IGBTs Improve to Satisfy Diverse Applications

Mar 1, 2008 12:00 PM
David Morrison ,, Editor in Chief

IGBT product developments appear to have accelerated lately with the introduction of several discrete devices and modules aimed at a variety of growing applications. Uninterruptible power systems and inverters for solar energy systems are among the applications driving recent IGBT development of late. But applications such as industrial welders, switch-mode power supplies (SMPS) and motor drives are also being targeted.

The new devices feature improvements in silicon and packaging that enable operation at higher switching frequencies, lower losses and better thermal management.

Earlier this month, Vishay introduced a series of half-bridge IGBT modules in the industry-standard Int-A-Pak package. The series consists of eight 600-V and 1200-V devices for high, hard-switching operating frequencies in standard and ultrafast speeds (Fig. 1).

The GA100TS60SFPbF and GA200HS60S1PbF offer standard punch-through (PT) IGBT technology, while the GA200TS60UPbF, GA75TS120UPbF and GA100TS120UPbF devices use Generation 4 technology for tighter parameter distribution and high efficiency. The GB100TS60NPbF, GB150TS60NPbF and GB200TS60NPbF modules offer Generation 5 nonpunch-through (NPT) technology for the added benefit of 10-ìs short-circuit capabilities.

The GA100TS60SFPbF and GA200HS60S1PbF are standard-speed devices optimized for hard-switching operating frequencies up to 1 kHz. The other six IGBTs are ultrafast modules copackaged with HEXFRED ultrasoft-recovery anti-parallel diodes for use in bridge configurations. The ultrafast devices are designed for operation from 8 kHz to 60 kHz in hard switching and > 200 kHz in resonant mode.

Current ratings range from 75 A to 200 A with low power losses, Vishay's new IGBT series is optimized for isolated and nonisolated converters, switches, inverters and choppers in high-frequency industrial-welding, UPS, SMPS, solar-inverter and motor-drive applications. For output inverter TIG welder applications, the IGBTs offer the lowest V_CEON at rated current available in the market for “S” series modules, according to the vendor (Table 1).

Samples and production quantities of the IGBT modules are available now. Pricing ranges from $42 to $72.71 depending on the model ordered.

Last month, International Rectifier introduced a family of 600-V IGBTs that it says can reduce power dissipation by up to 30% in UPS and solar-inverter applications up to 3 kW when compared with previous-generation IGBTs. These application-specific devices use IR's latest-generation field-stop trench technology to reduce conduction and switching losses, and are optimized for switching at 20 kHz with low short-circuit requirements. This combination enables higher-efficiency power conversion in UPS and solar-inverter applications (Fig. 2).

“Traditionally, IGBT devices have excessive switching losses at the frequencies used in UPS and solar inverters. IR's new Trench IGBT devices have lower switching energy coupled with low conduction losses. These lower losses provide higher efficiency, reducing the size of the unit and the cost of power generation to the end user,” says Carl Blake, IR's product marketing director, Energy Saving Products.

Copackaged with ultrafast soft recovery diodes, the new family of IGBTs has lower collector-to-emitter saturation voltage (V_CEON) and total switching energy (E_RS) than PT- and NPT-type IGBTs (Table 2). These IGBTs also feature a square reverse bias operating area and are 100% tested for clamped inductve load. The latter feature, which is akin to avalanche testing, is a first in the industry according to Blake.

Pricing for the devices begins at $0.68 for the IRGB4059DPbF, $0.82 for the IRGB4045DPbF, $0.84 for the IRGB4060DPbF, $1 for the IRGB4064DPbF and $2.79 for the IRGP4063DPbF, each in 10,000-unit quantities.

Another IGBT family introduced last month is the NX-Series from Powerex (Fig. 3). IGBTs in this series feature an industry-standard footprint and pinout, but with low thermal resistance thanks to the device's use of an aluminum nitride (AlN) ceramic substrate. The NX-Series was developed with a new package design that uses a building-block concept to provide multiple configuration options, improved manufacturability, reduced development time and lower cost. NX-Series IGBTs were designed for general-purpose motor drives. However, dual and single types are also applicable to power quality and alternate energy applications.

The NX-Series features high thermal conductivity AlN ceramic to provide improved heat transfer from the power chips to the heatsink. The result is lower chip temperature (T_J) and a more than 10-fold improvement in thermal cycle life.

A common base plate and case shell are used with interchangeable screw terminal box and pin terminals to create single, dual, seven-pack and converter-inverter-brake circuit configurations ranging from 75 A to 600 A at 600 V and 35 A to 600 A at 1200 V with NTC thermistor output in a 17-mm-thin package.

This series also uses the company's fifth-generation Carrier Stored Trench Gate Bipolar Transistor (CSTBT) chip technology. The CSTBT structure provides reduced switching and conduction losses compared to conventional IGBTs.The combination of AlN ceramic, high elastic Sn-Ag-Cu solder and a proprietary technique to ensure uniform solder thickness enable the devices to achieve high power-cycling capability. Samples of NX-Series IGBTs are available for $62 to $177 depending on the selected rating and configuration.

Late last year, IXYS released a family of fast 300-V IGBTs built in the the company's robust HDMOS IGBT process. These IGBTs can hard switch up to 100 kHz and carry current ratings ranging from 42 A to 120 A: IXGH42N30C3, IXGH60N30C3, IXGH85N30C3, IXGH100N30C3 and IXGH120N30C3. Although these are not the first 300-V IGBTs offered by IXYS, they operate at higher switching frequencies than the previously introduced devices.

These IGBTs are currently available in the TO-247 package. Additional package offerings will be available in the future. All the devices may also be copacked with IXYS' HiPerFRED fast diodes.

The combination of high switching speeds and low conduction losses gives power designers a new high value option for switching applications at 300 V and below. Historically, for circuits operating up to 300 V, the MOSFET has been the discrete device of choice. However, this new series of IGBTs offers an alternative to MOSFETs for circuits that are hard switching up to 100 kHz.

These devices are optimized for low V_SAT with a higher current-density capability than an equivalent MOSFET. Therefore, the 300-V IGBTs can operate with better efficiency and with a smaller die size, resulting in lower costs when compared to 300-V power MOSFETs. These devices are also rugged in unclamped inductive switching applications, comparable to most rugged power MOSFETs.

IXYS' 300-V IGBTs offer a cost-effective alternative to MOSFETs for applications such as power factor correction, UPS systems, inverters for solar energy, switch-mode or resonant-mode converters and power supplies, pulse generators, PWM light control, PWM heaters, capacitive discharge applications and various motor-control applications. In addition to these fast 300-V IGBTs, the company plans to introduce 600-V versions shortly.

Earlier last year, Semikron introduced what it described as “the first 100% solder-free IGBT module.” The SKiM module targets 22-kW to 150-kW train drive converters in electric and hybrid vehicles, and has a five times higher temperature cycling capability versus modules with base plate and soldered terminals.

The module's solder-free pressure contact technology and sintered chips increase temperature cycling capability to 10,000 cycles at Δ100K. Due to the high-temperature capabilities of T_J equals 175°C and T_AMBIENT equals 135°C, one separate coolant loop can be omitted when using the module.

Click here for the enhanced PDF version of this article