Superiority of the IGBT Compared to the MOSFET

The IGBT has certain advantages over the MOSFET at higher switching frequencies. However, at lower switching frequencies, the MOSFET typically exhibits lower total losses and a lower operating junction temperature. In this comparison, the selected IGBT and MOSFET devices have approximately the same die size and thermal impedance. This result may appear to contradict conventional wisdom, which often suggests that MOSFETs perform better at higher switching frequencies.

The observed performance advantage of the IGBT at higher frequencies can be attributed mainly to the significantly lower diode recovery loss component of the IGBT combined with a fast recovery diode (FRD). In addition, modern IGBT technology has achieved substantial improvements in minimizing tail current behavior. The reduced switching losses of the IGBT plus FRD, resulting from lower diode recovery losses, give the IGBT an advantage over the MOSFET at 20 kHz, which is considered a relatively high switching frequency for this type of application.

MOSFET switching losses, however, can be significantly reduced by using a gate driver with higher source and sink current capability, such as a driver with 2 A source and sink current. With improved gate drive performance, the total losses of the MOSFET can be reduced, allowing it to narrow the performance gap with the IGBT. The resulting higher dv/dt, however, may introduce undesirable effects such as high-frequency audible noise and increased levels of radiated electromagnetic interference (EMI).

At lower switching frequencies, where conduction losses dominate, the MOSFET benefits from the absence of a knee voltage in its forward conduction characteristics, along with its relatively low on-state resistance RDS(on). In this operating region, MOSFETs can achieve lower conduction losses compared to IGBTs.

While the IGBT remains the preferred device choice for this particular application example, the availability of MOSFETs with significantly lower RDS(on), improved diode recovery behavior, and stronger gate drive capability may begin to shift the balance in favor of the MOSFET. In such cases, the final decision often becomes a cost-to-performance comparison, commonly expressed as cost per ampere. In this regard, the IGBT typically maintains an advantage due to its much higher current density for a given die size.

Both IGBTs and MOSFETs are often available as viable options for a given application. It is therefore important to clearly understand the advantages and limitations of each device and to select the one that best meets the application requirements in terms of overall performance and cost. Although this is not always a simple task, greater familiarity with power semiconductor devices can greatly assist designers in navigating these complex design decisions.

Application Perspective

Given the wide availability of high-voltage power IGBTs and MOSFETs with breakdown voltage ratings ranging from 500V to 800V, designers are often faced with the challenge of selecting the most suitable device for a specific application and set of operating conditions. Choosing between an IGBT and a MOSFET requires careful consideration of performance, efficiency, switching behavior, and overall system requirements.

In the case of three-phase variable-speed motor drives with rated power levels between 300W and 5kW, using a DC bus voltage in the range of 300V to 400V and typically implemented with a six-switch topology, 600V to 650V IGBTs have traditionally been the preferred choice from an overall performance perspective. These IGBTs are commonly co-packaged with anti-parallel fast recovery diodes, providing robust switching performance and reliable operation in motor drive applications.

However, the availability of high-speed power MOSFETs with voltage ratings between 500V and 650V, low on-state resistance RDS(on), and relatively fast body diode recovery characteristics has raised an important question. With these improvements in MOSFET technology, designers are increasingly considering whether it is time for MOSFETs to replace IGBTs in certain power ranges and applications.

This shift depends on factors such as switching frequency requirements, efficiency targets, thermal performance, and cost considerations. As MOSFET technology continues to advance, the boundary between traditional IGBT and MOSFET application domains is becoming less defined, prompting designers to carefully re-evaluate device selection for modern power electronics systems.

Overload and Short Circuit in IGBTs and MOSFETs

Although the most modern generations of IGBTs and MOSFETs have improved tolerance and a very low probability of shutdown failures, it is still important to understand the conditions that should be avoided. Recognizing these issues early can significantly extend the lifespan of power semiconductors such as IGBTs and MOSFETs. It also helps engineers determine when these devices should be replaced once they reach their operational limits.

Essentially, the switching and turn-on behavior of IGBTs and MOSFETs under overload conditions does not differ greatly from their standard operation under nominal conditions. However, to prevent exceeding the maximum junction temperature and to ensure safe operation, the overload range must be limited. Excessive load current can increase power dissipation inside the device and may eventually lead to damage or destruction of components such as diodes due to dynamic failure mode effects.

