Thread: 7-16Vin 12Vout 6A Iout regulator plans

Update, heh, just finished testing and for some strange reason the regulator closest to Vout gets super toasty...

all my diodes seem to be fine (thought i might have blown one up soldering) and there aren't any bridged or connections as far as i can see..

it's weird, they get warmer as they get closer to the Vout side of the board.. R1 is barely warm, R2 is noticeably warm, R3 is pretty warm and R4 is burning hot

needless to say i killed the power as soon as i saw this but i don't have any test equipment (like a scope or a function generator or even a decent 12v power supply or anything.. just a cheap radio shack multimeter) to figure out where the problem is...

if anyone builds one of these PLEASE lemme know what happens and definetly consider these plans a prerelease version

Good luck
Ry

the best way to get components for this kind of thing is order samples from TI, that's how i did it (i live in canada and i still got them less than 3 days after i ordered them)..

just order one of each package type (the PT5071N and the PT5071A) one day and then go back the next day and order another pair, that's the 4 that you'll be using.

the other components are VERY standard, the diodes are really standard and i believe it's possible to use anything from LN5401 to LN5409... (not sure on that tho) and the caps may be the problem with it overheating so don't take my word for it..

and yes, it survives cranking/starting the engine without rebooting or even twitching one microvolt.

again, there are still unresolved bugs with this design. i don't reccomend building it with my specs until someone fixes it and tests it.

just order one of each package type (the PT5071N and the PT5071A) one day and then go back the next day and order another pair, that's the 4 that you'll be using.

Nice idea

But how much is the total cost if you were to buy?

budgetary pricing on the PT5071s is $21.20 at 1000 units, that's what their website says

i have no idea how much they'd be from distributors or even who would carry them.

boost-buck 12v regulation for a PW-70a

here's the thread that i pulled the designs from (and modified highly)

Hi !
I live in Finland and I got samples from TI in 3 days - thats pretty cool ! Now I plan to build the regulator using three PT5071s, but I'm wondering if it would be enough to use only two capacitors(maybe some higher quality tantalum type) - one on input and one on output. What do you think ? Have someone tested that configuration ?

Hey Greenwire,

I am confused on what the diodes are for? Do they prevent the (4) units from feeding back on each other? Do they keep the output balanced?

I didn't see any use of diodes on the TI spec sheet for the Vin and Vout lines, so that is what makes me think the above reasons.

But all in all a nice idea and I will lt you know if the Regs get hot for me two when I get it built.

dug1697: the diodes are schottkey diodes that isolate the chips' outputs from each other, the diodes ONLY isolate the outputs, the inputs are not isolated (only filtered by the caps). that second diode (the one to ground) is to bring the chip's voltage sensing up to a level that will compensate for the voltage drop across the other diode so you still get 12Vout.

pajka: i've been told that with each diode there's a potential for 500mV of noise, that's why a diode on each chip is necessary

i figured out what was happening with my PCBs. the impedance of the copper was adding up along the caps and because of that the chips saw more and more impedance on the input lines from the top of the board to the bottom..

i'm working on a new PCB right now but if ANYONE knows **** about analog PCB design any help or constructive smacks-to-the-jaw would be greatly appreciated.