I've deployed a homemade strobe system using Cree 10W LEDs in my homebuilt aircraft. My implementation uses a simple PIC controller to do the flashing, an IRL2505 mosfet (driven by an NPN transistor) for the switching, and a linear regulator (LM338T: LM338T - NS - PMIC - Voltage Regulators - Linear - Kynix Semiconductor) to limit the current to 5 amps. The system is using 7 Cree's in parallel for the landing light, and 8 in parallel for each wing strobe unit, each driven by an independent IRL2505/LM338 5 amp drive circuit.
After adding a protection diode to manage inductive field collapse on the wing mounted strobes, the system is working fine... however, more brightness is always better!
Here's the schematic:
So, my specific question is this... to make this brighter, I need to go beyond 5 amps. What options are there for a more efficient, higher output, physically small current regulator?
Some implementation constraints:
There is little to no space in the wingtips or nose for the electronics, and heat is also an issue... I can't afford to have something melting my wings! I've had to work hard to control the heat from the LEDs and also from the linear regulator/mosfet. So... space and heat are my enemies...!
Switching regulators may be the right option, but I've been reluctant to try designing one because by reputation they are inherently electrically noisy... I depend on my HF radios, GPS, bluetooth and Wifi (all currently in the airplane) - so adding electrical noise could be an issue.
Commercial LED based strobe systems for homebuilt aircraft are out there... and I've looked at them closely. I don't see current limiters. At all. And, they are plenty bright. What gives??? What don't I understand??? Are they just keeping the duty cycle so low that the LEDs can't overheat?
ANY thoughts, suggestions, comments, or ideas would be welcome.
Deploy a homemade strobe system using Cree 10W LEDs
in Instruments, Radios and Electronics
Posted
I've deployed a homemade strobe system using Cree 10W LEDs in my homebuilt aircraft. My implementation uses a simple PIC controller to do the flashing, an IRL2505 mosfet (driven by an NPN transistor) for the switching, and a linear regulator (LM338T: LM338T - NS - PMIC - Voltage Regulators - Linear - Kynix Semiconductor) to limit the current to 5 amps. The system is using 7 Cree's in parallel for the landing light, and 8 in parallel for each wing strobe unit, each driven by an independent IRL2505/LM338 5 amp drive circuit.
Details can be found in this instructable:
LED Landing Light for Experimental Aircraft
After adding a protection diode to manage inductive field collapse on the wing mounted strobes, the system is working fine... however, more brightness is always better!
Here's the schematic:
So, my specific question is this... to make this brighter, I need to go beyond 5 amps. What options are there for a more efficient, higher output, physically small current regulator?
Some implementation constraints:
ANY thoughts, suggestions, comments, or ideas would be welcome.
Thanks!