The development of power components and the transformation of power IC technology

In order to prevent global warming, reducing CO2 emissions has become a human issue. In order to reduce CO2 emissions, saving electricity and improving voltage conversion efficiency are urgent. In this context, ROHM contributes to saving electricity through technology used in LED lighting and improving conversion efficiency through power components.

To improve conversion efficiency, it is necessary to reduce losses. Power plants generate hundreds of thousands of volts of voltage, which are reduced to about 5V through wires and transformers, such as the voltage provided by the mobile phone chargers we are familiar with. The voltage is converted many times between the power plant and the charger, and losses occur with each conversion. One of the causes of these losses is the loss of power components. If these losses are reduced to zero, CO2 emissions can be greatly reduced. Although it is not possible to achieve zero completely, in order to get close to zero, ROHM is conducting repeated research and development day and night. ROHM believes that reducing losses and reducing CO2 emissions through these research and development results can increase the value of ROHM's corporate existence.

ROHM's development in the field of power components

When it comes to semiconductors, most people think of large-scale integrated circuits (LSI) that are processed with micro-processing. In order for LSI to work as required, a power supply that supplies electricity at the required voltage and current is indispensable. In this field of "supplying electricity in the required form", semiconductors also play an important role. Starting from the meaning of "processing electricity (power)", its core semiconductor components are called power devices or power semiconductors.

In terms of the application fields of power components, it is roughly divided into the fields of computers (PCs) and PC peripherals, about 30%, digital home appliances and automotive fields, about 15%, and white appliances, industry, and communications fields, about 30%. In the world of power components, it is no exaggeration to say that "there are as many types of power components as there are types of power supplies". In order to meet market demand, it is necessary to continuously improve the product lineup of various application circuits, easy-to-use packages, composite products, rated currents, and rated voltages, requiring diversified technical accumulation.

In the field of power components, ROHM has the industry's top-level product lineup. In addition to Si-based super junction (SJ)-MOSFET Note 1, MOSFET Note 2, bipolar transistor Note 3, Schottky barrier diode (SBD) Note 4, fast recovery diode (FRD) Note 5, diode (Di) Note 6, and Zener diode Note 7, ROHM has added new generation components such as silicon carbide (SiC Note 8) and gallium nitride (GaN Note 9), and is equipped with distinctive power component products in each voltage range.

[Figure 1] Transistor development trends

In particular, SiC has smoothly entered the manufacturing stage from world-class research and development. After achieving mass production of SiC SBD in April 2010, ROHM successfully achieved the world's first mass production of SiC MOSFET in December of the same year. In addition, since components alone cannot fully demonstrate the performance of SiC, ROHM began mass production of module products in 2011 to meet market demand.

※: According to a survey conducted by ROHM (as of November 13, 2012)

Rohm covers the high voltage range with SiC products, and covers the voltage range of several hundred volts with SJ-MOS and MOSFET. In recent years, Rohm has been working hard to expand the product lineup of several hundred volts. Of course, the expansion of traditional low-voltage range products is also being developed at the same time. The new structure MOSFET released in August 2012 is a product with a voltage of 40V and a current of up to 100A. The main factor of loss in this product, Ron, is only 1mΩ.

In addition, in the diode field, ROHM has successfully developed a high-heat-resistant SBD that has been considered to have extremely stringent requirements. This product can be used even in harsh temperature conditions such as in cars with increasingly higher levels of electrification, and can improve fuel efficiency.

In addition, ROHM is continuously improving the voltage resistance of the ICs that drive these power components. In the past, the voltage resistance of ROHM ICs was only tens of volts, but now the voltage resistance has been increased to 600V, which can drive power components with various voltage resistance levels.

For complete products that require insulation, you can use the gate driver with insulation function launched in May 2012. This product integrates three chips into one package, and through insulation, it is possible to separate the power supply and control parts, and the insulation withstand voltage has achieved 2500Vrms. This was successfully developed by ROHM by combining its IC circuit design technology, semiconductor (Wa) manufacturing technology and packaging technology, and has achieved mass production.

In addition, with the high voltage resistance of power components, a new series of resistor products for peripheral use, the high voltage resistance KTR series, has been developed. In the past, the voltage resistance was achieved by connecting low voltage resistance in series at high voltage generating parts (for example, the voltage part of the camera flash, which makes the xenon flash generate hundreds of volts instantly), but the KTR series products have achieved higher voltage resistance performance through structural improvement, and the voltage resistance of one resistor can reach more than 300V. The use of this product can reduce the number of parts in products such as digital cameras.

ROHM not only provides power components but also comprehensive improvement solutions including peripheral components for various withstand voltage levels.