I was wondering if I can receive a little more details about the capability of MPM6010. So, in its datasheet it is specified in the typical performance characteristics chapter that it works with 2 series LEDs which have a forward voltage of 6V together and also, all the typical application schematics have 2 series LEDS connected at the output. So my question is what is the maximum number of LEDS that could be connected to MPM6010 or can I connect how many LEDs I want as long as the output current doesn’t exceed 1.5A? Does this apply even to chip LEDs which have for example 2 LEDs on one chip?
Thanks for your question.
There is no limit on how many LEDs are connected, as long as the load doesn’t exceed 1.5A. However, note that the efficiency of the part will vary with your load current.
Refer to page 7 of the datasheet for the efficiency vs. LED current plots.
I’m not sure what you mean by your second question, but as long as the load doesn’t exceed 1.5A, then you will be fine.
I think that the talk about not exceeding 1.5A for the output current is confusing for this question. In a series string of LEDs, all LEDs share the same current so adding more LEDs to the string will have no impact on the current. Adding more LEDs will however increase the required voltage across the whole string to maintain the current. One thing that is not clear to me from the datasheet is “How is Vout related to Vin?” and I would like to see that explained. Max Vin is 36v so the sum total of the Vf drops across the LEDs cannot exceed 36v, but how close can it come? Since “Vin minimum” is listed as 4v, as a WAG I’d guess that the module needs 4v for its own use, so that up to 32v would be available for an LED diode string for a Vin of 36v, but again this is only a WAG.
Also speaking of page 7 of the datasheet, there is a graph of “Frequency vs. Vin” and the Y-axis is labeled “Frequency (kHz)”. I’m pretty sure that “kHz” is supposed to be “MHz”.