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current mode versus voltage mode for buck DC/DC

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hoonsk

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I see that most datasheets report that buck converter utilized voltage mode(VM) control. I heard that current mode (CM) has wider bandwidth and faster transient response, why the current trend for buck is still VM ? By the way, is it really that CM has wider bandwidth ?

Thanks.
 

Pavka

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The current feedback is really faster, but it also brings a kind of inherent unstability into the loop over the line voltage change.
May be this is the reason, but not for sure exactly the one.
 

Miguel Gaspar

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CM are faster and more stable, check for the article of ONSEMI SMPSRM/D pp21
VM are not good at line variations
CM are good at line and load variations

but the second loop is to avoid saturation on the magnetic core and the margin fase never goes to 360°.
another reference is :
Switch mode Power Supply SPICE cookbook, BAsso, MaGraw-Hill
you can find buck in VM and CM.
 

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