According to estimates by market research institutions, China's LED general lighting demand will reach 10 billion US dollars by 2015 and 22 billion US dollars by 2020. The gradual replacement of traditional lighting by LED lighting is the trend of the times. However, LED general illumination has many challenges, such as power density, power factor correction (PFC), space limitations, and reliability. ON Semiconductor is committed to providing a broad lineup solution for LED lighting, offering a wide range of products that meet the latest LED lighting standards, including AC-DC LED driver power solutions for general purpose lighting.
General Lighting Challenge and AC Mains Power LED Driver Topology
Energy efficiency is especially important for low power applications due to LED total efficacy requirements and thermal limitations; in many cases, power factor correction and harmonic processing are required for even lower power applications; especially in space-constrained applications, especially for bulb applications. High drive power density is required; overall power supply reliability is important for the life of the entire lamp; wide input supply voltage range should support up to 277 Vac; compatible with TRIAC dimming requirements. In addition, LED general lighting is subject to evolving standards and safety regulations such as Energy Star and IEC requirements.
Depending on the application requirements (size, energy efficiency, power factor, power, drive current), there are multiple topologies for driving LEDs with AC mains. ON Semiconductor offers a variety of power solutions for a variety of lighting applications.
Figure 1: Different AC mains power LED driver topologies
ON Semiconductor LED General Lighting AC-DC Solution
1) Power factor correction scheme
The 160 W Power Factor Correction (PFC) boosting solution from ON Semiconductor's NCP1611 or NCP1612 uses a non-isolated boost topology with lighter energy efficiency than traditional CrM PFCs; no additional components, high reliability and safety. The solution uses current-controlled frequency back-off (CCFF) CrM with boost or bypass diode short-circuit protection, pin open/short protection, optimized transient response, soft overvoltage protection, input undervoltage detection, and low total harmonics. Distortion configuration, overheat shutdown and other features.
Such PFC solutions also include NCP1607, NCP1608, NCP1615, and NCP1654 (non-isolated boost); NCL30000 (isolated single-stage flyback, non-isolated buck); NCL30001 (isolated single-stage flyback); NCL30002 (non-isolated buck) ; NCL30060 (single-stage flyback or step-down).
Taking NCL30000 as an example, the “average current steady current†topology can choose two configurations, one is buck configuration (including tapped inductor buck configuration); the other is buck-boost configuration, the inductor is not connected in series with LED string The input current waveform or distortion is independent of the output voltage drop. It is available for primary thyristor dimming for both isolated and non-isolated solutions, and the isolation scheme is 80-85% efficient.
2) Primary side control offline solution
Primary side steady flow (PSR) is also known as primary side control. Primary Side Control Offline LED Drivers do not use optocouplers, with ±1% (typ) precision LED current regulation accuracy, wide VCC range, high energy efficiency quasi-resonant control, robust protection feature combination, and wide operating temperature range (-40 Up to +125°C); support flyback and buck-boost topology with a power factor of approximately 0.9 for passive PFC inputs; this series can be used for LED bulb replacement, off-line LED drivers, recessed lights, indoor/outdoor accent lighting and Task light and LED electronic control unit.
Figure 2: Primary Side Control Offline Solution
Available options are NCL30080A/B, NCL30081A/B, NCL30082A/B, and NCL30083A/B (passive PFC control); NCL30085A/B, NCL30086A/B, NCL30087A/B, and NCL30088A/B (active PFC control). Its dimming control includes non-dimming, 3-step/5-step dimming, analog/digital, triac/ trailing edge trigger dimming, and more.
Product application:
1 AC air switch
2 AC contactor
3 Mechanical switch and electronic switch
4 Cable and wire
5 Automatic detection and calibration platform
6 Large current capacitor electrical appliances
7 Thermal relay, molded case circuit breaker, small circuit breaker and the required rated current, action current, short-circuit protection current, etc
Technic parameter:
constant current source
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