MR16 LED Lamp
MR16 (Multi-face Reflect 16, indicates the diameter of the lamp opening [50mm]) lamps are widely used in shops, decorative lighting, and other applications. The potential for applications of traditional halogen MR16 lamps are limited by their high power consumption, low efficiency, high heat generation, as well as the shortcoming that the filament can be easily damaged by mishandling or vibration. As a substitute technology for low voltage halogen lamps, LEDs are gaining widespread popularity because of many advantages that halogen lamps lack in terms of power efficiency, environment friendly, safety, long life and shock resistance.
The following sections will introduce two solutions for LED MR16 lamps.
Solution 1: The LED lamp driven by mains power. This solution features high efficiency and supports voltage of 90V ~ 265V AC without the need for traditional transformers. The mains power is rectified, and then stepped down by a DC-DC converter circuit into the required output current and voltage. The output current is controlled by a PWM controller (Pulse-Width Modulation controller) working on the basis of primary-side feedback or secondary feedback.
Solution 2: The substitute solution for traditional halogen lamps. This solution integrates LED driver circuit, LED lighting source, LED heat sink and LED lens into a LED module to replace halogen lamp bulbs. Because traditional halogen lamps run off a 12V AC power supply, a rectifier and a filter should be added before driver circuit to convert the 12V AC output of transformer to stable DC voltage. Then this DC voltage can be connected to LED driver circuit to provide a constant current to LEDs.
Generally, a 1W, or 3W, or 5W single LED or 3×1W high-Power LEDs connected in series can be selected as the lighting source for replacement of MR16. These LEDs can be single color or multi-color based on application requirements.
High-power LEDs will generate a large amount of heat while emitting light. Overheat leads to faster luminous decay, and even fatal damages to LEDs. Therefore a good thermal dissipation system is a guarantee for the proper operation of LEDs. Today most LEDs are mounted on the surface of MCPCBs which transfer heat to aluminum crusts for thermal dissipation.