04-08-2011 12:44 AM
I'm trying to connect my custom made peripheral board to Spartan 3AN starter kit through 6-pin Accessory header J20.
Peripheral board is simple.. It is a analog acquisition board which is digitally isolated with Analog devices ADum1402 isolator.
Acquisition board is communicating with Spartan 3AN starter kit by 3 wire SPI. Those 3 signals are connected to fpga through Adum1402.
My questions are:
1. Can I connect power supply from 6-pin Accessory header J20 to my peripheral board to power one side of Adum1402?
2. What is the highest current that can be given by power supply pins through 6-pin Accessory header J20?
Thanks in advance,
04-08-2011 07:30 AM
Given that the voltages for the board you are adding are the same as the voltages on the FPGA pcb, then at least you can consider powering the board that way.
Next, I would look at the shcematics, and look at what power regulators are used. Then I would look at the power "brick" that supples the whole board, and see how many watts it is rated at. Use the power esitimator to estimate the power needed by the FPGA for your design. Add up all the power needed, and see if exceeds the power supply capability. If it is even equal to the capability, then don't power it that way.
04-08-2011 08:20 AM
Then I would look at the power "brick" that supples the whole board, and see how many watts it is rated at.
Keep in mind that power bricks with greater current capacity might very well be available, if needed. If this is the case, you will still need to consider the current capacity of the individual voltage regulators on the board.
If you have the time and patience, eBay is a wonderfully diverse and fruitful shopping mart for AC-DC power bricks.
-- Bob Elkind