|Symbol of depletion mode IGBT|
The pulse repetition rates are boasted by the modern devices which consist of switching application and fall well within the ultrasonic range which are the frequencies which are ten times higher than the highest audio frequency handled by the device when the devices is used in the form of an analog audio amplifier.
The MOSFETs consisting of high current and characteristics of a simple gate-drive is combined with the bipolar transistors which has low-saturation-voltage capacity by the IGTB.
A single device is made by IGBT by combining the bipolar power transistor which acts as a switch and an isolated gate FET which acts as the control input.
Insulated-gate bipolar transistor (IGTB) is a new and recent invention of the time. The first-generation devices which were invented and launched in 1980s and the early years of 1990s were found to have slow switching process relatively and are prone to failure through different modes such as latchup (where the device will continue to be switched on and not turn off till the current keeps on flowing through the device) and secondary breakdown (where when high current flows through the device, a localized hotspot present in the device goes into thermal runaway and as a result burns the device).
There was a lot of improvement observed in the second-generation devices and the most new devices on the block, the third-generation devices are considered even better than the first tow generation devices.
The third-generation devices consist of MOSFETs with speed rivaling, and tolerance and ruggedness of excellent level. The devices of second and third generation consists of pulse rating which are extremely high which make them very useful in order to generate large power pulses in various areas such as plasma physics and particle. Thus the second and third generation devices have superseded mostly all the older devices such as triggered spark gaps and thyratrons used in these areas of plasma physics and particle.
These devices also hold attraction for the hobbyist of high-voltage due to their properties of high pulse ratings and availability in the market at low prices. This enables the hobbyist to control huge amounts of power in order to drive devices such as coilgums and Tesla coils.
By Surbhi Prakash