SiC power devices on full display at PCIM Europe

By Gina Roos, editor-in-chief

PCIM Europe, an international exhibition and conference for power electronics and its applications, hosted 515 exhibitors, 300 tutorials and workshops, and 107 forum presentations at this week’s show in Germany. More than 12,000 visitors walked the halls to see the latest power electronics on display, including wide-bandgap — gallium-nitride (GaN) and silicon-carbide (SiC) — devices that can deliver better performance than silicon.

While there have been some roadblocks to adoption, chipmakers are moving forward, offering these devices in new package styles and expanding product lines to better meet existing applications. They are also ramping up production to meet expected demand.

Here’s a roundup of some products showcased at this year’s conference:

Adding new package options to SiC product lines to meet existing product needs was one trend seen at the show. Infineon Technologies AG expanded its CoolSiC Schottky 1,200-V G5 diode portfolio  with the release of a TO247-2 package, which can replace silicon diodes for higher efficiency in automotive, solar energy, and industrial applications. The expanded 8.7-mm creepage and clearance distances offer extra safety in high-pollution environments.

Delivering higher efficiency, the CoolSiC Schottky 1,200-V G5 diode with a 10-A rating, as an example, can serve as a drop-in replacement for a 30-A silicon diode. The CoolSiC Schottky diodes in a TO247-2 pin package can be ordered now in five current classes: 10 A, 15 A, 20 A, 30 A, and 40 A.

When used in combination with a silicon IGBT or superjunction MOSFET, the CoolSiC Schottky 1,200-V G5 diode raises efficiency up to 1% compared to using silicon diodes. Infineon cites a Vienna rectifier stage or PFC boost stage used in three-phase conversion systems as an example, wherein the output power of the PFC and DC/DC stages can thus be increased by 40% or more.

Infineon also plans to release a portfolio of CoolSiC MOSFETs in discrete packages. These include a surface-mount device (SMD) portfolio and a 650-V CoolSiC MOSFET product family. Target applications include battery charging infrastructure, energy storage solutions, photovoltaic inverters, uninterruptible power supplies (UPS), motor drives, and server and telecom switched-mode power supplies (SMPS).

UnitedSiC also added new package options to its SiC device family . The company expanded its series of its UJ3C (general-purpose) and UF3C (hard-switched) 650-V SiC FETs with seven new TO220-3L and D2PAK-3L device/package combinations. The new devices are aimed at designers who prefer a three-lead, TO220 or D2PAK package option and want to enhance power performance in power-factor correction (PFC) circuits, LLC resonant converters, and phase-shifted full-bridge converters, said the company.

Target markets for the new UnitedSiC devices include data center servers, 5G base stations, and electric vehicles in power supplies, telecom rectifiers, and on-board chargers, respectively.

These devices can be used as a “drop-in-replacement” for existing Si IGBTs, Si FETs, SiC MOSFETs, or Si superjunction devices. Designers can improve system performance without needing to change the gate drive voltage, said UnitedSiC.

Both series of SiC FETs are based on UnitedSiC’s unique “cascode” circuit configuration, in which a normally on SiC JFET is co-packaged with a Si MOSFET to produce a normally off SiC FET device that has standard gate-drive characteristics. This results in a performance increase with lower conduction and switching losses, enhanced thermal properties, and integrated gate ESD protection in existing designs when using the “drop-in replacement” FETs.

Other new wide-bandgap devices were also demoed at the show. GaN Systems, as an example, demonstrated its new 650-V, 150-A GaN power transistor , claiming the industry’s highest-current 650-V GaN power transistor in the market. The GS-065-150 device delivers 100 times lower switching losses than comparable IGBTs, claiming a 99% reduction in switching losses.

Other products on display included the GS-065 low-current transistor line with EZDrive circuit compatibility. The combination of a smaller design with the EZDrive circuit eliminates the need for a discrete driver, which reduces the bill of materials cost and improves performance, said GaN Systems.

An interesting hybrid SiC and silicon-based device from ON Semiconductor was unveiled at the show. ON Semi showcased its new SiC-based hybrid IGBT  that combines both silicon and SiC-based technology, along with a related isolated high-current IGBT gate driver.

The AFGHL50T65SQDC hybrid IGBT offers low conduction and switching losses in multiple power applications thanks to the latest field-stop IGBT and SiC Schottky diode technology. The device consists of a silicon-based IGBT with a SiC Schottky barrier diode, which addresses the trade-off between the lower performance of silicon-based solutions and higher cost of SiC-based solutions, said ON Semi.

The AEC-Q101−qualified device can operate with junction temperatures as high as 175°C, making it suitable for demanding power applications, including automotive such as on-board electric vehicle (EV) and hybrid EV chargers.

ON Semi also released a range of isolated high-current IGBT drivers at PCIM. ON Semi said that the devices can source 7.8-A drive current and sink 7.1 A, which is more than three times the capability of some competing devices, and they have a greater current capability while operating in the Miller plateau. Target power applications for the NCD(V)57000 series include solar inverters, motor drives, UPS, and automotive applications such as powertrain and PTC heaters.

