Browse Prior Art Database

Translating Output Driver

IP.com Disclosure Number: IPCOM000085435D
Original Publication Date: 1976-Apr-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Gersbach, JE: AUTHOR

Abstract

Described is a translating output driver having improved power and performance for transistor-transistor logic output drivers in which current mirror driving feedback, shunt-series feedback, and feedback through the collector of the device at the output is featured, so that delay through a voltage translating driver is reduced by reducing the voltage swing.

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Translating Output Driver

Described is a translating output driver having improved power and performance for transistor-transistor logic output drivers in which current mirror driving feedback, shunt-series feedback, and feedback through the collector of the device at the output is featured, so that delay through a voltage translating driver is reduced by reducing the voltage swing.

The circuit inputs are current sources 14 and 15 which are differential in nature. These current sources pass through grounded base transistors, input transistors 1 and 2 to the current mirror circuit comprised of diode 3 and transistor 4, such that the output at the collector of the transistor 4 has little attenuation.

When the output current at the collector of transistor 4 is positive, transistors 5 and 6 and resistors 10 and 11 act as a transresistance amplifier whose gain is equal to the resistance of the resistor 10. The output driver transistor 8 is held off and the output voltage at node 16 is equal to voltage +V1.

When the output at the collector of transistor 4 is down, transistor 5 is off and transistors 6 and 8 are turned on and saturated. The voltage swings require that the bases of transistor 5 and 8 are about 300 millivolts and account for speed improvement, since the usual swings in transistor-transistor logic are from 1 to
1.5 volts.

The negative transition of the output voltage is enhanced by transistor 7 which holds transistor 6 out of saturation until the output vo...