Transient Performance Improvement for Constant On Time Control

A novel method to improve the load transient performance in constant on time (COT) control both in load step up and down is proposed along with its simple circuit implementation. When a large and fast load step up is introduced in COT control, increment of inductor current is limited by the constant on time (Ton) and the minimum off time which is also fixed by the power stage requirement, and eventually will create an undershoot at the output. On the other hand, in case of load step down, if load step is occuring at the beginning of Ton, instead of decreasing, inductor current keeps increasing till fixed Ton expires and therefore creates overshoot at the output. To solve this issue, a new method is presented to increase the Ton in COT control at load step up and decrease it at load step down very quickly. The novelty of this proposed method is that, it can reduce undershoot and the overshoot both in COT control using one simple circuit without affecting the steady state.
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For Information, Contact:
Li Chen
Licensing Associate
Virginia Tech Intellectual Properties, Inc.
(540) 443-9217
Syed Bari
Fred Lee
Qiang Li
Pei-Hsin Liu