Electronic pen wireless charging NFC testing device
Through the electronic pen wireless charging NFC test device composed of discrete components, the square wave signal is converted into a sine wave signal and signal amplification and digital feedback are performed, which solves the problem of unclear signal demodulation, and achieves low-cost troubleshooting and clear understanding of working conditions.
Patent Information
- Application Number
- CN202421294767.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-07
- Publication Date
- 2025-08-08
- Estimated Expiration
- 2034-06-07
AI Technical Summary
The existing electronic pen wireless charging NFC test device has unclear signal accuracy during the demodulation process, which makes it difficult to troubleshoot and is costly.
The control module, driving module, resonant network, wireless charging coil and acquisition module composed of discrete components are converted into sine wave signals for charging through square wave signals, and the amplification and digital feedback of the signals are achieved by using the demodulation unit, amplification unit and comparison unit.
It improves the convenience of troubleshooting, reduces testing costs, and achieves a clear understanding of the NFC working condition of the electronic pen wireless charging.
Smart Images
Figure CN223205600U_ABST
Abstract
Description
Technical Field
[0001] The utility model is applied to the technical field of circuit testing, and particularly relates to an electronic pen wireless charging NFC testing device. Background Art
[0002] The modulation and demodulation technology used in electronic pen wireless charging NFC test equipment is generally used for long-distance signal transmission. This is achieved by superimposing the useful signal on a high-frequency signal. Because high-frequency signals experience less signal loss over long distances than low-frequency signals, high-frequency modulation and demodulation are used for wireless charging and information exchange. During the modulation and demodulation process, demodulating the useful signal is particularly important. Since the amplitude of the useful signal itself is very low during the demodulation process, effectively extracting and analyzing this signal is crucial. Existing demodulation methods typically utilize integrated ICs for demodulation. This process prevents clear and effective visualization of the signal's accuracy, limiting troubleshooting and making it designer-unfriendly, leading to design blind spots. Furthermore, integrated ICs are relatively expensive.
[0003] If a solution that is convenient for debuggers to perform troubleshooting and low in cost can be provided, the above technical problems can be well solved. Utility Model Content
[0004] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide an electronic pen wireless charging NFC test device which is easy to troubleshoot and low in cost by performing modulation and demodulation through discrete components.
[0005] The technical solution adopted by the present invention is as follows: the present invention includes a control module, a drive module, a resonant network, a wireless charging coil and an acquisition module. The control module outputs a drive signal to the resonant network through the drive module. The resonant network is connected to the wireless charging coil. The wireless charging coil cooperates with the product to be tested. The resonant network feeds back a signal to the control module through the acquisition module. The acquisition module includes a demodulation unit, an amplification unit and a comparison unit connected in sequence.
[0006] As can be seen from the above scheme, the control module outputs a square wave signal through the driver module. The square wave signal is converted into a sine wave signal through the resonant network, and then fed to the electronic pen product by the wireless charging coil for charging. During this time, the electronic pen product's NFC will respond with a signal, which is fed back to the resonant network through the wireless charging coil. The demodulation unit collects the product feedback signal, and the amplification unit amplifies the effective signal. Finally, the comparison unit converts it into a digital signal and feeds it back to the control module, achieving closed-loop NFC communication. The final feedback digital signal allows debuggers to more clearly understand the working status of the electronic pen wireless charging NFC, while also reducing debugging personnel's testing costs.
[0007] A preferred solution is that the driving module includes two groups of half-bridge gate drivers and two groups of field-effect transistors, the input ends of the two groups of half-bridge gate drivers are respectively connected to the two output ports of the control module, the output ends of the two groups of half-bridge gate drivers are respectively connected to the control ports of the two groups of field-effect transistors, the two input ends of the field-effect transistors are respectively connected to the power supply and the ground line, and the output ends of the two groups of field-effect transistors are respectively connected to the two groups of ports of the resonant network.
[0008] A preferred solution is that the demodulation unit includes a demodulation chip, the two groups of ports of the resonant network are connected to the input end of the demodulation chip through an anti-reverse diode, and the output end of the demodulation chip is connected to the amplification unit.
