Requirements on High Performance LED Driver for Professional LED Lighting
Professional LED lighting is overcoming today many shortcomings of the first LED lighting systems. In the early days of LED lighting the focus was predominately on outperforming conventional bulb and tubes in term of power consumption, rather than on light quality. Since then the request for higher lighting quality has been rising step by step. Nowadays the features of high quality lighting includes not only deep dimming and flicker free light but also low standby power or full spectrum color control. The combination of these features is adding complexity at large scale to the LED lighting system and the LED driver electronics as well.
Simultaneously also regulatory requirements of LED lighting increased, setting limits for Power Factor or the lately introduced California Title 24 reduced flicker operation definition. On top of this, the variety of LED modules is exploding, demanding driver with wider window of operations. If this alone wouldn´t be challenging enough of course next year’s generation LED driver need to be less costly than previous one. Recent studies and designs of leading lighting companies respond to these challenges with resonant topologies LED driver, which can be effectively designed from 40Watt upwards. The paper will focus on some key performance attributes of resonant topologies which are currently rising in popularity for modern high performance led driver and explore their contributions to following aspects:
Efficiency – high efficiency is required to save energy but also to reduce the thermal dissipation of the driver. Even tough LED need to be thermally managed (cooling) most designs prefer to avoid that for the driver electronics for construction and cost reasons
Power Factor – all electronic equipment in the EU connected to public mains must comply with. EN 61000-3-2. There are specific requirements detailed for lighting based on power class
Harmonic Distortion – THD is important in any type of power system, specifically in LED driver low THD means higher power factor, lower peak currents, and higher efficiency. Standards include EN 61000xx and EN 12105
Low Standby Power – a dimmed LED luminaire need to react instantaneously on the dimmer signal and change from “lights-off” to any level of luminosity the user chooses via the control gear. Hence for large time of its life while lights are off, it remains in wait and see = standby mode
Protection – modern LED driver protect the valuable LED components in surge, overvoltage, over temperature situations and ensures no damage at hot-plug events
Time to light – a human friendly light responds to a tip on the switch without any noticeable delay time
Cost – factors like ease of design, build in protections and combo controller with power factor correction helping designers to meet cost targets with design of ever increasing complexity.
The semiconductor industries challenge is to support the LED driver manufacturer with sophisticated semiconductor solution helping to meet the ever increasing specification targets at ever decreasing cost targets.