Higher Power Density 1.6kV Fast Thyristor

IXYS Corporation has introduced a new pressure contact distributed gate thyristor with increased power density. This new fast thyristor with turn-off time of as little as 20 microseconds and current rating 1,955 Amps is symmetrical blocking with forward and reverse voltage equal to 1,600 Volts and therefore suitable for both voltage and current fed applications. Typical applications for this device include induction power supplies for melting, billet heating and surface treatments as well as resonant power supplies and pulse switches for applications including high power magnets and lasers.

The full symmetrical blocking device is available in three different switching classes at two standard voltage grades. Part number designations are as follows: 1,600-Volt parts are N1955MC16D with tq 20 microseconds, N1955MC16E with tq 25 microseconds and N1955MC16F with tq 30 microseconds; 1,400-Volt parts are N1955MC14D with tq 20 microseconds, N1955MC14E with tq 25 microseconds and N1955MC14F with tq 30 microseconds.

The device offers higher current, while retaining the same turn-off time, when compared to other parts in the same footprint package size. This new improved design has an average current rating of 1,955 Amps at a heat sink temperature of 55 degrees centigrade representing up to a 35 percent increase when compared to older designs in the IXYS UK product portfolio.

The improvement in performance is achieved by maximizing the die size and improved distributed gate geometry. The 56mm silicon dice are bonded to metal discs and encapsulated in fully hermetic 50mm electrode contact diameter ceramic packages, with an industry standard overall diameter of 74mm.

“Providing the correct thermal conditions are observed, with a repetitive di/dt rating of 1,000 Amperes per microsecond, the device can be used in applications with repetitive frequencies up to 25 kiloHertz,” commented Frank Wakeman, IXYS UK’s Marketing and Technical Support Manager.

The larger die sizes and higher current ratings offer more flexibility in customizing the parts to meet the needs of customer specific applications. The increase in current rating can be traded in adapting the turn-off characteristic to give faster turn-off even than the standard offering of 20 microseconds, or tailoring the reverse recovery for series operation.