I'm bored so another one to ponder.... zero and infinity

[ChrisGibboGibson]

Think SMPS

Aiming for "the ideal" can often clarify in one's own head the final
objectives. Or rather it sometimes can.

Accepting that ideal components are not available is what separates the
idealists from the engineers.

The ideal switch has zero on resistance and infinite off resistance.

A perfect transformer has infinite magnetising inductance, zero resistance,
zero leakage inductance and perfect magnetic coupling (unless we want
otherwise).

Now think about the effects of that on a typical SMPS

What topology would you use every time?

Gibbo

 

[Rich Grise]

On Fri, 15 Oct 2004 23:32:35 +0000, ChrisGibboGibson wrote:

Think SMPS

Aiming for "the ideal" can often clarify in one's own head the final
objectives. Or rather it sometimes can.

Accepting that ideal components are not available is what separates the
idealists from the engineers.

The ideal switch has zero on resistance and infinite off resistance.

A perfect transformer has infinite magnetising inductance, zero resistance,
zero leakage inductance and perfect magnetic coupling (unless we want
otherwise).

Now think about the effects of that on a typical SMPS

What topology would you use every time?

Every time? Whichever topology is appropriate to the application.

HTH!
Rich

 

[ChrisGibboGibson]

Rich Grise wrote:

On Fri, 15 Oct 2004 23:32:35 +0000, ChrisGibboGibson wrote:

Think SMPS

Aiming for "the ideal" can often clarify in one's own head the final
objectives. Or rather it sometimes can.

Accepting that ideal components are not available is what separates the
idealists from the engineers.

The ideal switch has zero on resistance and infinite off resistance.

A perfect transformer has infinite magnetising inductance, zero resistance,
zero leakage inductance and perfect magnetic coupling (unless we want
otherwise).

Now think about the effects of that on a typical SMPS

What topology would you use every time?


Every time? Whichever topology is appropriate to the application.

Ahh but that's the *real* question.

Given that we could achieve the above ideals which topology would you choose
under different circumstances and why?

Gibbo

 

[Pooh Bear]

ChrisGibboGibson wrote:

Think SMPS

Aiming for "the ideal" can often clarify in one's own head the final
objectives. Or rather it sometimes can.

Accepting that ideal components are not available is what separates the
idealists from the engineers.

The ideal switch has zero on resistance and infinite off resistance.

A perfect transformer has infinite magnetising inductance, zero resistance,
zero leakage inductance and perfect magnetic coupling (unless we want
otherwise).

Now think about the effects of that on a typical SMPS

What topology would you use every time?

There's a slight snag here.

If the transformer had infinite magnetising inductance, you could could
certainly never use it in a flyback design as you could never establish any
stored energy !

Graham

 

[ChrisGibboGibson]

Pooh Bear wrote:

ChrisGibboGibson wrote:

Think SMPS

Aiming for "the ideal" can often clarify in one's own head the final
objectives. Or rather it sometimes can.

Accepting that ideal components are not available is what separates the
idealists from the engineers.

The ideal switch has zero on resistance and infinite off resistance.

A perfect transformer has infinite magnetising inductance, zero resistance,
zero leakage inductance and perfect magnetic coupling (unless we want
otherwise).

Now think about the effects of that on a typical SMPS

What topology would you use every time?

There's a slight snag here.

If the transformer had infinite magnetising inductance, you could could
certainly never use it in a flyback design as you could never establish any
stored energy !

You're obviously the brightest one so far to read this thread!

But think carefully about what happens just below perfection.

Which topology now ?

Gibbo

 

[Ken Smith]

In article <20041015193235.25923.00002365@mb-m03.aol.com>,
ChrisGibboGibson <chrisgibbogibson@aol.com> wrote:
[... perfect stuff ...]

Now think about the effects of that on a typical SMPS

What topology would you use every time?

If I had to use the same topology for everything, I's use the Cuk
converter.

For a bucker, the simple forward converter usually makes more sense

For a wide input range, the flyback is usually better.

For multiple parasite outputs, the current fed forward converter is
usually best.

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