Hey all,
I've been building LED lighting projects for a long time and really enjoy it. The one limiting factor is my electronics knowledge. I've always used linear current regulators, which are very simple but also very inefficient. I want to change that! I know that I can buy plenty of these online, but I want to understand it fully and build one. My motivation is mostly for education.
My latest project requires driving 2 parallel strings of 3 LEDs each from a 14V source. Each string requires 2.9A. LED voltage is approximate 3.3V each at this current. A quick and dirty calc shows that efficiency with a linear regulator would be ~70%. I am aiming for more like 90% to 95%, with the ability to change LED configurations (see below).
I've been researching extensively and understand the basic principle of an RLC circuit, and that I most likely want a synchronous buck type driver since my voltage will always be higher than the series LED voltage. An asynchronous type looks like it will also work, but with lesser efficiency.
Here are some basic requirements:
Form factor - rectangular up to 1.5" x 2" x 1" this is very flexible
Input voltage - 14V standard, up to 30V spike (possible dirty voltage)
LED configurations - flexible 2s2p; 3s1p, 3s2p, 3s3p, 3s4p
Output current - constant 2.9A per string, so 2.9A, 5.8A, 8.7A, 11.6A total - if this means duplicating a single circuit capable of 2.9A that is fine. I don't need any fancy dimming, flashing, or anything like that. Simple and durable is most important.
Is it possible to use thru-hole components entirely?
I realize this is quite a bit of an undertaking, but I am willing to put in the effort. If someone could help by pointing me in the direction of a specific controller with data sheet so I can start reading up on it, that would be awesome. It's overwhelming with so many different options out there. By searching here, I found the PT4115, but the user required an external mosfet to actually drive the LEDs due to the current limitation.
Edit: Here is the post I was referring to: http://forum.allaboutcircuits.com/threads/buck-current-regulator-help-needed.80383/ See the bottom of the page.
Thanks a bunch to anyone willing to point me in the right direction.
I've been building LED lighting projects for a long time and really enjoy it. The one limiting factor is my electronics knowledge. I've always used linear current regulators, which are very simple but also very inefficient. I want to change that! I know that I can buy plenty of these online, but I want to understand it fully and build one. My motivation is mostly for education.
My latest project requires driving 2 parallel strings of 3 LEDs each from a 14V source. Each string requires 2.9A. LED voltage is approximate 3.3V each at this current. A quick and dirty calc shows that efficiency with a linear regulator would be ~70%. I am aiming for more like 90% to 95%, with the ability to change LED configurations (see below).
I've been researching extensively and understand the basic principle of an RLC circuit, and that I most likely want a synchronous buck type driver since my voltage will always be higher than the series LED voltage. An asynchronous type looks like it will also work, but with lesser efficiency.
Here are some basic requirements:
Form factor - rectangular up to 1.5" x 2" x 1" this is very flexible
Input voltage - 14V standard, up to 30V spike (possible dirty voltage)
LED configurations - flexible 2s2p; 3s1p, 3s2p, 3s3p, 3s4p
Output current - constant 2.9A per string, so 2.9A, 5.8A, 8.7A, 11.6A total - if this means duplicating a single circuit capable of 2.9A that is fine. I don't need any fancy dimming, flashing, or anything like that. Simple and durable is most important.
Is it possible to use thru-hole components entirely?
I realize this is quite a bit of an undertaking, but I am willing to put in the effort. If someone could help by pointing me in the direction of a specific controller with data sheet so I can start reading up on it, that would be awesome. It's overwhelming with so many different options out there. By searching here, I found the PT4115, but the user required an external mosfet to actually drive the LEDs due to the current limitation.
Edit: Here is the post I was referring to: http://forum.allaboutcircuits.com/threads/buck-current-regulator-help-needed.80383/ See the bottom of the page.
Thanks a bunch to anyone willing to point me in the right direction.