CN114679165A

CN114679165A - Touch key module and suspended touch key device

Info

Publication number: CN114679165A
Application number: CN202210596078.9A
Authority: CN
Inventors: 李兵; 李黎; 杨尚宾
Original assignee: Shenzhen Betterlife Electronic Science And Technology Co ltd
Current assignee: Shenzhen Betterlife Electronic Science And Technology Co ltd
Priority date: 2022-05-30
Filing date: 2022-05-30
Publication date: 2022-06-28
Anticipated expiration: 2042-05-30
Also published as: CN114679165B

Abstract

The invention discloses a touch key module and a suspended touch key device, relates to the technical field of household appliances, and solves the problem of low sensitivity of the conventional suspended touch key technology of the household appliances. The touch key module comprises a touch chip and a plurality of fusion circuits connected with the touch chip, wherein each fusion circuit comprises a touch key circuit and an LED lamp bead circuit, and the fusion circuits work in a fusion time-sharing mode. When the key is scanned, a detection pin at one end of the touch key circuit is connected with an anode control pin of the LED lamp bead circuit in the touch chip; when the LED is turned on or turned off, the detection pin at one end of the touch key circuit is disconnected with the anode control pin of the LED lamp bead circuit in the touch chip. The suspension touch key device can save a touch induction spring, save cost, reduce production difficulty, improve the signal quantity of touch induction and improve the suspension performance of the touch key.

Description

Touch key module and suspended touch key device

Technical Field

The invention relates to the technical field of household electrical appliances, in particular to a touch key module and a suspended touch key device.

Background

In the current household electrical appliances, whether large household electrical appliances such as refrigerators, air conditioners, range hoods and the like or small household electrical appliances such as microwave ovens, induction cookers, table lamps and the like, the key function is basically realized by adopting a capacitive touch key mode, and compared with mechanical keys, the touch key has the advantages of water resistance, stain resistance, durability and incomparable user experience. The touch key function is realized by adopting a special touch key chip and an induction sensor, the touch chip generally adopts a self-capacitance detection mode, a plurality of touch induction channel pins are arranged on the chip and connected to the induction sensor, when a finger of a person is close to a touch induction sensor area, the ground capacitance value on the corresponding induction channel can be changed, and the MCU in the chip judges whether the touch key is pressed down or not by detecting the change of the ground capacitance value of the induction channel.

As shown in fig. 1, for the conventional design of the touch key and the LED lamp of the current home appliance, the pins of the touch chip can be configured in multiple functions, and can be configured as a touch key channel or an LED driver, and the touch key and the LED lamp are controlled independently in different circuits in the conventional design. The design of the induction sensor is generally as follows, as shown in fig. 2, one is to design induction discs with different patterns and sizes by adopting copper sheets on a PCB, the design requires that a touch finger is closer (less than 5 mm) to the PCB, and the middle of the induction disc is preferably provided with middle media with higher dielectric constants such as plastics or acrylic, so that the structural design requirement is high, and the application in actual household appliances is relatively less; as shown in fig. 3, another way is that the sensing channel of the touch chip is connected to the corresponding sensing spring pin through the trace on the PCB, and the sensing spring is directly pushed to the position of the touch panel corresponding to the function area, and various key functions to be realized are silk-screened on the touch panel, one function corresponds to one spring, and a lamp bead is usually further provided in the middle of the spring to display whether the touch key is pressed down effectively, which has lower requirements on the structural design and the assembly of the whole machine, and the PCB can also be placed at a position far away from the touch panel and provide reliable sensing connection for an environment with strong vibration or large temperature change, so the design mode using the sensing spring as the touch sensor is the main mode of the current home appliance product sensor.

Although the induction spring is widely used as a touch sensor in the current household electrical appliance products, the induction spring also has some obvious disadvantages compared with the sensor designed by a copper sheet of a PCB (printed circuit board). Firstly, the material cost is additionally increased; secondly, the spring is large in size and low in production and welding efficiency; in addition, the spring is easy to deform and rust, the side sensitivity of the spring is high, the distance between adjacent springs cannot be too close, and the like. And to the touch-sensitive ware that directly uses the design of PCB board copper skin, generally require that PCB board distance from touch panel is less than 5mm, otherwise unsettled distance is too big, can lead to the response data little, receives external signal interference's problem easily. Therefore, a new suspension touch key scheme needs to be found, a touch induction spring is not used, and the problem that the inductor designed by using the copper sheet of the PCB has high requirements on the structure of the shell of the product can be solved.

