While there are notable differences between tools on the market, most share the same fundamental architecture and each of the key building blocks rely on MOSFET technology for converting and processing the energy from the battery to do useful work.
To achieve this, modern power MOSFETs need to offer low loss levels in a small convenient package. Some of the more recent MOSFET families specifically aimed at meeting the challenging needs of cordless power tool design are based on Toshiba's trench LV MOSFET process. The company’s U-MOS VIII and UMOS IX MOSFET range incorporates devices with ratings from 30V to 100V and offers some of the lowest RDS(ON) values on the market.
High-performance MOSFETs can extend the operational life of the tool, often significantly. However, there are more benefits associated with low RDS(ON); as the MOSFETs are more efficient, less heat is generated during operation. As a result the tool is cooler to the touch and more pleasant to use. This also means that there is less waste heat to remove, meaning that cooling devices such as heatsinks can be smaller, or often not needed at all, thereby making the tool smaller and lighter.
Toshiba has developed a white paper that discusses cordless power tool design in detail. To download it click here: