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Tunnel Diode A To D Converter

IP.com Disclosure Number: IPCOM000091609D
Original Publication Date: 1968-Apr-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Cotterman, HW: AUTHOR

Abstract

This circuit is for digitizing an analog signal and is useful when a nonlinear analog-to-digital conversion is required. Each stage 1...N is a latch consisting of a tunnel diode and transistor. A plurality of these stages is coupled together as in drawing A to provide the desired number of output digits at terminals A...N. The output is a logic level taken from the collector of the transistor. With the circuit energized, the negative trailing edge of the set pulse applied at S resets stage 1 via C1 and sets all other stages. This negative-going pulse turns transistor T1 off and saturates transistors T2...Tn.

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Tunnel Diode A To D Converter

This circuit is for digitizing an analog signal and is useful when a nonlinear analog-to-digital conversion is required. Each stage 1...N is a latch consisting of a tunnel diode and transistor. A plurality of these stages is coupled together as in drawing A to provide the desired number of output digits at terminals A...N. The output is a logic level taken from the collector of the transistor. With the circuit energized, the negative trailing edge of the set pulse applied at S resets stage 1 via C1 and sets all other stages. This negative-going pulse turns transistor T1 off and saturates transistors T2...Tn.

A ramp voltage Vin is converted to currents by resistors R1...Rn in stages
1...N and applied to the base of the associated transistor. The values of R1...Rn are selected for switching their respective tunnel diodes D1...Dn at desired input voltage levels. As Vin increases to a first predetermined level, D1 switches to its high-voltage state to turn T1 on. The output voltage at terminal A goes negative to ground. The negative-going pulse at terminal A resets stage 2, i.e., D2 switches to its low-voltage state turning T2 off, via coupling capacitor 2. At a second predetermined level of Vin, stage 2 resets, setting the third stage, not shown, on.

After Vin reaches its maximum voltage, one stage is reset and all others are set. The stage that is reset indicates which one of the plurality of predetermined levels is reached by the maxi...