How are power semiconductors evolving?

Editor's Note: In this feature, Andreas Glaser talks about how power devices have evolved along with other technologies in the semiconductor industry. These tools are now faster and smarter than ever before.

In these times of smartphones and iPads, Industry 4.0, and the Internet of Things, you would think the "heavyweights" of the semiconductor industry would be taking something of a backstage position. But appearances are deceiving – power supplies are more intelligent, more digital, more independent from networks, more localised and more efficient than ever before.

Power management ICs, switched controllers and metal-oxide-semiconductor field-effect transistors (MOSFETs) are core components of such systems. Growth markets and applications such as wireless charging, energy harvesting and digital power also require new technologies and new processes from the field of power electronics.

The fight is on for every last modicum of efficiency. Most innovations are achieved along three main lines:

1. Reductions in static and dynamic power dissipation enable the development of smaller constructions with the same power, significantly lower heat generation in applications and also higher efficiency of the overall system, which in respect of various standards (e.g. 80+ certificate) is becoming ever more important for product development.
2. The optimisation of thermal properties increases the service life of the components and the system.
3. The increased integration of construction elements ensures for example more compact construction, easier processing and simplified procurement of materials.

IGBTs

Bipolar switches, with their popular representatives, the discrete insulated-gate bipolar transistors (IGBTs) and IGBT modules, are currently seeing considerable growth in their use thanks to the greater integration of components and higher switching frequencies. The applications range from traditional motor control mechanisms to solar inverters to switched-mode PSUs. Modular solutions enable the creation of reliable, efficient and compact system solutions.

MOSFETs

Modern unipolar switches, the most prominent of them being the metal oxide semiconductor field-effect transistor, fulfil the need for miniaturisation and reduction in power dissipation with their lower internal resistance (Rd(son)) and lower parasitic capacitance. However, they present developers with new challenges, because such measures not only result in reduced losses but also higher switching frequencies.

The miniaturisation of the housing also contributes towards achieving faster switching speeds thanks to smaller chip surfaces. Controlling these fast-switching MOSFETs and thereby ensuring EMC (electromagnetic compatibility) is a key task in systems development. Such a problem can often be solved with the correct actuation of the MOSFET and with an optimised circuit/PCB layout. Fewer conductive tracks and intelligently arranged system components can reduce inductive leakage considerably. Perfectly coordinating or adapting the upstream MOSFET driver is one of the most critical aspects of circuit development.

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