Boost converter with higher-than-output input

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Mapuia

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With step-down voltage regulators -linear or switching - I think I have a good idea of what happens when the input voltage drops below the minimum required for proper regulation.

What happens if the input of a boost converter equals or exceeds the set output voltage? Does it simply continue to operate with reduced duty cycle? If necessary, please explain with reference to the generalized circuit below.

(I know there are buck-boost chips. This is not for a specific project. I'm just trying to understand the principle).
 

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The behavior is simply opposite to buck converter. While buck converter stops switching at 100 percent duty cycle, boost converter goes to 0 percent.
 

Does it mean that the input then goes directly through the diode unregulated, and that Vout will simply be Vin minus the diode drop (ignoring the DCR of L)?
 
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