IRFZ44N Mosftet with Arduino

[radhika]

Can you guide me what is the appropriate frequency to drive Bost chopper from 3.7V to 19.5V when I have 150uH of the inductor?

[Zero999]

Can you guide me what is the appropriate frequency to drive Bost chopper from 3.7V to 19.5V when I have 150uH of the inductor?

You don't design the boost converter round the inductor, but select the inductor to suit the application.

Here's a design guide from Texas Instruments
http://www.ti.com/lit/an/slva372c/slva372c.pdf

Another tutorial, which I haven't read in depth.
https://www.powerelectronicsnews.com/problems-solutions/the-dc-dc-boost-converter-power-supply-design-tutorial-section-5-1

And an example of an EE student's thesis, which I've only quickly scanned through, so it may contain errors.
http://ethesis.nitrkl.ac.in/4811/1/109EE0612.pdf

[oPossum]

The graph on the IRF540 datasheet, Figure 3  which was advised from oPossum to pick the Vgs for the desired current .

See comments above for more details.

For switching applications you must exceed that voltage so the MOSFET is not in the saturation region. Figure 3 shows the ohmic (linear) and saturation regions. The sloped part of the curve is the ohmic region. The horizontal part of the curve is the saturation region.

[malagas_on_fire]

I don't plan for use on  switch mode supply but to create a enable / disable 5V rail to another circuit using an auxiliary transistor, driven by an arduino.... let me just do a quick draw without values... and sorry for my poor english 

(Edit)

Here is a quick draw of the circuit.

1A peak and 200mA nominal of current 

[JS]

How much current will it have?

JS

[malagas_on_fire]

Check my comment above. I re-edit to include a quick draw and the desired current 1A peak and 200mA nominal

[JS]

You need a P channel mosfet to switch the high side directly, a level shifter to get well over the rail (at least 5V) or a gate driver.

JS

[malagas_on_fire]

Hi

Thanks for the information.

So it can't be done with a N channel between 5V and drain , source connected to ground? I have only N channel mosfet's laying around, but if the P channel is more suitable so be it.

[JS]

The N channel is easier to drive connecting it between the load and ground. Pusging the gatr to 5V you can probably live with 200mA at it... Try it and see how much losses you have.

JS

[Zero999]

I don't plan for use on  switch mode supply but to create a enable / disable 5V rail to another circuit using an auxiliary transistor, driven by an arduino.... let me just do a quick draw without values... and sorry for my poor english 

(Edit)

Here is a quick draw of the circuit.

1A peak and 200mA nominal of current

If you have a separate query then please start another thread, rather than hijacking this one, which is about making a boost converter, using an Arduino. Otherwise it causes confusion, about which post relates to which question.

[malagas_on_fire]

Okay sorry for the confusion and highjack this thread, more related to lazy of creating one.  I'll create one further since i'll try to do the experiment ASAP.

Can i link some of the posts of this thread just to do a follow up?

[Zero999]

Can i link some of the posts of this thread just to do a follow up?

Of course you may link to posts in other threads, including this one.

[ogden]

Can i link some of the posts of this thread just to do a follow up?

Of course you may link to posts in other threads, including this one.

I would say that it is highly recommended to do so when you leave thread you started/resurrected to create new one.

[radhika]

Respected,
I have tried to drive IRFZ44N using 555 timer as per you all suggested. And even got required 19.5V from 3.7V using 33uH Inductor, 22uF capacitor and 68kOHM as the load resistor.
But, when I tried building circuit practically, the inductor got burned (I used inductor of color code orange, orange, black) And it too effect the IRFZ44N MOSFET. What to do? Why it burned up?
https://postimg.cc/7b0hKtNB
https://postimg.cc/mPzgFdhN

According to the suggested calculation of 100KHz, where I need to use 3.9uH inductor, Cout = 330uH I got 10V which is unstable and slowly varying as my output https://postimg.cc/gwm1Pj9X
And then I used 33uH, I got the required results and that too burned up What to do?
Also, the battery I am using is 3.7V 4000mah battery. Is it the reason?

[ogden]

But, when I tried building circuit practically, the inductor got burned (I used inductor of color code orange, orange, black)

What is current rating of inductor you used? You shall not saturate inductor in your converter, it MUST have current handling margin. 33uH seems about right for 100KHz. I suggest to use widely popular inductor value you most likely have in your scrapbox, 100uH at 50KHz.

Your circuit does not have any feedback, PWM duty cycle is not controlled by output voltage which is very bad. Voltage can skyrocket, burn your downstream circuit in no time.

Don't use 555 to build switching supplies. [edit] Unless there is regulation feedback implemented somehow