With user demands increasing continuously for better, cheaper, and faster power solutions, power supply designs are expected to get tougher with time. Over and above, environmental initiatives such as lead-free designs are expected to add to this complexity because electrical parameters and performance will remain the same. Efforts are underway worldwide to reduce the lead content in electronic products to reduce their environmental impact when they are discarded. Consequently, tomorrow's power solutions will require advancements on several fronts simultaneously. Based on future requirements, some key areas were identified by Power Supply Manufacturers Association (PSMA) at its workshop in February in Miami, Fla. These included digital control schemes, semiconductors, passive components, magnetics, thermal management, and packaging. In fact, these deductions were the result of data presented by power supply manufacturers and end users at the PSMA workshop.
On the digital front, PSMA expects digital control schemes to play a significant role by 2008 — as the adage goes, better late than never. Power supply designers have begun adopting microprocessors and digital signal processors (DSPs) in various power supply solutions, slowly but steadily. They managed to elude these leading edge devices for a long time, but high complexity and performance goals are forcing them in the right direction. Consequently, in modern power supplies, microprocessors are performing supervisory functions and communications with the host processor, while DSPs are enabling power factor correction (PFC) in power supplies. Generated reference designs demonstrate the use of DSPs in PFC and digital control applications. Some others have generated proprietary digital control schemes to release digitally controlled PWM controllers for multiphase designs.
Digital control techniques are gaining momentum. Only a few years ago, DSP technology was a research curiosity for power supply designers. But, dramatic improvements in processing power at rapidly falling prices have changed that scenario. Algorithms developed at university research centers and DSP houses help to make this technology attractive for myriad power supply solutions.
While multiphase PWM controllers and efficient power MOSFETs continue to drive performance, new semiconductors such as SiC Schottky diodes are promising even higher levels of conversion efficiencies, eventually giving designers a new device to keep raising the performance bar of power conversion circuits. However, semiconductor improvements alone won't get us there. To meet targeted performance improvements of power supplies within the next five years, a concerted effort is necessary to improve capacitors, magnetics, and packaging concurrently.
Packaging has played a key role in enhancing the power density and efficiency of dc-dc and ac-dc converters. This trend will continue as designers look for further improvements through expanded use of integrated passives and multichip modules. As power density soars to new heights, the need to remove heat from power conversion elements will rise accordingly. This will prompt designers to make more use of thermal bus systems, indicates PSMA roadmap.
These developments should squeeze more juice from miniature packages. Then, we come to the question of what will it take to integrate a complete dc-dc converter or voltage regulator on a single chip. Do you see it on your radar screen?