Book is wrong about power stage transfer function for SMPS?

[grizedale]

Does any reader have the book "Switch Mode Power Supplies" by Christophe Basso?

Equation 2A-26, aong with parts 1 and 2 of the top of page 235 purports to give the control-to-output transfer function for DCM current mode flyback.

However, it is clearly wrong.

Equation 2A-26 doesnt even take into account the sense resistor.

...the parts 1 and 2 at top of page 235 are nonsense...........why do they tell what to do with the sense resistor and then not even use the sense resistor value in Equation 2A-26?

Do you agree that it is nonsense?

...and concerning parts 1 and 2 at the top of page 235..........why do they BOTH speak of current-mode.....what if its a voltage-mode flyback?...what is one supposed to do then?

Are you also in belief that this book is nonsense in this regard?

 

[BradtheRad]

I don't have the book, but this sort of incongruity is typical in any book.

When you can pick up these things it must show you could write your own book.

The author probably would like to convey all the vital concepts at the same time. But it can't all be done simultaneously.

So all an author can do is to build paragraph on paragraph. He might have presented a simplified explanation/equation initially...

with the intention of backtracking later in order to cover a detail or two that couldn't be made the first time through.

Some mistakes always creep in. Perhaps the diagram was print-ready while the text was still being composed. Or vice versa.

Same with the equation. Maybe it required special typefaces? Camera work?

Maybe the author saw the mistake and said to the publisher "I found another mistake that needs to be corrected."

But the publisher said, 'This will count as another author's change. As per your contract, we'll have to deduct $50 from your advance.' (If there was any advance for a technical book.)

And the author said 'No dice. I have a family to feed.'