So, taken the above mentioned values for the LEDs, 3 of them in series, what do I need to look for in an NPN to work with this? Is the value of RXFB what's going to set the current that the NPN turns on/off?
I know from the datasheet that Vref = 0.6V
I need to figure out what RXFB needs to be and what RB needs to be, which I assume applies to the NPN's base. And, is RXFB what will change based on the voltage drop for the LEDs used (red, green, or blue)?
With the "normal" operating circuit for the WS2801 (without the FET), RXFB is what controls the current sink for the LED. So on a (single) 20mA LED, RXFB is set to 30 Ohm. (IXOUT = VRef / RXFB)
Having an NPN in the circuit and I end up throwing my hands up in the air because I don't quite understand them and what's needed to trigger them.