[0009] A preferred solution is that the amplification unit includes an operational amplifier and a filtering component, the positive input terminal of the operational amplifier is connected to the demodulation unit, the negative input terminal of the operational amplifier is connected to the control signal output terminal of the control module, and the output terminal of the operational amplifier is connected to the comparison unit through the filtering component.
[0010] A preferred solution is that the comparison unit includes a high-speed hysteresis comparator, the positive input end of the high-speed hysteresis comparator is connected to the output end of the amplification unit, the negative input end of the high-speed hysteresis comparator is connected to the control signal output end of the control module, and the output end of the high-speed hysteresis comparator is connected to the input port of the control module. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 It is a connection block diagram of the utility model;
[0012] Figure 2 is a circuit schematic diagram of the driving module;
[0013] Figure 3 is a circuit schematic diagram of the resonant network;
[0014] Figure 4is a circuit schematic diagram of the demodulation unit;
[0015] FIG5 is a circuit diagram of the amplifying unit:
[0016] FIG6 is a circuit diagram of the comparison unit. DETAILED DESCRIPTION
[0017] like Figure 1 As shown in Figure 6, in this embodiment, the present invention includes a control module 1, a drive module 2, a resonant network 3, a wireless charging coil 4, and an acquisition module 5. The control module 1 outputs a drive signal to the resonant network 3 via the drive module 2. The resonant network 3 is connected to the wireless charging coil 4, which is in conjunction with the product under test 6. The resonant network 3 feeds back a signal to the control module 1 via the acquisition module 5. The acquisition module 5 includes a demodulation unit 51, an amplification unit 52, and a comparison unit 53 connected in sequence. The control module 1 is an FPGA component.
[0018] As shown in Figure 2, in this embodiment, the driving module 2 includes two groups of half-bridge gate drivers U800 / U801 and two groups of field effect transistors Q800 / Q801. The input ends of the two groups of half-bridge gate drivers U800 / U801 are respectively connected to the two PWM ports of the control module 1, and the HO ports and LO ports of the two groups of half-bridge gate drivers U800 / U801 are respectively connected to the two control ports in the two groups of field effect transistors Q800 / Q801. The two input ends of the field effect transistors Q800 / Q801 are respectively connected to the power supply and the ground line, and the output ends of the two groups of field effect transistors Q800 / Q801 are respectively connected to the two groups of ports of the resonant network 3. Two mirrored half-bridge gate drivers 1 drive the two FETs Q800 / Q801 at the back end. Control signals are sent by sending two opposing PWM signals to the half-bridge gate drivers U800 / U801, turning the corresponding FETs Q800 / Q801 on and off, forming a bidirectional drive circuit. The half-bridge gate drivers U800 / U801 are LMG1210RVRR driver chips. Furthermore, the control module 1 transmits NFC communication signals via the EN pin of the half-bridge gate driver U800.
[0019] As shown in Figure 3, the resonant network 3 consists of two LC filter networks, including a coupling network circuit and an EMC network circuit. This converts the square wave signal transmitted by the driver module 2 into a sine wave signal, facilitating the transmission of energy and signals to the wireless charging coil 4, which is a Kmin900 model.
[0020] As shown in Figure 4, in this embodiment, the demodulation unit 51 includes a demodulation chip U901. The two ports of the resonant network 3 are connected to the inputs of the demodulation chip U901 via anti-reverse diodes D902 / D905. The output of the demodulation chip U901 is connected to the amplification unit 52. The demodulation chip U901 is an LTC5507. When the electronic pen returns a signal, the signal passes through diodes to remove the DC signal before passing through the anti-reverse diodes D902 / D905 to reach the demodulation chip U901, completing the signal demodulation and generating the demodulated signal Venv.