Disclosure of Invention

The present invention is directed to a touch key module and a suspended touch key device, so as to solve the above technical problems. The technical effects that can be produced by the preferred technical scheme in the technical schemes provided by the invention are described in detail in the following.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention provides a touch key module which comprises a touch chip and a plurality of fusion circuits connected with the touch chip; each fusion circuit comprises a touch key circuit and an LED lamp bead circuit; the fusion circuit works in a fusion time-sharing mode; when the key is scanned, a detection pin at one end of the touch key circuit is connected with an anode control pin of the LED lamp bead circuit in the touch chip; when the LED is turned on or turned off, the detection pin at one end of the touch key circuit and the anode control pin of the LED lamp bead circuit are disconnected in the touch chip.

Preferably, the touch key module further comprises a plurality of sensing discs, and each of the fusion circuits is connected with one of the sensing discs; each fusion circuit further comprises a resistor, and the resistor is used for adjusting the current of the LED lamp bead circuit; the resistor is connected in series between the touch key circuit and the induction disc.

Preferably, each LED lamp bead circuit is a light emitting diode; an anode control pin of the light-emitting diode is connected or disconnected with a detection pin at one end of the touch key circuit in the touch control chip, and a cathode of the light-emitting diode is connected between the resistor and the induction disc; and one end of the resistor is connected with the detection pin at the other end of the touch key circuit.

Preferably, each LED lamp bead circuit is a plurality of light emitting diodes connected in parallel; the light-emitting diodes connected in parallel are connected or disconnected with the detection pin at one end of the touch key circuit in the touch chip, and the common cathodes of the light-emitting diodes are connected between the resistor and the induction disc; and one end of the resistor is connected with the detection pin at the other end of the touch key circuit.

Preferably, each LED lamp bead circuit is a plurality of light emitting diodes connected in parallel; an anode control pin of each light-emitting diode is connected or disconnected with a detection pin at one end of one touch key circuit inside the touch control chip, and a common cathode of the light-emitting diodes is connected between the resistor and the induction disc; and one end of the resistor is connected with the detection pin at the other end of the touch key circuit.

Preferably, the touch chip comprises a GPIO control module, a touch key detection circuit, and a plurality of pads; each bonding pad is respectively connected with the GPIO control module and the touch key detection circuit through two switches, and the bonding pad is also respectively connected with the touch key circuit and the LED lamp bead circuit.

Preferably, the touch key detection circuit comprises an operational amplifier and an analog-to-digital converter; each bonding pad is connected with the input end of the operational amplifier through one of the two switches, and the output end of the operational amplifier is connected with the analog-to-digital converter.

Preferably, the touch key circuit and the LED lamp bead circuit work in the fusion time-sharing mode; the fused time-sharing mode comprises key scanning time and LED lamp-on time; in the key scanning time, the detection pin of the touch key circuit is connected with the control pin of the LED lamp bead circuit in the touch chip to jointly output a touch key scanning signal; in the LED lighting time, the detection pin of the touch key circuit and the control pin of the LED lamp bead circuit are disconnected in the touch chip; when the LED is turned on, the detection pins of the touch key circuit are both at a low potential, the control pins of the LED lamp bead circuit are both at a high potential, and when the LED is turned off, the detection pins of the touch key circuit and the control pins of the LED lamp bead circuit are both at a low potential.

According to another aspect of the present invention, there is also provided a suspended touch key device, including the touch key module, the touch panel and the display module described above; LED lamp pearl, the display module of LED lamp pearl circuit all set up touch panel's one side, touch chip, response dish all set up touch panel's another side, LED lamp pearl with touch panel's height can pass through LED lamp pearl pin is adjusted, LED lamp pearl, response dish and touch panel constitute a touch-sensitive ware.

Preferably, the induction disc is a PCB copper sheet induction disc, and the touch panel is a PCB board.

