CN-122001359-A - Self-adaptive capacitive touch key system and self-adaptive adjusting method

CN122001359ACN 122001359 ACN122001359 ACN 122001359ACN-122001359-A

Abstract

The invention relates to the technical field of touch keys, and discloses a self-adaptive capacitive touch key system and a self-adaptive adjusting method. The system comprises a reference capacitor, a touch capacitor, a memristor, an auxiliary discharging resistor, a first switch, a second switch, a third switch and a microcontroller. The switching between the self-adaptive adjusting mode and the touch detection mode can be realized by controlling the states of the switches and the elements through the microcontroller. In the self-adaptive regulation mode, the reference capacitor is utilized to automatically regulate the resistance value of the memristor according to the capacitance drift of the reference capacitor through the discharging process of the memristor so as to maintain the constant reference time determined by the memristor and the reference capacitor. The real-time self-compensation of the hardware level is realized, no software algorithm is needed, and the problems of false triggering, response failure and the like caused by standard capacitance drift due to environmental temperature and humidity change and material aging of the traditional capacitance touch key are solved. The method has the advantages of quick response, low power consumption, high reliability and nonvolatile memory capacity.

Inventors

YU JIANGFENG
LI JIAN
SONG FEI

Assignees

珠海格力电器股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260127

Claims (10)

1. The self-adaptive capacitive touch key system is characterized by comprising a reference capacitor, a touch capacitor, a memristor, an auxiliary discharging resistor, a first switch, a second switch, a third switch and a microcontroller; the common end of the first switch is connected with a charging voltage source, and the control end of the first switch is connected with the common end of the second switch; The common end of the second switch is connected with the common ends of the reference capacitor and the third switch, and the two control ends of the second switch are respectively connected with the memristor and the auxiliary discharging resistor; the control end of the third switch is connected with the touch capacitor; The microcontroller is respectively connected with the control ends of the first switch, the second switch and the third switch and used for controlling the on-off of each control end, and the switching system works in a self-adaptive regulation mode or a touch detection mode; the self-adaptive adjustment mode is configured to enable the resistance value of the memristor to be self-adaptively adjusted according to the capacitance value drift of the reference capacitance by controlling the discharging process of the reference capacitance through the memristor so as to maintain the reference time of the touch key system.
2. The adaptive capacitive touch key system of claim 1, wherein in the adaptive adjustment mode, the system comprises a first charge circuit, a discharge adjustment circuit, and a bleed circuit; the first charging circuit is configured to charge the reference capacitance; The discharging adjusting circuit is configured to discharge the charged reference capacitor through the memristor so as to adaptively adjust the resistance value of the memristor; the bleeder circuit is configured to discharge residual charge from the discharged reference capacitance.
3. The adaptive capacitive touch key system of claim 2, wherein the first switch, the second switch, and the reference capacitor are in sequential communication to form a first charging circuit for charging the reference capacitor; The charging voltage V1 of the first charging circuit is higher than the resistance change threshold voltage Vth of the memristor, and the charging time of the first charging circuit is a fixed first preset value t.
4. The adaptive capacitive touch key system of claim 3, wherein the reference capacitor, the second switch and the memristor are sequentially connected to form a discharge adjustment circuit for discharge adjustment; The fixed discharge time t1 of the discharge regulating circuit is smaller than the first preset value t, and the fixed discharge time t1 is smaller than the decay time tm required by the charging voltage V1 to discharge to the resistance change threshold voltage Vth.
5. The adaptive capacitive touch key system of claim 2, wherein the reference capacitor, the second switch and the auxiliary discharge resistor are sequentially connected to form a bleeder circuit for bleeding the reference capacitor; After the discharge adjusting circuit performs discharge for a fixed discharge time t1, the reference capacitor is switched to the bleeder circuit, so that the reference capacitor bleeder residual charge through the bleeder circuit.
6. The adaptive capacitive touch key system of claim 1, wherein in the touch detection mode, the system comprises a second charging circuit and a discharge detection circuit; the second charging circuit is configured to charge a total capacitance formed by the reference capacitance and the touch capacitance; The discharge detection circuit is configured to perform discharge detection on the charged total capacitance; the microcontroller is used for recording the real-time discharging time of the total capacitor, judging that a key is pressed when the real-time discharging time exceeds the reference time and reaches a preset threshold value, and switching to the self-adaptive regulation mode.
7. The adaptive capacitive touch key system according to claim 6, wherein the first switch, the second switch, the third switch, the reference capacitance, and the touch capacitance are sequentially connected to form a second charging circuit for charging the total capacitance; the charging voltage V2 of the second charging circuit is lower than the resistance change threshold voltage Vth of the memristor, and the charging time of the second charging circuit is a fixed first preset value t.
8. The adaptive capacitive touch key system of claim 6, wherein the total capacitance, the second switch, and the memristor are sequentially connected to form a discharge detection circuit for discharge detection; The microcontroller is internally provided with a timer for recording the real-time discharge time.
9. An adaptive adjustment method applied to the adaptive capacitive touch key system of claim 1, comprising: detecting whether a key is idle; If the key is idle, the first switch is controlled to be closed so as to charge the reference capacitor, after the charging is completed, the first switch is controlled to be opened, the second switch is controlled to be communicated with the memristor, so that the memristor discharges the reference capacitor, and the resistance of the memristor is adaptively adjusted according to the capacitance drift of the reference capacitor, so that the reference time of the touch key system is maintained; And if the key is not idle, controlling the first switch and the third switch to be closed so as to charge the total capacitance formed by the reference capacitance and the touch capacitance, and after the charging is completed, controlling the first switch to be opened and controlling the second switch to be communicated with the memristor so as to enable the memristor to discharge the reference capacitance and record real-time discharge time, and judging that the key is pressed when the real-time discharge time exceeds the reference time to reach a preset threshold value.
10. The method of claim 9, wherein the step of controlling the first switch to be closed to charge the reference capacitor, controlling the first switch to be opened and controlling the second switch to be connected to the memristor after the charging is completed to discharge the reference capacitor by the memristor, and further adaptively adjusting a resistance of the memristor according to a capacitance drift of the reference capacitor to maintain a reference time of the touch key system comprises: Controlling the first switch to be closed and controlling the third switch to be opened so that the first switch, the second switch and the reference capacitor are sequentially communicated to form a first charging circuit for charging the reference capacitor; The first charging circuit is controlled to charge the reference capacitor by adopting a charging voltage V1, wherein the duration of the charging voltage V1 is longer than the resistance change threshold voltage Vth of the memristor; after charging is completed, the first switch is controlled to be disconnected, the second switch is controlled to be communicated with the memristor, and the reference capacitor, the second switch and the memristor are sequentially communicated to form a discharge regulating circuit for discharge regulation; Controlling the discharge regulating circuit to discharge the charged reference capacitor by adopting a fixed discharge time t1, wherein the fixed discharge time t1 of the discharge regulating circuit is smaller than the first preset value t, and the fixed discharge time t1 is smaller than decay time tm required by the charge voltage V1 to discharge to the resistance change threshold voltage Vth; after the discharge adjusting circuit finishes discharging for the fixed discharge time t1, the second switch is controlled to be communicated with the auxiliary discharge resistor, so that the reference capacitor, the second switch and the auxiliary discharge resistor are sequentially communicated to form a bleeder circuit for bleeder of the reference capacitor, and further the reference capacitor is used for bleeder residual charges through the bleeder circuit.

