Light-emitting diode (LED) display screen constant-current driving circuit with plurality of mirror image ratios

Abstract

The invention discloses a light-emitting diode (LED) display screen constant-current driving circuit with a plurality of mirror image ratios. The driving circuit comprises a reference voltage source circuit, a constant-current regulation circuit, a voltage sampling circuit, a current mirror image ratio self-regulation circuit, a current mirror circuit and a display frame data processing circuit. The reference voltage source circuit comprises a seven-stage ring oscillator and a band-gap reference circuit. The constant-current regulation circuit comprises a comparator, a current biasing tube and an external grounding resistor. The current mirror circuit comprises a plurality of current mirror image tubes. The display frame data processing circuit comprises a plurality of display frame data processing units. An output driving channel port of the circuit is provided with a voltage-resistant circuit comprising two N-channel metal oxide semiconductor (NMOS) tubes. A first-stage current mirror group comprises a plurality of current mirror image tubes. A second-stage current mirror group comprises a plurality of current mirror image tubes. The driving circuit has a plurality of mirror image ratios, and has the advantages that gray levels of an LED display screen can be regulated and added, the brightness contrast of the LED display screen can be improved, the problem of voltage resistance of the output driving channel port is solved with lower cost, and the like.

Description

[0001] This application is a divisional application with the application number 201110301641.7, the application date is September 28, 2011, and the invention title is "Constant Current Drive Circuit for LED Display with Optional Mirror Ratio". technical field [0002] The invention relates to a driving circuit, in particular to a LED display constant current driving circuit with various mirror ratios. Background technique [0003] Light-emitting diode is a current control device, which has the advantages of high brightness, small size, low power consumption, good monochromaticity, fast response speed, and long service life. Large, medium and small LED displays are composed of light-emitting diode arrays, which can be used to display various information such as text, graphics, images, animations, market prices, videos, etc., and light-emitting diodes with three primary colors of red, green and blue The full-color LED display screen composed of it can display delicate color im...

AI Technical Summary

Problems solved by technology

However, since the brightness of a light-emitting diode is determined by the current that drives it, the value of M will be restricted by the constant current accuracy of the drive current and the current consistency between different current drive channels, so it is difficult to establish a very accurate more The system of gray level and brightness contrast relationship, which in turn affects the display quality of the entire full-color LED display

[0005] In addition, in order to improve the overall brightness of the LED display and adapt to the environment with strong light, some LED displays will be designed and produced by stringing several LEDs together to increase the brightness, but such a solution will increase the power supply voltage of the entire system At the same time, it is also required that the output drive channel port of the LED drive circuit has the characteristics that the withstand voltage can be improved

In order to make the output drive channel port of the LED drive circuit have the characteristics of improved withstand voltage, the main solution is to use a higher withstand voltage processing technology or use a withstand voltage drive tube for each data output port to drive the LED. string, but both options will increase the cost of the overall system

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