[0021] As shown in Figure 5, in this embodiment, the amplification unit 52 includes an operational amplifier U902 and a filtering component. The positive input of the operational amplifier U902 is connected to the demodulation unit 51, the negative input of the operational amplifier U902 is connected to the control signal output of the control module 1, and the output of the operational amplifier U902 is connected to the comparison unit 53 via the filtering component. During signal processing, the amplification unit 52 amplifies the demodulated signal Venv from the demodulation unit 51. Because the demodulated signal Venv contains a DC offset voltage, the voltage signal DAC_IN1 output by the control module 1 is adjusted to offset the DC offset voltage from the demodulation unit 51, resulting in an amplified voltage signal Venv1. After high-pass filtering by the filtering component, the DC offset signal is further filtered out, resulting in a complete AC signal Venv2.
[0022] As shown in Figure 6, in this embodiment, the comparison unit 53 includes a high-speed hysteresis comparator U900. The positive input of the high-speed hysteresis comparator U900 is connected to the output of the amplification unit 52, the negative input of the high-speed hysteresis comparator U900 is connected to the control signal output of the control module 1, and the output of the high-speed hysteresis comparator U900 is connected to the input port of the control module 1. Because the signal received by the control module 1 is a digital signal, the high-speed hysteresis comparator U900 converts the AC analog signal Venv2 after front-end amplification into a digital signal Signal_OUT. The high-speed hysteresis comparator U900 is a TLV3501 comparator chip. The threshold voltage of the high-speed hysteresis comparator U900 is adjusted by setting the voltage value of DAC_IN2 of the control module 1, thereby increasing the circuit flexibility. After passing through the high-speed hysteresis comparator U900, the digital signal Signal_OUT enters the control module 1 for signal analysis, enabling NFC signal transmission from the product end.
[0023] Although the embodiments of the present invention are described with practical solutions, they do not limit the meaning of the present invention. For those skilled in the art, it is obvious to modify the implementation scheme and combine it with other solutions based on this description.
Claims
1. An electronic pen wireless charging NFC test device, characterized by: It comprises a control module (1), a driving module (2), a resonant network (3), a wireless charging coil (4) and an acquisition module (5), wherein the control module (1) outputs a driving signal to the resonant network (3) through the driving module (2), the resonant network (3) is connected to the wireless charging coil (4), the wireless charging coil (4) cooperates with a product to be tested (6), the resonant network (3) feeds back a signal to the control module (1) through the acquisition module (5), and the acquisition module (5) comprises a demodulation unit (51), an amplification unit (52) and a comparison unit (53) connected in sequence.
2. The electronic pen wireless charging NFC test device according to claim 1, characterized in that: The driving module (2) includes two groups of half-bridge gate drivers (U800 / U801) and two groups of field effect transistors (Q800 / Q801), the input ends of the two groups of half-bridge gate drivers (U800 / U801) are respectively connected to the two output ports of the control module (1), the output ends of the two groups of half-bridge gate drivers (U800 / U801) are respectively connected to the control ports of the two groups of field effect transistors (Q800 / Q801), the two input ends of the field effect transistors (Q800 / Q801) are respectively connected to the power supply and the ground line, and the output ends of the two groups of field effect transistors (Q800 / Q801) are respectively connected to the two groups of ports of the resonant network (3).
3. The electronic pen wireless charging NFC test device according to claim 1, characterized in that: The demodulation unit (51) includes a demodulation chip (U901), two groups of ports of the resonant network (3) are connected to the input end of the demodulation chip (U901) through anti-reverse diodes (D902 / D905), and the output end of the demodulation chip (U901) is connected to the amplification unit (52).
4. The electronic pen wireless charging NFC test device according to claim 1, characterized in that: The amplification unit (52) includes an operational amplifier (U902) and a filtering component, wherein the positive input terminal of the operational amplifier (U902) is connected to the demodulation unit (51), the negative input terminal of the operational amplifier (U902) is connected to the control signal output terminal of the control module (1), and the output terminal of the operational amplifier (U902) is connected to the comparison unit (53) through the filtering component.
5. The electronic pen wireless charging NFC test device according to claim 1, characterized in that: The comparison unit (53) includes a high-speed hysteresis comparator (U900), the positive input end of the high-speed hysteresis comparator (U900) is connected to the output end of the amplification unit (52), the negative input end of the high-speed hysteresis comparator (U900) is connected to the control signal output end of the control module (1), and the output end of the high-speed hysteresis comparator (U900) is connected to the input port of the control module (1).