There are several types of backlight sources used in LCD display modules: 1. LED backlight; 2. EL backlight; 3. CCFL backlight. Nowadays, our company mainly uses LED backlighting, which has the advantages of simple and practical operation, long service life, low power consumption, and high brightness.
Below is an introduction to LED backlight sources:

1. Multiple colors available: red, green, blue, white, orange, yellow, purple, blue...

2. Color matching: Red, green, and blue are the three primary colors, and using these three color backlights can create seven colors. The same backlight can also choose several colors, which can achieve more uses according to customer preferences.

3Working voltage: DC power supply, with red, orange, and yellow colors supplied at 2.0V, and green, blue, and white colors supplied at 3V~3.3V.

4Working current: The optimal current for a single LED is generally between 10mA and 15mA, with 20mA being the maximum current, which can easily burn out the LED. Therefore, we require users to use LEDs with a working current not exceeding 15mA (single lamp).

5Circuit principle: LEDs do not require driving and can be powered directly. If it is a backlight with multiple LEDs, we usually design it in parallel, so the voltage remains unchanged and the current increases (current=number of LEDs * 10mA). If there are special requirements, we will also design it in series with LEDs, so that the working voltage increases and the working current remains unchanged. The bottom backlight source of a typical COB module, which is yellow green in color, is connected in parallel into two groups, but connected in series because the operating voltage is around 4V.