An Ultra High Speed - Large Safe Operating Area Switching Power Transistor with New Fine Emitter Structure

The switching power supply conversion frequency has been raised annually as switching power supplies have become more compact and light. To realize high frequency power supply, circuit component frequency must also be raised and switching transistors are required to have a high-speed switching and large safe operating area. Previously, a high-speed switch was assumed to be incompatible with a large safe operating area. Scattering (S) parameters have been used to realize that this contradictory relationship can be solved by lowering base resistance. Switching transistors which have ultrahigh voltage (1200 V), high speed switching characteristics (rise time tr=200 ns, storage time tstg=2500 ns, fall time tf=70 ns), and a large safe operating area (secondary breakdown current Isb=8A, collector-emitter clamped voltage (VCEX (clamp) = 900 V) have been developed by using a newly devised fine emitter structure and the SiO2 planar structure.