Current source logic gate

A current source logic gate with depletion mode field effect transistor (“FET”) transistors and resistors, comprising:

• a current source comprising a transistor and a current source resistor;
• a current steering switch input stage comprising a transistor to switch current through the current source bias resistor on an input logic level high state to set an output stage bias point or on an input logic level low state to allow the output stage to self-bias;
• and
• a resistor divider level shifting output stage comprising a first resistor and a second resistor to set the output stage point and produce valid output logic signal states, wherein
• the transistor of the current steering switch input stage functions as a switch to provide at least two operating points.

A current source logic gate with depletion mode field effect transistor (“FET”) transistors and resistors, comprising:

• a first N channel depletion mode FET (“first transistor”) with gate, source, and drain terminals;
• and
• a second N channel depletion mode FET (“second transistor”) with gate, source, and drain terminals, wherein
• the first transistor is configured to act as a current source, and is positioned above the second transistor,
• the drain terminal of the first transistor is tied to a positive voltage relative to ground,
• the gate terminal of the second transistor acts as an input to the current source logic gate,
• the source terminal of the second transistor is tied to ground, and the drain terminal of the second transistor is tied through a first resistor to the source terminal of the first transistor and directly to the gate terminal of the first transistor, and
• the source of the first transistor is further tied to a second resistor in series with a third resistor, a remaining lead of the third resistor is tied to a negative voltage relative to ground, and a node common to the second and third resistors is the output of the current source logic gate.