JPH0245523U

JPH0245523U -

Info

Publication number: JPH0245523U
Application number: JP12245588U
Authority: JP
Priority date: 1988-09-19
Filing date: 1988-09-19
Publication date: 1990-03-28

Description

【図面の簡単な説明】第１図は本考案の液晶駆動電圧発生回路を示す
回路図、第２図は本考案の液晶駆動電圧発生回路
を備えたマイクロコンピユータ内におけるコモン
駆動回路及びセグメント駆動回路を示すブロツク
図、第３図は、第１図における第２抵抗のインピ
ーダンスと、第１図及び第２図によつて作成され
たコモン駆動電圧と、液晶表示装置による表示の
コントラストとの関係を示す図である。２，３，４，５，６…第１抵抗、７，８，９…
第２抵抗、１０，１１，１２，１３…トランスフ
アゲート、１４…スイツチ制御回路、１５―１，
１５―２……１５―ｎ…コモン駆動回路、１７―
１，１７―２……１７―ｍ…セグメント駆動回路
。[Brief Description of the Drawings] Figure 1 is a circuit diagram showing the liquid crystal drive voltage generation circuit of the present invention, and Figure 2 is a common drive circuit and segment drive circuit in a microcomputer equipped with the liquid crystal drive voltage generation circuit of the present invention. FIG. 3 is a block diagram showing the relationship between the impedance of the second resistor in FIG. 1, the common drive voltage created according to FIGS. 1 and 2, and the contrast of the display by the liquid crystal display device. FIG. 2, 3, 4, 5, 6...first resistor, 7, 8, 9...
Second resistor, 10, 11, 12, 13...Transfer gate, 14...Switch control circuit, 15-1,
15-2...15-n...Common drive circuit, 17-
1, 17-2...17-m...Segment drive circuit.

Claims

[Claims for utility model registration] (1) Connected in series between the first power source and the second power source,
A plurality of first resistors that create common drive voltages and segment drive voltages that are respectively applied to the common electrode and the segment electrode of the liquid crystal display device according to the voltage obtained at each connection point, and among the plurality of first resistors. between one end of the resistor to which the first power source is applied and the first power source, and/or
a plurality of second resistors connected in parallel between one end of the resistor to which the second power supply is applied among the plurality of first resistors and the second power supply; and a predetermined resistance among the plurality of second resistors. to control the voltage levels of the common drive voltage and the segment drive voltage by selecting the plurality of second
A liquid crystal drive voltage generation circuit comprising a plurality of switch circuits connected in series to a resistor and a switch control circuit for controlling on/off of the switch circuits, and controlling the contrast of display by the liquid crystal display device. . (2) connected in series between the first power source and the second power source,
a plurality of first resistors that create a common drive voltage and a segment drive voltage to be respectively applied to the common electrode and the segment electrode of the liquid crystal display device based on the voltage obtained at each connection point; between one end of the resistor to which the first power source is applied and the first power source, and/or
a plurality of second resistors connected in parallel between one end of the resistor to which the second power supply is applied among the plurality of first resistors and the second power supply; and a predetermined resistance among the plurality of second resistors. to control the voltage levels of the common drive voltage and the segment drive voltage by selecting the plurality of second
a plurality of switch circuits connected in series to the resistors; a switch control circuit that controls on/off of the switch circuits; and a switch control circuit that controls on/off of the switch circuits; A microcomputer comprising: a common drive circuit and a segment drive circuit, each of which generates a common drive voltage and a segment drive voltage, respectively, to which a voltage is applied and whose voltage level is controlled.