Practical Design Of A Buck Converter
Peak Current Control Circuit
by Dennis L Feucht

A major disadvantage of voltage control is the output network, with its complex pole-pair resonance. A related disadvantage is that the output network forms a second-order low-pass filter which causes the response time at the output to be increased. By driving this network with a current source instead, the series inductor no longer appears in the transfer function and the resonance is removed.

To get around the disadvantages of voltage control, a simple and elegant scheme was devised years ago that controls the peak inductor current. The current is sensed, fed back, and D controlled so that the peak current is the commanded value.

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