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Speed Up Circuit for Nor Circuits Using Insulated Gate, Field Effect Transistors

IP.com Disclosure Number: IPCOM000095823D
Original Publication Date: 1964-Jul-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Axelrod, MS: AUTHOR

Abstract

The circuit is for the performing of Nor logic and utilizes insulated-gate, field-effect transistors. The structure of the circuit assumes the capability of fabricating two types of devices on the same substrate, i. e., a depletion mode device and an enhancement mode device.

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Speed Up Circuit for Nor Circuits Using Insulated Gate, Field Effect Transistors

The circuit is for the performing of Nor logic and utilizes insulated-gate, field- effect transistors. The structure of the circuit assumes the capability of fabricating two types of devices on the same substrate, i. e., a depletion mode device and an enhancement mode device.

The circuit of drawing 1 accomplishes the speeding up of the switching of more basic circuits by decreasing both the turnon delay and the rise and fall times. The output at point B in the circuit is the complement of the output at point A. That is, as the output voltage Vo goes from Vlow to Vhigh, the voltage at point B, Vb goes from Vhigh to Vlow. Devices 10 and 12 are depletion mode insulated-gate, field-effect transistors while devices 14 and 16, 18 and 20 are enhancement mode insulated-gate, field-effect transistors. Using the depletion mode devices 10 and 12 as the circuit load, the load line on the characteristics of the enhancement mode devices depends upon the state of the circuit as shown in drawing 2. The following table defines circuit states:

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CIRCUIT OFF Vhigh Vlow Vlow - Vhigh Y.

The voltage at B does not change significantly during the switching of the circuit. Capacitor C can be used to ensure this. During turnon, the current available to charge the load capacitor is greater than the current available in the basic circuit, (Ic - Ie)> (Ic - Ib), therefore the rise time is shorter. T...