded.

[0014] In an alternative embodiment, the electronic pen further comprises: a coding processing circuit, wherein the first end of the coding processing circuit is connected with the output end of the DC-DC circuit, the second end of the coding processing circuit is connected with the third end of the control circuit, and the third end of the coding processing circuit is connected with the coding part; and the coding processing circuit is used to condition the coding voltage. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the specific embodiments of the utility model or the technical solutions in the prior art, the drawings needed to be used in the following specific embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the utility model, and those skilled in the art can also obtain other drawings according to these drawings without creating creative labor.

[0016] Figure 1 is a component diagram of the coding voltage regulation circuit according to an embodiment of the present application;

[0017] Figure 2 is a specific circuit structure diagram of the coding voltage regulation circuit and the DC-DC circuit according to an embodiment of the present application;

[0018] Figure 3 is a voltage line graph of the regulated voltage and the DC-DC circuit output voltage according to an embodiment of the present application;

[0019] Figure 4 is a component diagram of another coding voltage regulation circuit according to an embodiment of the present application;

[0020] Figure 5 is a component diagram of another coding voltage regulation circuit according to an embodiment of the present application. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0022] In the present embodiment, a coding voltage regulation circuit is provided, as shown in Figure 1 The coding voltage regulation circuit comprises a control circuit, a voltage dividing circuit and a voltage feedback regulation circuit.

[0023] As shown in Figure 1 The first end of the control circuit is connected with the first end of the voltage feedback regulation circuit; the second end of the voltage feedback regulation circuit is connected with the feedback end of the DC-DC circuit in the electronic pen, and the third end of the voltage feedback regulation circuit is grounded; the first end of the voltage dividing circuit is connected with the output end of the DC-DC circuit, the second end of the voltage dividing circuit is connected with the feedback end of the DC-DC circuit, and the third end of the voltage dividing circuit is grounded.

[0024] Specifically, the DC-DC circuit comprises a voltage conversion circuit (i.e. a DC-DC chip) and its peripheral circuit, which is used to realize conversion and regulation of voltage and then output the coding voltage to the coding component. The voltage conversion circuit adjusts the amplitude of the coding voltage based on the voltage at its feedback end.

[0025] Specifically, the control circuit outputs a PWM signal or a regulating voltage to the voltage feedback regulating circuit, and the voltage feedback regulating circuit feeds back the PWM signal or the regulating voltage to the feedback end of the DC-DC circuit, so that the amplitude of the code voltage output by the DC-DC circuit is controlled by the duty cycle of the PWM signal or the amplitude of the regulating voltage.

[0026] Optionally, the control circuit receives the duty cycle of the PWM signal and the gain of the regulating voltage input by a user, adjusts the duty cycle of the PWM signal and the amplitude of the regulating voltage, and the voltage dividing voltage is a pure resistance, and the voltage feedback regulating circuit is a pure resistance and a capacitor, so that the voltage at the feedback end of the DC-DC circuit is only controlled by the change of the duty cycle of the PWM signal or the change of the amplitude of the regulating voltage, so as to achieve the purpose of actively regulating the code voltage.

[0027] It can be understood that when the PWM signal is input, the voltage at the feedback end of the DC-DC circuit is controlled by the average voltage value of the PWM signal.

[0028] In some optional embodiments, the voltage feedback regulating circuit comprises a filter circuit, wherein a first end of the filter circuit is connected to the first end of the control circuit, a second end of the filter circuit is grounded, and a third end of the filter circuit is connected to the feedback end of the DC-DC circuit, and the filter circuit is used to output a direct current voltage after filtering the PWM signal or the regulating voltage.

[0029] Optionally, as shown in Figure 2 , the filter circuit comprises a first resistor R1 and a first capacitor C1, wherein a first end of the first resistor R1 is connected to the first end of the control circuit respectively, a second end of the first resistor R1 is connected to a first end of the first capacitor C1 and the feedback end of the DC-DC circuit (i.e. the FB end of U1) respectively, and a second end of the first capacitor C1 is grounded. However, the filter circuit is not limited to the structure shown in Figure 2 , but can be other filter circuits for outputting a direct current signal, which is not limited herein.

[0030] Specifically, the first resistor R1 and the first capacitor C1 constitute an RC filter circuit to achieve the purpose of outputting only a direct current voltage.

[0031] Optionally, as shown in Figure 2 , the voltage feedback regulating circuit further comprises a second resistor R2, wherein the second end of the first resistor R1 is connected to the feedback end of the DC-DC circuit through the second resistor R2.

