US 4,792,706 AGranted

ECL gates using diode-clamped loads and Schottky clamped reference bias

AssigneeTexas Instruments Incorporated

InventorsKevin M. Ovens, Bobby D. Strong

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Abstract

The disclosure relates to a logic circuit wherein the voltage regulators of the ECL circuits, which use resistor ratios, the values of which are difficult to control in the formation of semiconductor circuits, are replaced by a series of diodes, the areas of which are very easy to control in semiconductor fabrication, to set the threshold voltages for the transistors. Diode voltage ratios are very controllable since the diodes change only about 18 millivolts for every factor of two in current change. Thresholds can therefore easily be set in five and ten millivolt increments, this being the procedure utilized herein. Embodiments are disclosed using the basic circuit in a stacked configuration to provide AND/NAND operation in addition to the OR/NOR operation of the basic embodiment.

Claims20

Dependent claims

A logic circuit which comprises:

(a) first and second semiconductor devices having collector electrodes, control electrodes and emitter electrodes, said emitter electrodes connected to a common node,
(b) a source of voltage coupled to said emitter electrodes,
(c) a reference voltage source coupled to said collector electrodes, and
(d) threshold voltage setting means coupled across said source of voltage and said reference voltage source including a first, Schottky diode and a first resistor in series therewith, the junction of said first Schottky diode and said first resistor being coupled to said control electrode of said first semiconductor device to provide a threshold voltage equal to the forward bias voltage of the first Schottky diode,
(e) logic signal input means connected to the control electrode of said second semiconductor device,
(f) first output means connected to one of the collector electrodes of one of said semiconductor devices;
(g) first means for setting high and low output levels of said first output means, said first level setting means including a parallel connected combination of a second diode and a second resistor coupled between said reference voltage source and the collector connected to said first output means, to provide a difference in high and low output levels equal to the forward bias of the second diode.

4 more elements

Dependencies are inferred from the claim text.