Description

Self-adaptive capacitive touch key system and self-adaptive adjusting method Technical Field The embodiment of the invention relates to the technical field of touch keys, in particular to a self-adaptive capacitive touch key system and a self-adaptive adjusting method. Background The capacitive touch key technology is used as a core interface of modern man-machine interaction, and is widely applied to the fields of household appliances, industrial control, automobile electronics and the like due to the advantages of simple structure, good sealing performance, high reliability and the like. The basic principle is that the sensing capacitance change caused by the contact of the finger of the human body is detected, namely, when the finger approaches to the key, the formed touch capacitance is connected with the reference capacitance of the key in parallel, so that the total capacitance of the detection node is increased, and the system judges the occurrence of a touch event by measuring the change of the charge and discharge time constant of the node passing through the fixed resistor. However, the long-term stability of this technology is severely limited by environmental factors and material aging. For example, fluctuation of ambient temperature and humidity and medium performance attenuation in long-term use of a circuit board can lead to slow drift of a reference capacitance value in an induction loop, and the drift can change the reference time of a system, so that a preset touch judgment threshold value is invalid, and further reliability problems such as false triggering or response failure are caused. To solve the above problem, the current mainstream scheme relies on a software calibration algorithm of a microcontroller to implement compensation by periodically sampling the reference capacitance value and dynamically updating the reference time parameter in the software. However, such software schemes have inherent limitations, such as the need to interrupt normal touch detection during calibration, resulting in an interruption in the user operation experience, and for example, the calibration period is generally long (tens to hundreds of milliseconds) for balancing accuracy and real-time, and it is difficult to cope with rapid environmental abrupt changes, and for example, complex digital filtering and calibration algorithms run continuously, consuming considerable processor resources and system power consumption, and having obvious disadvantages in low power consumption or resource limited application scenarios. In recent years, memristor elements having nonvolatile memory characteristics have received attention from the industry. Memristors are two-terminal devices with resistance values that can be adjusted and maintained by the history of the amount of charge flowing through them, and this characteristic makes them exhibit great potential in the fields of simulated neuromorphic computation, adaptive filtering and intelligent sensing. The prior art has explored the use of the variable resistance characteristics of memristors to construct adaptive circuits. However, the memristor is applied to a specific scene of a capacitive touch key to construct a reference time self-adaptive compensation mechanism, so that the defects of large delay, high power consumption, interference to user experience and the like of a software calibration scheme are thoroughly avoided, and the memristor is not disclosed in the prior art. Disclosure of Invention The embodiment of the invention provides a self-adaptive capacitive touch key system and a self-adaptive adjusting method, which aim to solve the problems of reference capacitance drift caused by environmental factors and material aging of the capacitive touch key system in the prior art and the defects of large delay, high power consumption, interference to user experience and the like of the traditional software calibration scheme. In a first aspect, an embodiment of the present invention provides an adaptive capacitive touch key system, which is characterized by comprising a reference capacitor, a touch capacitor, a memristor, an auxiliary discharge resistor, a first switch, a second switch, a third switch, and a microcontroller; the common end of the first switch is connected with a charging voltage source, and the control end of the first switch is connected with the common end of the second switch; The common end of the second switch is connected with the common ends of the reference capacitor and the third switch, and the two control ends of the second switch are respectively connected with the memristor and the auxiliary discharging resistor; the control end of the third switch is connected with the touch capacitor; The microcontroller is respectively connected with the control ends of the first switch, the second switch and the third switch and used for controlling the on-off of each control end, and the switching system works in a self-adaptive regulation