The implementation of one of the technical schemes of the invention has the following advantages or beneficial effects:

the touch key module of the invention combines the touch key and the pins of the LED together in the key scanning time, separates the touch key and the LED display function in the LED lighting time, and processes the touch key and the LED display function in a time-sharing working mode, thereby improving the touch sensing sensitivity and achieving the purpose of removing the touch sensing spring. The suspension touch key device provided by the invention adopts the touch key module, so that a touch induction spring can be omitted, the cost is saved, the production difficulty is reduced, the touch induction signal quantity can be increased, and the suspension performance of the touch key is further improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without inventive efforts, wherein:

FIG. 1 is a circuit diagram of a conventional design of a touch button and an LED lamp of a household electrical appliance in the prior art;

FIG. 2 is a schematic diagram of a prior art copper sheet inductor using a PCB board;

fig. 3 is a schematic diagram illustrating a design of a touch key of a household appliance in the prior art;

FIG. 4 is a schematic diagram of a touch key module according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a fusion circuit according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of another fusion circuit according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a touch chip circuit according to an embodiment of the invention;

FIG. 8 is a schematic diagram of the touch key scanning time and the LED lighting time during a complete cycle according to the embodiment of the present invention;

fig. 9 is a front perspective view of a suspended touch key device according to an embodiment of the present invention;

fig. 10 is a rear perspective view of a suspended touch key device according to an embodiment of the invention.

1. A touch chip; 11. a GPIO control module; 12. a touch key detection circuit; 2. a fusion circuit; 21 touch key circuit; 22. an LED lamp bead circuit; 221. LED lamp beads; 3. an induction disc; 4. a touch panel; 5. and a display module.

Detailed Description

In order that the objects, aspects and advantages of the present invention will become more apparent, various exemplary embodiments will be described below with reference to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various exemplary embodiments in which the invention may be practiced. The same numbers in different drawings identify the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. It is to be understood that they are merely examples of processes, methods, apparatus, etc., consistent with certain aspects of the present disclosure, as detailed in the appended claims, and that other embodiments may be used, or structural and functional modifications may be made to the embodiments set forth herein, without departing from the scope and spirit of the present disclosure.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," and the like are used in the orientations and positional relationships illustrated in the accompanying drawings for the purpose of facilitating the description of the present invention and simplifying the description, and do not indicate or imply that the elements so referred to must have a particular orientation, be constructed in a particular orientation, and be operated. The terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. The term "plurality" means two or more. The terms "coupled" and "connected" are to be construed broadly and may include, for example, a fixed connection, a removable connection, a unitary connection, a mechanical connection, an electrical connection, a communicative connection, a direct connection, an indirect connection via intermediate media, and may include, but are not limited to, a connection between two elements or an interactive relationship between two elements. The term "and/or" includes any and all combinations of one or more of the associated listed items. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In order to explain the technical solution of the present invention, the following description is made by way of specific examples, which only show the relevant portions of the embodiments of the present invention.

The first embodiment is as follows:

as shown in fig. 4, an embodiment of the invention provides a touch key module, which includes a touch chip 1 and a plurality of fusion circuits 2 connected to the touch chip 1. Specifically, each fusion circuit 2 comprises a touch key circuit 21 and an LED lamp bead circuit 22, and the fusion circuit 2 works in a fusion time-sharing mode. During key scanning, a detection pin at one end of the touch key circuit 21 is connected with an anode control pin of the LED lamp bead circuit 22 in the touch chip; when the LED is turned on or off, the detection pin at one end of the touch key circuit 21 and the anode control pin of the LED lamp bead circuit 22 are disconnected inside the touch chip 1. The detection pin and the LED control pin of the touch key circuit 21 are connected together in the key scanning time, so that the touch key circuit has two advantages, namely, the two pins of the LED lamp bead become a part of the touch sensor, the influence of distributed capacitance between the two pins of the lamp bead is eliminated, the sensing area is increased, and the sensing sensitivity is improved; secondly, in the key detection process, the voltages at two ends of the LED are the same, so that the problem of reverse voltage cannot occur, and the influence on the service life of the LED is reduced. The circuit applied to household appliances can improve the touch induction sensitivity and achieve the purpose of removing the touch induction spring. It should be noted that touch key detection and LED control are two independent circuits in the existing product, and are controlled by different pins of the touch chip 1. In the invention, the detection pin of the touch key circuit 21 and the control pin of the LED lamp bead circuit 22 are integrated into a circuit to work in a time-sharing way. When touching, the two pins are both touch key detection lead-in pins (connected together); when the LED is controlled, the two pins are respectively changed into control pins (separated) of the anode and the cathode of the LED, and the lamp is controlled to be turned on or turned off by different output voltages. The invention provides 3 embodiments of the fusion circuit 2. Further, the touch key module of the present embodiment further includes a plurality of sensing pads 3, and each of the fusion circuits 2 is connected to one of the sensing pads 3; each fusion circuit 2 further includes a resistor R (R1-R3 in 3 LED bead circuits, respectively) for adjusting the current of the LED bead circuit 22, and the resistor R is connected in series between the touch key circuit 21 and the induction panel 3. It should be further noted that the number of the touch chips 1 and the fusion circuits 2 is determined according to the actual situation of the household appliance, and the touch key circuit 21 is a circuit formed by touch keys.

