nikisalli

modified 9 years ago

5v to 12v 1A boost converter

1267

1d 04:56:05

I love this circuit! It turns 5v in 12v at 1A max! This is awesome! And it's also variable! What's better? It has feedback so if you change load the output voltage will not change.
For this awesome circuit you need:
555 timer 
Resistors
A small transistor like bc547 or 2n3904
A 10 mH inductor 
A 70mohm or less n channel mosfet
Two capacitors (bigger is better)
An opamp (lm358 or 324 or 339 ecc.)
A potentiometer 10 to 100kohm
And some smaller capacitors.
-nikisalli 

published 9 years ago

hurz

9 years ago

Niki, check whats happens in the moment you reach 12V. Take a look at the coil current and what the mosfet is doing. This needs some improvements. Keep it up!

nikisalli

9 years ago

Hurz now that you're here do you know how to recognize magnetic permeability of a toroid nucleus? Because i have some toroids and i don't know how to calculate inductance because i don't know magnetic permeability!

hurz

9 years ago

Depends on the material and highly varies. If you don't have a specification for this core you have to do try and error. Just do some windings and measure the inductivity. You can then calculate form the number of turns and measured inductivity proportional to your needed number of turns roughly.

nikisalli

9 years ago

This is the problem i can't measure inductance!

hurz

9 years ago

What target inductivity you want? 1uH 100uH 10mH 1H? Roughly

nikisalli

9 years ago

10mH

hurz

9 years ago

You do have a function generator, Best is sine wave?

nikisalli

9 years ago

Yes but it's a Bluetooth module with a function generator on the phone but from 1 to 100hz the waves are perfect.

hurz

9 years ago

Scope?

nikisalli

9 years ago

No but i always wanted one

nikisalli

9 years ago

But i have a very efficient frequencymeter so i was thinking to make an oscillator and measure the frequency maybe

hurz

9 years ago

Thats a good idea.

hurz

9 years ago

This might be good start for you http://everycircuit.com/circuit/4995846865158144

nikisalli

9 years ago

Mmm but to have precise results i need something on the milliseconds because with nanoseconds arduino Can't calculate that

hurz

9 years ago

Sure, with 10mH you go into ms.

nikisalli

9 years ago

Mmm i've seen your new circuit but can you make it more slower? At 10-5ms that would be perfect for my my microcontroller

Matus

9 years ago

This circuit looks good. Just one problem that coil reactance 2xPIxfxL = is only 37,8R and it's taking more than 10A (5V) ! It should happen because of cap on output but how is possible to reduce these peaks on input?

GingerKing

9 years ago

Lol more like "how to burn mosfets 101". Please do some simple power calculations.

hurz

9 years ago

The power dissipation at mos would be ok, its strong enough. But as i said in my first comment, the stop condition (12V reached) 555 is in reset but the mosfet loads the coil for the next shot. But this is waste of energy.

Chryseus

9 years ago

I love the smell of smoking MOSFETs, also 1kHz is way too low unless you want a massive and expensive inductor

hurz

9 years ago

Right, the frequency is to low for an efficient upconverter.

GingerKing

9 years ago

13A x 3V = ?Watts hurz

hurz

9 years ago

And you forgot the DC resistance of a 10mH coil. I guess its around 500mOhm minimum. So before this mosfet get in trouble the coil will burn, right?

GingerKing

9 years ago

P = (I^2)×R = (13^2)x0.5 > (13)x3 so yeah the coil is also on fire. Good point

GingerKing

9 years ago

I honestly dont have a mosfet that can handle 39W. I feel as if my load should be receiving thar much power.

nikisalli

9 years ago

Mmm i didn't see those 10 A on the power supply and the coil XD

nikisalli

9 years ago

You're right guys with this circuit in real life i can cook omelettes

hurz

9 years ago

Niki, i have updated the oscillator circuit for you. But as you can see from comments your upconverter needs a redesign. Higher frequency with smaller inductivity and a different control logic. And dont forget to include the coil DC resistance. Keep it up.

nikisalli

9 years ago

Ok thank you hurz👍

WTFCircuit

9 years ago

I don't want to be mean, but I said you the same thing yesterday...

hurz

9 years ago

@gingerking, you have to make a decision were the power is going. To the coil or to the mosfet. Mosfet saturation voltage will be low so power dissipation is also low. Its the coil which is going to be hot

nikisalli

9 years ago

Yes but with hurz is more safe...

WTFCircuit

9 years ago

😞

parabellum2909gmailcom

9 years ago

Великолепно!

jpoulin0901

9 years ago

Your oscillation frequency depends on the simulation speed for some reason..

ingandrestamayo

9 years ago

But, your op amp requires 15 v vcc, but, it is ok, good job.

nikisalli

9 years ago

No my opamp only requires 5v dc

nikisalli

9 years ago

Sorry i don't understand😓

hurz

9 years ago

Comment at wrong circuit 8-)

nikisalli

9 years ago

Ok...

psteichen

9 years ago

The little LEDs have the cool little flames that shoot out if you overload them. Great idea! But why not all components and even the traces? Could be configurable based on variable component specs...

nikisalli

9 years ago

I know that if you overload this with 1A the coil will implode but that's an example in real life you shouldn't use a so high load!

hurz

9 years ago

Niki, you understand what psteichen want from you? I don't :-(

nikisalli

9 years ago

He wants that all the components in ec to burn like leds

nikisalli

9 years ago

He's a a pyromaniac

hurz

9 years ago

That's ok ;-)

schmobi2001

5 years ago

Hi. I have built this using one smaller capacitor about 1500 microfarad and lm386. I can adjust voltage just fine but as soon as I apply load the voltage drops below 5 volt. Any idea why?

schmobi2001

5 years ago

Added one big capacitor around 1000 microFarad but still I can only apply a small load at best with a stable voltage. As soon as I apply a high load the voltage drops. Also tried different mosfets and conductors with no better result. Is the lm386 the problem? The feedback does not work properly.

add comment in editor