Tech Primer
MR16 (Multiface Reflect 16, indicates the diameter of the lamp opening [50mm]) lamps are widely used in the applications such as shop and decorative lighting. The potential for applications of traditional halogen MR16 lamps are limited by their high power consumption, low efficiency, high heat output, as well as the shortcoming that the filament can be easily damaged by mishandling or vibration. As a substitute technology for the low voltage halogen lamps, LEDs is are gaining widespread popularity, they feature many advantages that halogen lamps lack, including power efficiency, environment friendly construction, safety, long life and shock resistance. The following sections will introduce two solutions for LED MR16 lamps.
Solution 1: the substitute solution for traditional halogen lamps. This solution integrates LED driver circuit and LED lamp into a LED module to replace the halogen lamp bulb. The LED driver circuit comprises rectification and filter circuits, LED driver chip with MOSFET, power indicator, current sensing resistors (Rs) and Schottky diodes, etc. Because traditional halogen lamps run off a 12V AC power supply, a rectifier and a filter should be added before the driver circuit to convert the 12V AC output of the transformer to stable DC power. The DC supply can then be connected to the LED driver circuit.
Solution 2: the LED lamp driven by isolated mains power. This solution features safety, high efficiency, and supports voltage of (90V - 264V AC without the need of traditional transformer. The mains power is rectification, and then stepped down by a DC-DC converter circuit into the required output current and voltage. This output current is controlled by the CC controller (constant current controller) working on the basis of primary feedback or secondary feedback. Generally, a 1W, or 3W, or 5W single LED or 3×1W high brightness LEDs connected in series can be selected to be the lighting source for the MR16 replacement. High power LEDs generate a large amount heat when emitting light. Overheating is destructive to the LEDs, resulting in rapid attenuation of lighting capability and great reduction of service life. Therefore, a solution providing sufficient heat dissipation should be attached.
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