Xilinx FPGAs in battery-powered scenarios

Hey,

I've been reluctant recently on envisaging a Virtex-4 device as being
operational in a battery-powered situation. The inrush configuration
current, high static power consumption, and the non-uniform power
exhibited subject to temperature rise are amongst few to name about the
shortcomings of SRAM FPGAs in general. Having said that, the
unprecedented versatile reconfigurable processing power is yet the
decisive factor in prototyping intensive DSP operations. My question
is: has any body come across a scenario in which a large FPGA was
battery-powered. I'm in the phase of deciding on solutions to employ
for my active research so it's quite critical. I don't want to start my
research with a major gap in my rationale. Can any veteran in here
comment on the topic please. Is it really ridiculous to think about
powering a large SRAM FPGA from a battery? Would really appreciate all
comments. What's the cheapest price ever a smallest Virtex-4 device was
reported?

Cheers,
-Manny

Manny schrieb:

> Hey,
>
> I've been reluctant recently on envisaging a Virtex-4 device as being
> operational in a battery-powered situation. The inrush configuration
> current, high static power consumption, and the non-uniform power
> exhibited subject to temperature rise are amongst few to name about the
> shortcomings of SRAM FPGAs in general. Having said that, the
> unprecedented versatile reconfigurable processing power is yet the
> decisive factor in prototyping intensive DSP operations. My question
> is: has any body come across a scenario in which a large FPGA was
> battery-powered. I'm in the phase of deciding on solutions to employ
> for my active research so it's quite critical. I don't want to start my
> research with a major gap in my rationale. Can any veteran in here
> comment on the topic please. Is it really ridiculous to think about
> powering a large SRAM FPGA from a battery? Would really appreciate all
> comments. What's the cheapest price ever a smallest Virtex-4 device was
> reported?
>
> Cheers,
> -Manny

I was considering V4 lately for portable battery powered gadget
and did not see it feasible (different reasons).

for you it all depends
1) how much battery power you have
2) what else except FPGA takes power
3) required battery operation time
4) what FPGA is doing

the best for battery is V4-FX12 when used with PPC (less power than
MB!)
every other Virtex4 or Virtex5 means more static power to the extent
that
it drains the battery on static current only!

smallest power an V4FX12 based system takes is about 1W
so if your battery has 3w/hr then it will operate 3 hours.

pricing - thumb guess ia that if you are would be able to get prices
below 70USD you would not be asking. So expect pricing between 70 and
100

Antti

Manny, here would be my order of concern:
1. How much, and what type of, logic do I need
2. How fast should it run (can I time-division multiplex?)
3. What is the smallest and cheapest device that fits those
requirements
4. How much power does it draw while working, and in stand-by
5. In-rush current is not a concern anymore, and batteries are actually
very good at supplying lots of current for a very short time.

Virtex-4 LX 15 and '25 and '40 are the smallest, for Virtex-5 it is
presently the LX50
Really small devices with Virtex-like features and performance are not
in high demand.
Most low-end applications do not require that many features and that
much performance, and they use Spartan-3 devices. For very low
complexity and power consumption, use CoolRunner CPLDs.
Peter Alfke, Xilinx Applications
===============
Manny wrote:
> Hey,
>
> I've been reluctant recently on envisaging a Virtex-4 device as being
> operational in a battery-powered situation. The inrush configuration
> current, high static power consumption, and the non-uniform power
> exhibited subject to temperature rise are amongst few to name about the
> shortcomings of SRAM FPGAs in general. Having said that, the
> unprecedented versatile reconfigurable processing power is yet the
> decisive factor in prototyping intensive DSP operations. My question
> is: has any body come across a scenario in which a large FPGA was
> battery-powered. I'm in the phase of deciding on solutions to employ
> for my active research so it's quite critical. I don't want to start my
> research with a major gap in my rationale. Can any veteran in here
> comment on the topic please. Is it really ridiculous to think about
> powering a large SRAM FPGA from a battery? Would really appreciate all
> comments. What's the cheapest price ever a smallest Virtex-4 device was
> reported?
> 
> Cheers,
> -Manny

