Systems, circuits, devices, and methods with bidirectional bipolar transistors
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 of operating a power-packet-switching power converter, comprising:
driving a first array of bidirectional switches to drive power into a link inductor which is paralleled by a capacitor;
driving a second array of bidirectional switches to draw power onto an output line from said inductor;
wherein each said bidirectional switch comprises n-type emitter regions on opposing faces of a p-type base region, and p-type base contact regions on said opposing faces of said p-type base region;
wherein driving each said bidirectional switch comprises:
when one said face of one said bidirectional switch is desired to be in passive off mode, clamping a voltage of the respective base contact region to be less than or equal to a voltage of the respective emitter region plus a Schottky diode drop;
when one said face of one said bidirectional switch is desired to be in active off mode or in diode mode, shorting the respective base contact region to the respective emitter region; and
when one said face of one said bidirectional switch is desired to be in active on mode, injecting minority charge carriers into the respective base contact region.
2. The method of operating a power-packet-switching power converter of claim 1 , wherein driving each said bidirectional switch further comprises driving the bidirectional switch into a reduced beta mode.
3. A method of operating a power-packet-switching power converter, comprising:
driving a first array of bidirectional switches to drive power into a link inductor which is paralleled by a capacitor;
driving a second array of bidirectional switches to draw power onto an output line from said inductor;
wherein each said bidirectional switch comprises n-type emitter regions on opposing faces of a p-type base region, and p-type base contact regions on said opposing faces of said p-type base region;
wherein driving each said bidirectional switch comprises:
when one said face of one said bidirectional switch is desired to be in passive off mode, clamping a voltage of the respective base contact region to be less than or equal to a voltage of the respective emitter region plus a Schottky diode drop;
when one said face of one said bidirectional switch is desired to be in active off mode or in diode mode, shorting the respective base contact region to the respective emitter region; and
when one said face of one said bidirectional switch is desired to be in active on mode, injecting minority charge carriers into the respective base contact region;
wherein driving each said bidirectional switch further comprises driving the bidirectional switch into a regime with high carrier densities.
4. A method of operating a power-packet-switching power converter, comprising:
driving a first array of bidirectional switches to drive power into a link inductor which is paralleled by a capacitor;
driving a second array of bidirectional switches to draw power onto an output line from said inductor;
wherein each said bidirectional switch comprises n-type emitter regions on opposing faces of a p-type base region, and p-type base contact regions on said opposing faces of said p-type base region;
wherein driving each said bidirectional switch comprises:
when one said face of one said bidirectional switch is desired to be in passive off mode, clamping a voltage of the respective base contact region to be less than or equal to a voltage of the respective emitter region plus a Schottky diode drop;
when one said face of one said bidirectional switch is desired to be in active off mode or in diode mode, shorting the respective base contact region to the respective emitter region; and
when one said face of one said bidirectional switch is desired to be in active on mode, injecting minority charge carriers into the respective base contact region;
wherein driving the selected bidirectional switch drives sufficient current through selected base contact region to generate a total nonequilibrium carrier concentration, in the interior of said p-type base region, which is more than thirty times as great as the off-state equilibrium majority carrier concentration, to thereby lower the voltage drop across the switch.
5. The method of operating a power-packet-switching power converter of claim 1 , wherein the respective p-type base contact regions in said bidirectional switches are more highly doped than the rest of the respective p-type base region.
6. The method of operating a power-packet-switching power converter of claim 1 , each said bidirectional switch further comprising a thin layer of tunnel oxide between each said n-type emitter region and the respective p-type base region.
7. The method of operating a power-packet-switching power converter of claim 1 , each said bidirectional switch further comprising a thin layer of tunnel oxide between each said n-type emitter region and a respective emitter metallization.
8. The method of operating a power-packet-switching power converter of claim 1 , wherein the n-type emitter regions in each said bidirectional switches and the respective p-type base region are heterojunctions.
9. The method of operating a power-packet-switching power converter of claim 1 , wherein the n-type emitter regions of each said bidirectional switch are amorphous silicon and the respective p-type base region is substantially monocrystalline silicon.
10. The method of operating a power-packet-switching power converter of claim 1 , wherein the n-type emitter regions of each said bidirectional switch are polycrystalline silicon and the respective p-type base region is substantially monocrystalline silicon.
11. The method of operating a power-packet-switching power converter of claim 1 , each said bidirectional switch further comprising oxide-filled trenches between each said n-type emitter region and respectively adjacent p-type base contact regions.
12. The method of operating a power-packet-switching power converter of claim 1 , said bidirectional switches further comprising a respective edge termination structure which comprises an n-type region in a p-type region.
13. The method of operating a power-packet-switching power converter of claim 1 , wherein, when emitter regions on one said face of one said bidirectional switch are acting as emitters, the emitter regions on the opposing face act as collectors.