CN102624372A - A touch button circuit - Google Patents

Abstract

Disclosed in the invention is a touch key circuit, comprising wiring terminals, a multi-channel touch key control chip and multipath key circuits. Each of the key circuits respectively comprises: a key, which is connected with an input end of the multi-channel touch key control chip; a triode, whose base electrode is connected with an output end corresponding to the input end; and a diode. Specifically, an input end of the diode is connected with an emitter of the triode and an output end of the diode is connected with a key port of one of the wiring terminals. The output end of the multi-channel touch key control chip is connected with a power source by pull-up resistor and a collector of the triode is grounded. According to the disclosed touch key circuit, the multi-channel touch key control chip is employed and detection on a key state by a main program control chip through the wiring terminals is realized by connection and disconnection of the triodes and diodes, thereby further realizing an objective of control on multiple keys, simplifying the circuit structure, reducing the number and cost of devices. Moreover, when it is needed to support the multiple keys, extension can be carried out conveniently, so that extensibility is improved and complexity of the extension is reduced.

Description

A touch button circuit

technical field

The invention relates to the field of mobile communication equipment, in particular to a touch button circuit.

Background technique

Existing touch button circuit structure as shown in Figure 1, comprises: connect the connection terminal 11 of main board control chip, described connection terminal comprises seven ports; Voltage dividing resistor 12, described voltage dividing resistance is divided into three groups, each group It includes two resistors connected in parallel; a touch key control chip 13, and in FIG. 1 there are six touch key control chips, a filter capacitor 14 and a diode 15 connected to each touch key control chip.

It can be seen from the figure that the existing touch key circuit adopts a touch IC (integrated circuit, integrated circuit board) single-channel output mode, that is, one touch key control chip corresponds to one channel output. When there are many keys to be supported, the structure of the circuit will be very complicated and the cost will be high.

Contents of the invention

In view of this, the present invention provides a touch button circuit. The specific plan is as follows:

A touch key circuit, comprising: wiring terminals, a multi-channel touch key control chip and a multi-channel key circuit, wherein the number of channels of the multi-channel touch key control chip is greater than or equal to the number of touch key circuits;

Wherein, each button circuit includes: a button connected to the input terminal of the multi-channel touch button control chip, a triode whose base is connected to the output terminal corresponding to the input terminal, and an input terminal connected to the emitter of the triode a diode, the output end of the diode is connected to the key port of the terminal; the output end of the multi-channel touch key control chip is connected to the power supply through a pull-up resistor; the collector of the triode is grounded;

When the button is not pressed, the output terminal outputs a high level, the triode is cut off, the diode is turned on, and the button port detects a high level;

When the button is pressed, the output end outputs a low level, the transistor is turned on, the diode is turned off, and the button port detects a low level.

Preferably, it further includes: a filter module connected to the power input terminal of the multi-channel touch key control chip, and the filter module includes: a filter capacitor.

Preferably, the filter module further includes: a magnetic bead connected in parallel with the filter capacitor.

Preferably, the button circuit further includes: a voltage dividing resistor with one end connected to the input terminal of the diode, and the other end of the voltage dividing resistor connected to the connecting terminal.

Preferably, it also includes a protocol interface, the protocol interface is connected to the multi-channel touch key control chip, and is used to read the value of the internal register of the multi-channel touch key control chip.

Preferably, it also includes a pull-down module connected to the key confirmation port on the connection terminal, and the pull-down module includes a pull-down resistor, a pull-down capacitor, or a parallel-connected pull-down resistor or pull-down capacitor.

Preferably, the connecting terminal is connected to a display board with programmable programming.

It can be seen from this that the touch key circuit disclosed in the present invention adopts a multi-channel touch key control chip, and realizes that the main program control chip detects the state of the keys through the connection terminals through the on-off of the triode and the diode, and then realizes the control of multiple keys. The purpose is to simplify the circuit structure, reduce the number and cost of devices, and when it is necessary to support multiple keys, it can be easily expanded, which improves the scalability and reduces the complexity of expansion.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a schematic structural diagram of a touch button circuit in the prior art;

2 is a schematic structural diagram of a touch button circuit disclosed in an embodiment of the present invention;

FIG. 3 is a schematic diagram of the connection structure between the connection terminal and the button circuit disclosed by the embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The invention discloses a touch button circuit, its structure is shown in Figure 2, including: a terminal 21, a multi-channel touch button control chip 22, a multi-channel button circuit 23, wherein the multi-channel touch button control chip 22 The number of channels is greater than or equal to the number of the touch key circuits. It can be seen from FIG. 2 that the touch key circuits in this embodiment include 6 key circuits.

Wherein, each button circuit includes: a button 231 connected to the input terminal of the multi-channel touch button control chip 22, a transistor 232 whose base is connected to the output terminal corresponding to the input terminal, and an input terminal connected to the transistor 232. The diode 233 connected to the emitter, the output end of the diode 233 is connected to the key port of the terminal 21; the output end of the multi-channel touch key control chip 22 is connected to the power supply through the pull-up resistor 234; the triode 232 The collector is grounded.

Take the first button circuit as an example, including button KEY_1, KEY_1 is connected to the input terminal CS1 of the multi-channel touch button control chip, and then connected to the base of the transistor Q1 through the first output terminal S1, and the emitter of Q1 is input to the diode D1 The output terminal of the diode D1 is connected with the button interface of the wiring terminal. The structure of other button circuits is the same as that of the first button circuit.

