Balanced voltage-to-current converter with quiescent current control

A voltage-to-current converter comprising:

• a first cell which comprises:
• a first input terminal, a second input terminal and an output terminal, a first current source, a first transistor having a first main electrode, a second main electrode and a control electrode, having a main current path defined by the first and the second main electrode of the first transistor and coupled to the first current source at a first node for the passage of a first current to be supplied by the first current source, and having a junction defined by the first main electrode and the control electrode of the first transistor and connected in a forward direction between the first node and the first input terminal, a second current source, a second transistor of a first conductivity type, having a first main electrode connected to the second input terminal, a control electrode connected to the first node, and a second main electrode coupled to the second current source at a second node, and a third transistor of the first conductivity type, having a first main electrode connected to the first input terminal, a control electrode connected to the second node, and a second main electrode coupled to the output terminal, characterised in that the second current source comprises a controllable current source having a control input, wherein the first cell further comprises a differential amplifier having an output and inputs which are arranged to compare a voltage difference between the control electrode and the first main electrode of the third transistor with a reference voltage which is a measure of the current through the third transistor, a first and a second common input terminal, a second cell identical to the first cell, the first input terminal of the first cell and a second input terminal of the second cell being interconnected at the first common input terminal, and the second input terminal of the first cell and a first input terminal of the second cell being interconnected at the second common input terminal, an adder having inputs coupled to respective outputs of the respective differential amplifiers of the first and second cells, and having an output coupled to the respective control inputs of the second current sources of the first and second cells to supply a respective control signal to the control inputs, and a reference voltage source to supply the reference voltage for the first and the second cell.