Bidirectional two-base bipolar junction transistor operation, circuits, and systems with diode-mode turn-on
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 bipolar semiconductor device which includes both first-conductivity-type emitter/collector regions and also second-conductivity-type base contact regions on each of both opposed surfaces of a semiconductor die, comprising the actions of:
at turn-on, when an external voltage difference applied between the emitter/collector regions has a polarity such that the emitter/collector region on the first of said surfaces can act as the collector of a vertical bipolar transistor while the emitter/collector region on the second of said surfaces acts as the emitter of the same vertical bipolar transistor,
beginning turn-on by shorting the base contact and emitter/collector regions on the first surface together, without driving the base contact region on the second surface, to thereby conduct current as a diode without external base current power; and thereafter
applying base current to one but not both of the base contact regions.
2. The method of claim 1 , wherein the emitter/collector regions are n-type, and the step of applying base current sources current to said base contact region.
3. The method of claim 1 , wherein the emitter/collector regions are p-type, and the step of applying base current sinks current from said base contact region.
4. The method of claim 1 , whereby said step of beginning turn-on conducts current between the emitter/collector regions on both said surfaces with a diode voltage drop characteristic of a p-n junction between the emitter/collector region on the second surface and the semiconductor die.
5. A method for switching a power bipolar semiconductor device which includes distinct first and second first-conductivity-type emitter/collector regions which are not electrically connected together except through the semiconductor die, and also includes distinct first and second second-conductivity-type base contact regions which are respectively close to the first and second collector/emitter regions and which are not electrically connected together except through the semiconductor die comprising:
at turn-on, when an external voltage difference is applied between the emitter/collector regions with a polarity such that the first emitter/collector region, on a first surface of the semiconductor die, can act as the collector of a vertical bipolar transistor while the second emitter/collector region, on a second surface of the semiconductor die, acts as the emitter of the same vertical bipolar transistor,
beginning turn-on by shorting the first base contact region and the first emitter/collector region together, to thereby conduct current between the first and second emitter/collector regions as a diode without external base current; and thereafter
applying base current at one but not both of the base contact regions.
6. The method of claim 5 , wherein the emitter/collector regions are n-type, and the step of applying base current sources current to said base contact region.
7. The method of claim 5 , wherein the emitter/collector regions are p-type, and the step of applying base current sinks current from said base contact region.
8. The method of claim 5 , whereby said step of beginning turn-on conducts current between the first and second emitter/collector regions with a diode voltage drop characteristic of a p-n junction between the second emitter/collector region and the semiconductor die.