Power semiconductors can be found in electrical and electronic products all around us. They are critical components, functioning like each device's heart by controlling its power supply. Fuji Electric Device Technology (FDT) aims to contribute to energy conservation on a global scale by boosting the efficiency of power semiconductors.
“By raising the efficlency of the power semiconductors that regulate power suppy in electrical devices, we hope to cut the energy consumption of electrical and electronic equipment the world over.”
Power semiconductors: vital, ubiquitous and unseen components
Power semiconductors are all around us in electric and electronic products such as mobile phones, digital cameras, PCs and plasma televisions. If the CPU and memory of a computer can be considered the brain, then power semiconductors function like the heart of the product by controlling the power supply.
"FDT continues to develop technology to raise the efficiency of power semiconductors with the aim of contributing to the improved conservation of energy by electrical and electronic products throughout the world", Eiji Kuroda, General Manager, Information & Power Supplies Group, Semiconductor Business Division, Fuji Electric Device Technology says. The power semiconductors supplied by the Fuji Electric Group are fitted into televisions, PCs, mobile handsets and many other products that are exported around the world.
Technical developments to cut power losses inside semiconductors
Whenever electricity passes through a semiconductor, chip resistance typically results in a loss of transmitted power of 10
15% on average. So, for example, of the power in a 220 watts supply, approximately 20 watts is dissipated due to conversion to heat. Reducing the amount of heat produced, which would cut power losses, holds one of the keys to lowering the power consumption of products that contain semiconductors. The technical history of power semiconductors is one of various improvements introduced to reduce power losses, which ranged as high as 6070% when these products were originally launched. The first series regulator type featured a constant flow of current through the device. The more advanced switching type cut power losses substantially, to around 30%, by switching the power on and off up to 100,000 times per second to reduce waste. Kuroda stresses: "In 2002, FDT introduced the M-Power series of power semiconductors, which significantly cut the losses in power occurring during on-off switching. This reduced overall power losses to approximately 6%."
Technical progress in cutting power losses in power semiconductors
Environmental burden reduction on a chip
Power semiconductors are intimately connected to reducing the environmental burden of products. The first consideration is standby power consumption. If standby power losses could be cut to zero, it has been calculated that the energy saved in Japan alone would be equivalent to the power output of two nuclear power stations. The power semiconductor is the main device controlling standby power. Major improvements have been made in recent years: for instance, standby power consumption for many products has been reduced to less than 100mW, from an average of 34W as recently as 2000.
The technical drive to squeeze multiple components onto a single chip is contributing to smaller and thinner products, in the process saving resources. Traditionally, a power supply circuit contained one chip with a control function, a separate chip to switch the current on and off, plus an inductor for voltage conversions. FDT has successfully integrated these three components into a single-layer chip approximately 3mm square.
Another area where FDT is working to lower the environmental burden of power semiconductors is by reducing the amounts of harmful substances used in production processes. FDT has now switched to lead-free solder for nearly all its products.
The quest to eliminate power losses completely
Successive technical innovations have helped power semiconductors come a long way in efficiency terms from the days when power losses were of the order of 70%. But the limits to further efficiency gains based on conventional approaches are now in view. Solving this problem will either mean switching from silicon-based chips to a different material or entail a radical structural transformation of the semiconductor. FDT is working on the latter approach, and plans to launch a new generation of power semiconductors from around 2009 based on a radically different structural design. "The perfect power semiconductor would produce no heat despite controlling the power input, thereby keeping power losses as close to zero as possible. The quest at FDT is to develop such a product to make a significant contribution to global society on the energy conservation front", Kuroda says.
Further evolution of magnetic disks
Magnetic disks
With the advent of the ubiquitous network society, demand for magnetic disks is expanding beyond computer hard disks to new IT-related applications and broader range of applications are expected. At the same time, attention is focusing on the development of new high-density hard disks for the next generation of drives using perpendicular magnetic recording technology in place of the longitudinal recording methods used to date (since these are now approaching physical limitations).
FDT began developing perpendicular recording technology for high-performance hard disks in 1999. In line with market moves to put these new methods into practical use, in 2005 FDT shipped initial samples of a 2.5-inch 80GB hard disk based on perpendicular magnetic recording technology ahead of competitors. In 2006, FDT invested in a dedicated new production line for 2.5-inch hard disks. Full-scale production of these next-generation disks is currently in planning.
