ultra low voltage converter?? (0.4v)

[huzefasi]

Did you give up on building a 4/3 SLR

not given up. I am always thinking up new ideas only they most of them are outside my skill range. This has gone to the list of future projects. Some of my requirements such as powerful liquid lens and "micro OLED/ large CMOS sensor on a single chip" are not yet available.

 

[huzefasi]

Any inputs on this:
LM2727 - N-Channel FET Synchronous Buck Regulator Controller for Low Output Voltages
**broken link removed**

 

[blueroomelectronics]

Then why not tell us what it was you were trying to build. Maybe we can shed some light on the idea.

 

[bountyhunter]

Thats too bad. Thanks for your input though, I got to rethink this to see if there another way. My priority is light weight and really compact size.

You do realize that 0.4V @107A is close to 50W of load power. Given the poor efficiency it will have, that means the converter will be at least an 80W converter. You do realize it's impossible to make an 80W converter that is light and compact and runs off one Li battery?

BTW: when dealing with massively high currents, source impedance is critical and Li is not the best chemistry for that: Ni-MH and NI-Cd are both much better (lower internal impedance) so they can deliver higher peak current with less internal power burned in the process.

Ni-Cds have been used for applications where the load current is extremely high like portable soldering irons.

 

[bountyhunter]

Any inputs on this:
LM2727 - N-Channel FET Synchronous Buck Regulator Controller for Low Output Voltages
**broken link removed**

You need to connect with an experienced power engineer who can advise you on what's actually possible so you won't keep trying to stuff an elephant into a mailbox.

I happen to be an experienced power management designer, but aparrently am not trustworthy enough to know the secret of what you are trying to do. So, hire a contractor for $100k and he will tell you what's up. I wouldn't start the conversation off with trying to build an 80W converter running off a Li battery. Tell him what you are actually trying to accomplish and then become a giant ear......

He will probably mention that an 80W converter, even if it achieves 75% efficiency, has to dissipate about 20W of power into free air. That's not possible in something small and compact, at least not in the conventional definitions of those words.

 

[blueroomelectronics]

I still can't figure out what 0.4V @ 107A would be useful for?

 

[Sceadwian]

Nothing that I can think of, except a very ineffective heater, at that current the wire thickness you'd need to efficiently transfer the current to whatever possible load there might be would be closer to being bar stock than wire at those currents.

The original poster may want to rethink his idea or give us some more details. Regardless of weather or not this is for a possible commercial application is irrelevent. If the device is succesful or useful it will be reverse engineered almost immediately but other companies. The patent system is so badly broken that it would like not protect your idea in the first place. No one here is out to steal anything and as long as it's not an energy from nothing project people here will help.

 

[blueroomelectronics]

Hmm we'll probably never know.

 

[mneary]

My PC motherboard uses half a dozen converters in parallel to supply the CPU (1.1V, 50A?). I know it's tricky to put power supplies in parallel, but I would start with that sort of concept. Of course I would synchronize and interleave the switch drive to reduce the source current peaks.

The CPU power supply uses 12V as its input, which as suggested here, does make the design more sensible. It's cooled by forced air, which helps. Still, this design definitely wasn't done over a weekend by a novice.

OP hasn't mentioned regulation. If it can run open-loop, it reduces the complexity further.

[edit] I looked up some of the chips in my PC. The data sheet for the ADP3418 shows a 0.8375-1.6A 95A power supply example.[\edit]

 

[Mr RB]

That chip won't work. It's got to produce 107A from a little battery... For 30 minutes.
He needs a better chip than your PC one.

 

[mneary]

All beside the point. I only posted the reference to show 100A isn't impossible. But you already knew that. For the enjoyment of others, the schematic of a small 100A class low voltage power supply should be instructive. Five square inches isn't exactly an elephant all for 100A.

True, OP is beginning with an unreasonable battery and has no comprehension of P=V*I . Aside from that.... how else is he going to power his home made super resolution camera?

He also needs 12V, forced air, the remaining (obsolete ) chips, MOSFETs and other components in the schematic, and a whole lot of skill. .