Method and system of operating a bi-directional double-base bipolar junction transistor (B-TRAN)
Operating a bi-directional double-base bipolar junction transistor (B-TRAN). One example is a method comprising: injecting charge carriers at a first rate into an upper base of the transistor, the injecting at the first rate results in current flow through the transistor from an upper collector-emitter to a lower collector-emitter, and the current flow results in first voltage drop measured across the upper collector-emitter and the lower collector-emitter; and then, within a predetermined period of time before the end of a first conduction period of the transistor, injecting charge carriers into the upper base at a second rate lower than the first rate, the injecting at the second rate results in second voltage drop measured across the upper collector-emitter and the lower collector-emitter, the second voltage drop higher than the first voltage drop; and then making the transistor non-conductive at the end of the conduction period.
1. A method of operating a bi-directional double-base bipolar junction transistor, the method comprising:
injecting charge carriers at a first rate into an upper base of the transistor, the injecting at the first rate results in current flow through the transistor from an upper collector-emitter to a lower collector-emitter, and the current flow results in a first voltage drop measured across the upper collector-emitter and the lower collector-emitter, and then, within a predetermined period of time before the end of a first conduction period of the transistor,
injecting charge carriers into the upper base at a second rate lower than the first rate, the injecting at the second rate results in second voltage drop measured across the upper collector-emitter and the lower collector-emitter, the second voltage drop higher than the first voltage drop; and then
making the transistor non-conductive at the end of the first conduction period; and then
injecting charge carriers at a third rate into the lower base of the transistor, the injecting at the third rate results in current flow through the transistor from the lower collector-emitter to the upper collector-emitter, and the current flow results in third voltage drop across the lower collector-emitter and the upper collector-emitter; and then, within a predetermined period of the end of a second conduction period,
injecting charge carriers into the lower base at a fourth rate lower than the third rate, the injecting at the fourth rate results in fourth voltage drop measured across the lower collector-emitter and the upper collector-emitter, the fourth voltage drop higher than the third voltage drop; and then
making the transistor non-conductive at the end of the second conduction period.
2. A switch assembly comprising:
a bipolar junction transistor defining an upper base, an upper collector-emitter, a lower base, and a lower collector-emitter;
a driver defining an upper-base terminal coupled to the upper base, an upper-conduction terminal coupled to the upper collector-emitter, a lower-base terminal coupled to the lower base, and a lower-conduction terminal coupled to the lower collector-emitter, the driver configured to:
inject charge carriers at a first rate into the upper base, the injecting charge carriers at the first rate results a first conductivity through the transistor from the upper collector-emitter to the lower collector-emitter;
predict the end of a first conduction period, and within a predetermined period of time before the end of the first conduction period,
inject charge carriers into the upper base at a second rate lower than the first rate, the injecting charge carriers at the second rate results in second conductivity through the transistor from the upper collector-emitter and to the lower collector-emitter, the second conductivity lower than the first conductivity; and then
make the transistor non-conductive at the end the first conduction period.
3. The method of claim 1 wherein making the transistor non-conductive at the end of the first conduction period further comprises directly coupling the lower base of the transistor to the lower collector-emitter of the transistor, and extracting charge carriers from the upper base.
4. The method of claim 3 further comprising, after extracting charge carrier from the upper base, electrically floating the upper base.
5. The method of claim 1 further comprising, prior to injecting charger carriers at the first rate, injecting charge carriers into the upper base at a fifth rate higher than the first rate, the injecting charge carriers at the fifth rate to decrease switching time from an off-mode to a conductive state of the transistor.
6. The method of claim 1 wherein making the transistor non-conductive at the end of the first conduction period further comprises:
ceasing the injecting charge carriers into the upper base;
electrically floating the upper base; and
directly coupling the lower base of the transistor to the lower collector-emitter of the transistor.
7. The method of claim 1 wherein injecting charge carriers at the first rate through the upper base further comprises coupling a first voltage source between the upper collector-emitter and the upper base.
8. The method of claim 7 wherein injecting charge carriers at the second rate through the upper base further comprises coupling a second voltage source between the upper collector-emitter and the upper base, the second voltage source distinct from the first voltage source.
