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TOPswitch HX feedback loop?

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cupoftea

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Hi,
The expression for "Transfer function of a Voltage Mode Flyback power stage" is in the form of "vout(s)/vErr(s) = "

("vErr" refers to the Error voltage of the Feedback loop Error amplifier)
This is then multiplied by the "Error Amplifier and Modulator transfer function" which is in the form of "vErr(s)/vout(s) = "

However, the attached (page 467) gives the Transfer function for the TOPswitch Error Amp and Modulator in the form of "D(s)/vout(s)".

......So how can we use it to produce the overall open loop transfer function, ?...since it would need to be in the form of "vout(s)/vErr(s) = "
 

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  • Pg 466.pdf
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  • Pg 467.pdf
    508.8 KB · Views: 68

So how can we use it to produce the overall open loop transfer function, ?
By multiplying with flyback transfer function, probably discussed at a different place in the book. You didn't give a citation, thus we can't check.
 
Thanks, the attached is the voltage mode Flyback Power stage transfer function (it says buckboost but ayk, you derive flyabck from buckboost)
The attached is from the other book by the same author, of the stuff in the top post.

I think you will agree that the open loop feedback loop transfer function for voltage mode flyback in dcm or ccm cannot be calculated from this little lot?
 

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  • Voltage mode flyback.zip
    1.1 MB · Views: 66

So, Apologies...Back to the original thread..

The following (below) links show that there is no way for anyone to do a TOPswitch-HX flyback design in CCM, and assure its stability.....
An offline Flyback is often in CCM at the low level of the universal mains input (eg at 90VAC input).
TOPswitch-HX is also not covered any more by the PI Expert or PI Designer software.




 

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