EveryCircuit - Parallel buck converters

alejo38001

8 years ago

Very Good

arnav47

8 years ago

OMG never seen a pro Circuit lke

selman

8 years ago

Let's wait for hurz on this one ...

LeButch

8 years ago

Believe me, he will come... Expect him.

nikisalli

8 years ago

Hurz isn't the only one who can comment. Why don't you try to answer instead?

LeButch

8 years ago

Hmm... Good idea...

hurz

8 years ago

But HURZ seems to be the only user who is helpful on the root topic which niki posted.

nikisalli

8 years ago

Well answer then! I never get bored with this converters

hurz

8 years ago

Biki dont be a fool http://everycircuit.com/circuit/6349990357368832

rich11292000

8 years ago

Ask google already. For starters you want them synchronized.

nikisalli

8 years ago

@hurz wut? That is another topic

nikisalli

8 years ago

rich but what happens if they aren't synchronized? I didn't find anything on google so i think the ripple just gets amplified

LeButch

8 years ago

You know Hurz. He does not to need arguments to critisize you, he simpely is sooooo much better than you

nikisalli

8 years ago

I know he knows much more things than me. That's why i'm asking

LeButch

8 years ago

Right, but he can not argument properly...

hurz

8 years ago

Brainiac LeBitch is so helpful like trolls are.

hurz

8 years ago

Niki, isn't this thread here an alternative solution cuz the flayback one seems to not work because of to low perrformance? If the flayback is at 95% efficency you do not need this parallel "buggy buck" thing here. Lets see what LeBitch can contribute in technical sense here on this topic. I dont expect much and he must learn when he better shuts up. Im affraid this will be a long way

hurz

8 years ago

Niki, do you think your robo can carry a lipo 20s 18650 pack?

nikisalli

8 years ago

I already have the battery 3S 1500mAh

nikisalli

8 years ago

The flyback converter was just a test. It isn't for the robot. For the robot i was thinking about a synchronous converter but i'm having problems making the bootstrap. This of paralleling small converters was just an idea because i have limited space in the robot and i don't need low ripple

LeButch

8 years ago

I do not have to. I am so dump, that I don't know when to shut up.

hurz

8 years ago

@nikisalli, check if you can use a normal smps 110V AC to 5V DC 30A. Just set it to 110V and supply it with high enough DC. Maybe a 10s lipo 36V - 42V is already high enough. 5V output suppose to be ok and 30A? They are available in 20,30,40, ... whatever. Check this http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=132189957040&category=181925&pm=1&ds=0&t=1509341722000&ver=0&cspheader=1

nikisalli

8 years ago

I can't put a 10S lipo and a big smps on the robot. It is powered by a three cell 1300mAh lipo battery with 20C and i just need a step down converter to turn 12V to 5V for the servos

hurz

8 years ago

Its unclear what you really need and not. What is "big" and whats not. I dont think its a matter of big, its a matter whats needed!

nikisalli

8 years ago

I need some kind of efficient converter that can stay in a 3*3*8cm space and have an output of 5V and 15A minimum

nikisalli

8 years ago

The converter i'm using now is a buck converter that uses schottky diodes and gets hot quite fast with a 8A load. Those diodes should have ~0.7V of Vf and so they dissipate 0.7W for each ampere and it is too much

nikisalli

8 years ago

I saw some small 3A synchronous buck converters online and i thought i could parallel like 6 of them to have a big current output

viki26

8 years ago

Hey dude whats its out put

nikisalli

8 years ago

The blue line on the scope

eekee

8 years ago

It's pushing over 20W output, which I guess is good. The current through each coil (and presumably each transistor) averages 1.5A, can they handle that? Anyway, it's neatly made; easy to examine, which I appreciate.

nikisalli

8 years ago

In reality it should go over 80W output at 5V with single 3A synchronous converters

eekee

8 years ago

Oh right!

hurz

8 years ago

Another ideab i have is the combi of some lipo's and a DPS5015 from rdtech. Check ebay

nikisalli

8 years ago

The dps5015 is too big :/ i need this regulator inside the robot in a 4*4*8cm space

nikisalli

8 years ago

I've recently seen some people putting SBECs in parallel. Those are basically synchronous rectification buck converters so i guess it can be done

hurz

8 years ago

The board of DPS5015 is about 10x8x5 . I tested for you to remove the display/keypad after programming the setup. You just need the mainboard!!!!

nikisalli

8 years ago

It's too big

nikisalli

8 years ago

It is never going to fit in my robot :/

hurz

8 years ago

So what is the smallest you can make? A solution without buck converter, 2s 7p lipo2200mAh 7.2V15.4Ah, 14 times 18650 for about 1hour at 15A fun?

nikisalli

8 years ago

Mmmmmm i saw some synchronous converters on aliexpress that are pretty small and can delivery 15A max. I was thinking to use something like that because my main problem is the diode in the converter getting hot too fast for it's Vf

hurz

8 years ago

But why do you care how they are designed internaly. Just take the spec max current out and efficiency and give a a shit how they do it. If you are interested in asynchron design and low Vf check this TEA1761 but it wont help you as long you havn't done a 'make or buy' decission!

nikisalli

8 years ago

I just decided to buy a 20A SBEC from hobbyking. It looks powerful and it's pretty small