Voltage controlled pulse skipping modulation: Extension towards the ultra light load

This paper presents the concept of a voltage controlled pulse skipping modulation (VCPSM) in a dc-dc converter, which improves the efficiency, ripple magnitude, and transient response over a wide range of light load condition. The duty ratio of VCPSM, instead of remaining constant as in a classical PSM, is controlled using the voltage mode control with an additional input voltage feed-forward along with an adjustable voltage. Because of the synchronization with the external clock, it facilitates the design of the input filter with reduced EMI problems. The sampled data model, averaged small signal model, and average power loss model are obtained to analyze the stability, dynamic performance, and efficiency, respectively. The simulation results are presented to compare the performance of VCPSM with its classical counterpart. Because of the absence of the any current sensing circuit, VCPSM may be useful for improving light load performance of high frequency power management ICs.