Linear regulators would add 1-1.6 W of power consumption depending on battery voltage.
73,
John KD6OZH
----- Original Message ----- From: "Chuck Green" [email protected] To: [email protected] Cc: "'Dave Black (Work)'" [email protected]; "'Dave Black (Home)'" [email protected]; "'David Smith'" [email protected]; [email protected]; "'Samsonoff@Mac. Com'" [email protected]; "'Juan.Rivera (Work)'" [email protected] Sent: Saturday, July 28, 2007 22:30 UTC Subject: [eagle] Re: Receiver Spec vs. ATP, a few Suggestions and aQuestion or Two
Hi Juan,
I think the reason you have not seen much regarding the CAN-Do redesign is that, as far as I know, no one has stepped up to do the power supply redesign. Until that happens, not much else will happen.
I'm not thrilled with the idea of giving up the switching power supply. Remember that the efficiency hit must be multiplied by 10-15, the number of CAN-Do's on the satellite.
The "dead-bug" modification is intended to fly. Those who were not around in the early days have no idea what loose wires have flown successfully in the past. That's not to say we should encourage such things, just that it's not as ugly to those of us who have seen much worse in the past as you might think. Because of the IC's mass (very small) it is probably very secure just the way you see it. But we will also epoxy a radiation shield to it and then conformal coat the whole thing with a heave conformal coating which will make it very difficult for anything to move.
I'm ready to start a new design (layout) just as soon as someone gives us a new power supply design that is quieter, and hopefully, more efficient than the 90% we now have.
Chuck
Juan Rivera wrote:
Bdale,
It would be a trade-off. I've put out all the information I have and everyone knows my opinions. I think someone else is supposed to be looking into this but I forgot who it is since nothing has been posted. I'd like to see some alternative suggestions from the experts on the CAN-Do, the enclosure, and the EMI situation in general.
By the way, do I have a prototype CAN-Do module or was the intent to fly this version with the dead-bug step-down converter hanging by three leads and a few wires?
Juan
-----Original Message----- From: Bdale Garbee [mailto:[email protected]] Sent: Saturday, July 28, 2007 2:41 PM To: [email protected] Cc: 'John B. Stephensen'; David Smith; Dave Black (Work); Dave Black (Home); [email protected]; Samsonoff@Mac. Com; Juan.Rivera (Work) Subject: Re: [eagle] Receiver Spec vs. ATP, a few Suggestions and aQuestion or Two
On Fri, 2007-07-27 at 21:23 -0700, Juan Rivera wrote:
I have a few thoughts... The CAN-Do switching step-down converter is only supplying 11 milliamps. If we take a slight efficiency hit we could just go to a simple linear regulator and completely eliminate the radiated and conducted EMI emission problem from CAN-do. That eases the EMI filtering and shielding requirements for every single payload. That seems like a good trade-off to me.
Hrm. What makes you say "a slight efficiency hit"?
Doing this on one or two modules that are particularly susceptible to noise *may* make sense (and I'm certainly open to considering this as an alternative), but we're already on our second power supply design on the CAN-Do! because the original switcher, which was more efficient than a linear regulator, was deemed too inefficient to fly on P3E by our AMSAT-DL friends.
Bdale
Via the Eagle mailing list courtesy of AMSAT-NA [email protected] http://amsat.org/mailman/listinfo/eagle
Via the Eagle mailing list courtesy of AMSAT-NA [email protected] http://amsat.org/mailman/listinfo/eagle