Altera_Forum
Honored Contributor
Honored ContributorIm curious why
Noone had any advice about running Cyclone II based boards off rechargeable batteries? Is there something I dont know where it's a bad idea?
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25 Replies
Altera_ForumHi there. I saw your original post but had no particular advice to offer, so I didn't bother. However, I hate to see you neglected so here's my opinion.
I can see no reason why you can't run your Cyclone II system from rechargeable batteries. Depending on the device you use, I can imagine that the current drain could be pretty high. I am just about to get my first Cyclone II based prototype board back from the manufacturers and so I'm still feeling my way a bit with the power requirements. In order to derive the necessary core, PLL and I/O supply voltages from your battery I'd look at using a multi-output switched mode controller. A rep. from Arrow showed me a little evaluation board the other day for a Linear Technology device which occupied a very small board area and needed only tiny external components. I'm sure National Semi etc. will do similar devices. One other thought. If you haven't started your design yet, should you be looking at Cyclone III instead? Maybe others could comment.- Altera_Forum
Thanks Sharky, it's going to be a toy/game thing, so I dont know If my idea will work with the cyclone II if the battery life will be short, I'm planning a "laser tag" sort of device pair. I found that national semi stuff on google, I may have to figure out which option of theirs to use.
So sounds like you work with this stuff, thats great. I just do it as a hobby since I was educated as an Engineer and enjoy it. Defense plants around here just want people who have been on the job with this stuff for 10 years. - Altera_Forum
Hi Evil. I'm a bit surprised that nobody has come forward with a more helpful response on the power requirement question. I suppose it does depend a lot on the device you're thinking of using and what sort of external components you'll need. If the project is mostly for your own personal enjoyment and education then you should go ahead with it anyway.
My design uses an EP2C20F256 device with some external flash and SRAM for program memory (I'm using NIOSII). Apart from that I've got a few A/D converters, digital I/O etc. I tried to estimate the likely power consumption using the Powerplay feature of Quartus, but to be entirely honest it's going to be a bit of a 'finger in the air' approach. I'll let you know how I get on. In the meantime, good luck in your endeavours. Sharky - Altera_Forum
My needs for power are minimal (insert joke about me not really being evil here), the Cyclone II FPGA (144 pin type so I have a chance of soldering it). the EPCS chips, a few buttons, some small relays controling things from another bigger battery. It's just a toy/game prototype, so I'd rather carry extra batteries then build a 1.2v/3.3v warp drive.
This is my first PCB build and design, using PCB123 unless you know a better solution. I was a computer Engineer but never did much soldering, hoping the weller WES-51 I got may make it easier. - Altera_Forum
I haven't worked yet on battery powered FPGA system, but I would recommend that you try to keep the current consumption as low as possible in your design (being battery powered). When powering from a battery, you will also have to consider FPGA power up in-rush current requirements, which can affect more when the battery is partially drained.
- Altera_Forum
Thanks, Im hoping these national seminconductor regulators will take care of that, I am beginning to suspect the external components for the regulators must be chosen carefully to do that, It needs a few capacitors, inductors and resistors that be soldered together several different ways. Hopefully I will have enough code written in a few weeks to start building designing a board, then building it.
- Altera_Forum
National Semi regulators sounds like linear regulators. Switchers are much better for power limited applications. I have power limited Altera designs, and I use the LTC3415 for core voltages for its efficiency. (You have to pay a little more attention to power supply noise.) Linear Tech also has an easier to use LTM series. Also easy to use is a series from MuRata that specifically targets FPGA voltages, MPD family.
- Altera_Forum
Just to prove you're not mad to try, look what turned up in my in-box today:
http://www.fpgajournal.com/articles_2007/20070904_proof.htm - Altera_Forum
Thanks, my research is pointing towards National Semiconductor LP3990s for the 1.2 and 3.3 volts I'd need to run a Cyclone II, not sure if the version of Quartus II I am running (free vers with cyclone II dev kit) will work with Cyclone III.
Their reference designs show more complicated board designs with several capacitors. inductors and resistors, I may try to get by with just capacitors from input voltage to ground, and from output voltage to ground. I am not sure if that linear technology one with the QFN package is something I can hand solder, with the contacts on the bottom. Maybe when I sell a few copies of my first game design, the second version can have that. - Altera_Forum
The Quartus II web-edition (free version) supports Cyclone III device family. See supported devices list at http://www.altera.com/products/software/products/quartus2web/features/sof-quarweb_features.html
I think that you could benefit from low power features of Cyclone III compared to Cyclone II if it suites your design requirements. May be a Cyclone III in a QFP package...