"Manny" <mloulah@hotmail.com> wrote in message 
news:1160755594.427130.118490@m73g2000cwd.googlegroups.com...
> Hey,
>
> I've been reluctant recently on envisaging a Virtex-4 device as being
> operational in a battery-powered situation. The inrush configuration
> current, high static power consumption, and the non-uniform power
> exhibited subject to temperature rise are amongst few to name about the
> shortcomings of SRAM FPGAs in general. Having said that, the
> unprecedented versatile reconfigurable processing power is yet the
> decisive factor in prototyping intensive DSP operations. My question
> is: has any body come across a scenario in which a large FPGA was
> battery-powered. I'm in the phase of deciding on solutions to employ
> for my active research so it's quite critical. I don't want to start my
> research with a major gap in my rationale. Can any veteran in here
> comment on the topic please. Is it really ridiculous to think about
> powering a large SRAM FPGA from a battery? Would really appreciate all
> comments. What's the cheapest price ever a smallest Virtex-4 device was
> reported?
>
> Cheers,
> -Manny

Keep in mind that non-nuclear submarines are run on batteries and they tend 
to use significantly more power than a Virtex-4.  What you're willing to use 
for batteries will determine whether you can achieve your goals.

It seems that increasing battery technology has a practical upper limit for 
ultra-portables.  If you have a battery-powered cell phone, running 60 watts 
through the device would make it unusuable because of the heat genereated in 
the confined footprint.  If you're not going for ultra-portable or single 
AA-cell powered devices, your options are wide open.  Consider that a small 
Virtex-4 has lower power requirements than the laptop's processor alone. 

Manny,

Just one comment:

There has been no "in rush" or "bonus" current needed since Virtex II
(V2, V2P, V4, V5 have no "inrush" for Vccint, the datasheet specifies
the minimum Iccint required to power on and configure).

What you describe was common for Virtex E, and older families.  However,
we decided that was unacceptable, so we fixed it (a long time ago, now).

Austin

Manny wrote:
> Hey,
> 
> I've been reluctant recently on envisaging a Virtex-4 device as being
> operational in a battery-powered situation. The inrush configuration
> current, high static power consumption, and the non-uniform power
> exhibited subject to temperature rise are amongst few to name about the
> shortcomings of SRAM FPGAs in general. Having said that, the
> unprecedented versatile reconfigurable processing power is yet the
> decisive factor in prototyping intensive DSP operations. My question
> is: has any body come across a scenario in which a large FPGA was
> battery-powered. I'm in the phase of deciding on solutions to employ
> for my active research so it's quite critical. I don't want to start my
> research with a major gap in my rationale. Can any veteran in here
> comment on the topic please. Is it really ridiculous to think about
> powering a large SRAM FPGA from a battery? Would really appreciate all
> comments. What's the cheapest price ever a smallest Virtex-4 device was
> reported?
> 
> Cheers,
> -Manny
> 

Manny,

Further:

http://www.xilinx.com/prs_rls/2006/end_markets/0644_gendynamics.htm

It seems that GD has selected V4 for a software defined radio, and it is
portable (battery operated).

One nice thing about a radio application is that it is not operating
continuously (as they are shooting at one another on the battlefield).

Another useful element of the JTRS SDR radio is that is does not even
load the configuration for a particular modulator or demodulator until
it receives, or wishes to transmit in that mode.  Only one "waveform" is
ever active at a time, and only as transmit, or as receive, and other
than that, the FPGA is (probably) powered down and waiting.

(I profusely apologize for any marketing contained in this posting:  any
such marketing content should be considered as such, and treated
accordingly.)

