CCFL (cold cathode fluorescent lamp) backlight technology on traditional LCD display devices has some inherent flaws, such as narrow color gamut, low energy utilization, high power consumption and short lifespan. Therefore, people have been looking for alternative technologies and products, with LED backlight technology becoming a widely adopted choice.

The application fields of LED backlight mainly include LCD TVs. LED backlight technology can significantly improve picture quality, especially color saturation. LED backlight displays can achieve a wide color gamut, making up for the shortcomings of insufficient colors in LCD devices. Some LCD TV panels with LED backlights even exceed the requirements of Adobe RGB and NTSC color standards, reaching an NTSC ratio of more than 100%. Among them, the LCD TV panel with LED backlight launched by a certain company emphasizes the performance of bright red and dark green, making the colors more realistic. In addition, the flat light source characteristics of the LED backlight enable it to achieve regional color and chromaticity adjustment, thereby achieving more accurate color reproduction and meeting the image quality requirements of graphic publishing and graphic design work. By dynamically adjusting brightness and contrast, LED backlight can also achieve better picture quality when displaying different pictures.

The following are five optimization solutions for LED circuit design:

Driver for 60 white LEDs:

Using the LT3598 driver, which has 6 channels, the current of each LED string is set to 20mA. Analog dimming and digital dimming functions are provided through the CTRL pin and PWM pin respectively.

Driver for 36 white LEDs:

Using the LT3598 driver, which has 4 channels, the current of each LED string is set to 25mA. The LT3598 is designed to drive up to 6 strings of LEDs with output voltages up to 44V.

Driver for 20 white LEDs:

Using the LT3598 driver, which has 4 channels, the current of each LED string is set to 20mA. The LED dimming function can be achieved through an analog dimming circuit on the CTRL pin and a pulse width modulation dimming circuit on the PWM pin.

Car battery powered driver for 20 LEDs:

Using the LT3598 driver, which has 2 channels, the current of each LED string is set to 90mA. The LT3598 accurately regulates LED current even when the input voltage is higher than the LED output voltage.

LED driver for 30 white LEDs:

Using the LT3598 driver, which has 3 channels, the current of each LED string is set to 60mA. The switching frequency is programmable with an external resistor and ranges from 200kHz to 2.5MHz.

LT3598 is a general-purpose LED driver with built-in power switch, suitable for driving multiple strings of LEDs. It has stable PWM dimming ratio detection function and can provide high PWM dimming ratio. Additionally, when all LED strings are open circuit, the voltage loop will regulate the output voltage. The advantage of LED as a backlight source is that it can replace the use of color filters. By using three-color RGB LED and color sequence technology, we take advantage of the persistence characteristics of human eyes.