Complementary color multi-color LED backlight TFT Display Module

Various colors of LED have developed As led technology matures, costs are also dropped significantly. Output current more than 300mA LED driver circuit common inductive switching and linear power drive mode is also useful co-driven switching and linear power supplies. Linear power drive circuit almost no ground bounce and ripple interference circuit, commonly used in the EMC requirements of the occasion.OLED Display
The multi-color LED color mixing complementary color backlight technology is the focus of present research. As early as 2000, Japan had to produce multi-chip LED backlight products. Subsequently, the major companies have launched high-performance multi-chip-type LED backlight LCD. But specifically how to color mixing complementary color few now open literature.
Although the LED lights of red, green and blue colors mixed backlight wide color gamut, but there is a red edge phenomenon. In this paper, a white LED as the main light source, then as a complementary color light orange light and blue light, get a screen white field color temperature (6 500 ± 100) K or less, the color coordinates u 'in less than 0. 198 ± 0. 01 v '0 468 ± 0 01 Within the standard white light.Low Temperature Display
2 fill color circuit diagram
White LED is excited with the Blu-ray $ phosphor white LCD screen on the decay of the short-wave component is greater than the long-wave component, the white light emitted from the LED light out yellowish color screen, both need to make up the Blu-ray, but also complement red.
In the case of flow through a typical current of 20mA at room temperature orange lamp voltage is 2V, the blue lamp voltage is 3V, the white lamp voltage is 3V.
The three kinds of lights are a string of eight. Orange light in the typical current circumstances only need about 16V, less than 60% of the efficiency of the drive circuit linear constant current source, the power loss is less than 1W Orange is the complementary color; linear white light and blue light Power efficiency over 85%.
3 LED lights each way linear constant current source driver, each channel set sum of current 200mA, to ensure each LED string lamp current is the typical current of 20mA, as shown in Figure 1. Each route of the constant current source independent of the PWM dimming signal with the same frequency, the frequency is fixed, the duty time varies with different brightness dimming change.
FPGA as a controller, according to the dimming command of the host computer to adjust the PWM duty cycle, so as to control the brightness of the backlight; sampling color sensor data, fine-tune the PWM duty cycle of the orange light and blue light, color temperature does not guarantee temperature changes unchanged.