Austin


Manny wrote:
> Hey,
> 
> I've been reluctant recently on envisaging a Virtex-4 device as being
> operational in a battery-powered situation. The inrush configuration
> current, high static power consumption, and the non-uniform power
> exhibited subject to temperature rise are amongst few to name about the
> shortcomings of SRAM FPGAs in general. Having said that, the
> unprecedented versatile reconfigurable processing power is yet the
> decisive factor in prototyping intensive DSP operations. My question
> is: has any body come across a scenario in which a large FPGA was
> battery-powered. I'm in the phase of deciding on solutions to employ
> for my active research so it's quite critical. I don't want to start my
> research with a major gap in my rationale. Can any veteran in here
> comment on the topic please. Is it really ridiculous to think about
> powering a large SRAM FPGA from a battery? Would really appreciate all
> comments. What's the cheapest price ever a smallest Virtex-4 device was
> reported?
> 
> Cheers,
> -Manny
> 

Thanks a lot guys, all comments are really useful and I'm definitely
gonna reason much about them.

My application is definitely gonna be DSP intensive. The bad news is
that it's basically a CDMA application so many things have to run in
parallel in a multiple access system, the more things can run in
parallel the more robust the model is and thus yielding in terms of
performance. The good news is that we'r not talking about RF signals in
here, so things doesn't need to run real fast. My major concern is that
things are quite coupled at the moment i.e. lots of things depends on
stuff that are yet to be fully characterized. As we might have settle
for less perfect hardware (not talking digital in here), our model
would grow more complicated as to accommodate for these imperfections.
The online reconfigurability of the system  is also highly desirable as
functionality can change in time. So a CPLD won't do, not even a
low-cost spartan although ultimately we might have to sacrafice
reconfgurability. The only bright side in this mess is that I might be
able to argue, once the system has been fully developed, that certain
functionalities have to be ported to ASIC. I'm keen on having as much
DSP power as possible as there are advanced issue on the agenda such as
Doppler Effective and AOA estimation. So there is no doubt that I'll
end up time sharing the available DSP slices. For prototyping, I think
it always make sense to get a bit more than what you expect to use.
Virtex-4 FX12 seems a reasonable start with the open possiblity to
migrate to V-5 once the rest of the family is introduced.

Cheers,
-Manny

Austin Lesea schrieb:

> Manny,
>
> Just one comment:
>
> There has been no "in rush" or "bonus" current needed since Virtex II
> (V2, V2P, V4, V5 have no "inrush" for Vccint, the datasheet specifies
> the minimum Iccint required to power on and configure).
>
> What you describe was common for Virtex E, and older families.  However,
> we decided that was unacceptable, so we fixed it (a long time ago, now).
>
> Austin
>
Austin,

please check Xilinx publication EN049(v 1.3) page 2
for Virtex-5 power requirements during configuration

Antti

Antti,

We are still characterizing the parts and process, so we don't want to
put anything in the data sheet for V5 until we are done.

But, there is no surge, or big Iccint that is required for V5...

Austin



Antti wrote:
> Austin Lesea schrieb:
> 
>> Manny,
>>
>> Just one comment:
>>
>> There has been no "in rush" or "bonus" current needed since Virtex II
>> (V2, V2P, V4, V5 have no "inrush" for Vccint, the datasheet specifies
>> the minimum Iccint required to power on and configure).
>>
>> What you describe was common for Virtex E, and older families.  However,
>> we decided that was unacceptable, so we fixed it (a long time ago, now).
>>
>> Austin
>>
> Austin,
> 
> please check Xilinx publication EN049(v 1.3) page 2
> for Virtex-5 power requirements during configuration
> 
> Antti
> 

>I've been reluctant recently on envisaging a Virtex-4 device as being
>operational in a battery-powered situation. The inrush configuration
>current, high static power consumption, and the non-uniform power
>exhibited subject to temperature rise are amongst few to name about the
>shortcomings of SRAM FPGAs in general. Having said that, the
>unprecedented versatile reconfigurable processing power is yet the
>decisive factor in prototyping intensive DSP operations. My question
>is: has any body come across a scenario in which a large FPGA was
>battery-powered. I'm in the phase of deciding on solutions to employ
>for my active research so it's quite critical. I don't want to start my
>research with a major gap in my rationale. Can any veteran in here
>comment on the topic please. Is it really ridiculous to think about
>powering a large SRAM FPGA from a battery? Would really appreciate all
>comments. What's the cheapest price ever a smallest Virtex-4 device was
>reported?

You said Xilinx fpga, but maybe actel's eeprom (?) based fpgas will do better
for battery applications?