Best way to step down 110v DC to light 20 LED (WHITE)

I need to light 20 white LEDs at 110V DC.. What will be the best way..

The purpose is to use the LED set for signal. So there should be very minimal chance of failure of the set..

Please suggest..

nemo4all said:

I need to light 20 white LEDs at 110V DC.. What will be the best way..

The purpose is to use the LED set for signal. So there should be very minimal chance of failure of the set..

Please suggest..

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New brand name high product quality torus transformer, fuses, Graetz bridge, filtering capacitors, several voltage regulator each for separated chain of LEDs, high quality LEDs, quality resistors with higher power ratings that is needed. LEDs running under maximum electrical specification (voltage-current). Whole PCB except LEDs lens protected with protection coating or epoxy.

Of course there is small SMPS and dedicated LED driver ICs for this, but you mention best way and "minimal chance of failure".



Best regards,
Peter

nemo,



You can prevent damage to LEDs if ensure proper operation under rated SOA.

Oppositely to incandescent lamp which can convert instantaneous energy on a slew rate heat growth, LEDs shows different behavior, allowing instantly convert in Light supplied energy, what can shift from rated SOA.

Take in mind that you must also consider that usually, Blue LEDs are most susceptible to burn than Red ones.
That´s because in order to generate Blue spectrum light is required much more energy than is necessary to generate Red light.



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If you don't need isolation then there are many low cost integrated buck converters available, like the LYTswitch family from power integration. Reliability is mostly an issue of how well you specify your SOA, how you select components, and how you manufacture it. So unless you have some sort of preliminary design you can't really talk about reliability.

mtwieg said:

...unless you have some sort of preliminary design you can't really talk about reliability.

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In fact, and due to those 20 LEDs probably will be placed on the same net, final product MTBF will decrease for a 20th factor ( what means, 1/20 of 1 LED life cycle ).


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andre_teprom said:

In fact, and due to those 20 LEDs probably will be placed on the same net, final product MTBF will decrease for a 20th factor ( what means, 1/20 of 1 LED life cycle ).


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Click to expand...

What do you mean by MTBF..??

Take a look here :

MTBF


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