Bidirectional two-base bipolar junction transistor devices, operation, circuits, and systems with diode-mode turn-on and collector-side base driven
Methods, systems, circuits, and devices for power-packet-switching power converters using bidirectional bipolar transistors (BTRANs) for switching. Four-terminal three-layer BTRANs provide substantially identical operation in either direction with forward voltages of less than a diode drop. BTRANs are fully symmetric merged double-base bidirectional bipolar opposite-faced devices which operate under conditions of high non-equilibrium carrier concentration, and which can have surprising synergies when used as bidirectional switches for power-packet-switching power converters. BTRANs are driven into a state of high carrier concentration, making the on-state voltage drop very low.
1. A method for switching a power semiconductor device which includes both an n-type emitter/collector region, and also a p-type base contact region, on each of both first and second surfaces of a p-type semiconductor die, and which has an ON state and an OFF state, comprising the steps of:
at turn-on, when an external voltage difference is applied between the emitter/collector regions, shorting the more positive one of the emitter/collector regions together with the base contact region on the same one of the surfaces, to thereby conduct current with a diode voltage drop characteristic of a p-n junction between the emitter/collector region and the semiconductor die; and thereafter
in the ON state, flowing base current through the base contact region which is nearer the more positive one of the emitter/collector regions, without flowing base current through the other of the base contact regions;
wherein the base contact region on the first surface is not electrically connected to the base contact region on the second surface, except through the semiconductor die itself;
and wherein the emitter/collector region on the first surface is not directly electrically connected to the emitter/collector region on the second surface, except through the semiconductor die itself;
whereby bidirectional switching is achieved with an on-state voltage drop which is less than the diode drop.
2. The method of claim 1 , wherein the semiconductor die is silicon.
3. The method of claim 1 , further comprising, in the OFF state, floating one of the base contact regions.
4. The method of claim 1 , whereby said shorting allows current to flow between the shorted base contact and emitter/collector region on the opposite surfaces as through a diode.
5. The method of claim 1 , wherein said step of flowing base current comprises sourcing current to said base contact region.
6. A method for switching a power semiconductor device which includes both a p-type emitter/collector region, and also an n-type base contact region, on each of both first and second surfaces of an n-type semiconductor die, and which has an ON state and an OFF state, comprising the steps of:
at turn-on, when an external voltage difference is applied between the emitter/collector regions, shorting the more negative one of the emitter/collector regions together with the base contact region on the same one of the surfaces, to thereby conduct current with a diode voltage drop characteristic of a p-n junction between the emitter/collector region and the semiconductor die; and thereafter
in the ON state, flowing base current through the base contact region which is nearer the more negative one of the emitter/collector regions, without flowing base current through the other of the base contact regions;
wherein the base contact region on the first surface is not electrically connected to the base contact region on the second surface, except through the semiconductor die itself;
and wherein the emitter/collector region on the first surface is not directly electrically connected to the emitter/collector region on the second surface, except through the semiconductor die itself;
whereby bidirectional switching is achieved with an on-state voltage drop which is less than the diode drop.
7. The method of claim 6 , wherein the semiconductor die is silicon.
8. The method of claim 6 , further comprising, in the OFF state, floating one of the base contact regions.
9. The method of claim 6 , whereby said shorting allows current to flow between the shorted base contact and emitter/collector region on the opposite surfaces as through a diode.
10. The method of claim 6 , wherein said step of flowing base current comprises sinking current from said base contact region.