IN Brief:
- Toshiba has developed a 6500V trench-type second-generation IEGT chip for high-voltage power conversion.
- The ST2000JXH35A press-pack device targets HVDC transmission, STATCOM equipment, and industrial motor drives.
- Higher-voltage device strings can simplify converter architectures and reduce system size in high-power infrastructure.
Toshiba Electronic Devices & Storage has developed a 6500V-rated trench-type second-generation injection enhanced gate transistor chip for high-voltage power conversion systems.
The company has also commercialised the ST2000JXH35A, a 6500V/2000A press-pack IEGT incorporating the new chip. The device is designed for DC power transmission systems, static synchronous compensators, and industrial motor drives, where semiconductor devices are connected in series to support high output voltages.
Moving from 4500V-class devices to a 6500V-class rating allows fewer devices to be connected in series for the same converter output voltage. Toshiba gives an estimated reduction of approximately 33% in a ±500kV HVDC system, based on 334 series units using a 6500V-rated device compared with 500 units using a 4500V-rated device. A smaller series stack can reduce converter size, weight, gate-drive complexity, insulation interfaces, and some balancing requirements.
The device uses a shorted dummy cell structure in the cell region, removing floating regions that can create unstable potential distribution. Toshiba has also optimised mesa width and introduced an N-barrier layer beneath the P-base layer to improve carrier transport. Those changes are intended to distribute current more uniformly during turn-off while supporting short-circuit capability under high-voltage operating conditions.
Breakdown voltage stability is addressed through a termination region incorporating guard rings and a semi-insulating layer to disperse the electric field. Toshiba has also optimised the interface process between the semi-insulating layer and silicon to suppress breakdown voltage variation under bias stress. The developed chip has been evaluated through turn-off and short-circuit testing at a 4500V test voltage, with the short-circuit condition specified at a maximum pulse width of 10µs.
The advance arrives as grid and industrial power electronics absorb heavier demands from renewable generation, long-distance transmission, converter-fed industrial drives, and network stabilisation equipment. HVDC systems are being deployed where large quantities of electricity must move over long distances, while STATCOM equipment is increasingly used to support voltage stability and reactive power compensation. Semiconductor voltage rating, switching loss, conduction loss, packaging, and cooling all feed directly into converter scale and serviceability.
Power semiconductor development is spreading across several device classes rather than moving in a single direction. Work on power-module design workflows and SiC pairing tools reflects the engineering pressure around faster design iteration, parasitic management, and thermal behaviour. Toshiba’s IEGT work occupies a different voltage and infrastructure tier, but the underlying constraint is similar: device performance has to survive contact with converter architecture.
Press-pack construction remains important in high-power systems because it supports double-sided cooling and mechanically clamped stacks, with reliability characteristics suited to infrastructure equipment. The package choice affects current sharing, thermal impedance, maintainability, and fault behaviour, not just the electrical rating printed on the datasheet. In HVDC and large industrial drives, those packaging attributes can decide whether a device can be used in practical converter valves.
Wide-bandgap devices continue to expand in EV charging, traction, compact industrial drives, renewable inverters, and data-centre power systems, but high-voltage utility-scale conversion still depends heavily on silicon devices with established reliability data and proven high-power package formats. Toshiba’s development reinforces that mature power semiconductor families are still being advanced, particularly where voltage, current, and lifetime requirements sit beyond the practical reach of many newer device options.
The technology details were presented at PCIM Europe 2026 in Nuremberg, placing the device within Europe’s wider power electronics discussion. Grid reinforcement, HVDC deployment, and industrial electrification are pushing converter engineering towards higher voltages and denser equipment. Higher-rated press-pack IEGTs cannot remove the hard work of converter qualification, but they can simplify one of the most stubborn parts of high-power design: building large, reliable series-connected semiconductor stacks without allowing size and complexity to run away from the system.