[0032] In some optional embodiments, as shown in Figure 2As shown, the voltage dividing circuit includes a third resistor R3 and a fourth resistor R4, wherein a first end of the third resistor R3 is connected to the output end of the DC-DC circuit, and a second end of the third resistor R3 is connected to a first end of the fourth resistor R4 and a feedback end of the DC-DC circuit respectively.

[0033] Optionally, the voltage dividing circuit is not limited to Figure 2 The structure in the figure can also be a plurality of pure resistors in series, parallel or series-parallel, which is not limited herein. The voltage dividing circuit feeds back the voltage divided from the output voltage of the DC-DC circuit to the feedback end of the DC-DC circuit, so that the DC-DC circuit adjusts the output voltage according to the voltage dividing closed loop.

[0034] Referring to Figure 2 After the voltage feedback adjusting circuit and the voltage dividing circuit are set, the voltage at the feedback end of the DC-DC circuit is only controlled by the duty ratio of the PWM signal and the amplitude of the adjusting voltage (i.e. VA), and the specific principle is as follows:

[0035] Figure 2 In the figure, IR2 = IR1 + IR3, that is, the current on R3 plus the current on R2 is equal to the current on R4. Solve IR3, since the PWM signal generates a direct current voltage through the filter circuit due to different duty ratios, the average input voltage at the left end of R1 is:

[0036] VPWMAVG = VPWMHigh * Duty (1)

[0037] Wherein, VPWMAVG is the average voltage; VPWMHigh is the high voltage value of the PWM signal; and Duty is the duty ratio of the PWM signal.

[0038] Alternatively, the input voltage at the left end of R1 is input by the DAC of the control circuit, and the 1 voltage is defined as VA (wherein VA is written only for the convenience of the following), therefore, IR3 = (VA-VFB) / (R1+R2).

[0039] Based on the above, the current output by the DC-DC circuit is:

[0040] IR1 = (VOUT-VFB) / R3 (2)

[0041] Wherein, VFB is the feedback end voltage of the DC-DC voltage.

[0042] Then the current from FB to GND is:

[0043] IR2 = VFB / R4 (3)

[0044] According to IR2 = IR1 + IR3, the following can be obtained:

[0045] VFB / R4 = (VOUT-VFB) / R3 + (VA-VFB) / (R1+R2) (4)

[0046] Based on formula (4), the output voltage expression of the DC-DC circuit is:

[0047] VOUT = VFB*[R3 / R4 + 1 + R3 / (R1+R2)] - VA*R3 / (R1+R2) (5)

[0048] In formula (5), according to the specification of the DC-DC circuit, VFB is a constant value, and the four resistors R1-R4 are constant values, then

[0049] B = VFB*[R3 / R4 + 1 + R3 / (R1+R2)] (6)

[0050] A = R3 / (R1+R2) (7)

[0051] Based on formula (5)-(7), the output voltage of the DC-DC circuit is:

[0052] VOUT = B-A*VA (8)

[0053] As can be seen from formula (8), VOUT is a linear equation of VA, and it is completely possible to use PWM or VA to adjust the output VOUT voltage, and the VOUT voltage is used as the driving voltage of the coding processing circuit to achieve the adjustment of the coding voltage.

[0054] Based on formula (8), a linear curve of VA and VOUT can be formulated. Assuming that R1=2K, R2=2K, R3=25K, R4=1K, and VFB=1.25V, the formula VOUT=36.75-9.4*VA is obtained. Assuming that the voltage range of VA can be set to (0-3.3V), then the corresponding relationship is as shown in Table 1, and any voltage from 19.69V to 40.31V can be achieved, and the linear curve is as shown in Figure 3 .

[0055] In some optional embodiments, as shown in Figure 4 , the coding voltage adjustment circuit further comprises an MCU control circuit, wherein the MCU control circuit is connected with the second end of the control circuit, and the MCU control circuit is used to control the control circuit to adjust the duty cycle of the PWM signal or adjust the amplitude of the voltage.

[0056] Specifically, the MCU control circuit can also control the running state of the DC-DC circuit or the state of the coding component, that is, the MCU control circuit can control the logic of the entire electronic pen.

[0057] Specifically, the DC-DC circuit can be internally provided with the DC-DC circuit body and the controller thereof, so as to achieve the purpose of high integration, and the controller can also be arranged outside the DC-DC circuit, wherein the controller can be an MCU control circuit, and the controller arranged outside the DC-DC circuit can be timely repaired when the DC-DC circuit is damaged.

[0058] In some optional embodiments, as shown in Figure 5 The code printing voltage regulating circuit further comprises a wireless communication module, wherein the MCU control circuit receives a duty cycle control instruction or a gain control instruction through the wireless communication module, the duty cycle control instruction is used to modify the duty cycle of the PWM signal, and the gain control instruction is used to modify the amplitude of the regulating voltage.

