Miller plateau in Buck Converter Synchronous

The slope of the Miller Plateau is generally shown to have a zero, or a near-zero slope, but this gradient depends on the division of drive current between Cgd and Cgs. If the slope is non-zero then some of the drive current is flowing into Cgs. If the slope is zero then all the drive current is flowing into Cgd. This happens if the Cgd x Vgd product increases very quickly and all the drive current is being used to accommodate the change in voltage across Cgd. As such, QGD is the charge injected into the gate during the time the device is in the Miller Plateau. It should be noted that once the plateau is finished (when Vds reaches its on-state value), Cgd becomes constant again and the bulk of the current flows into Cgs. The gradient is not as steep as it was in the first period t2, because Cgd is much larger and closer in magnitude to that of Cgs.

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unclejed613 said:

https://www.vishay.com/docs/73217/an608a.pdf

because you have two capacitances at work, Cgd and Cgs.

from page 3

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