The Expanding Footprint of Power Conversion


Christopher Rexer, Senior Director, Power MOSFETs at ON Semiconductor

Christopher Rexer

Power conversion solutions continue to expand throughout our personal lives.  As a result, the professional challenges and opportunities for power engineering experts continue to grow.  From the time we wake each day, we connect to the world, monitor our health, commute to our jobs, prepare meals, relax and entertain.  To support the advances in these products, power device engineers continue the unending pursuit of power switch technology improvements.   

Power systems experts continually work with a passion to break barriers which were inconceivable even a decade ago.  They continually drive to develop new techniques to solve these problems such as increasing converter frequency to improve efficiency and reduce component and board size, while providing solutions in an environment for consistency of product delivery.  The technical approaches are enabled by continuous advancements in the power switch and packaging technologies.  Modern power MOSFET technologies from 25 Volts to nearly 1000 Volts use charge balance techniques to reduce conduction losses and provide improved switching characteristics.  Advanced construction techniques propel IGBT performance improvements enabling both reduced Vce(sat) and improved switching performance.  Packaging advancements such chip scale packaging, package miniaturization, elimination of wirebonds, use of high temperature capable materials, creative die placement and effective manufacturing techniques enable the full benefit of the advanced chip design to be achieved.   Opening a new door to advance the industry for the highest power density solutions are Gallium Nitride (GaN) power switches.

Our lives have become tied to connectivity.  Over the last decade, the reliance of communication in all aspects of our lives is largely defined by our portable devices.  This is now expanding even further with recent offerings of wearable devices.  The expansion of portable applications requires us to charge batteries efficiently, to control the battery safely, and to have the highest efficiency solution for extended battery life.  Miniature MOSFETs for battery control and load control applications are fundamental to these devices.  ON Semiconductor delivers these solutions including chip scale MOSFETs as well as the smallest packaged MOSFET available in the market:  NTNS3193NZ at only 0.6x0.6x0.4mm.

To keep our connectivity portable, adaptors are used to charge the batteries.  This conversion from an AC power to the DC battery voltage often requires us to carry this adaptor with us.  The ability to shrink this adaptor to a smaller form factor and to decrease the weight can be achieved with new power switches built using GaN.  The fundamental attributes of switches built using this new material enable low conduction losses and very high switching speeds.  As a result, power system designers are able to increase the switching frequency of the converter, thereby reducing the size of the passive components enabling the small, lightweight adaptor.  GaN switches also enable highly efficient power conversion in higher power applications such as photovoltaic microinverters and high power conversion solutions.  ON Semiconductor has worked collaboratively with Transphorm to offer co-branded GaN products.  The first of these are 600V switches in the TO-220 package such as the NTP8G206N, with a 150milliohm typical Rds(on).

The wide use of portable devices drives a huge amount of data transfer and storage. Server clusters, supporting the vast amount of data, provide several hundreds of exabytes of storage worldwide, with estimates of this amount doubling every two years. The efficiency of a server cluster is impacted by the computation performance as well as the power conversion systems. The telecommunication and networking industry requires highly efficient power conversion delivered reliably.   Since power conversion efficiency is highly regarded, power MOSFETs with low losses are a building block for these systems.  Products in the ON Semiconductor Trench 6 and Trench 8 technologies meet this challenge and are available in 25 Volt to 100 Volt offerings such as the NTMFS5C604NL.

In our lives, many of us use the automobile as the means of commuting. The electronic content of automobiles continues its expansion as new applications are being developed to reduce emissions, improve fuel economy, and advance active safety and convenience solutions.  Electric vehicles and hybrid electric vehicles have changed the industry, providing additional options to the consumer for means of propulsion.  Power devices such as IGBTs and wide bandgap switches are a fundamental enabler for these vehicles.   Across all automobiles, the quantity of brushless DC (BLDC) motors is projected to double over the next 5 years.  These motors are used in features such as electronic power steering, compressors and start-stop systems, and additional applications for motors are being developed.  Advanced power MOSFETs in thermally advanced packages enable the widespread use of these motors.  An example is the NVMFS5C404N, a 40V MOSFET in the 5x6mm package with a maximum Rds(on) of only 0.7milliohms.

The wide range of power conversion solutions are readily supported using ON Semiconductor advanced power MOSFETs, IGBTs and GaN switches for these applications.  Our engineers will join those from around the world to continue to the pursuit of new products to enable highly efficient power solutions.

Source: Bodo's Power Systems, July 2015