/diy/ - Do It Yourself

So this is my first time reading and using a datasheet of this complexity. Basically I'm building an LED array that can be controlled by pwm from a microcontroller. For various reasons I'm using an LM3406 (http://www.ti.com/lit/ds/symlink/lm3406.pdf).).

I'm currently 'following' design example 1 and performing the calculations for the exact parameters of the parts I need for my particular circuit. In the first calculation for Ron it wants D, which I think is duty cycle. However, I plan on possibly running this at 350, 700, and 1500mA and with different duty cycles based on pwm. To get the different currents, which are determined by a resistor, I was going to include little switches and all 3 resistors.

So based on the fact that I'm going to be dimming it, what value for D should I use in the calculation?

Whoring
Startup costs $20 at a thrift sore

Earn $500/day tax free.

I though about this just to use bulbs that don't cost $600 every 2000 hours. But I figure I'm rich what the fuck and just bought four bulbs instead. When they are all burned out I may try to hack my projector to use a different lamp, unless by then I can find an led or laser projector that meets my requirements.