SWITCHINGPOWER TRANSISTORWITH NEW FINE EMITTER STRUCTURE
Yasutaka Nakatani, Isamu Kuruyu · 1983
The switchingpower supplycnnversion frequencyhas been raised annuallyas switching-powersupplieshave become more compact and light. To realize highfrequency power supply,circuit component frequencymust also be raised and switching transistors are requiredto have a high-speedswitchingand largesafe operatingarea. Previously,a high-speed switch was assumed to be incompatible with a large safe operatingarea. Scattering (5) parameters have been used to realize that this contradictoryrelationship can be solved by lowerinag base resistance. Switchingtransistorswhich have ultrahigh voltage(1200V), highspeedswitching characteristics (risetime tr=200 ns, storage time tstg=2500ns, fall time tf=70 ins),and a largesafe operatingarea (secondarybreakdown current Isb=8A, collector-emitterclampedvoltageCVCEX