A Study on the Effectiveness of Using a Hybrid Topology in Improving the Power Efficiency and Voltage Regulation over a Wide Input Range of DC-DC Converters

DC-DC converters are used to convert and regulate voltages depending on the requirement of the specific load. There are two types of DC-DC converter: (1) linear regulators and (2) switching regulators. A linear regulator has a small output voltage ripple but its power efficiency degrades when the difference between the input voltage and output voltage increases. On the other hand, the switching regulator has better power efficiency compared to the linear regulator. The switching regulator can convert wide range of input voltages while maintaining high power efficiency and it can also step-up voltages which a linear regulator cannot. The drawback for switching regulator is the need for control circuit that controls the switches and regulation. The switching regulator has also the problem of relatively larger output voltage ripple, which is not suitable for sensitive circuits. In this paper, a hybrid topology was proposed to combine the advantages of the two DC-DC converters. From the simulation of the three converters, the linear regulator only has an efficiency of 28.058% while the switching regulator and hybrid power converter have efficiencies of 49.0881% and 45.6753%, respectively. In addition, input voltages from 0.5V to 5V were tested on the three regulators that would result in a regulated output voltage of 1V. The linear regulator can only regulate voltages above 1V and the PMOS transistor used has a operating voltage of 2.5V which limits the upper voltage boundary of the linear regulator to 3.5V. The switching regulator can regulate wider range of input voltages but due to power loss across the converter, the switching regulator cannot produce a constant output voltage of 1V when the input voltage ranges from 0.5V to 0.7V. The three converters were designed and implemented in a 65nm CMOS process.