White light LEDs require 3V per diode. One way to power them involves power management that includes voltage conversion from the AC line. This class is called “DC Solutions” to highlight the fact that they convert AC line power into lower voltage DC to power an array of LEDs. Another approach makes nearly direct use of the AC line; this solution is called “High-Voltage LED Lighting.”
Key Issues in DC Solutions
Today’s DC solutions using constant-current power supplies need many discrete electronic components, resulting in large form factor, lower efficiency, and poorer power factor. Most importantly, additional components add cost, limiting use of DC solutions in lighting applications.
DC solutions are not always optimal. They may be limited by use of transformers, inductors, capacitors, bleeder circuit required to support current Triac dimmers, and optoisolators, all adding to the cost, size and weight, reducing power efficiency, creating EMI issues and possibly acoustic noise.
Large capacitors in DC supplies can reduce system longevity. Since the capacitors burn out faster at high temperatures, some solutions restrict temperature but also necessarily limit LED drive capability resulting in lower lumens per given light source. Also, larger size of DC Solutions makes it impossible for them to fit inside small-size bulbs. In addition DC solutions require many electronic parts in the bulb or tube which create a large carbon footprint in production of these components.
These limitations in DC solutions have restricted their mass-market adoption.
High Voltage AC as Desirable Solution
High voltage solutions that support direct AC input present the optimal solution. This approach eliminates many of the components required in a DC design. Its advantages can include:
lower cost than other approaches
improved efficiency and power factor
extending the power supply life time to match LEDs’ five to ten years operating life
light quality comparable to incandescent
reduced power supply size to fit within small bulb sockets
reduced system weight
eliminates transformer, electrolytic capacitors, and many discrete components
This solution provides rectified regulated AC line power to the LED array and obviates the need for capacitors and their limitations. It addresses many design problems with DC solutions and optimizes the performance and cost of the bulb. An AC solution enables lower-cost LED solutions compared to other lighting technologies on a total cost of ownership (TCO) basis.
An optimal AC solution would be a single chip AC driver with minimal support components. Though desirable, this is difficult to achieve from technology and engineering perspective. Despite years of development efforts by many semiconductor companies, no viable, production-worthy, commercially available solutions have existed until now.
Opening a new era, Exclara is the first company to offer a viable cost-effective high voltage LED solution. Using its patent-protected HVX technology, Exclara now makes high voltage LED drivers economically and physically effective to use in a commercially available product. HVX’s many advantages are revolutionizing the LED market and paving the path for worldwide widespread adoption of LED solutions in lighting.