As LED cost decreases and has been massively applied to various lighting applications. In this article, we’ll focus on the development trends in LED lighting applications and the LED power controller solutions from ON Semiconductor.
Robust power solution for stable product quality
As LED technology keeps progressing, the launch of LED featuring various colors and high brightness has further expanded LED applications to a wide range of new markets. As LED cost continues to drop, which was mainly used in indicator lamps in the past, and now can be applied to automotive applications and consumer electronics to replace the traditional light sources, like incandescent and fluorescent lamps. Now, we can see LED applied in products including smartphones, LCD TVs and building and general lighting. In the next few years, LED will be used in LED lighting solutions. It could offer more benefits of flexible thanks to the programmable capability and agility of lighting applications.
As a low-voltage component, the forward voltage of LED ranges from <2V to 4.5V, depending on the required color and current. Moreover, LED needs to be driven by a constant current to ensure brightness and the desired color. It requires power conversion to integrate different power supplies, including AC input, solar panels, 12V automotive batteries, direct power supplies or low-voltage alternating systems, or even to be integrated with the alkaline, nickel-based or rechargeable lithium batteries.
With its specialized experience in low- and high-voltage technology, power management solutions built up over the years, ON Semiconductor applies its expertise to solve various challenges that SSL is facing now. ON Semiconductor releases SSL solutions for portable displays, car interior lighting, rectifiers for LED indicators and areas including building, industry, automotive and portable applications.
NCL30288, the power factor corrected quasi-resonant primary side current-mode controller for LED lighting from ON Semiconductor, is an AC-DC power factor corrected flyback controller designed for isolated and non-isolated buck-boost/SEPIC constant current LED drivers. The controller operates in a quasi-resonant to provide optimal efficiency and embeds a proprietary control method which allows the LED current to be tightly regulated from the primary side (thus eliminating the need for a secondary−side feedback circuitry, an offset and an optocoupler). The device, with a minimum number of external components, is integrated with a robust suite of safety protections to simplify the design. This device is specifically intended for very compact space-efficient designs.
The features of NCL30288 include constant current control with primary-side feedback, tight current regulation, power factor correction with low harmonic distortion, wide Vcc range, line feedforward for enhanced regulation accuracy, wide temperature range (-40-125°C), low startup current (13μA typ.) and such capabilities as valley lock out, auto-recovery, secondary diode short, LED open and short circuit protections .
Compared with other products in the market, NCL30288 requires no optocoupler nor secondary control circuit. It does not need to classify the LED or be altered during production for better accuracy. Its specification is superior to the industrial demands for lighting, supports universal power applications (90-305V), and simplifies the support to LED forward voltage range, protects overheating of LED drivers under harsh conditions, features powerful agility for troubleshooting and robust troubleshooting for general LED system failures and supports applications in outdoor and high-temperature environments. NCL30288 can be applied to integral LED electronic drivers, end products such as LED bulbs, LED power drivers, LED light engines, LED tubes and LED system electronic control devices.
ON Semiconductor expanded its lines for LED lighting through the acquisition of Fairchild in Sep. 2016. FL7740, a constant-voltage primary side regulation PWM controller for power factor correction, features wide universal input range (90 VAC-305 VAC), precise CV regulation (<±3%) in the steady state, CV regulation in the load transient (<±10%) Its differentiated dynamic function can minimize overshoot and undershoot of output voltage in line and load transient condition.
When applied to smart lighting, FL7740 realizes a standby power of less than 0.3 W at 100 mW load conditions. The power factor is higher than 0.9 even at half load conditions when enabling a PF optimizer for wide output power scalability. Startup time is less than 0.2 sec with built-in high voltage startup circuit and output voltage reaching the target CV level by loop gain transition technique during startup. This device comes with various protections against overload, output diode short, sensing resistor short and open, output short and overvoltage to ensure high system reliability.
The LED power controller from ON Semiconductor can accelerate the development of related products and guarantee the stability of products and will be one of the best choices for product development.
