Power Factor Corrected Dimmable LED Driver
The NCL30000 is 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.
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 V'cc 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.

Features
• Very Low 24 uA Typical Startup Current
• Constant On Time PWM Control
• Cvcle-bv-CycIe 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
• TR1AC Dimmable LED Based PAR Lamps
• Power Factor Corrected Constant Voltage Supplies