LED and LCD display driving circuit supporting integrated touch key functionTechnical Field
The invention relates to the technical field of touch screen key functions and display driving circuits, in particular to an LED and LCD display driving circuit supporting an integrated touch key function.
Background
Hundreds of millions of mechanical buttons of household appliances, consumer electronics, industrial control applications and the like have been replaced by capacitive sensing buttons, the use of capacitive sensing control technology makes the applications more beautiful, easy to use, flexible and durable, and the display device is an essential module in electronic products, including LED indicator lamps, LED display screens, LCD display screens and the like.
Capacitive touch key needs extra driver chip in use than traditional mechanical key, the touch drive that uses in the present touch class electronic product is the single-chip mode mostly, the part is MCU integration, MCU integrated touch drive, when MCU's pin selection is the touch mode, its function is just single solidification, occupy an MCU pin, it is more that equipment needs touch key, shared MCU pin number is just corresponding more, MCU's encapsulation peripheral hardware cost all corresponding increase, single function touch driver chip not only faces the same cost problem, also face extra chip and taken up inside PCB space problem when equipment is miniaturized, based on above defect and not enough, it improves to be necessary to current technique, design a LED that supports integrated touch key function, LCD display driver circuit.
Disclosure of Invention
The invention mainly solves the technical problem of providing the LED and LCD display driving circuit supporting the integrated touch key function, which can realize the integration of touch driving in an LED or LCD display driving chip, does not additionally increase chip pins, realizes the time-sharing multiplexing function of the LED or LCD display driving and the touch driving pins, simplifies the product design peripheral circuit, reduces the number of elements, reduces the cost and improves the product stability.
In order to solve the technical problems, the invention adopts a technical scheme that: the LED and LCD display driving circuit comprises an LED and an LCD driving chip, wherein driving pins of the LED and the LCD driving chip are two poles and marked as SEG and COM, each SEG pin consists of a touch driving circuit, an LED/LCD driving circuit, a filter circuit and a function switch, a logic control circuit of the LED and LCD driving chip is connected with the touch driving circuit and the LED/LCD driving circuit which are connected in parallel, the touch driving circuit and the LED/LCD driving circuit which are connected in parallel are connected to the SEG pins through the function switch, and the circuit is connected with the filter circuit; and each COM pin is connected with the logic control circuit through a state control switch.
Preferably, the SEG pins and the COM pins in corresponding numbers are selected according to the number of the LED display points and the LCD display points, and the LED display point array and the LCD display point array are connected with the corresponding SEG pins and the COM pins.
Preferably, the SEG pin output has four driving states, which are a high level, a middle level (1/2, 1/3, 1/4 level, etc.), a low level, and a touch detection state; the COM pin output has four driving states, namely high level, medium level (1/2, 1/3, 1/4 level and the like), low level and high resistance state.
Preferably, the touch driving circuit and the LED/LCD driving circuit correspond to touch driving and display driving, respectively, the touch driving and the display driving share a chip pin SEG in a time-sharing switch driving manner, the time-sharing switch is a function switch, in the display driving mode, a COM pin is used for scanning in a cyclic low level state, the time from COM1 scanning to COMn scanning is T, the next time is T1, and the total execution period is T + T1 corresponding to the touch driving mode.
Compared with the prior art, the invention has the beneficial effects that:
the circuit can realize the integration of touch drive in the LED or LCD display drive chip, does not additionally increase chip pins, and realizes the time-sharing multiplexing function of the pins of the LED or LCD display drive and the touch drive. The product design peripheral circuit is simplified, the number of elements is reduced, the cost is reduced, and the product stability is improved
Drawings
Fig. 1 is a circuit diagram of a display driving circuit of an LED and an LCD supporting an integrated touch key function.
Fig. 2 is an application circuit diagram of an LED and LCD display driving circuit supporting an integrated touch key function.
FIG. 3 is a schematic diagram of the total execution cycle of an LED and LCD display driver circuit supporting the integrated touch key function.
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that the advantages and features of the invention can be more readily understood by those skilled in the art, and the scope of the invention will be more clearly defined.
Referring to fig. 1 to 3, an embodiment of the present invention includes:
a support LED, LCD display drive circuit of the integrated touch key function, this kind of support LED, LCD display drive circuit of the integrated touch key function includes LED, LCD driver chip, the drive foot of LED, LCD driver chip is two poles, mark SEG and COM, every SEG foot is by touching the drive circuit, LED/LCD driver circuit, filter circuit, function change-over switch to make up, LED, logic control circuit of LCD driver chip connect touch drive circuit and LED/LCD driver circuit connected in parallel, touch drive circuit and LED/LCD driver circuit connected to SEG foot through the function change-over switch in parallel, connect with the filter circuit on the circuit; each COM pin is connected with the logic control circuit through a state control switch, and the circuit connection is shown in figure 1.
And selecting corresponding quantities of SEG and COM pins according to the number of the LED and LCD display points, and connecting the LED and LCD display point arrays with the corresponding SEG and COM pins as shown in figure 2.
The SEG pin outputs four driving states, namely a high level, a middle level (1/2, 1/3, 1/4 levels and the like), a low level and a touch detection state; the COM pin output has four driving states, namely high level, medium level (1/2, 1/3, 1/4 level and the like), low level and high resistance state.
The touch driving circuit and the LED/LCD driving circuit respectively correspond to touch driving and display driving, the touch driving and the display driving share a chip pin SEG pin in a time-sharing switch driving mode, a time-sharing switch is a function switching switch, in a display driving mode, COM pins are adopted for circulating low-level state scanning, the time from COM1 scanning to COMn scanning is T, the next time is T1, corresponding to the touch driving mode, the total execution period is T + T1, and the execution period is shown in FIG. 3.
When the LED and LCD display driving circuit supporting the integrated touch key function works, when a pin is used for display driving, the logic control circuit controls all the function change-over switches to enable the SEG pin to be connected to the LED/LCD driving circuit, and simultaneously the touch driving circuit is disconnected, the LED/LCD driving circuit outputs three driving states of high level, medium level (1/2, 1/3, 1/4 level and the like) and low level through the SEG pin according to display requirements, and simultaneously the logic control circuit controls all the state control switches according to the display requirements to enable the COM pin to output three driving states of high level, medium level (1/2, 1/3, 1/4 level and the like) and low level to circularly scan in T time; when the pins are used for touch driving, in the time T1, the logic control circuit controls all the function switches to enable the SEG pins to be connected to the touch driving circuit, the LED/LCD driving circuit is disconnected, the logic control circuit controls the state control switch to enable the COM pins to be changed into a high-resistance state, the touch driving circuit sends out touch detection waveforms through the SEG pins, and when touch is detected, the logic control circuit is informed to modify corresponding registers, and the display driving and the touch driving are completed in a circulating mode.
According to the LED and LCD display driving circuit supporting the integrated touch key function, the touch drive can be integrated in the LED or LCD display driving chip, the chip pins are not additionally arranged, the time-sharing multiplexing function of the pins of the LED or LCD display driving and the touch driving is realized, the product design peripheral circuit is simplified, the number of elements is reduced, the cost is reduced, and the product stability is improved.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.