PCIM 2013 Digest

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GBTs and IGBT drivers

British company Amantys used PCIM to launch its Power Insight technology last year, so it’s no surprise that the company retained a big presence at the show this year. The company’s booth had a live demo of their Power Insight IGBT monitoring software with live data coming from traction converters on board trains in the field in Portugal, thanks to its collaboration with railway maintenance giant EMEF (Figure 1). The software uses existing PWM and fault signals that are used to control the IGBT to monitor the device’s health in real time and sends information to the train management system. Timely decisions can then be made on whether maintenance is required, streamlining maintenance efforts. Amantys is also partnering with various semiconductor manufacturers to incorporate Power Insight into their IGBT modules; Hitachi and Fuji Electric have been signed up so far.

CT-Concept previewed a dual-channel IGBT driver which can handle voltages of up to 4.5kV. The 2SC0635T’s signal isolation is transformer based, making a cost saving when compared to fibre optic equivalents. As with all the latest IGBT drivers from the company, it’s based on their proprietary ASIC which integrates driving, monitoring, status acknowledgement, DC-DC converters and isolation of all signals between the control and power sections.

Also launching at PCIM were a couple of new families of IGBTs; one for consumer appliances like rice cookers and microwave ovens, the other for solar inverters and UPSs. Designed to make these applications more energy efficient, according to manufacturer ON Semiconductor, the new Field Stop II IGBTs improve switching characteristics to reduce losses by up to 30% compared to the previous generation of products. Case temperature has also been reduced by 20%. The consumer products, NGTBxxN120IHRWG and NGTBxxN135IHRW, also have reduced conduction losses for induction heating and soft switching applications operating at frequencies of 15 to 30kHz. The NGTBxxN120FL2WG and NGTBxxN135FL2WG, for industrial use, have an operational junction temperature range of -55 to +175°C and increase in current ratings up to 100A in TO-247 packages.


Figure 1. The Amantys and EMEF teams demonstrated live data from field trials in Portuguese trains at the show

MOSFETs

A newly-invented hybrid MOSFET-IGBT device was unveiled by Rohm at the show, which is designed to combine the best features of both device types into one part. Details of exactly how they have combined the structures of a superjunction MOSFET and an IGBT were a little sketchy, but the company did show off a chart of the expected features of the new devices (Figure 2). The idea is to combine the high switching speed of a superjunction MOSFET with the high voltage/high temperature capability of an IGBT. Samples will arrive this summer.

Toshiba has integrated high speed diodes into its superjunction MOSFET packages. High speed (fast recovery) diodes, essential for protecting the MOSFET in switch mode power supplies, can allow faster switching frequencies if their reverse recovery time, trr, is quick enough (Figure 3). Diodes in the three new devices offer trr of 100ns (TK16A60W5), 135ns (TK31J60W5) and 150ns (TK39J60W5). Additionally, a 30% reduction in RDS(ON)*A (on-resistance x area) is down to Toshiba’s latest DTMOS IV process, which means space could be made in the same TO-220SIS/TO-3P(N) packages to incorporate the diode. DTMOS IV uses only one epitaxial process to build the superjunction structure. The resulting structure gives the MOSFETs better high temperature characteristics too.


Figure 2. Rohm’s Hybrid MOS devices, which combine superjunction MOSFET and IGBT structures, offer the best of both worlds in terms of characteristics

PCIM was also the venue for three MOSFET launches from Taiwanese manufacturer Advanced Power Electronics Corp (APEC). These devices, which are described as competitively priced, feature RDS(ON) as low as 0.19Ω. The AP11S60-HF-3, AP14S50-HF-3 and AP20S60-HF-3 high voltage MOSFETs also offer low gate charge and low conduction and switching losses. They provide a high blocking voltage to withstand voltage surges in demanding power systems, and can be used in PFC correction and PWM stages.

Keeping cool was the name of the game over at International Rectifier’s booth, where the company introduced a new family into its COOLiRFET MOSFET range for automotive applications. Many applications run cooler using these devices than with other high performance MOSFETs, according to the company. In the new series are 22 40V N-channel MOSFETs, featuring IR’s Gen12.7 trench technology. They are AEC-Q101 qualified, which requires that there is no more than a 20% change in RDS(ON) after 1,000 temperature cycles of testing. The benchmark D2Pak-7P AUIRFS8409-7P delivers RDS(ON) max as low as 0.75mΩ at 10VGS with a current rating up to 240A.


Figure 3. Toshiba’s superjunction MOSFETs with integrated high speed diodes have decreased their reverse recovery times to 100ns

Power modules

Power IC supplier Vicor showed off new models in its Picor Cool-Power line, which are intended for 24 and 28V applications, or those with demanding temperature requirements. These DC-DC converter modules are based on the ZVS (zero voltage switching) topology which allows higher frequency switching (900 kHz in this series) at higher input voltages without compromising efficiency. The PI31xx series provides up to 334W/in3 and 2250V input to output isolation in a package smaller than a standard isolated 1/16th brick. Vicor recommends pairing these modules with its QuietPower EMI filters, which at less than 25% of the size of competing offerings, maximises density.

Meanwhile, Infineon chose PCIM to launch three EconoDUAL automotive qualified power modules for commercial, construction or agricultural vehicles which need extended reliability. These modules withstand more than three times better thermal cycling capability and better thermal shock capability by a factor of ten compared to the industry standard. They offer the highest power density available in this footprint; up to 600A/1200V. Copper wire bonding reduces internal lead resistance, while a new soft diode improves the modules’ EMI behaviour.

Mitsubishi’s offering in the automotive power module sector was the J1 series for driving inverters in hybrid and electric vehicles. This series currently comprises two parts; the 650V/600A CT600CJ1A060 and the 900V/400A CT400CJ1A090. Six CSTBT (carrier stored trench-gate bipolar transistor)-type IGBTs are in one package, saving space, and reducing collector-emitter saturation voltage to 1.4/1.7V. The package allows direct cooling via cooling fins, improving heat radiation by 40%, compared to previous products.

Best of the Rest

GaN systems was at the show hoping to prove that gallium nitride is ready for adoption in real applications and is a long way beyond the laboratory stage. GaN offers higher operating temperatures than silicon devices combined with high breakdown strength, so is well suited to power designs. The company has developed a new GaN transistor topology, called ‘Island Technology’, which is set to reduce size and cost of GaN devices by a factor of four.


Figure 4. Intelligent analogue functions are included with Microchip’s PIC16F753 MCU, making it perfect for power supplies and power management circuits in a variety of applications

MCU giant Microchip revealed an 8-bit micro with intelligent analogue and core-independent peripherals that it said would be perfect for power supplies and power management applications (Figure 4). The PIC16F753’s features include a complementary output generator that produces complementary waveforms for inputs such as comparators and PWM peripherals, an op amp with 3MHz of gain bandwidth product, and a 9-bit DAC.

And finally: one of the more interesting new ideas from the show was Cymbet’s solid state battery. These tiny batteries can replace coin cells, but since they’re made using standard silicon processes, are essentially a battery IC with no toxic chemicals. The rechargeable battery die can be packaged with another IC, perhaps as a backup battery for a clock IC, easily. The company announced that these batteries had been proven safe for implantable medical devices at the show.