State-machine realization of second-order sliding-mode control for synchronous buck DC-DC converters

The paper presents a second-order sliding-mode (SOSM) control approach for synchronous buck dc-dc converters. The SOSM controller is implemented digitally, using a simple state machine, which does not require current sensing or an integral term. A hysteresis is introduced to control the switching frequency. The SOSM controller results in fast transient responses without overshoots, and is robust against parameter uncertainties. The proposed approach is verified by experimental results on a 1.25 V, 10 A prototype.