A simple sliding-mode control circuit for buck DC-DC converters

This paper presents the theoretical and practical considerations to construct a DC-DC buck converter for low-power applications. The control law is based on the sliding-mode control theory that fits the physical behavior of the DC-DC converter. The experimental results show that is possible to construct a simple control by monitoring one of the circuit state variables (voltage on the capacitor). The sliding-mode control helps to drive the output DC value in spite of the circuit variations and load conditions. The experimental results show a reliable regulated voltage of 3.3 V and 4.3 V with a 125kHz reference frequency.