[0059] Specifically, when the system detects that the writing of the electronic pen is disturbed or the water is not smooth, different VA voltage values are automatically adjusted through an algorithm (by modifying the PWM duty cycle or the DAC output VA) to achieve the purpose of modifying the VOUT voltage, so as to adapt to different disturbance sources and improve the writing fluency.

[0060] Specifically, the DC-DC circuit can be internally provided with the DC-DC circuit body and the controller thereof, a wireless communication module, so as to achieve the purpose of high integration, and the controller and the wireless communication module can also be arranged outside the DC-DC circuit, and the wireless communication module arranged outside the DC-DC circuit can be timely repaired when the wireless communication module is damaged.

[0061] In the embodiment, an electronic pen is provided, which comprises the code printing voltage regulating circuit, the DC-DC circuit and the electronic pen body of the above embodiments and any optional embodiments thereof.

[0062] The first end of the control circuit is connected with the first end of the voltage feedback regulating circuit; the second end of the voltage feedback regulating circuit is connected with the feedback end of the DC-DC circuit, and the third end of the voltage feedback regulating circuit is grounded; the first end of the voltage dividing circuit is connected with the output end of the DC-DC circuit, the second end of the voltage dividing circuit is connected with the feedback end of the DC-DC circuit, and the third end of the voltage dividing circuit is grounded; the output end of the DC-DC circuit is connected with the code printing component of the electronic pen body, and the DC-DC circuit is used to output the code printing voltage to the code printing component.

[0063] The control circuit outputs the PWM signal or the regulating voltage to the voltage feedback regulating circuit, and the voltage feedback regulating circuit feeds back the PWM signal or the regulating voltage to the feedback end of the DC-DC circuit, so that the amplitude of the code printing voltage output by the DC-DC circuit is controlled by the duty cycle of the PWM signal or the amplitude of the regulating voltage.

[0064] In some optional embodiments, as shown in Figure 2As shown, the DC-DC circuit includes: a voltage conversion chip U1, a fifth resistor R5, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a first diode D1 and a first inductor L1.

[0065] like Figure 2 As shown, the input end of the voltage conversion chip U1 inputs the power supply voltage VIN, the input end of the voltage conversion chip U1 is respectively connected to the first end of the first inductor L1, the first end of the fifth resistor R5, and the first end of the second capacitor C2, the enable end of the voltage conversion chip U1 is connected to the second end of the fifth resistor R5, the output end of the voltage conversion chip U1 is respectively connected to the second end of the first inductor L1 and the anode of the first diode D1, the feedback end of the voltage conversion chip U1 is respectively connected to the second end of the voltage divider circuit, the second end of the voltage feedback regulation circuit, and the first end of the third capacitor C3, the ground end of the voltage conversion chip U1 is grounded; the second end of the second capacitor C2 is grounded; the second end of the third capacitor C3 is connected to the cathode of the first diode D1, the first end of the fourth capacitor C4, and the coding component; the second end of the fourth capacitor C4 is grounded.

[0066] Figure 2 In the embodiment, the voltage conversion chip U1 can step up or down the input voltage to obtain the coding voltage, and the first inductor L1, the second capacitor C2, the third capacitor C3 and the fourth capacitor C4 all realize filtering.

[0067] In some optional embodiments, the electronic pen further includes: a coding processing circuit, wherein a first end of the coding processing circuit is connected to the output end of the DC-DC circuit, a second end of the coding processing circuit is connected to the third end of the control circuit, and the third end of the coding processing circuit is connected to the coding component; the coding processing circuit is used to regulate the coding voltage.

[0068] Specifically, the coding voltage has a built-in voltage conditioning circuit that can condition the coding voltage. The conditioning process is not limited to de-jittering, filtering, impedance matching, etc., and is not limited here. Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A coding voltage regulating circuit, characterized in that: The coding voltage regulation circuit includes: a control circuit, a voltage divider circuit, and a voltage feedback regulation circuit, wherein: The first end of the control circuit is connected to the first end of the voltage feedback regulation circuit; The second terminal of the voltage feedback regulation circuit is connected to the feedback terminal of the DC-DC circuit in the electronic pen, and the third terminal of the voltage feedback regulation circuit is grounded; A first end of the voltage divider circuit is connected to the output end of the DC-DC circuit, a second end of the voltage divider circuit is connected to the feedback end of the DC-DC circuit, and a third end of the voltage divider circuit is grounded; The control circuit outputs a PWM signal or a regulated voltage to the voltage feedback regulation circuit, and the voltage feedback regulation circuit feeds back the PWM signal or the regulated voltage to the feedback end of the DC-DC circuit, so that the amplitude of the coding voltage output by the DC-DC circuit is controlled by the duty cycle of the PWM signal or the amplitude of the regulated voltage.