In terms of short circuit conditions, both IGBTs and MOSFETs are generally designed with short-circuit capability. This means they can withstand short circuits under specific conditions and can be actively turned off without damaging the power semiconductor devices. Proper protection circuits and system design are still essential to prevent long-term damage and maintain reliable operation in power electronics systems.

Hi-Rel 1.2kV SiC Module Announced by Wolfspeed

 Wolfspeed has expanded the use of silicon carbide technology for outdoor systems in transportation and renewable energy applications with the introduction of a new high-reliability 1.2kV SiC power module. Announced at PCIM 2017, this industry-first module successfully passes stringent environmental qualification tests for simultaneous high humidity, high temperature, and high voltage operation.

This new reliability benchmark enables system designers to confidently deploy SiC power modules in outdoor applications such as transportation, wind energy, solar power, and other renewable energy systems. These environments have traditionally posed challenges for safe and stable device operation due to extreme conditions. Passing these tests demonstrates the robustness and maturity of silicon carbide technology for demanding real-world applications.

The all-SiC power module is rated at 300A with a blocking voltage of 1.2kV. It was tested under severe environmental conditions, including 85 percent relative humidity and an ambient temperature of 85 degrees Celsius, while biased at 80 percent of its rated voltage, equivalent to 960V. Successful operation under these conditions provides strong confidence in the long-term reliability and durability of SiC power devices.

Performance under biased stress testing further validates the overall robustness of silicon carbide technology across a wide range of applications. This achievement highlights the suitability of SiC power modules for next-generation power conversion systems that must operate efficiently and reliably in harsh environments.

According to Alstom, silicon carbide components enable the design of compact, lightweight, and low-loss power converters required for railway transportation applications. Achieving the benchmark for high temperature and high humidity operation under high bias voltage represents a critical milestone in the adoption of SiC devices for demanding transportation markets.

The module is powered by new Wolfspeed silicon carbide MOSFETs, part number CPM2-1200-0025A, along with Gen5 Schottky diodes. Both components have passed the same harsh environmental qualification tests at the die level. The module delivers a low on-resistance of just 4.2 milliohms and achieves more than five times lower switching losses compared to similarly rated, latest-generation IGBT modules.

Advanced module construction techniques are employed, including high thermal conductivity aluminum nitride substrates and optimized assembly methods. These design features ensure compliance with industry requirements for thermal cycling and power cycling while supporting high efficiency and high power density operation.

Wolfspeed stated that this 1200V SiC module reflects its commitment to enabling future power electronics markets by meeting anticipated system requirements for 2020 and beyond. The module is available under part number WAS300M12BM2 and can be driven using existing Wolfspeed gate drivers designed for 62mm power modules.

IGBT Modules Segmentation and Market Growth Factors

The global power electronics market is currently undergoing an inevitable modernization. This transformation includes IGBT modules, which are increasingly replacing outdated and legacy equipment. Driven by rapid technological advancement and the simplicity and efficiency of IGBT technology, these devices are becoming a preferred solution in modern power systems. This article discusses the growth drivers and market segmentation of IGBT modules and thyristors.

Due to continuous technological development and the introduction of smart grids in the energy sector, the global market for IGBTs and thyristors is expected to grow significantly in the near future. Population growth and the rising demand for large scale and reliable energy sources are also expected to accelerate market expansion.

IGBTs and thyristors are widely used as power supplies, controllers, and inverters in power electronics applications to meet the increasing demand for solid state switching devices. The growing number of households, along with expanding industrial and energy infrastructure, is expected to further drive market demand in the coming years.

Both IGBTs and thyristors offer several advantages, including reduced switching times and minimal switching losses. These characteristics make them well suited to support future electricity demand while improving overall energy efficiency in modern power systems.

The global IGBT and thyristor market can be segmented based on application areas such as Flexible AC Transmission Systems FACTS and High Voltage Direct Current HVDC systems. Among these, FACTS applications currently hold a leading position due to their role in congestion management, voltage stabilization, frequency stabilization, power flow control, and overall grid stability.

Other application areas include electric and hybrid vehicles EV and HEV, renewable energy systems, liquid level regulation, transportation systems, lighting control, pressure control, motor drives, and various industrial automation applications. This wide range of use cases highlights the growing importance of IGBT modules in energy infrastructure and industrial control.

