Voltage to current converter with variation-free MOS resistor

摘要

A voltage controlled current source circuit of the present invention includes first reference current coupled to a voltage control node. A current input of a voltage controlled impedance is reproduced at the voltage control node through a current mirror as a second reference current. The voltage resulting from the action of the first and second reference currents is coupled to a voltage control input of the voltage controlled impedance. In one embodiment, a control voltage is provided to the gate of a transistor. The source of the transistor is coupled to the current input of a second voltage controlled impedance circuit to produce an output current at the drain of the transistor. The second voltage controlled impedance circuit has a voltage control input coupled to the voltage control input of the first voltage controlled impedance and to the voltage control node.