Closing the loop

AN1517

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DocID8827 Rev 3

Equation 13

Where K is equal to 0.076. Therefore the PWM gain is also equal to:

Equation 14

This means that even if the input voltage changes, the error amplifier does not change its

value to keep the loop in regulation, thus ensuring a better line regulation and line transient

response.

To sum up, the open loop gain can be written as:

Equation 15

Example 1















The gain and phase bode diagrams are plotted respectively in Figure 11 and Figure 12.

Figure 11. Module plot

–



=



1

K

----

const

==

Gs





+

--------------------









s



=