Liquid crystal display and keyboard scan compatible circuit and electronic product using same

• Main Authors: CHEN YINGZHOU, XU YAOFENG, LUO SHIMING
• Format: Patent
• Language: Chinese; English
• Published: 29.01.2014
• Subjects: ADVERTISING; ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICESUSING STATIC MEANS TO PRESENT VARIABLE INFORMATION; CRYPTOGRAPHY; DISPLAY; EDUCATION; PHYSICS; SEALS

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 enhance