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Tunnel Diodes Used to Speed Up Silicon Transistor Switching

IP.com Disclosure Number: IPCOM000074318D
Original Publication Date: 1971-Apr-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Strickland, SA: AUTHOR

Abstract

Tunnel diodes coupled into the base circuit of a silicon transistor permit rapid switching of that transistor as a threshold level is passed from an input signal.

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Tunnel Diodes Used to Speed Up Silicon Transistor Switching

Tunnel diodes coupled into the base circuit of a silicon transistor permit rapid switching of that transistor as a threshold level is passed from an input signal.

Tunnel diodes 10 and 11 are connected to the base of transistor 12 through resistor 15 to provide a unique turn-on drive for 12 when the base of 16 has reached a threshold level. Transistor 16 and resistor 18 illustrate one application of means for introducing the input to the combination of 10, 11 and 12. A 5 nanosecond turn-on transition at output 2O can be realized using an exponential signal at input 21 with a time constant of about 150 microseconds whereas this output turn-on transition would require several microseconds in the past.

For illustrative purposes, assume that 21 is at a +6 volt level so that 16 is off and node 22 is at a slightly negative potential, the reverse voltage of 10 and 11. 12 will be off since its base is at a negative voltage of about the voltage at 22 less the IR drop of 15. 20 would then be at +3 volts. An exponential input at 21 starting at +6 volts and discharging towards ground will cause 16 to commence conducting current. This current increases as the voltage at 21 decreases. Current through 10 and 11 builds up but 12 will remain off until the diode Ip current is reached. At this point, the forward voltage VF drop of 10 and 11 switches to the high forward voltage VF' state. This tunnel diode switching through...