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 localized, and more efficient then ever before. Power management ICs, switched controllers and metal–oxide–semiconductor field-effect transistors (MOSFETs) 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:
- 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.
- The optimization of thermal properties increases the service life of the components and the system.
- The increased integration of construction elements ensures for example more compact construction, easier processing, and simplified procurement of materials.
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.
Modern unipolar switches, the most prominent of them being the metal oxide semiconductor field-effect transistor, fulfill the need for miniaturization 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 miniaturization 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 optimized 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.
AECQ-100-certified components with an expanded temperature range of up to 125 °C are increasingly in demand for automotive applications. In extreme environmental conditions, such as those under the hood of a car, components may even need to withstand temperatures up to 200 °C. Manufacturers here are called upon to meet these more stringent customer needs with innovative bonding solutions. Conventional processing methods here reach limits that prevent functional safety and robustness from being guaranteed.
Wide Band Gap Switches
Wide band gap components with silicon carbide (SiC) and gallium nitride (GaN) switches and J-FETs stand out with their high performance in terms of power dissipation and with their excellent thermal properties. They achieve low power dissipation levels while maintaining high switching frequencies and high cut-off voltages, which is of particular interest in energy-efficient systems such as UPS, solar, photovoltaic and e-mobility applications. In order to assess whether the higher costs involved in such technology or components are financially worthwhile, the system costs must be taken into consideration, because these generate savings elsewhere. For example, where significantly smaller passive components are adequate, solenoids and filters can also be smaller. Heatsinks – a cost factor in their own right – can also be significantly reduced in terms of construction and size, or may even be rendered fully unnecessary.
These innovations will contribute towards developing more efficient, more convenient, more powerful, and more compact end devices. They enable power supply adapters to be installed directly into the device (laptop), and also allow sensors, small motors and devices connected to the internet of things to be self-sufficiently supplied with power. Even the wireless transfer of power is possible with higher power densities. Technologies such as silicon carbide (SiC) and gallium nitride (GaN), which are in a nascent phase of their product lifecycle, serve as an extra boost for this development. As these technologies continue to mature, they will also continue to conquer new markets and applications. Still, they won't completely replace the technologically mature, highly reliable silicon components, as these offer major benefits in terms of horizontal integration, robustness, and cost.