9. The method of claim 7 wherein injecting charge carriers at the second rate through the upper base further comprises lowering an output voltage of the first voltage source.
10. The method of claim 1 wherein injecting charge carriers at the first rate through the upper base further comprises coupling a first current source between the upper collector-emitter to the upper base.
11. The method of claim 10 wherein injecting charge carriers at the second rate through the upper base further comprises coupling a second current source between the upper collector-emitter and the upper base.
12. The method of claim 10 wherein injecting charge carriers at the second rate through the upper base further comprises lowering current output of the first current source.
13. The method of claim 1 wherein, prior to injecting charge carriers at the first rate, making the transistor conductive by directly coupling the upper collector-emitter the upper base.
14. The method of claim 1 wherein the first voltage drop is less 0.2 Volts or less, and the second voltage drop is greater than 0.4 Volts.
15. The switch assembly of claim 2 wherein the driver further comprises:
a controller;
a first voltage source defining a first voltage output;
a first electrically-controlled switch defining a first connection coupled to the first voltage output, a second connection coupled to the upper base, and a first control input coupled to the controller; and
wherein when the driver injects charge carriers at the first rate into the upper base, the controller is configured to make the first electrically-controlled switch conductive by asserting the first control input.
16. The switch assembly of claim 15 further comprising:
a second voltage source defining a second voltage output, the second voltage source distinct from the first voltage source;
a second electrically-controlled switch defining a first connection coupled to the second voltage output, a second connection coupled to the upper base, and a second control input coupled to the controller; and
wherein when the driver injects charge carriers at the second rate into the upper base, the controller is configured to make the second electrically-controlled switch conductive by asserting the second control input.
17. The switch assembly of claim 15 further comprising:
a setpoint input defined by the first voltage source, the setpoint input coupled to the controller; and
wherein when the driver injects charge carriers at the second rate through the upper base, the controller is configured to lower a voltage applied to the first voltage output.
18. The switch assembly of claim 2 wherein the driver further comprises:
a controller;
a first current source defining a first current output;
a first electrically-controlled switch defining a first connection coupled to the first current output, a second connection coupled to the upper base, and a first control input coupled to the controller; and
wherein when the driver injects charge carriers at the first rate into the upper base, the controller is configured to make the first electrically-controlled switch conductive by asserting the first control input.
19. The switch assembly of claim 18 further comprising:
a second current source defining a second current output, the second current source distinct from the first current source;
a second electrically-controlled switch defining a first connection coupled to the second current output, a second connection coupled to the upper base, and a second control input coupled to the controller; and
wherein when the driver injects charge carriers at the second rate into the upper base, the controller is configured to make the second electrically-controlled switch conductive by asserting the second control input.
20. The switch assembly of claim 18 further comprising:
a setpoint input defined by the first current source, the setpoint input coupled to the controller; and
wherein when the driver injects charge carriers at the second rate through the upper base, the controller is configured to lower a current applied to the first current output.
21. The switch assembly of claim 2 further comprising:
a controller;
a means for generating charge carriers;
a first electrically-controlled switch defining a first connection coupled to the means for generating charge carriers, a second connection coupled to the upper base, and a first control input coupled to the controller;
a second electrically-controlled switch defining a first connection coupled to the lower collector-emitter, a second connection coupled to the lower base, and a second control input coupled to the controller; and
wherein when the driver makes the transistor non-conductive, the controller is configure to:
make the first electrically-controlled switch conductive by asserting the first control input to extract charge carriers through the upper base; and then
make the first electrically-controlled switch non-conductive by de-asserting first control input; and
make the second electrically-controlled switch conductive by asserting the second control input.
22. The switch assembly of claim 2 wherein when the driver makes the transistor non-conductive, the driver is configured to directly couple the lower base of the transistor to the lower collector-emitter of the transistor, and extract charge carriers from the upper base.
23. The switch assembly of claim 22 wherein when the driver makes the transistor non-conductive, the driver is further configured to, after extraction of charge carrier from the upper base, electrically float the upper base.
24. The switch assembly of claim 2 , wherein the driver is further configured to, prior to injecting charger carriers at the first rate, injecting charge carriers into the upper base at a third rate higher than the first rate, the injecting charge carriers at the third rate to decrease switching time from an off-mode to a conductive state of the transistor.