5v+Vin LT1302-5

[Donziboy2]

Hey guys/gals I'm building a custom minty with a custom NIMH charger all rolled into one package, home built so it wont be so tiny and I was looking at voltages. I'm using a home made solar panel to charge the battery and power the minty/charger during the day. From what I understand its not safe to run the LT1302-5's input at or near 5v, but from the datasheet if you add a 10ohm resister before the caps at the Vin it will work. Has anyone tried this? I'm getting the last of my parts in next week and was trying to figure out what size solar panel ill be making and a few small pieces, I would rather not have to add extra diodes to drop voltage in between the battery and the LT. I'm an electronics student at the local ITT Tech so I have access to silly scopes and power supplies during the week. But since LT1302-5's are hard to come by (as in buy 100 from LT or pay $8 each and $20 for under $100 orders) I figured I would ask for input before I burn one trying....

I'm using a low power version of the 555 charge controller from Michael Davis. http://www.mdpub.com/555Controller/index.html

I'd like to thank Linear Technology for the free samples now, just encase I kill them before I get done

also Cadsoft EAGLE FTW

[Donziboy2]

Ill give some visual help as to what im doing also. I think I can shrink in a little more but this is close to a finished product. Well it will be once i get all the parts in and can prototype it on a solder-less.

[Donziboy2]

Anyone?


Well update, I tested the charge controller portion after receiving last of my parts and after getting it bread-boarded like Mike I ran into a small snag... well burn actually.
I used mikes design except for smaller transistor and mosfet, the transistor worked fine but the mosfet was kicking the coil on during discharge phase and while powering the coil it was getting a little on the hot side... as in I touched it and burned myself..... Ill learn someday not to touch without licking first.

Removed mosfet, r6 and r7 from his design and took the transistor right to my coil and all set, the charge controller running on a 5v line pulls about 7mA in discharge and 27mA on charge with coil active.
I'm using a Fugi FTR-MYAA4.5D relay for low power usage.
Anyway, back to my original question, has anyone tried the extra resistor/cap i asked about in my first post...... Would really appreciate it, I try to stick to one burn a week.

[Donziboy2]

Ok, built my solar panel, built my circuit, did some fine tuning and it seems to work pretty well, it does have a few quarks but nothing serious.
It would be nice to find an efficient way to give more then 5v to the LT1302-5, but for now ill be happy that it works.
My solar cell build was less then perfect so I only get about 1-1.5w from a 2.5W panel, I cracked 2 cells:( Its enough to trickle charge the 3 AA 3000mA NIMH batts I have it running.

Guess ill move onto using up the rest of my cells on an 18v 9W panel.