Electronic circuit to communicate information as an electrical current on two wires such that the electrical current is stabilized by measuring a voltage on a transistor within the electronic circuit

An electronic circuit disposed upon a major surface of a semiconductor substrate, comprising:

• an electrical current receiving node, the electrical current receiving node operable to receive a state current signal from outside of the electronic circuit;
• an electrical current transmitting node, the electrical current transmitting node operable to transmit the state current signal to outside of the electronic circuit;
• a first transistor having first and second electrical current passing nodes and operable to pass a first electrical current between the first and second electrical current passing nodes of the first transistor, the first transistor also having a control node operable to control the first electrical current, and the first electrical current passing node of the first transistor coupled to the electrical current receiving node;
• a voltage reference source operable to generate a predetermined reference voltage, wherein the control node of the first transistor is coupled to receive a voltage related to the predetermined reference voltage;
• a second transistor having first and second electrical current passing nodes and operable to pass a second electrical current between the first and second electrical current passing nodes of the second transistor, the second transistor also having a control node operable to control the second electrical current, the second electrical current passing node of the first transistor coupled to the first electrical current passing node of the second transistor, and the second electrical current passing node of the second transistor coupled to the electrical current transmitting node;
• a voltage sensing circuit first and second input nodes and an output node, a voltage at the output node indicative of a voltage difference between the first and second input nodes, the first input node of the voltage sensing circuit coupled to the control node of the first transistor, the second input node of the voltage sensing circuit coupled to the second electrical current passing node of the first transistor, and the output node of the voltage sensing circuit coupled to the control node of the second transistor;
• and
• a portion of the electronic circuit coupled to the second electrical current passing node of the first transistor, wherein the portion of the electronic circuit is operable to use a circuit portion electrical current having a circuit portion voltage, wherein the first electrical current includes both the second electrical current and the circuit portion electrical current, wherein the electronic circuit is operable to control the second electrical current to maintain a predetermined sum of the second electrical current and the circuit portion electrical current.