Other Parts Discussed in Thread: TPS923652
Tool/software:
Hello,
I'm having trouble getting the TPS61165 to power a 35 V 0.33 A LED.
I believe it's the boost converter reaching it's natural limit?
VIN = 12 V
CTRL = 12 V
Target current 0.323 A (= 0.2 V / 0.62 R)
I've simplified my prototype down to this:
The issue is that the driver is only outputting 0.28 A.
I started with 10 uH inductor (VLCF5020T-100M1R1-1 as per datasheet recommendation)
Increased inductance to ~19.4uH (with parts I had spare), this increased my current marginally to 0.285 A, still 15% lower than I need.
Using the SLVC366 design tool's graphs, I recorded the current with different PWM duty cycles and you can clearly see the SMPS topping out.
(Although my final design is based on analog dimming using the SLVC366 technique, I have made a simplified version to narrow down this issue)
If I increase my input voltage, the output current rises along with it, until it stops at 0.323 A, when VIN is ~13.8 V
If I try a lower forward voltage LED, the correct current also flows.
My next idea is to try a larger, lower resistance 22 uH inductor, but I wanted to see if this was even a suitable application for this IC?
I appreciate that while 35 V is below the 38 V recommended maximum output voltage, it's still cutting it close.
Thanks in advance
