Browse Prior Art Database

Emitter Coupled Logic to T/2/L True Complement Generator

IP.com Disclosure Number: IPCOM000078089D
Original Publication Date: 1972-Nov-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Hockedy, R: AUTHOR

Abstract

This circuit accepts emitter-coupled logic (ECL) signals that swing small voltages and deliver low currents, and translates them into transistor-transistor logic (TTL) signals that swing large voltages and deliver large currents. The circuit simultaneously generates true-complement signals that are independent of the characteristics of the devices used in the circuit and of the ambient temperature of the circuit.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 69% of the total text.

Page 1 of 2

Emitter Coupled Logic to T/2/L True Complement Generator

This circuit accepts emitter-coupled logic (ECL) signals that swing small voltages and deliver low currents, and translates them into transistor-transistor logic (TTL) signals that swing large voltages and deliver large currents. The circuit simultaneously generates true-complement signals that are independent of the characteristics of the devices used in the circuit and of the ambient temperature of the circuit.

A reference voltage is impressed upon the base of T4 and an input signal impressed on the base of transistor T3. This input signal is of a level such that it swings around the reference voltage applied to the base of transistor T4. This input signal and reference voltage sets up current flows in diodes D2 and D1, and in the base-emitter portion of transistor T1 and transistor T2.

If it is considered that the input signal is held at exactly the reference, the current through diode D1 and transistor T1 will set the voltage at the collector of transistor T1 to be identical to that of the voltage at the base of transistor T1. The same voltage is dropped across the resistor R in each leg of the circuit. If the signal now moves slightly above the reference, say in the order of 500 millivolts, the voltage at the collector of transistor T1 is 500 millivolts higher than at the base of T1. This means that transistors T5 and T6 become saturated and the collector node of transistor T5 is held in the down state...