I hook it up as in the image from Google Code Archive - Long-term storage for Google Code Project Hosting.
I have replaced the 2k resistor with the 68 k resistor, one of the outputs from the tlc goes to the ctl-in of the buckpuck, as well as through the 10k resistor to +5v. vin and vout on the buckpuck connected to an external power supply, led+ and led - to the led, common ground between tlc and buckpuck (either led - or vin, doesnt seem to make a difference).
hc