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Liquid crystal display and keyboard scanning compatible circuit and electronic products using it

A technology of keyboard scanning and liquid crystal display, applied to static indicators, instruments, etc., can solve problems such as inefficiency in system design

Inactive Publication Date: 2015-11-18
GENERALPLUS TECH INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, such an approach is obviously too inefficient for system design

Method used

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  • Liquid crystal display and keyboard scanning compatible circuit and electronic products using it
  • Liquid crystal display and keyboard scanning compatible circuit and electronic products using it
  • Liquid crystal display and keyboard scanning compatible circuit and electronic products using it

Examples

Experimental program
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Effect test

no. 1 example

[0119] Since the main application of passive liquid crystal panels is in small-sized products, such as mobile phones, portable electronic amusement equipment, etc., in order to reduce the use of peripheral components and reduce the complexity of external circuit design, the present invention proposes a design of electronic products concept. Figure 4 It is a circuit block diagram of the electronic product according to the first embodiment of the present invention. Please refer to Figure 4 , the electronic product includes a passive liquid crystal display panel 401 , 3×3 buttons 402 and a liquid crystal display and keyboard scanning compatible circuit 403 . The basic function of the liquid crystal display and keyboard scanning compatible circuit 403 is a driving circuit for driving the passive liquid crystal display panel 401 . In this embodiment, the liquid crystal display and keyboard scanning compatible circuit 403 additionally adds a keyboard scanning function. Due to th...

no. 2 example

[0140] Figure 8 It is a schematic circuit diagram of the liquid crystal display and keyboard scanning compatible circuit 403 according to the second embodiment of the present invention. Please refer to Figure 8 The segment signal input and output peripheral circuits of the liquid crystal display and keyboard scanning compatible circuit 403 especially refer to pins that can be used for keyboard scanning and liquid crystal driving at the same time. The liquid crystal display and keyboard scanning compatible circuit 403 includes a driving microprocessing unit 801 , a plurality of common bonding pads COM, a plurality of segment bonding pads SEG, a plurality of input and output ports PT and a plurality of input and output circuits I / O.

[0141] Although only 8 common bonding pads COM and 8 segment bonding pads SEG are shown in the above embodiment, those with ordinary knowledge in the technical field should know that the number of the above-mentioned pins is based on the passive...

no. 3 example

[0153] Figure 10 Shown is the peripheral circuit of the segment signal input and output of the liquid crystal display and keyboard scan compatible circuit 403 according to the third embodiment of the present invention. Please refer to Figure 10 , this circuit includes an internal control logic circuit 1001, a first pull-up control circuit 1002, a second pull-up control circuit 1003, a first pull-down control circuit 1004, a second pull-down control circuit 1005, a first PMOS Field effect transistor PMOS1, second PMOS field effect transistor PMOS2, first NMOS field effect transistor NMOS1, second NMOS field effect transistor NMOS2, a first electrostatic protection circuit 1006, the second electrostatic protection circuit 1007, a first welding pad 1008, a second welding pad 1009, a first auxiliary metal oxide semiconductor field effect transistor 1010, a second auxiliary metal oxide semiconductor field effect transistor 1011, a second auxiliary metal oxide semiconductor field...

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Abstract

The invention discloses a liquid crystal display and keyboard scan compatible circuit and an electronic product using same. In order to increase flexibility of liquid crystal drive circuit application, the circuit is characterized in that when liquid crystal drive is not performed, the COM / SEG pin position of a chip is used as GPIO to perform key scanning, a Bulk of an input-output PMOS (p-channel metal oxide semiconductor) transistor of the COM / SEG pin position of the liquid crystal drive circuit is connected to VLCD to prevent communication of the circuit under a non-control situation. The circuit has the advantages that in order to solve the problems that when the COM / SEG pin position is used for key scanning, severe substrate effect causes the input-output PMOS transistor to have no low voltage high drive current capacity, an extra auxiliary transistor is parallelly connected beside the input-output PMOS transistor of the original COM / SEG pin position, low voltage drive capacity of key scanning is enhanced, low-voltage impedance can be lowered, external application circuit elements can be saved, and element cost can be lowered.

Description

technical field [0001] The present invention relates to a driving circuit, and more specifically, the present invention relates to a liquid crystal display and keyboard scanning compatible circuit. Background technique [0002] Since K.F.Braun invented the Brown tube (cathode ray tube) in 1897, until 1929, Vladimir Kosma Zworykin, a Russian scientist of the American RCA company known as the "father of television", invented the automatic "scanning electron beam" design, and After the color TV went on the market in 1954, until today, for nearly a century, the main display technology application of human beings has always been based on cathode ray tube (Cathode Ray Tube, CRT) technology. However, since the commercialization of flat-panel displays in the early 1990s, a new generation of display technology has been developed day by day. In terms of mass production scale and product application popularity, Liquid Crystal Display (LCD) undoubtedly ranks first. The mainstream of fl...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G09G3/36G09G3/20
Inventor 罗世明许耀峰陈映州
Owner GENERALPLUS TECH INC