NCL30000是中小型開關電源控制器，適用于單級PFC LED驅動器。NCL30000具有非常低24uA的起動電流，工作電流僅2mA，能逐個周期進行電流保護，可提供500mA電流源，主要用在LED驅動電源，商業和住宅區LED裝飾照明，PFC恒壓電源。本文介紹NCL30000主要特性，方框圖，簡化應用框圖和簡化反激應用框圖，以及NCL30000LED2GEVB評估板電路圖和材料清單（BOM）。
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, transconductance 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.
NCL30000主要特性：
Very Low 24 uA Typical Startup Current
Constant On Time PWM Control
CyclebyCycle 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 PbFree, Halogen Free/BFR Free and are RoHS Compliant
NCL30000典型應用：
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
圖1。NCL30000方框圖
圖2。簡化NCL30000應用框圖
圖3。簡化反激應用框圖：次級恒流控制