I'm setting the current by changing the voltage on the control pin.
I'm having trouble with the LEDs overheating:
@ If = 50mA (1/3 of Itest), they reach a stable temperature of 85°C. @ If = 100mA (2/3 of Itest), they go >150°C.
The PCB they're mounted on is 1.6mm FR4 with minimal copper coverage.
- Is the overheating caused by a lack of cooling? Are manufacturer's specs measured with in some kind of active cooling setup?
- It was my understanding that a CC driver keeps the current constant and the dimming happens by changing the voltage supplied to the LEDs. That's not what I'm seeing. Why?
- My plan for driving the LEDs was to use an accordingly sized CC driver. Since I can't seem to be able to drive these LEDs safely at If > 50mA, how do I prevent them from going over that number in hardware?
Here's my attempt to calculate a current-limiting resistor based on this tutorial:
If = 50 mA @ Vf = 2.53 V (measured) R = (Vs - V) / If = (48 V - 2.53 V * 16) / 50 mA = 160 Ohm
However, the maximum current I'm seeing after connecting this resistor in series is 31.3 mA. What gives?