Optimizing the Transient Behavior and Frequency Response of Constant Frequency One Cycle Control: The Charge Control Modulator

This paper presents a new pulse width modulator capable of adjusting the conversion duty ratio in only one switching period, when any disturbance of the input voltage, output current or output voltage occurs. The proposed modulator is based on the calculation of the variation of the electric charge required to restore the steady state operation in only one switching period, and therefore is designated by "one cycle charge control"- O3C. It was shown, theoretically, by simulation and experimentally, that the use of this modulator in a buck converter presents, as a major advantage, the fact that the output voltage gain is not limited by the cutoff frequency of the output filter. As a consequence, very low output ripple can be achieved without compromising the dynamic response of the converter.