Multi-level ECL series gating with temperature-stabilized source current

Claim 1

In a circuit having multiple bistable gating levels which operates over predetermined circuit voltage and temperature ranges, in which the gating levels are connected in series between a first circuit voltage node and a circuit current source connected to a second circuit voltage node and generating a circuit current, and in which a circuit output signal is provided through an output emitter follower connected at its collector to said first circuit voltage node, and at its base to the gating level connected to the first node, wherein each of said gating levels includes a binary element responsive to an output signal substantially equivalent to said output signal for assuming a state providing a conductive path for the circuit current, the state of said output signal being determined by the states of said gating levels, the improvement comprising, in combination; said circuit current source including a first resistor and a first current source transistor having a collector connected to one of said gating levels, an emitter connected through said first resistor to said second node, and a base; an output follower current source for generating said output signal, said output follower current source including a second resistor and a second current source transistor having a collector connected to the emitter of said output emitter follower, an emitter connected through said second resistor to said second node, and a base; and a voltage regulation means connected to the bases of said first and second current source transistors for providing a bias voltage to said current source transistors which maintains a constant voltage drop over said first and second resistors within the limits of said operating circuit voltage and temperature ranges.