Toshiba Develops 6500V Press-Pack IEGT Chip with High Turn-Off and Short-Circuit Capability that will Contribute to Higher Voltage Operation and Equipment Downsizing
June 15, 2026
Toshiba Electronic Devices & Storage Corporation
Kawasaki, Japan－Toshiba Electronic Devices & Storage Corporation ("Toshiba") has developed a 6500V-rated trench-type second-generation Injection Enhanced Gate Transistor (IEGT)[1] chip with high turn-off capability[2] and short-circuit capability[3]. Increasing the voltage rating from the standard 4500V class to 6500V secures a reduction in the number of devices connected in series for the same output voltage, which will help to realize simpler system configurations and smaller power conversion equipment. Toshiba has also commercialized a 6500V press-pack IEGT (PPI)[4] incorporating the chip for use in applications such as DC power transmission systems, STATCOM[5], and industrial motor drives.
The adoption of renewable energy is expanding with efforts worldwide to promote decarbonization. Power generation sites and consumption areas are often located far apart, driving the deployment of DC power transmission systems for long-distance and large-capacity power transmission. At the same time, grid stabilization is becoming increasingly important, and the use of STATCOM is also expanding. In high-voltage power conversion systems such as DC power transmission systems and STATCOM, power semiconductor devices are connected in series. Increasing the voltage rating of each device enables a reduction in the number of series-connected devices, contributing to simpler system configurations and smaller equipment size.
Toshiba has been mass-producing 4500V-class PPI devices. However, for 6500V-class operation, ensuring adequate turn-off and short-circuit capability under higher voltage conditions has been a key challenge. This requires precise control of carrier (charge) transport inside the device. In addition, variation in breakdown voltage observed in bias tests has also been an issue that needed to be addressed.
The newly developed 6500V IEGT chip (Figure 1) adopts a shorted dummy cell structure in the cell region, eliminating floating regions that can lead to unstable potential distribution. In addition, the mesa width (the current conduction region between dummy trenches) is optimized, and an N-barrier layer is introduced beneath the P-base layer (a layer that controls carrier transport). These structural optimizations improve carrier distribution and transport, resulting in more uniform current distribution during turn-off and enabling stable operation with sufficient turn-off capability and short-circuit capability under high-voltage conditions. In addition, Toshiba confirmed an improved trade-off between conduction loss[6] and switching loss (loss generated during gate turn-on and turn-off) (Figure 2).
In the termination region, a structure incorporating guard rings to disperse the electric field and a semi-insulating layer has been adopted (Figure 3), enabling a breakdown voltage exceeding 6500V. Furthermore, optimization of the interface process between the semi-insulating layer and the silicon suppresses breakdown voltage variation observed in non-optimized processes under bias stress conditions, resulting in stable breakdown characteristics (Figure 4).
The developed chip has been evaluated through turn-off and short-circuit tests at a test voltage of 4500V, confirming its applicability in high-voltage systems. Toshiba has commercialized a 6500V/2000A press-pack IEGT, “ST2000JXH35A,” incorporating this chip. In HVDC systems, the use of 6500V devices can reduce the number of series-connected devices by approximately 33% compared with 4500V devices[7], contributing to reduced system size and weight. Toshiba will continue to develop press-pack IEGTs for high-voltage power conversion applications and expand its product lineup to support the advancement of power infrastructure.
Details of this technology were presented at Power Conversion and Intelligent Motion (PCIM) Europe 2026, held in Nuremberg, Germany, from June 9 to 11, 2026.
Notes:
[1] IEGT (Injection Enhanced Gate Transistor): A power semiconductor device in which the emitter structure of an IGBT (Insulated Gate Bipolar Transistor) is optimized to mitigate the sharp increase in on-state voltage associated with high-voltage operation.
[2] Turn-off capability: The ability to safely interrupt current during switching. High turn-off capability: Evaluated at turn-off test voltage (VCC) = 4500V.
[3] Short-circuit capability: The ability to withstand a short-circuit condition without device failure. Evaluated at a short-circuit test voltage (VCC) = 4500V, with a maximum short-circuit pulse width (tpsc) of 10µs.
[4] PPI (Press-Pack IEGT): A press-pack package incorporating IEGT chips.
[5] STATCOM (Static Synchronous Compensator): Equipment used for voltage stabilization and reactive power compensation in power systems.
[6] Conduction loss: Power loss generated when current flows through the device.
[7] Based on Toshiba’s estimated value
Assuming use in a ±500kV direct current transmission system, the comparison is based on operating voltage conditions appropriate for each voltage rating.
Required number of series-connected units when using a 6500V-rated device at 3000V: 334 units
Required number of series-connected units when using a 4500V-rated device at 2000V: 500 units
Reducing the number of series units from 500 to 334 results in an estimated reduction of approximately 33%.
For more information on the 6500V/2000A press-pack IEGT "ST2000JXH35A" incorporating this chip, please visit the following:
6500V Press Pack IEGT Contributing to Higher Voltage and Size Reduction for DC Power Transmission Systems and Industrial Motor Drives
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