As further shown in fig. 4, as an alternative embodiment, each LED lamp bead circuit 22 is a light emitting diode D (in the figure, the light emitting diodes in the 3 LED lamp bead circuits are D1-D3, respectively). In each circuit, the anode control pin of the light emitting diode D is connected or disconnected with the detection pin at one end of the touch key circuit 21 inside the touch chip 1, the cathode of the light emitting diode D is connected between (one end of) the resistor R and the sensing panel 3, and the (other) end of the resistor R is connected with the detection pin at the other end of the touch key circuit 21.

As shown in fig. 5, as an optional implementation manner and as an extension of the fusion circuit 2, the LED lamp bead circuit 22 may be a parallel connection of a plurality of LEDs, or one touch key circuit 21 with two or more LEDs with different colors. Specifically, each LED lamp bead circuit 22 is a plurality of parallel-connected light emitting diodes D (in the figure, the light emitting diodes in one LED lamp bead circuit are D4-D5, respectively). In each circuit, the common anode control pins of the multiple parallel light emitting diodes D are connected or disconnected with the detection pin at one end of the touch key circuit 21 inside the touch chip 1, the common cathode of the multiple light emitting diodes D is connected between (one end of) the resistor R and the sensing panel 3, and (the other end of) the resistor R is connected with the detection pin at the other end of the touch key circuit 21.

As shown in fig. 6, as an optional implementation manner and as an extension of the fusion circuit 2, the LED lamp bead circuit 22 may be a parallel connection of a plurality of LEDs, or one touch key circuit 21 with two or more LEDs with different colors. Specifically, each LED lamp bead circuit 22 is a plurality of parallel-connected light emitting diodes D (in the figure, the light emitting diodes in one LED lamp bead circuit are D10-D11, respectively). In each circuit, the anode control pin of each light emitting diode D is connected or disconnected with the detection pin at one end of one touch key circuit 21 inside the touch chip, the common cathode of the light emitting diodes D is connected between (one end of) the resistor R and the sensing pad 3, and (the other end of) the resistor R is connected with the detection pin at the other end of the touch key circuit 21.

As shown in fig. 7, in order to ensure that the touch key detection pins of the touch key circuit 21 are connected with the LED control pins during the scan cycle of the touch key circuit 21, the touch chip 1 includes a GPIO control module 11 (General-purpose input/output (GPIO)), a touch key detection circuit 12, and a plurality of pads PA (PA 0-PA7 in the circuit diagram). Each pad PA is connected with the GPIO control module 11 and the touch key detection circuit 12 through two switches respectively, and the pads PA are also connected with the touch key circuit 21 and the LED lamp bead circuit 22 respectively. Specifically, the touch key detection circuit 12 includes an operational amplifier CAO and an analog-to-digital converter ADC; each pad PA is connected to the input of the operational amplifier CAO through one of the two switches, and the output of the operational amplifier CAO is connected to the analog-to-digital converter ADC.

