IC vendors are addressing the issues related to multiple, interrelated power rails on PC boards
It's no news that almost every designer is interested in low-power design and power management, whether to maximize battery life, minimize battery size, reduce operating expenses, or improve the thermal situation. This imperative involve s a combination of choosing low-power ICs, using low-power topologies where possible (watch those power-dissipating pull-up resistors), invoking various shut-down and sleep modes, and more, as a few tactics.
But I am also seeing another power trend, one which has been standard in bigger systems such as servers, but is now migrating down to much more modest consumer products. This is the need to carefully manage the many semi-independent power rails, both individually and with respect to each other. It is not unusual for even a small consumer product, such as a multimedia center, cell phone, or home controller, to have half a dozen or more power rails with different nominal values, noise specs, current capacity, regulation, and other parameters, especially fit the product has real-world inputs and outputs with their unique requirements.
Along with all these rails engineers face issues of on/off sequencing, linking between some of the rails, thermal and current monitoring, and reporting of rail status. This is why we're seeing a lot of power management ICs (yikes, another acronym for me to remember: PMIC) from different vendors, who have spotted a small but nicely growing niche for PMICs targeted at smaller systems, and have the analog and mixed-signal design and process know-how to fill it.♦