Adapters and battery chargers are designed to provide power solutions for portable and desktop applications, ranging from cell phones and set-top boxes to notebook computers and flatbed scanners. The North America external ac-dc power supply market is expected to grow to nearly $1 billion in 2003. Due to the proliferation of cell phones, PDAs and Wi-Fi-enabled notebook computers, this market is likely to experience faster, rather than slower, growth in the next few years. Following the trend in the electronics devices they power, adapters and battery chargers are becoming increasingly smaller, lighter, more efficient, and more functional thanks to the latest development in the semiconductor industry and the use of high performance power ICs.
Infineon Technologies' (www.infineon.com) new 500V CoolMOS power MOSFETs are high-voltage, switch-mode power supply power ICs, which allow the development of cost-effective and highly efficient power supplies. They are designed for use in a number of types of electronic equipment, including adapters for notebook computers and LCD displays. The area-specific resistance of these MOSFETs is smaller than that of conventional MOSFETs, which reduces power losses while increasing the efficiency of the application. In a 120W adapter for notebook computers, for example, the power losses of a standard 500V power MOSFET are 5.4W. With the new 500V CoolMOS, the overall power losses of the MOSFET can be reduced by 45% to 3W. As a result, the efficiency of the notebook adapter is improved by 2% from 90 to 92%.
Artesyn's (www.artesyn.com) SSL40C Series is a universal input, ac-dc external power supply in a 4.6532.40 31.08in plastic enclosure. It provides up to 40W of power under natural convection cooling and is suitable for a host of applications, such as digital cameras, cordless phones, modems, and hand-held PCs. Standard features include universal ac input, over-voltage and short-circuit protection, and compliance with EN55022 level B for conducted emissions. Output voltages range from 12 to 48V. The SSL40C has full international safety approvals to provide safety extra-low-voltage output.
In response to the sharp increase for on-the-go, portable power, Ault Inc. (www.aultinc.com) has launched its Transport 75 (TR75) mobile power adapter. The TR75 can power more than 200 laptop computer models in vehicles with 12Vdc output, and has short-circuit, under-voltage and over-voltage protection. It comes in several models, with output voltages ranging from 15.7 to 24.1Vdc, and a maximum output power of 75W.
While Ault's TR75 is targeting the laptop market, Phihong's (www.phihong.com) compact folding-prong adapter finds its niche in powering PDAs, cell phones, digital cameras, and MP3 players. Phihong offers several custom models ranging from 3 to 10W. The input range on all of these models is 90 to 365Vac. The new ultra-small adapter features increased energy efficiency and low costs.
Battery chargers are external ac-dc power supplies with battery recharging capabilities. The evolution of battery chargers reflects the advances in battery technology. For many years, nickel-cadmium (NiCd) batteries have been the standard for portable electronic equipment. The combined effects of environmental problems and increased demand for power have led to the development of new battery technologies, such as nickel-metal hydride (NiMH) and lithium-ion (Li-Ion)/lithium-polymer (Li-P). These new battery tech-nologies require more sophisticated charging and protection circuitry. To a large extent, the reliability and longevity of a rechargeable battery hinges upon the quality of the charger. At the heart of a quality charger is the battery charger IC.
Intersil's (www.intersil.com) ISL6292 IC is claimed to be the industry's smallest and most advanced Li-Ion/Li-P battery charger IC. Designed for a wide range of hand-held device applications, this charger IC saves valuable space in its near-chip-scale, 333mm, dual flat no-lead package while offering high thermal efficiency along with full voltage protection, current protection and Intersil's Thermaguard temperature-controlled, charge-rate protection. The ISL6292 accepts a wide range of voltage sources, including voltage and current limited wall-plug modules and USB bus power. It operates as a linear charger when the ac adapter is a voltage source by charging the cell in a constant- current and then constant-voltage profile. The constant voltage is either 4.1 or 4.2V with 1% accuracy. Charge current is resistor-programmable. The advanced IC is equipped with Intersil's AnyAdapter technology, which enables up to 750% less thermal generation than competing solutions, thus allowing a significant reduction in charge time for similar operating conditions.
Linear Technology's (www.linear.com) LTC1980 is a switching regulator battery charger that combines both battery charging and system power supply functions in a small, 24-lead SSOP. The LTC1980 operates from a regulated or unregulated input-supply voltage, which can be above or below the battery voltage by automatically performing step-up or step-down dc-dc conversion. The LTC1980 is not only a stand-alone, single-cell and dual-cell, Li-Ion battery charger, but it also charges NiCd, NiMH and lead-acid batteries. The device is suitable for industrial hand-held PCs, memory backup boards, RAID systems, servers, uninterrupted power supplies and medical equipment.
The multi-unit battery charger jointly developed by GMP Companies (www.gmp-companies. com) and Motorola Energy Systems Group (www.motorola.com/ies/ESG) aims to provide energy management for their new LifeSync wireless electro-cardiogram system in the hospital critical care unit environment, where desktop space is scarce.
The eight-pocket charger is about the size of a toaster and has a concise and intuitive interface that displays
each battery's fuel gauge information. The charger regularly calibrates each battery's fuel gauge to ensure accuracy. During the calibration cycle, a battery is discharged and the fuel gauge's drift is corrected. Heat generated during the discharge process is removed from the unit via induced natural convection to ensure the battery pockets remain cool. This unique product architecture eliminates the need for a fan to provide forced-air cooling and reduces the cost.
Potrans' (www.potrans.com) 5W universal charger, on the other hand, works with such applications as mobile phones, MP3 players, and other smaller electronic devices. Measuring 2.2831.2631.14in and weighing less than 2.7oz, the charger is only one-third the size of a credit card. It comes with over-current, over-voltage, over-load and short-circuit protection. The power consumption is less than 0.3W at any input condition under the no-load, standby stage. The leakage current is less than 0.15mA at an input voltage of 250Vac, 60Hz. The product meets many industry safety standards and has two available voltages of 5 and 6V.