As shown in fig. 8, the touch key circuit 21 and the LED lamp bead circuit 22 work in a fusion time-sharing mode, where the fusion time-sharing mode includes key scanning time and LED lighting time. In the key scanning time, the detection pin of the touch key circuit 21 is connected with the control pin of the LED lamp bead circuit 22 inside the touch chip 1, and a touch key scanning signal is output together. In the LED lighting time, the detection pin of the touch key circuit 21 and the control pin of the LED lamp bead circuit 22 are disconnected in the touch chip 1; when the LED is lighted, the detection pins of the touch key circuit 21 are all at a low potential, and the control pins of the LED lamp bead circuit 22 are all at a high potential; when the LED is off, the detection pin of the touch key circuit 21 and the control pin of the LED lamp bead circuit 22 are both at low potential. Generally, the scanning time of one touch key circuit 21 is about 0.5-1 ms, the keys of the household appliance are generally less than 12 keys, the period of the scanning time of the touch keys plus the LED display time can be set to 20ms (the frequency is 50 Hz), the period time can be adjusted according to the number of the keys, the frequency is higher than 50Hz, and the sensitivity of the touch key circuit 21 and the LED display effect are not affected. Specifically, fig. 8 shows a complete cycle of KEY scanning time and LED lighting time, a 20ms cycle is taken as an example (the cycle can be adjusted according to the number of KEYs), the scanning detection of all touch KEY circuits 21 is completed in the front 10ms, the LED lighting time is taken in the rear 10ms, if the LED corresponding to the KEY needs to be lit, in the lighting cycle, the control pin (e.g., LED 1) of the LED lamp bead circuit 22 is pulled high, the detection pin (e.g., KEY _ 1) of the touch KEY circuit 21 is pulled low, and the current of the LED lamp bead circuit 22 can be adjusted by the middle series resistor R, so that the LED lamp can be lit. Of course, the control pin of the LED lamp bead circuit 22 may also be configured in a constant current mode or other modes to control the lamp to be turned on.

It should be noted that the touch chip 1 is provided with a 5V external power supply, the power supply is connected to the VCC port of the touch chip 1, the VSS port of the touch chip 1 is grounded, and a capacitor is connected between the 5V external power supply and the ground. In addition, the touch chip 1 is further provided with two data receiving and transmitting ports RXD and TXD.

To sum up, in this embodiment, the conventional method of completely separating the touch key circuit from the display LED lamp circuit in the household appliance is abandoned, and a new method is adopted, in which the touch key and the LED pin are integrated together at the key scanning time, and separated at the LED lighting time, and the touch key and the LED display function are processed in a time-sharing manner, so as to improve the touch sensing sensitivity and achieve the purpose of removing the touch sensing spring.

Example two:

as shown in fig. 9 to 10, an embodiment of the present invention further provides a floating-touch key device, which includes the touch key module, the touch panel 4 and the display module 5 according to the first embodiment. Specifically, LED lamp bead 221 of LED lamp bead circuit 22, display module 5 all set up the one side at touch panel 4, and touch chip 1, response dish 3 all set up touch panel 4's another side, and LED lamp bead 221 and touch panel 4's height can be adjusted through LED lamp bead 221 pin, and LED lamp bead 221, response dish 3 and touch panel 4 constitute a touch-sensitive ware. Further, the induction plate 3 is a PCB copper sheet induction plate, and the touch panel 4 is a PCB plate. When the touch key circuit 21 works, a copper sheet sensor and an LED lamp bead 221 which are designed on the touch panel 4 (such as a PCB) are combined together to form a new sensor, two metal pins of the lamp bead and a plastic shell (a touch panel) also form a part of the touch sensor, and the characteristic that the welding height of the lamp bead can be adjusted is utilized, so that the sensor of the part of the lamp bead is close to the touch panel 4 as much as possible, the distance can reach 1-2 mm, the suspension distance is greatly reduced, and the sensing sensitivity of the touch key in the touch key circuit 21 is improved; when the LED display works, the two pins become control interfaces of the LED lamp, and the LED is lightened or extinguished.

Therefore, the touch key circuit and the LED lamp bead circuit are integrated together in the key scanning time and separated in the LED lighting time, and a time-sharing working mode is formed. In the period of 20ms, the first 10ms is touch key scanning time, the touch key detects foot and LED control foot and links together in that the chip is inside, like this two pins of response dish and lamp pearl on the PCB board, the plastic casing (touch panel) of lamp pearl forms a touch-sensitive ware jointly, recycle lamp pearl welding height can nimble advantage of adjusting, satisfy the altitude problem of different household electrical appliances product structures, thereby promote touch-sensitive sensitivity, reach the purpose of removing the touch-sensitive spring.

