N-channel mos buck converter

263

02:12:33

At the end i decided to make a bootstrap with my hcpl-3120 2.5A gate drivers, a diode, a capacitor and a few resistors for pulldown and current protection. I will make a badass 10uH toroidal inductor to handle the high currents and put a few capacitors toghether to make 10mF. I don't know what to use as controller for the mosfet because i don't really understand why hurz says to not think about pwm everytime.
-niki

published 9 years ago

hurz

9 years ago

I do not want you to think to much about the digital part before you understand the analoge one! How can you control something you dont understand?

nikisalli

9 years ago

You're right

nikisalli

9 years ago

So what do i have to do?

hurz

9 years ago

3dB corner frequency of your prefered LC combo is what?

hurz

9 years ago

What does this mean for you "digital" regulator?

nikisalli

9 years ago

The problem is that i can't find the "perfect" filter. This LCR one goes in resonance at 500Hz but if i change the C and R it goes in resonance too

nikisalli

9 years ago

What do i have to do if no filter is perfect?

hurz

9 years ago

Right, all filter do resonate. But dampening can avoid/reduce it. You have to find the right combination of L and C which gives you a low R for dampening. R you get for free as parasite from ESR and Rdson from mosfets and PCB layout and you get also magnetic losses for free which will also helps to reduce resonance... the combination 10uH and 10mF is not to bad. I choose 47uH 7A from Talema ESR 26mOhm , a big 22mF 40V low ESR cap I haven't measured and a Mosfet IRFP540Z with 35mOhm Rdson. All together works almost perfectly as expected. The digital part I tested with arduino Due and about 15kHz and a sigma delta modulator.

nikisalli

9 years ago

Nice. What should i use as digital part? I want something like ne555 and opamps or pwm ics like tl494 ka7500 or 3842/3/4/5

hurz

9 years ago

Arduino Due

hurz

9 years ago

if you want start here http://everycircuit.com/circuit/5767007612174336

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