2. The coding voltage regulating circuit according to claim 1, characterized in that: The voltage feedback regulation circuit includes: a filter circuit, wherein: The first end of the filter circuit is connected to the first end of the control circuit, the second end of the filter circuit is grounded, and the third end of the filter circuit is connected to the feedback end of the DC-DC circuit. The filter circuit is used to filter the PWM signal or the regulated voltage and then output a DC voltage.

3. The coding voltage regulating circuit according to claim 2, characterized in that: The filter circuit includes: a first resistor and a first capacitor, wherein: The first end of the first resistor is respectively connected to the first end of the control circuit, and the second end of the first resistor is respectively connected to the first end of the first capacitor and the feedback end of the DC-DC circuit; The second terminal of the first capacitor is grounded.

4. The coding voltage regulating circuit according to claim 3, characterized in that: The voltage feedback regulation circuit further includes: a second resistor, wherein: The second end of the first resistor is connected to the feedback end of the DC-DC circuit through the second resistor.

5. The coding voltage regulating circuit according to claim 1, characterized in that: The voltage divider circuit includes: a third resistor and a fourth resistor, wherein: The first end of the third resistor is connected to the output end of the DC-DC circuit, and the second end of the third resistor is connected to the first end of the fourth resistor and the feedback end of the DC-DC circuit respectively.

6. The coding voltage regulating circuit according to claim 1, characterized in that: Also includes: MCU control circuit, where The MCU control circuit is connected to the second end of the control circuit, and the MCU control circuit is used to control the control circuit to adjust the duty cycle of the PWM signal or adjust the amplitude of the voltage.

7. The coding voltage regulating circuit according to claim 6, characterized in that: Also includes: Wireless communication module, wherein The MCU control circuit receives a duty cycle control instruction or a gain control instruction through the wireless communication module. The duty cycle control instruction is used to modify the duty cycle of the PWM signal, and the gain control instruction is used to modify the amplitude of the regulation voltage.

8. An electronic pen, characterized in that: include: The coding voltage regulating circuit, DC-DC circuit and electronic pen body according to any one of claims 1 to 7, wherein: The first terminal of the control circuit is connected to the first terminal of the voltage feedback regulation circuit; The second terminal of the voltage feedback regulation circuit is connected to the feedback terminal of the DC-DC circuit, and the third terminal of the voltage feedback regulation circuit is grounded; A first end of the voltage divider circuit is connected to the output end of the DC-DC circuit, a second end of the voltage divider circuit is connected to the feedback end of the DC-DC circuit, and a third end of the voltage divider circuit is grounded; The output end of the DC-DC circuit is connected to the coding component of the electronic pen body, and the DC-DC circuit is used to output the coding voltage to the coding component; The control circuit outputs a PWM signal or a regulated voltage to the voltage feedback regulation circuit, and the voltage feedback regulation circuit feeds back the PWM signal or the regulated voltage to the feedback end of the DC-DC circuit, so that the amplitude of the coding voltage output by the DC-DC circuit is controlled by the duty cycle of the PWM signal or the amplitude of the regulated voltage.

9. The electronic pen according to claim 8, characterized in that The DC-DC circuit includes: a voltage conversion chip, a fifth resistor, a second capacitor, a third capacitor, a fourth capacitor, a first diode and a first inductor, wherein: The input end of the voltage conversion chip inputs the supply voltage, the input end of the voltage conversion chip is respectively connected to the first end of the first inductor, the first end of the fifth resistor, and the first end of the second capacitor, the enable end of the voltage conversion chip is connected to the second end of the fifth resistor, the output end of the voltage conversion chip is respectively connected to the second end of the first inductor and the anode of the first diode, the feedback end of the voltage conversion chip is respectively connected to the second end of the voltage divider circuit, the second end of the voltage feedback regulation circuit, and the first end of the third capacitor, and the ground end of the voltage conversion chip is grounded; The second terminal of the second capacitor is grounded; The second end of the third capacitor is connected to the cathode of the first diode, the first end of the fourth capacitor, and the coding component; A second terminal of the fourth capacitor is grounded.

10. The electronic pen according to claim 8, wherein Also includes: Coding processing circuit, wherein, The first end of the coding processing circuit is connected to the output end of the DC-DC circuit, the second end of the coding processing circuit is connected to the third end of the control circuit, and the third end of the coding processing circuit is connected to the coding component; the coding processing circuit is used to regulate the coding voltage.

Images