Thermal simulations: watt per second.

Hello,

I have modelled an IC and I would like to set a block in my model (the IC) that produces a heat wave that is spread through the other components: PCB, solderballs, etc.

I am using the 'Heat transfer in solids' module. How can I set my boundary condition to increase the produced heat (power) of the IC block at 1 watt/second?

I have used time-dependent simulation and I have set my solver to the range 0-10 seconds, with step 1 second. But I cannot figure out how I can make it work... to increase the power of the IC.

Thank you alot beforehand