One of the hot topics at the 21st Annual Applied Power Electronics Conference (APEC) in Dallas, TX was — heat. The need for higher efficiency power and the resulting lower temperatures could finally give power electronics engineers more respect.
Co-sponsored by IEEE's Industrial Applications Society (IAS) and Power Electronics Society (PELS), and Power Sources Manufacturing Association (PSMA), APEC presentations and tradeshow exhibits identified the need for higher efficiency and lower temperatures in computing and consumer electronic products including automobiles. To meet the requirements for energy-efficiency products from programs such as the U.S. Environmental Protection Agency's Energy Star and 80 PLUS, many companies presented, promoted and demonstrated their latest technological offerings. Here is a sample of three of the newest semiconductor products.
Power Factor Correction (PFC) IC Controls Dual-output for Increased Efficiency
Fairchild's FAN7528 operates in the critical conduction mode and integrates a dual-output control function to increase efficiency in universal ac input supplies. The dual-output control automatically senses ac line voltage eliminating an input voltage-sensing circuitry to reduce power loss by 80mW. A patent-pending variable on-time control method significantly cuts total harmonic distortion (THD) to provide even greater efficiency. In switch-mode power supply (SMPS) designs under 250W, such as notebook adaptors, the PFC controller IC reduces standby power as much as 320mW. For more information about Fairchild Semiconductor's FAN7528, go to http://rbi.ims.ca/4922-599.
SmartRectifier IC Improves Efficiency
Using proprietary HVIC technology, International Rectifier's IR1167 SmartRectifier IC, eliminates the current transformer control circuits that waste energy sensing polarity shifts with the accompanying large reversing currents through the synchronous rectification (SR) MOSFETs. The IC uses a new technique for precise, direct sensing of voltage thresholds across the MOSFETs allowing fast, accurate control to minimize power losses. In addition to reducing the SR parts count by 75 percent, the IC can increase overall system efficiency by 1 percent and reduce MOSFET temperature by 10C. For more information about International Rectifier's IR1167, go to http://rbi.ims.ca/4922-600.
Secondary Control ICs Increase Computer Power Supply Efficiency
Philips Electronics GreenChip SR products, the TEA1761 and TEA1762, are secondary control ICs that integrate both synchronous rectification (SR) and primary feedback/control in a single unit. Designed for Philips' silicon on insulator (SOI) process, which accommodates a wide voltage range, the TEA1762 includes additional protection circuitry that requires an SO14 package and the lower cost TEA1761 comes in a SO8 package. When used as the secondary control IC for notebook adapters, the GreenChip SR improves the efficiency of laptop computer adapters by three to five percent. For more information about Philip's Semiconductor's TEA1761, go to http:// rbi.ims.ca/4922-601.