The schematic diagram of the structure of connecting terminal 21 connected to the 6-way button circuit is shown in Figure 3, as can be seen from the figure,

The connection terminal 21 includes: data scanning ports GRID5, GRID6 and GRID7, which are used to send scanning signals to scan button circuits, GRID5 corresponds to the 1st and 2nd button circuits, GRID6 corresponds to the 3rd and 4th button circuits, and GRID7 corresponds to the 5th and 6th button circuits The button circuit, the button confirmation ports KEY1 and KEY2 are used to confirm which button in the button circuit is pressed, the ground port GND is grounded, and the power port VCC is connected to the 5V power supply. The 2nd, 4th and 6th key circuit share a key confirmation port KEY2, and the 1st, 3rd and 5th key circuit share another key confirmation port KEY1, and the key confirmation port is multiplexed.

This embodiment adopts the control method of dynamic scanning. Taking the first button circuit as an example, when KEY_1 is not pressed, the output terminal of the channel touch button control chip outputs a high level, the transistor Q1 is turned off, and the diode D1 is turned on. KEY1 detects a high level; if KEY_1 is pressed, the output level of the first output port on the multi-channel touch key control chip is low. At this time, the transistor Q1 is conductive, the other transistors are not conductive, and the diode D1 is not conductive. When the other diodes are turned on, KEY1 detects the active level-low level, the data scanning port GRID5 determines that the key in the 1st or 2nd key circuit is pressed, and the combination of the two discrimination results determines that KEY_1 is pressed Down.

The connection terminal 21 in this embodiment is connected to the display board with a control chip that can be programmed. The main control chip can detect the state of the key through the connection terminal, and then realize the purpose of controlling multiple keys.

This embodiment does not limit the above connection methods, as long as the detection of each key circuit and the connection relationship for determining the purpose of the key are all within the scope of protection of this embodiment.

Further, the touch key circuit also includes: a filter module 24 connected to the power input terminal of the multi-channel touch key control chip 22, and the filter module 24 includes: a filter capacitor 241 for filtering out AC interference during communication Furthermore, the filter module 24 also includes a magnetic bead 242 connected in parallel with the filter capacitor 241 to improve electromagnetic interference and optimize circuit performance.

In addition to the above structure, as shown in FIG. 2 , the key circuit in the touch key circuit disclosed by the present invention further includes: a voltage dividing resistor 235 , one end of the voltage dividing resistor is connected to the diode input end, and the other end is connected to the connection terminal. In addition to realizing voltage division, the voltage dividing resistor 235 also acts as a current limiter for the button circuit, so as to ensure that the working current of the diode and triode will not exceed the load, cause damage, and affect the normal operation of the circuit.

The touch button circuit disclosed in this embodiment also includes: a pull-down module 25. The pull-down module in this embodiment includes: a pull-down resistor 251 and a pull-down capacitor 252 connected in parallel to eliminate interference in the button circuit and ensure that the button confirmation port KEY1 and The level detected by KEY2 has only two states, high or low, which ensures the accuracy of the detection process.

This embodiment does not limit that the pull-down module must include both a pull-down resistor and a pull-down capacitor, and may also include a pull-down resistor or a pull-down capacitor separately.

Further, the touch key circuit disclosed in this embodiment also includes a protocol interface 26, which is connected to the multi-channel touch key control chip 22 through a 4-pin connection terminal, and is used to read the value of the register in the multi-channel touch key control chip 22 .

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same and similar parts of each embodiment can be referred to each other. As for the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and for the related information, please refer to the description of the method part.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (7)

1. A touch key circuit, characterized in that it comprises: a terminal block, a multi-channel touch key control chip and a multi-channel key circuit, wherein the number of channels of the multi-channel touch key control chip is greater than or equal to the touch key circuit quantity; Wherein, each button circuit includes: a button connected to the input terminal of the multi-channel touch button control chip, a triode whose base is connected to the output terminal corresponding to the input terminal, and an input terminal connected to the emitter of the triode a diode, the output end of the diode is connected to the key port of the terminal; the output end of the multi-channel touch key control chip is connected to the power supply through a pull-up resistor; the collector of the triode is grounded; When the button is not pressed, the output terminal outputs a high level, the triode is cut off, the diode is turned on, and the button port detects a high level; When the button is pressed, the output end outputs a low level, the transistor is turned on, the diode is turned off, and the button port detects a low level. 2 . The circuit according to claim 1 , further comprising: a filter module connected to the power input terminal of the multi-channel touch key control chip, and the filter module includes: a filter capacitor. 3. The circuit according to claim 2, wherein the filter module further comprises: a magnetic bead connected in parallel with the filter capacitor. 4. The circuit according to claim 3, wherein the button circuit further comprises: a voltage dividing resistor with one end connected to the input terminal of the diode, and the other end of the voltage dividing resistor connected to the connecting terminal. 5. The circuit according to claim 4, further comprising a protocol interface, the protocol interface is connected to the multi-channel touch key control chip, and is used to read registers in the multi-channel touch key control chip value. 6. The circuit according to claim 5, further comprising a pull-down module connected to the button confirmation port on the terminal, the pull-down module comprising a pull-down resistor, a pull-down capacitor or a pull-down resistor or a pull-down capacitor connected in parallel . 7. The circuit according to claim 6, wherein the connecting terminal is connected to a display panel with a programmable program.

Images