The design I'm working on is 16 chips on a 10cm x 8cm board. Each board has a PIC USB controller but also supports I2C. This allows chaining multiple boards together so they use only one USB port. I'm targeting a 2 layer board to keep costs very low. If I run into problems with 2 layers then I'll bump up to 4 layer but that increases pcb cost by 3-4x. Right now parts cost estimate for one board is about $20 including pcb, not including ASIC, heat sink, assembly or parts shpg. ($20/16 chips is $1.25 per chip.)
I'll post my design on github eventually after final specs come out. You could panelize 8 boards on a larger 20cm x 32cm pcb for production. Then you would have 4 BIG boards total. Or whatever combination works. On each panel you would tie the sections together with I2C bus (4-wire ribbon cable), have one USB port and make a power splitter lead to distribute the 12V. 8 units using 32W each is 256W per BIG board. You could run two boards off a good 650W supply. Smaller boards give a bit more flexibility in arranging them for cooling.
I'll post more as I progress or check here: http://github/bkkcoins
Don't expect anything until after Avalon docs are released.
I'll post my design on github eventually after final specs come out. You could panelize 8 boards on a larger 20cm x 32cm pcb for production. Then you would have 4 BIG boards total. Or whatever combination works. On each panel you would tie the sections together with I2C bus (4-wire ribbon cable), have one USB port and make a power splitter lead to distribute the 12V. 8 units using 32W each is 256W per BIG board. You could run two boards off a good 650W supply. Smaller boards give a bit more flexibility in arranging them for cooling.
I'll post more as I progress or check here: http://github/bkkcoins
Don't expect anything until after Avalon docs are released.
Thank you Bkk, man this design sounds really great. I will keep an eye on your github.
This being a sort of DIY project, how difficult would it be for an average Joe with a small amount of chips and some soldering experience to put together? Too risky?
I am refreshing your git already 
