Advanced IGBTs and MOS-gate drivers

The development of proprietary processes has improved the performance of so called Second Generation IGBTs to operate up to 25 kHz and some of these advanced devices have even benefited in their nomenclature-being termed as Switching IGBTs. The most recent proprietary process advance has resulted in achieving a significant level of conductivity modulation of the JFET component of the MOSFET part of the IGBT. This process which has the proprietary title of Deep Enhancement dramatically lowers the intrinsic off-set voltage of the device. Alpha killing of the PNP ensures that latch-up of the parasitic thyristor during normal operation cannot occur. Deep enhanced products tends to concentrate the preponderance of their collector current through the PNP structure. Life-time control by increased dosage of electron irradiation results in IGBTs which can now be incorporated in square wave applications at frequencies up to 50 kHz. The V_CS(ON) of these deep enhanced products are competitive with the switching devices. A detailed examination of the turn-off behaviour of these deep enhanced parts will show a total turn-off time (including all of the tail-time) to be 0.25 microseconds typically. Adaptation of special driving techniques will enable the use of these parts in high power DC/DC converters operating at frequencies of 150-250 kHz