High-performance, energy-efficient IGBTs

Insulated gate bipolar transistors can help electronics designers rise to meet new challenges

BY LUCY A. SNYDER

Gasoline prices show no signs of ending their upward climb, and so shipping costs and all other energy generation costs continue to rise alongside petroleum. At the same time, electricity demand has never been higher. Equally bad, petrochemical prices have inevitably risen, leading to increased component costs for electronics manufacturers. In the face of these high costs and more stringent regulations, engineers are under more pressure than ever before to improve product performance, increase circuit efficiency, reduce product size, and improve the efficiency of manufacturing processes.

MOSFET equivalent circuit of IGBT.

Furthermore, regulatory agencies are increasing minimum energy efficiency requirements for electronic products, and they are putting more pressure on manufacturers to reduce their emissions of greenhouse gases and toxic solid and liquid wastes. Likewise, more and more cost- and environment-conscious consumers are demanding low-consumption devices that contain few hazardous materials.

And there lies the silver lining in this looming cloud of economic doom: electronics designers have many opportunities to create new products to satisfy the increasing demand for “green” products and products based on solar and other alternative energy sources. Experts estimate that the demand for solar inverters is growing by about 30% each year; consumers want less expensive devices, and one important way to reduce product costs is to increase solar inverter efficiencies.Insulated gate bipolar transistors (IGBTs) can help product designers rise to meet the challenges they face in creating better products that offer improved circuit efficiency and performance. Also known as conductivity-modulated field-effect transistors, these devices are cousins to MOSFETs, and they are primarily used for power switching in a variety of applications.

These voltage-controlled devices are widely available on the market, and using the right IGBT in an advanced switching power device instead of a comparable MOSFET may result in improved energy efficiency and lowered product costs.

Several suppliers, many switching applications

For instance, ON Semiconductor offers nearly 20 different models of IGBTs for electronic automobile ignitions, fuel injection systems, and other applications requiring switching high currents and high voltages. The company’s models feature monolithic circuitry with integrated ESD and overvoltage protection.

Infineon offers several high speed IGBTs that are intended for high-frequency power switching applications. The company’s TrenchStop IGBTs offer low saturation voltages, higher temperature stability and low conduction losses and are intended for motor drive applications. Dynamic switching behaviors in these transistors allow for decreased energy losses during turn-off and lowered electromagnetic interference.

STMicroelectronics manufactures strip-based PowerMESH IGBTs that are used in applications such as motor drives, electronic automobile ignitions, light dimmers, high-frequency electronic ballasts, light dimmers, welding equipment, uninterruptible power supplies, and household appliances. These 300 to 1,200-V transistors provide low voltage drops and are intended for more efficient product designs. The company’s “V” series IGBTs are intended for fast, high-frequency applications and are available with and without free-wheeling diodes.

Microsemi offers a dozen models of application-specific IGBTs that operate at 600 and 1,200 V. The company’s IGBTs provide hard switching, and soft switching. These IGBTs are mainly intended for welding equipment, induction heaters, and telecommunications and medical electronics.

Planar IGBT cell configuration.

Their DL series offers ultra-soft recovery diodes that reduce electromagnetic interference, reduce conduction power losses, and reduce or eliminate the need for a snubber. Microsemi’s Power MOS8 IGBTs work in 600- and 900-V devices and offer punch-through technology and fast switching for applications such as industrial equipment, battery chargers, and solar inverters.

Innovative Field Stop Trench Technology

Fairchild Semiconductor has developed various types of IGBT technologies tailored to a wide range of applications. For instance, they offer Field Stop Trench IGBTs that feature the new Field Stop structure and Trench Gate cell design along with high-speed switching and low saturation voltage.

These 600- and 1,200V transistors are targeted at uninterruptible power supplies and solar inverters as well as microwave ovens and induction heating applications. They offer electronics designers reduced conduction losses and switching losses and maximized efficiency. All of Fairchild’s different IGBT technologies have been optimized to reduce drift resistance, and the Trench Gate gets rid of the parasitic JFET resistance of the MOSFET part of the device’s structure.

NPT trench vs. field stop trench.

Compared to conventional NPT-Trench IGBTs, Fair-child’s FGA20N120FTD model provides 25% less conduction power loss and 8% less switching losses. This not only makes the device more energy efficient, it reduces the operating temperature considerably.

Therefore, applications using these IGBTs need less cooling, which further reduces power consumption and increases efficiency and reliability. These transistors also feature zero voltage switching technology and built-in fast-recovery diodes, which also improve product reliability.

Fairchild’s transistors maintain consistent performance and reduced failures in avalanche-mode operation through Fairchild’s Field Stop technology, which provides a tight parameter distribution and increased avalanche energy withstand capability. These devices are designed for long life and are ideal for applications where high performance and low switching and conduction losses are crucial.

In today’s bracing energy market, electronics designers must be concerned with producing power-efficient devices, and choosing the right IGBT for the job is key. No matter what your manufacturing needs are, there’s a transistor on the market to meet them. ■

Visit http://IGBTs.electronicproducts.com to see full coverage of insulated gate bipolar transistors (IGBTs). Fairchild Semiconductor is a global leader delivering energy-efficient power analog and power discrete solutions. The conservation of energy and the development of energy-efficient products is a critical challenge facing the world today. Fairchild plays a pivotal role in answering these design issues that conserve energy with energy-efficient products that address the many critical environmental challenges that face the world today. Fairchild is The Power Franchise, providing leading-edge silicon and packaging technologies, manufacturing strength and system expertise for consumer, communications, industrial, portable, computing and automotive systems. An application-driven, solution-based semiconductor supplier, Fairchild provides online design tools and design centers worldwide as part of its comprehensive Global Power Resource. Please contact us on the web at www.fairchildsemi.com.

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