any license fee for “Plummer’s device.” Other IGBT manufacturers also paid the license fee for Becke's patent. Applications , the IGBT is the second most widely used power transistor, after the power MOSFET. The IGBT accounts for 27% of the power transistor market, second only to the power MOSFET (53%), and ahead of the RF amplifier (11%) and bipolar junction transistor (9%). The IGBT is widely used in consumer electronics, industrial technology, the energy sector, aerospace electronic devices, and transportation. Advantages The IGBT combines the simple gate-drive characteristics of power MOSFETs with the high-current and low-saturation-voltage capability of bipolar transistors. The IGBT combines an isolated-gate FET for the control input and a bipolar power transistor as a switch in a single device. The IGBT is used in medium to high-power applications like switched-mode power supplies, traction motor control and induction heating. Large IGBT modules typically consist of many devices in parallel and can have very high current-handling capabilities in the order of hundreds of amperes with blocking voltages of . These IGBTs can control loads of hundreds of kilowatts. Comparison with power MOSFETs An IGBT features a significantly lower forward voltage drop compared to a conventional MOSFET in higher blocking voltage rated devices, although MOSFETS exhibit much lower forward voltage at lower current densities due to the absence of a diode Vf in the IGBT's output BJT. As the blocking voltage rating of both MOSFET and IGBT devices increases, the depth of the n- drift region must increase and the doping must decrease, resulting in roughly square relationship decrease in forward conduction versus blocking voltage capability of the device. By injecting minority carriers (holes) from the collector p+ region into the n- drift region during forward conduction, the resistance of the n- drift region is considerably reduced. However, this resultant reduction in on-state forward voltage comes with several penalties: The additional PN junction blocks reverse current flow. This means that unlike a MOSFET, IGBTs cannot conduct in the reverse direction. In bridge circuits, where reverse current flow is needed, an additional diode (called a freewheeling diode) is placed in parallel (actually anti-parallel) with the IGBT to conduct current in the opposite direction. The penalty isn't overly severe because at higher voltages, where IGBT usage dominates, discrete diodes have a significantly higher performance than the body diode of a MOSFET. The reverse bias rating of the N-drift region to collector P+