Adjusting circuit of contrast ratio of liquid crystal display (LCD)

A technology for adjusting circuits and contrast, applied in instruments, static indicators, etc., to solve problems such as inability to achieve contrast adjustment

Inactive Publication Date: 2013-06-12
上海格立特电力电子有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the contrast adjustment of the LCD screen is adjusted by analog voltage, that is, the contrast control is realized through the magnitud

Method used

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  • Adjusting circuit of contrast ratio of liquid crystal display (LCD)

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Embodiment

[0010] like figure 1 As shown, it is a schematic diagram of a liquid crystal screen contrast adjustment circuit provided by the present invention. In the figure, the U1 digital output port P1.7 is connected to the input end of the resistor R2, and the output end of the resistor R2 is connected to the input end of the resistor R1. The resistor The output terminal of R1 is connected to the contrast analog input port VLCD of the liquid crystal display LCD, the connection terminal of the resistor R2 and the resistor R1 is connected to the VSS of the liquid crystal display LCD through the capacitor C1, and the output terminal of the capacitor C1 is connected to the VSS of the liquid crystal display LCD The connection of VSS is grounded, the VDD of the liquid crystal display LCD is connected with the power supply, and the U1 is the CPU controlled by the keyboard.

[0011] The present invention uses a filter circuit composed of resistors R1, R2 and capacitor C1 to filter and generate...

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Abstract

The invention relates to an adjusting circuit of a contrast ratio of a liquid crystal display (LCD). The adjusting circuit of the contrast ratio of the LCD is characterized in that a digital output port P1.7 of U1 is connected with an input end of a resistor R2, an output end of the resistor R2 is connected with an input end of a resistor R1, an output end of the resistor R1 is connected with a contrast ratio analog quantity adjusting input port (VLCD) of the LCD, connecting ends of the resistor R2 and the resistor R1 are connected with a VSS of the LCD through a capacitor C1, the connecting position of an output end of the capacitor C1 and the VSS of the LCD is grounded, and the VSS of the LCD is connected with a power supply. According to the adjusting circuit of the contrast ratio of the LCD, utilized components by the circuit are few, transition from digital quantity to analog quantity is achieved, and the adjusting circuit is simple and reliable.

Description

technical field [0001] The invention relates to a liquid crystal screen contrast adjustment circuit. Background technique [0002] The keyboard display of the general-purpose inverter usually uses a digital tube display, that is, it can only display numbers, but not Chinese or English. When it is necessary to display Chinese and English, it is necessary to use an LCD screen as a display. The LCD screen can only display clearly by adjusting the contrast under different lighting conditions. At present, the contrast adjustment of the LCD screen is adjusted by analog voltage, that is, the contrast control is realized through the magnitude of the analog voltage, while the CPU controlled by the keyboard only has digital output, which cannot realize the function of contrast adjustment. Contents of the invention [0003] The object of the present invention is to provide a liquid crystal screen contrast adjustment circuit capable of realizing digital adjustment. [0004] In order...

Claims

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Application Information

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IPC IPC(8): G09G3/36
Inventor 杨跃农
Owner 上海格立特电力电子有限公司
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