Bidirectional two-base bipolar junction transistor operation, circuits, and systems with double base short at initial turn-off
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 power-packet-switching power converter, comprising:
a plurality of phase legs which each include at least two fully bidirectional switches which can connect a respective external line to either side of a link inductor which is paralleled by a capacitor, each said bidirectional switch comprising:
first and second first-conductivity-type emitter/collector regions on opposing faces of a second-conductivity-type semiconductor mass, and
first and second second-conductivity-type base contact regions on the opposing faces, in proximity to the first and second emitter/collector regions respectively;
control circuitry which, repeatedly, turns on two selected ones of said bidirectional switches to drive energy from two respective input lines into said inductor, and then turns off all of said switches to disconnect said inductor, and then turns on a different two selected ones of said bidirectional switches to drive energy from said inductor onto two output lines; and
a drive circuit which, when the control circuitry selects one of the bidirectional switches for turn-on, first shorts the emitter/collector region which is instantaneously acting as a collector to the associated base contact region, without driving the other base contact region, and then drives a base contact region of that switch, to forward bias the associated emitter/collector-base junction and permit majority carriers to flow to the other emitter/collector region on the opposing surface.