Hello everyone,

I am working on a circuit where I need to drive an M530L4 LED (3.6W) with 1µs pulses. To achieve this, I am using an IRLU024NPBF NMOS transistor driven by a high-side gate driver (UCC27511A). Below, you can find the schematic I simulated in LTSpice.



Find below the simulation results, where:

1. Green trace: MCU pulse input
2. Blue trace: Gate Voltage
3. Red trace: Gate current
4. Cyan trace: LED current

Please note that the exact LED and MOSFET models used in the simulation are not identical to the real components, but their electrical characteristics are quite similar.

However, when I replicate the circuit in real life, I observe the following waveforms, where:

1. Yellow trace: MCU pulse input
2. Pink trace: Gate Voltage
3. Cyan trace: LED current

My goal is to achieve an LED current waveform that is as close to a square pulse as possible. Ideally, I would like to reduce the switching times even further.

Any suggestions would be greatly appreciated.

Thanks in advance!

 

I have serious doubts that you can do better with those chosen components. What evidence can you offer to suggest that your goal is achievable. The current in the LED is your main limitation.

 

PCB layout is critical. It looks like you have long wires. There is definitely inductance in the LED wires. There is ringing in the turnoff. What capacitors are you using?
Adding 10 ohms of gate resistance should help the oscillation.
There is a 4" long ground wire on your scope probe. Not good for looking at fast edges.
Show a picture of your work.