EveryCircuit - Asynchronous MOS Pre-Regulator

6 years ago

what is this for? Why not a linear regulator without switching?

6 years ago

The linear regulator is on the right. The switching part is to minimize the voltage drop over the power transistor of the linear regulatir

hurz

6 years ago

i see which part is switching and which part is not. But this does not lower the power dissipation, somewhere the voltage must drop, think about

kiani

6 years ago

A 20 H transformer,, big enough for a power plant on mars.!

thebugger

6 years ago

Well, some of the power drops through the Mosfet, but other than that, I cannot see it leaking through anywhere. This is pretty much the way the old SCR pre-regulators worked, just with TRIACS after/before the transformer.

thebugger

6 years ago

For instance, check this example where the input current draw, seems to be less than the output current draw. This means that something creates a non-linear relationship between input/output current, which is uncharacteristic for linear power supply

kiani

6 years ago

The inductance of transformer 20H. Stores energy....

hurz

6 years ago

the power you waste with "switching" is identical to the power you would dissipae if you use only one linear regulator. So it does not help! Its just generating noise.

hurz

6 years ago

http://everycircuit.com/circuit/5817357044547584

thebugger

6 years ago

Why would you make it with a 63V supply and dissipate half the heat through the 5ohm resistor. I am not following your analogy

thebugger

6 years ago

And kiani, by the way 20H is a regular transformer. Check your resources again. This is primary inductance, not mutual inductance that's 20H

thebugger

6 years ago

And much of the transformer here is fictional - there's like a third of all the things that an engineer will take into consideration when designing a transformer.

hurz

6 years ago

You never follow me 😎, but you must follow physics and from your mosfet to mains the power does drop and truns into heat ! Follow physic and you understand. Without an inductivity you just shift the point where you burn the power, your switching mosfet is useless and just generates noise. You better only use a linear regulator as i already said. Follow physics. What you need is a buck converter PLUS a linear regulator, that would make sense. Chopping the current with a mosfet is waste of energy.

jason9

5 years ago

So, I’ve stared at this circuit for a while and I see somewhere there must be a voltage drop, but I can’t actually pinpoint the location. I think the inductance of the transformer is the missing inductor required to make this work.

jason9

5 years ago

Hmm, thinking about it more I think the inductor is in the wrong position to act as a buck converter, which is what the switching part of this circuit seems to be doing, except it’s buck converting 37V to 34V, which makes me wonder what the switching business is all about because a 3V voltage drop isn’t much. Why not just take a few winding off the secondary? Seems to work just as well.