T
treez
Guest
Hello,
This concerns a LED lamp with Vin = 20V to 140V, and output needs to be 20W.
We had a LED lamp done for us. They did a Buck converter with output of about 12V...it actually is a buck converter with an output current regulated to 1.66A….its made up of paralleled strings of three_LEDs_in_series. Actually ten strings of three_LEDs_in_series…all paralleled. There are no dropping resistors to equalise the currents.
It is said that equal string current is obtained by using matched LEDs.
Also, since the LEDs are totally enclosed in a plastic tube, (it’s a tube light) and sit on a metal core PCB, it is said that the LEDs are all obviously going to be well thermally coupled.
I suppose its true that the LEDs are likely be well thermally coupled, since they are all encased in this totally un-ventilated enclosure……the LEDs are about 2.5cm apart, but still, the total enclosure in this internally hot enclosure should ensure good thermal coupling.
However, I must admit I would have done a buckboost converter and put all leds in a single series string.
But am i just being old-fashioned?
Is this the age of leds_in_parallel with no dropping resistors, and just rely on the encasement in a non ventilated enclosure to give good thermal coupling between paralleled leds
This concerns a LED lamp with Vin = 20V to 140V, and output needs to be 20W.
We had a LED lamp done for us. They did a Buck converter with output of about 12V...it actually is a buck converter with an output current regulated to 1.66A….its made up of paralleled strings of three_LEDs_in_series. Actually ten strings of three_LEDs_in_series…all paralleled. There are no dropping resistors to equalise the currents.
It is said that equal string current is obtained by using matched LEDs.
Also, since the LEDs are totally enclosed in a plastic tube, (it’s a tube light) and sit on a metal core PCB, it is said that the LEDs are all obviously going to be well thermally coupled.
I suppose its true that the LEDs are likely be well thermally coupled, since they are all encased in this totally un-ventilated enclosure……the LEDs are about 2.5cm apart, but still, the total enclosure in this internally hot enclosure should ensure good thermal coupling.
However, I must admit I would have done a buckboost converter and put all leds in a single series string.
But am i just being old-fashioned?
Is this the age of leds_in_parallel with no dropping resistors, and just rely on the encasement in a non ventilated enclosure to give good thermal coupling between paralleled leds
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