I need to design a power supply that is powered from a single Li-ion cell (3-4.2V) and provides 3.3V up to 500mA and 5V up to 1A. I have three solutions in mind, one is boost converter to 5V and then a LDO for 3.3V, second is a buck/boost for 3.3V and a separate boost converter for 5V and the third is boost converter for 5V then cascade (input for 3.3V conv. is 5V) a buck converter for 3.3V.
Since I am using batteries a LDO seems inefficient (cca. 64%). So I am curious which of these solutions is better in terms of efficiency? And would I have issues if the dc-dc converters were running on different frequencies?