Designing power management from a system perspective

Power management technology has changed dramatically over the past decade. The wave of portable and personalized electronic products has changed the landscape of the consumer electronics market, rewriting the rules of power supply design, integrated features and efficiency, and pushing intelligent power management and system knowledge to the forefront of product design.

We can compare today's power management environment to the situation in the late 1980s. The 1980s and early 1990s were dominated by NPN linear regulators, simple circuits for shifting voltage levels that required little intelligence. In addition, because portable electronics were just becoming popular and power was cheap and plentiful, there was no reason to require linear regulators to operate at high efficiency.

Fast forward to today, we see dozens of different types of switching regulators joining the ranks of power management, and power efficiency has increased from 10% to 80% or even higher today. This has a wide range of impacts: longer battery life for portable devices; and significantly reduced energy use and heating/cooling costs for high-power systems.

Given what is at stake, efficient power management is no longer a standalone consideration or an afterthought. Whether supporting end loads or AC-DC performance specifications, the strength of emerging power management technologies lies not only in their ability to convert different levels, but also in their ability to be integrated into the system as part of a complete system solution.

Therefore, in addition to the usual questions about voltage and current requirements, system designers should consider a number of questions at the beginning of the design process, such as:

How does the interaction of power devices with other system ICs affect noise or efficiency levels?

How does the application of intelligent power management contribute to overall design innovation?

How can real-time feedback about power systems be used to improve system performance and value?

For example, in base station applications, using intelligent power technology to handle AC-DC and isolated DC-DC power conversion can cut system power losses in half. The technology can also be used to monitor signal chain requirements and interact with data converters, amplifiers and other devices to improve overall system efficiency by another 30%.

Data converters, in particular, require very low noise and well-regulated supplies to minimize overall system ripple. System designers may find themselves in a situation where they spend months painstakingly optimizing the linearity, noise performance, and other characteristics of a data acquisition system, only to see performance severely degraded by supply noise and poor transient response once the power supply components are added.

Low-noise switching regulators will increasingly replace linear regulators, but this requires suppliers who are not only good at power management but also understand the entire signal chain and system-level design considerations.