How is the LED driver integrated circuit?
|For LED drivers, the output control is the current flowing through the LED. The voltage is usually no longer the object of concern, so some of the effects of voltage may be ignored. In fact, the LED light is basically a light-emitting diode. After the LED light is turned on, the voltage increases and the current increases exponentially, which easily damages the LED light. Therefore, the LED lamp requires a special LED driver chip to ensure its constant current output function.|
Traditionally, LED dimming is accomplished by adjusting the forward current flowing through the LED with a DC signal or a filtered PWM signal. Reducing the LED current adjusts the LED light output density. However, a change in the forward current causes a change in the color of the LED's illumination because the chromaticity of the LED varies with the current. Many applications, such as LCD HDTVs and automotive backlights, do not allow for any deviation in the LED's illumination color. Wide dimming ranges are required in these applications due to differences in ambient light and the small changes in light intensity perceived by the human eye. By using the PWM signal to control the intensity of the LED, LED dimming can be achieved without changing the color of the illumination.
Clearly, LEDs have become the mainstream choice for backlighting large LCD flat panel displays used in HDTVs. However, system designers still need LED driver ICs that meet their specific design performance requirements. Therefore, LED driver ICs must be able to meet the input voltage range and the desired output voltage and current requirements of the conversion topology, providing sufficient current and voltage for many different types of LED configurations.