It's pretty safe to say that the mobile telephone is now the most pervasive computing platform in the world. And frankly, it's hardly fair to descriptively limit today's wireless devices by calling them "phones." Evolutions in technology density and access bandwidth have conspired to deliver feature-happy mobile applications like gaming, multimedia content delivery (video!), DVB-H, MP3 audio, photography, text messaging, web surfing, and blogging. With consumers and mobile workers clamoring to commandeer new functionality in a 24/7 fixed-mobile convergence world, the mobile devices that stay powered up the longest are the ones destined to make the most money for service providers and content producers.
But mobile device developers are handcuffed by the size/power constraints of industrial-design esthetics and implausibly long expectations for battery life. Power issues only intensify as increasingly complex RF modulation schemes, high-speed data protocols, finer-line semiconductor geometries, and decreasing core voltages drive a need for better power efficiencies in wireless connected devices.
Lightweight, easy to use and relatively cheap, the LDO has been the longstanding choice for regulating battery power, particularly below 150 mA of load current. But the energy wasted by linear conversion has crossed a threshold of intolerability, causing developers to turn to efficient switch-mode power converters that use non-resistive (ideally) dynamic energy storage and transfer to decrease wasted power. Hitherto more complex, switch-mode converters with integrated inductors offer the electrical performance of a high-efficiency switching DC-DC converter with the size, simplicity, and low part-count normally associated with a linear regulator. As a result, the technical risk associated with switching (pun intended) to a more efficient solution has become negligible.
As engineers, we are the stewards of energy in every item we design. Economics and eco-ethics make us responsible for seeking out the most energy efficient power conversion techniques possible, and today's innovative advances in power management should compel us all to replace linear regulators with switch-mode converters.
Paul Greenland is Vice President of Marketing at Enpirion. firstname.lastname@example.org