Cascaded linear regulator application with positive voltage tracking switching regulator

This paper presents the design, simulation, and hardware implementation of a proposed method for improving efficiency of voltage regulator. Typically, voltage regulator utilized for noise-sensitive and low-power applications involves the use of a linear regulator due to its high power-supply rejection ratio properties. However, the efficiency of a linear regulator heavily depends on the difference between its input voltage and output voltage. A larger voltage difference across the linear regulator results in higher losses. Therefore, reducing the voltage difference serves as the key in increasing regulator's efficiency. This study hence proposes a pre switching regulator stage with positive voltage tracking cascaded to a linear regulator to provide an input voltage to a linear regulator which is slightly above the output of the linear regulator. The tracking capability is further required to provide the flexibility in generating different positive output voltage levels while maintaining high overall regulator's efficiency. Results from simulation and hardware implementation of the proposed system indicated the efficiency improvement of up to 23% in cases where an adjustable output voltage is deemed necessary. Load regulation performance of the proposed method also indicated better result compared to the case without the output voltage tracking method.