Hi everyone :)
First post in this forum and its a bit of a long shot...
Main goal is to use a pair LM3463 to drive a larger fixture ( 48" x 10" ) to simulate the daylight by mixing the LED string colors ( Yellow, Cool White, Deep Red, Green, Royal Blue, Blue, Violet, and Cyan ). I'm also planning to produce a number of these boards mainly geared towards a DIY / Enthusiast market. The issue with that is that everyone will be using different LED's therefore string voltages are going to be different as well as current requirements.
As mentioned above, needing an individually controlled 8ch LED driver... means using two LM3463. Each chip will be configured as master and jumpers will installed on the Gate drivers to enable or disable channels as needed. In my configuration, each chip will be only using 4ch ( ch0, ch2, ch4, ch5 even though all channels will be populated but ch1 and ch2 will be disabled ) this way I can have full control of each string of LED's to achieve true PAR output and being able to simulate solar and lunar events.
Main reason for picking the LM3463 is because it drives its output through FET's.
I searched high and low for a suitable driver that is capable of Analog, PWM or Serial and able to go to drive larger strings that require up to 1250mA +, this was my only option. After perusing the documentation i came to the conclusion that by using larger output devices and a bit of tweaking it should suit the build just fine. The FET I had in mind is either the IRFB4615 or IRFIB41N15D
All 12 FET's would be mounts on a sizable heat sink ( 150mm x 140mm x 36mm ) and most likely will employ active thermal management using the main micro controller that will also drive the duet.
Back to the DIY aspect...
I still need to figure some odds and ends like:
1.- Output Current Level Adjust:
Replacing the resistor with multi-turn pot for current adjustment would make it more DIY friendly and an optional 10k NTC across it for current reduction based on LED heat sink temperature.
2.- Start Up Current Control: ???
3.- MOSFET Power Limit Setting:
Looking for no more than 2000 - 2500mA / Ch, keeping in mind that each "half" will be driven by separate supplies
4.- Fault De-bounce capacitor:
Using an 22nF 25V
5.- DHC: added it in, but won't be using this feature due to the different string voltage levels
Any input would be appreciated!