Re: NejTech Evolution - a new BOOST driver - preparing to build prototypes
So umm anyway. Got my output MLCC's today and I finished the basic design for an adjustable version. But let's see how the fixed version prototype works first.
Re: NejTech Evolution - a new BOOST driver - preparing to build prototypes
Darn, still not here. You wouldn't believe what dream I just had. I was looking through my mailbox for these boards, dug up at least a dozen bubble wraps and none of them was the boards...
Re: NejTech Evolution - a new BOOST driver - It lives!!! (sorta)
with a 3.8V input, how much current can it pump out at 5.1V? Also, can you please take a scope plot of the turn on characteristics as well as the output ripple using the loading state provided at the start of my post?
Re: NejTech Evolution - a new BOOST driver - It lives!!! (sorta)
Oh - so you don't know how effective of a boost driver it is. The problem is that a lot of these boost drivers CAN boost from, say, 3.7V to 6V, but only up to like 100mA or whatever. They are often limited. But we'll see.
Re: NejTech Evolution - a new BOOST driver - It lives!!! (sorta)
I would be interested to know not so much how high it can boost in terms of voltage, but how high the current can go, presuming some amazing supply like a 20A capable LifePo4?
What current output could this boost driver provide? (presuming it was boosting to the Vf that corresponded to that particular current on the diode's IV curve)
Re: NejTech Evolution - a new BOOST driver - It lives!!! (sorta)
That's the joke - National did not specify a current limit in the datasheet... The only max current that was specified was "Switch current limit", which was 2.8A MAX. I'll try to make the next prototypes with ferrite inductors, the current ones are using iron powder. However, ferrite inductors are larger, so I will need to use less than 10uH in order to make them fit.
Re: NejTech Evolution - a new BOOST driver - It lives!!! (sorta)
Wolf: Nope, just idea > datasheet > eagle > real life
Kmor: See here: Magnetic core - Wikipedia, the free encyclopedia
Iron powder
Powdered cores made of hydrogen reduced iron have higher permeability but lower Q. They are used mostly for electromagnetic interference filters and low-frequency chokes, mainly in switched-mode power supplies.
Ferrite
Ferrite ceramics are used for high-frequency applications. The ferrite materials can be engineered with a wide range of parameters. As ceramics, they are essentially insulators, which prevents eddy currents, although losses such as hysteresis losses can still occur.
As said before, ferrite core + high current + 10uH = large