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Re: Flight Computers



On Tuesday 30 April 2002 12:53 am, Dennis Ray Wingo wrote:

> The new solar cells from Emcore and Spectralab that run at 28% efficiency
> should help you raise the power budget to around 10-11 watts including
> battery recharge overhead.  Also, with Lithium Ion cells they should be
> able to support the power budget as well.

I believe it is Spectralab that falls underneath our corporate umbrella.  I 
should have saved the web site address at work.   As I recall, they sold
some "second grade" quality panels, so it might be worth testing on
terra firma...

> With DC/DC converter technology now in the mid to high 90's this brings the
> overall power system efficiency up.  We used Shottky barrier diodes on
> SEDSAT that had a .42 volt forward voltage drop that is much better than
> standard silicon's 0.6 volt.

Having designing a few converters, 90 percent is about the best you can do
even with synchronous rectification.  Usually these efficiency ratings are
also quoted at full load and are worse at light load (controller power 
comsumption remains relatively constant).

> It would be very interesting to do a microsat with all advanced stuff to
> see how far you could push the power systems technology.  Also, the low
> power electronics that are available now should allow for some really cool
> systems.

Having the ability to control clock rates and start/stop processors as 
required would help to conserve a lot of energy. It also helps to control
the amount of heat you have to get rid of.

73
Mike W4LNA
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