Products, Materials + Tools | Jul 20, 2010

On Semiconductor Presents Power Factor Corrected Dimmable LED Driver

On Semiconductor introduces its NCL30000 LED Driver, a switch mode power supply controller intended for low to medium power single stage power factor (PF) corrected LED Drivers. The device is designed to operate in critical conduction mode (CrM) and is suitable for flyback as well as buck topologies.

Constant on time CrM operation is particularly suited for isolated flyback LED applications as the control scheme is straightforward and very high efficiency can be achieved even at low power levels. These are important in LED lighting to comply with regulatory requirements and meet overall system luminous efficacy requirements. In CrM, the switching frequency will vary with line and load and switching losses are low as recovery losses in the output rectifier are negligible since the current goes to zero prior to reactivating the main MOSFET switch.

Housed in a compact 8-pin surface mount package, the NCL30000 achieves high power factor (> 0.95) in a single-stage topology by using a critical conduction mode (CrM) flyback architecture, thereby eliminating the need for a DC-DC conversion stage. Constant on-time CrM operation is particularly suited to isolated flyback LED applications, as the control scheme is straightforward and very high efficiency can be achieved - even at low power levels. This is important in LED lighting in order to support compliance with regulatory requirements and meet overall system efficacy requirements.
Typical applications include LED driver power supplies, LED-based down lights, TRIAC dimmable LED-based lamps and power factor corrected constant voltage supplies. This device is compatible with both leading edge TRIAC-based and trailing edge transistor-based dimmers. Depending on the dimmer used, the LED output can be controlled down to < 2 percent.
Three up to 15 W reference designs are provided and are intended to drive from 4-15 LEDs at 350 mA. They can however, be easily modified to support power levels ranging from 5 W to 30 W:
• NCL30000LED1GEVB: 115 Vac version, 90 to 135 Vac input line  (TRIAC Dimmable)
• NCL30000LED2GEVB: 230 Vac version, 180 to 265 Vac  (TRIAC Dimmable)
• NCL30000LED3GEVB: Extended universal version, 90 to 305 Vac
The device features a programmable on time limiter, zero current detect sense block, gate driver, trans-conductance error amplifier as well as all PWM control circuitry and protection functions required to implement a CrM switch mode power supply. Moreover, for high efficiency, the device features low startup current enabling fast, low loss charging of the VCC capacitor. The current sense protection threshold has been set at 500 mV to minimize power dissipation in the external sense resistor. To support the environmental operation range of Solid State Lighting, the device is specified across a wide junction temperature range of -40°C to 125°C.
• Very Low 24 uA Typical Startup Current
• Constant On Time PWM Control
• Cycle-by-Cycle Current Protection
• Low Current Sense Threshold of 500 mV
• Low 2 mA Typical Operating Current
• Source 500 mA / Sink 800 mA Totem Pole Gate Driver
• Reference Design for TRIAC and Trailing Edge Line Dimmers
• Wide Operating Temperature Range
• No Input Voltage Sensing Requirement
• Enable Function and Overvoltage Protection
• These Devices are Pb-Free, Halogen Free/BFR Free and are RoHS Compliant
Typical Applications:
• LED Driver Power Supplies
• LED Based Down Lights
• Commercial and Residential LED Fixtures
• TRIAC Dimmable LED Based PAR Lamps
• Power Factor Corrected Constant Voltage Supplies

Other key features of the NCL30000 include a programmable on time limiter, zero current detect sense block, gate driver, plus all other pulse width modulation (PWM) circuitry and protection functions needed to implement a CrM switch mode power supply. The NCL30000 is the key device in a fully tested, GreenPoint® reference design for offline high power factor triac dimmable LED drivers intended for ENERGY STAR® commercial and residential luminaires. The reference design documentation can be found along with the other reference designs listed above on the ON Semiconductor website.
“Our customers have a need for dimmable LED driver solutions that are compatible with existing wiring and controls,” said Christophe Warin, AC-DC business unit manager at ON Semiconductor. ”The NCL30000 offers excellent dimming performance down to greater than 2 percent. This device is ideally suited for isolated flyback but can also be used with non-isolated buck topologies.”
Packaging and Pricing:
The Pb, halogen and BFR free NCL30000 is RoHS compliant and is available in an eight-pin SOIC package. It is priced at $0.45 per unit in 10,000 unit quantities. Samples are available now.  Projected lead-time for production quantities is currently eight to 12 weeks after receipt of order (ARO).
For additional information, please visit ON Semicondutor's product page at, or download the datasheet.

About ON Semiconductor:
ON Semiconductor provides an extensive range of LED driver solutions for a diverse range of applications from portable battery powered products to interior automotive lighting to general and architectural solid state lighting products powered directly from the AC line. ON Semiconductor leverages its expertise and strength in power management and high volume manufacturing to develop application specific LED drivers tailored to the needs of the evolving portable, consumer, industrial and automotive marketplaces. The solutions ON Semiconductor develops for LED Lighting meet or exceed regulatory requirements throughout the world.
ON Semiconductor (Nasdaq: ONNN) is a premier supplier of high performance, energy efficient, silicon solutions for green electronics. The company's broad portfolio of power and signal management, logic, discrete and custom devices helps customers to quickly and cost-effectively solve their unique design challenges in automotive, communications, computing, consumer electronics, LED lighting, medical, industrial, military/aerospace and power applications. ON Semiconductor operates a world-class, value-added supply chain and a network of manufacturing facilities, sales offices and design centers in key markets throughout North America, Europe, and the Asia Pacific regions. For more information, visit