LED (light-emitting diode) display screen constant-current driving circuit with optional mirror image ratio

Abstract

The invention discloses an LED (light-emitting diode) display screen constant-current driving circuit with an optional mirror image ratio. The constant-current driving circuit comprises a reference voltage source circuit, a constant-current adjusting circuit, a voltage sampling circuit, a current mirror image ratio self-adjusting circuit, a current mirror circuit and a display frame data processing circuit, wherein the reference voltage source circuit comprises a seven-loop oscillator and bandgap reference circuit; the constant-current adjusting circuit comprises a comparator, a current offset tube and an external ground resistance; the voltage sampling circuit comprises a differential comparator and a logic processing circuit; the current mirror image ratio self-adjusting circuit comprises a plurality of logic and time sequence circuits; 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; and the output drive channel port of the circuit is provided with a 13V withstand voltage circuit which comprises two NMOS (N-channel metal oxide semiconductor) transistors. The driving circuit provided by the invention has the advantages of increasing the gray levels of the LED display screen, increasing the brightness contrast and solving the withstand problemof the output drive channel port with low cost.

Description

technical field [0001] The invention relates to a driving circuit, in particular to a constant current driving circuit of an LED display screen with self-selected mirror image ratio. Background technique [0002] 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 images. In the full-color LED display, in order to improve the display quality of the display and adapt it to various light environments such as day, night, cloudy, sunny, etc., as well as different display backgrounds such...

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

[0004] 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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