The high-current single-channel IGBT drivers with internal galvanic safety isolation are designed to provide high efficiency and high reliability. Features include complementary inputs, open drain fault and ready outputs, an active Miller clamp, accurate undervoltage lockout (UVLO), DESAT protection with soft turnoff, negative gate voltage pin, and separate high and low driver outputs for system design flexibility.

SiC capacity ramps up
Several chipmakers, including Cree, Infineon, and Microchip, announced production capacity and volume-production expansions in preparation for increased demand over the next five years.

Cree Inc. announced that it will invest up to $1 billion in the expansion of SiC capacity. The company plans to build a new state-of-the art, automated 200-mm SiC fabrication facility and a materials mega factory at its U.S. headquarters campus in Durham, North Carolina. The project will be completed in 2024.

The expansion is expected to deliver a 30-fold increase in SiC wafer fabrication capacity and a 30-fold increase in SiC materials production to meet expected market growth by 2024. The SiC market is forecast to reach $1.5 billion in 2023, with a compound annual growth rate of 31% between 2017 and 2023, according to Yole Développement (Yole).

Cree’s plan includes additional capacity for its Wolfspeed silicon-carbide business with the buildout of an existing structure, a 253,000 square-foot, 200-mm power and RF wafer fabrication facility. In addition, the new North Fab will be fully automotive-qualified and will provide nearly 18 times more surface area for manufacturing than exists today, initially opening with the production of 150-mm wafers.

Both Infineon and Microchip are ramping up volume production for several of their SiC devices. Infineon announced volume production for its line of 1.200-V CoolSiC MOSFETs  devices. They are rated from 30 mΩ to 350 mΩ and are available in TO247-3 and TO247-4 packages. Engineering samples for most package options will be available in Q4 2019 with the exception of the 1,200-V CoolSiC MOSFETs in the TO247 package, which is available now.

Building up its portfolio of SiC power products, Microchip Technology Inc., via its Microsemi subsidiary, announced the production release of a family of SiC power devices . Offering the inherent advantages of wide-bandgap technology, including ruggedness and performance advantages, the new products include 700-V SiC MOSFETs and 700-V and 1,200-V SiC Schottky barrier diodes (SBDs).

Microchip’s SiC power product portfolio, totaling more than 35 discrete products, consists of SiC die, discretes, and power modules across a range of voltages, current ratings, and package sizes.

Microchip said that its SiC MOSFETs and SBDs offer more efficient switching at higher frequencies and pass ruggedness tests at levels required for long-term reliability. The SiC SBDs perform approximately 20% better than other SiC diodes in unclamped inductive switching (UIS) ruggedness tests that measure how well devices withstand degradation or premature failure under avalanche conditions, which occur when a voltage spike exceeds the device’s breakdown voltage, said Microchip.

The SiC MOSFETs exhibit excellent gate oxide shielding and channel integrity with little lifetime degradation in parameters even after 100,000 cycles of repetitive UIS (RUIS) testing.

More than wide-bandgap
There were more components on display in addition to GaN and SiC devices.  A couple of those products included coreless current sensors that tout performance improvements.

Allegro MicroSystems showcased its coreless current sensor IC  and the first device in its family of QuietMotion brushless DC (BLDC) motor control solutions. The AMT49406 is claimed as the first-to-market field-oriented control (FOC) BLDC electric motor controller that is customer-code−free. An FOC algorithm is fully integrated for the best efficiency and acoustic noise performance. Several other product technologies, including fan and pump motor drivers, power monitoring ICs, and magnetic rotary encoders, were also on display.

All of these products target space savings, efficiency, and safety. But back to the current sensor. The ACS37650 coreless current sensor IC saves space by eliminating the need for a concentrator core in high-current sensing applications, such as electric vehicle traction inverters. Other features include closed-loop sensing with extremely low noise and high resolution and operation over an extended automotive temperature range.

Allegro’s automotive-qualified 1-MHz current sensor ICs also demoed at the show provide faster and higher current-sensing ranges in space-saving packages. Allegro said that these current sensor ICs are more reliable than transformers and help reduce bill of materials. Applications include automotive on-board chargers, industrial power supplies, and intelligent motion applications.

Infineon also announced a new family of current sensors , comprised of precise and stable coreless Hall sensors, that allows designers to program parameters such as current range, overcurrent threshold, and output mode. Unveiled at PCIM Europe 2019, the XENSIV TL1497, the first member of this family, covers measurement ranges from ±25 A to ±120 A and addresses industrial applications like electric drives up to 50 kW and photovoltaic inverters.

The TLI4971 employs temperature and stress compensation to ensure that sensitivity error is as low as 2% at room temperature. Infineon said that the sensitivity error can be reduced below 2% with a single-point in-system calibration.

The current sensor, which has two output pins for fast overcurrent signals, enables designers to program threshold levels of the overcurrent signals and thus adopt them to system requirements without requiring further external components, so signals can be used for pre-warning and system shutdown. The current sensor also provides a signal in case of an over- or undervoltage condition for the supply voltage. Samples will be available in August.