It's no longer enough to look at power subsystem design separate from system-wide implications
Power-management technology has undergone a sea change in the past 10 years. The wave of portable, personalized electronic products that has transformed the consumer market landscape has re-written the rules for power design, integration and efficiency by moving intelligent power management and system knowledge to the forefront of product design.
Contrast today’s power-management environment to the late decades of the last century. The 1980’s and early 1990’s were dominated by NPN linear regulators, which are simple circuits that convert voltage levels and require very little intelligence. Also, because portable electronics were just coming into their own—and because power was cheap and plentiful—linear regulators had little reason to operate at high levels of efficiency.
Fast forward to today and we see that linear regulators have been joined by dozens of different kinds of switching regulators, which have advanced power efficiency from previous levels as low as 10 percent to efficiencies of 80 percent or more. These range from portable devices where the benefit is longer battery life, to high-power systems where energy usage and heating/cooling are becoming a significant cost concern.
Given what is at stake, highly efficiency power management is no longer a stand-alone consideration or something that can be addressed as an afterthought. Whether supporting a point-of-load or AC-DC specification, the benefit of emerging power management technology is not only in its ability to convert different voltage levels but in its ability to be integrated as part of a total system solution.
Because of this, system designers should be asking themselves a series of questions early in the design process in addition to the usual questions about voltage and current requirements.
- What effect will power components have on noise or efficiency levels as they interact with other system ICs?
· How can the application of intelligent power management contribute to overall design innovation?
· How can real-time feedback on the power system improve system performance and value?
In a base-station application, for example, the use of intelligent power to handle AC-DC and isolated DC-DC power conversion can cut system power losses in half. This same intelligence can be used to monitor signal chain requirements and interact with data converters, amplifiers, and other components to provide another 30 percent improvement in overall system efficiency.
Data converters, in particular, often require very low noise and well-regulated power supplies to minimize the overall system waves. System designers can spend months optimizing their data acquisition system for linearity, noise performance, and other issues--only to find that, when they add the power components, they lose much of that performance due to power supply noise, poor transient response.
The replacement of linear regulators with low-noise switching regulators will continue to gain momentum, but this will require suppliers that are adept not only at power management, but who understand the entire signal chain and system-level design considerations.
About the author
is Vice President of Power Management Products and Portable Computing and Handsets for at Analog Devices, Inc. He is responsible for product development and all related marketing of the company’s power management technology, as well as the strategic direction for Portable products. He earned a Bachelor of Arts Degree in Physics from the University of California, Berkeley, as well as completed the Stanford AEA Executive Institute program in 1999. He can be reached via email at email@example.com.