Good morning,
my name is Massimo (from Rome, Italy) and I would like to receive some advice relevant to a problem that I have in using a ZXLD1360 LED driver. From the datasheet, I understood that this driver is able to control the current flowing in the LED by the value of a single resistor between Vin and Isense pins. In my circuit (equal to the typical application diagram shown in the datasheet), I have a resistor of 0.13 ohms between these two pins, for an average current of 770 mA (ADJ pin left open). I have to use two different types of LEDs for my applications: One XICATO XSM8040 and one CREE XP-E. The problem that I don't understand it is that the circuit seems not to be able to control the current in the LED: in particular, while maintaining the resistor of 0.13 ohms between the two Vin and Isense pins, when XICATO LED is connected, the current flowing is about 750 mA, while when the CREE LED is connected, the current flowing is about 250 mA. I am not able to understand why this happens, and this creates a serious problem, because I would like to increase the current flowing in the CREE LED, but I'm not able to control this by adjusting the resistor.
May you help me to understand how to use this driver?
Many thanks.
Best Regards
Massimo

 

Hi Massimo,
Welcome to AAC.
Do you have a datasheet for ZXLD1360 LED driver that you can post.?

E

 

Hi Eric,
many thanks for your reply.
here attached please find the data sheet of the device by Diodes Incorporated.
Best Regards
Massimo

Hi Massimo,
Welcome to AAC.
Do you have a datasheet for ZXLD1360 LED driver that you can post.?

E

 

Hello,

Wich version of the 8040 led do you have?


The voltage across the led differs per type.

The voltage drop of the XP-E is much lower as the 8040.
You could try to use 2 or 3 XP-E leds in series.

Bertus

 

Hi Bertus,
I use the version 400 lumen (8040-400-B).
Of course the XICATO voltage drop is more than two times the voltage drop of XP-E (around 7V vs around 3.2V).
But probably this is my misunderstanding: I thought that this controller were more or less a current generator, able to maintain the current flow constant, indipendently from the voltage drop of the particular LED used. In this sense, I thought that the only limitation were the maximum number of LEDs is series, limited by the Power Supply voltage (12V in my case).
Best Regards
Massimo

Hello,

Wich version of the 8040 led do you have?

View attachment 170404
The voltage across the led differs per type.

The voltage drop of the XP-E is much lower as the 8040.
You could try to use 2 or 3 XP-E leds in series.

Bertus