LDO-assisted vs. linear-assisted DC/DC converters: A comprehensive study and comparison

This paper deals with a comprehensive study and comparison on the conventional linear-assisted converter and a new structure named, LDO-assisted converter based on a new class-AB LDO regulator instead of the conventional linear one, in terms of efficiency, output ripple, and load transient response. The new structure reduces difference between input and output voltages and also switching frequency of the buck converter, corresponding to higher power efficiency, desired for power management systems of battery operated devices like biomedical implants and energy harvesting applications. A comparison analysis is done and the results are validated in HSPICE in a 0.18 μm CMOS process.