Power Management Applications Get Latest 1700V and 2500V XPT™ IGBTs Launched by IXYS

IXYS Corporation a leading manufacturer of power semiconductors and integrated circuits for power management energy efficiency and motor control applications has announced the launch of its latest 1700V and 2500V XPT™ IGBTs. These high voltage IGBTs are designed for advanced power management applications that demand high efficiency fast switching and reliable high power performance.

The newly released XPT™ IGBTs offer collector current ratings ranging from 26A to 178A. This wide range makes them ideal for high voltage power management high speed power conversion and industrial power electronics applications. Selected devices are also available with co packed anti parallel fast recovery diodes enabling compact and efficient IGBT power module designs.

IXYS Corporation has a long standing reputation for delivering advanced IGBT technology and innovative power semiconductor solutions. The company was among the pioneers in developing high voltage IGBTs for power management systems particularly in transportation medical equipment and manufacturing applications where efficiency and reliability are critical.

The new 1700V and 2500V XPT™ IGBTs are designed using the patented IXYS Extreme Light Punch Through XPT™ technology combined with advanced IGBT fabrication processes. This results in reduced thermal resistance minimal tail current low switching losses low conduction losses and fast switching performance all of which contribute to higher system efficiency and improved thermal management.

A key advantage of these high voltage XPT™ IGBTs is the positive temperature coefficient of the on state voltage. This feature allows safe parallel operation of IGBT devices. As a result system designers can implement cost effective high power solutions compared to series connected lower voltage IGBTs while reducing gate drive circuitry simplifying system design and improving overall reliability.

The optional co packed fast recovery diodes are optimized for low reverse recovery time and smooth switching waveforms. These characteristics significantly reduce electromagnetic interference EMI making the devices suitable for high frequency and high voltage switching applications.

A wide range of high voltage and high speed power management applications can benefit from these new XPT™ IGBTs. Typical uses include high voltage converters and inverters power pulse circuits laser and X ray generators high voltage power supplies high voltage test equipment capacitor discharge circuits medical switching systems high voltage circuit protection and high voltage AC switches.

The XPT™ IGBTs are available in several international standard power semiconductor packages including SOT 227 TO 247 PLUS247 ISOPLUS i5 Pak™ TO 247HV TO 247PLUS HV and TO 268HV. The latter three packages feature increased creepage distances between leads providing enhanced insulation and robustness against high voltage stress.

Example part numbers from the new XPT™ IGBT family include IXYH24N170C IXYN30N170CV1 IXYH30N170C and IXYH25N250CHV. These devices offer collector current ratings of 58A 88A 108A and 95A respectively and provide flexible reliable solutions for modern high voltage power management and industrial power electronics systems.

Basic and Physical Differences Between IGBT and MOSFET

After evolving side by side over the last three decades, Insulated Gate Bipolar Transistors (IGBTs) and Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) now dominate the power semiconductor market. They are widely used in applications such as motor drives, uninterruptible power supplies (UPS), and solar inverters. A common design question is therefore where IGBTs provide the best fit and when it makes more sense to choose a MOSFET.

The IGBT is a power semiconductor device that combines the output characteristics of a bipolar junction transistor with the gate drive characteristics of a MOSFET. As a result, the IGBT is a minority carrier device with high input impedance and high current carrying capability. This allows it to handle high power levels efficiently while maintaining relatively simple gate drive requirements.

MOSFETs, on the other hand, are majority carrier devices. They offer very fast switching speeds and low switching losses, especially in low to medium voltage applications. However, as voltage ratings increase, the on state resistance of a MOSFET rises significantly. This increase limits efficiency and current handling capability at higher voltages.

Compared to MOSFETs, IGBTs are better suited for applications that require high current operation at higher voltage levels. Their bipolar conduction mechanism enables lower conduction losses at high voltages, making them more scalable for medium and high voltage power applications. This characteristic makes IGBTs a preferred choice in industrial motor drives, traction systems, renewable energy inverters, and high power UPS systems.

From a physical structure perspective, an IGBT integrates a MOSFET input stage with a bipolar output stage. This hybrid structure allows voltage controlled gate operation combined with high current density conduction. MOSFETs rely entirely on the electric field effect and therefore require larger die areas to support high current at elevated voltage levels.

In practical design terms, MOSFETs are generally preferred for low voltage applications, typically below 600V, where high switching frequency and efficiency are critical. IGBTs are typically chosen for applications above this voltage range, where high power density, robustness, and current capability are more important than extremely fast switching speed.