To sum up, touch key circuit and the LED display circuit of this embodiment in with household electrical appliances merge the design, form a new touch-sensitive ware with two pins of PCB board copper sheet design and LED lamp pearl and plastic casing together, and adopt the mode of timesharing work to accomplish touch key scanning and LED display function, recycle the advantage that LED lamp pearl weld height can be adjusted, reduce inductor and touch panel's unsettled distance, and then promote touch key's unsettled performance. By adopting the suspension touch key device, a touch induction spring can be omitted, the cost is saved, the production difficulty is reduced, the touch induction signal quantity can be improved, and the suspension performance of the touch key is further improved.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A touch key module is characterized by comprising a touch chip and a plurality of fusion circuits connected with the touch chip;

each fusion circuit comprises a touch key circuit and an LED lamp bead circuit;

the fusion circuit works in a fusion time-sharing mode; when the key is scanned, a detection pin at one end of the touch key circuit is connected with an anode control pin of the LED lamp bead circuit in the touch chip; when the LED is turned on or turned off, the detection pin at one end of the touch key circuit and the anode control pin of the LED lamp bead circuit are disconnected in the touch chip.

2. The touch key module of claim 1, further comprising a plurality of sensing pads, wherein each of the fusion circuits is connected to one of the sensing pads;

each fusion circuit further comprises a resistor, and the resistor is used for adjusting the current of the LED lamp bead circuit; the resistor is connected in series between the touch key circuit and the induction disc.

3. The touch key module of claim 2, wherein each of the LED lamp bead circuits is a light emitting diode;

an anode control pin of the light-emitting diode is connected or disconnected with a detection pin at one end of the touch key circuit in the touch control chip, and a cathode of the light-emitting diode is connected between the resistor and the induction disc;

and one end of the resistor is connected with the detection pin at the other end of the touch key circuit.

4. The touch key module of claim 2, wherein each of the LED lamp bead circuits is a plurality of parallel light emitting diodes;

the common anode control pins of the plurality of light-emitting diodes connected in parallel and the detection pins at one end of the touch key circuit are connected or disconnected in the touch control chip, and the common cathode of the plurality of light-emitting diodes is connected between the resistor and the induction disk;

5. The touch key module of claim 2, wherein each of the LED lamp bead circuits is a plurality of parallel light emitting diodes;

an anode control pin of each light-emitting diode is connected or disconnected with a detection pin at one end of one touch key circuit inside the touch control chip, and a common cathode of the light-emitting diodes is connected between the resistor and the induction disc;

6. The touch key module of claim 1, wherein the touch chip comprises a GPIO control module, a touch key circuit detection circuit, and a plurality of pads;

each bonding pad is respectively connected with the GPIO control module and the touch key detection circuit through two switches, and the bonding pad is also respectively connected with the touch key circuit and the LED lamp bead circuit.

7. The touch key module of claim 6, wherein the touch key detection circuit comprises an op amp and an analog-to-digital converter;

each bonding pad is connected with the input end of the operational amplifier through one of the two switches, and the output end of the operational amplifier is connected with the analog-to-digital converter.

8. The touch key module of claim 1, wherein the touch key circuit and the LED lamp bead circuit operate in the fused time-sharing mode;

the fused time-sharing mode comprises key scanning time and LED lamp-on time;

in the key scanning time, the detection pin of the touch key circuit is connected with the control pin of the LED lamp bead circuit in the touch chip to jointly output a touch key scanning signal;

in the LED lighting time, the detection pin of the touch key circuit and the control pin of the LED lamp bead circuit are disconnected in the touch chip; when the LED is lighted, the detection pins of the touch key circuit are all at a low potential, and the control pins of the LED lamp bead circuit are all at a high potential; when the LED is turned off, the detection pin of the touch key circuit and the control pin of the LED lamp bead circuit are both at low potential.

9. A touch-key device, comprising a touch-key module, a touch panel and a display module according to any one of claims 1 to 8;

LED lamp pearl, the display module of LED lamp pearl circuit all set up touch panel's one side, touch chip, response dish all set up touch panel's another side, LED lamp pearl with touch panel's height can pass through LED lamp pearl pin is adjusted, LED lamp pearl, response dish and touch panel constitute a touch-sensitive ware.

10. The overhead touch key device of claim 9, wherein the sensing pad is a PCB copper sheet sensing pad and the touch panel is a PCB board.