1. An implantable neurostimulation system comprising: a pulse generator comprising: a multiple output current stimulator circuit comprising: a current source; a first resistor coupled to the current source to provide a reference voltage; at least one output side transistor having a current output terminal for providing an output current; a second resistor coupled between a voltage source and the at least one output side transistor to thereby provide a common sensing voltage; and a differential amplifier comprising: a first input coupled to the reference voltage; a second input coupled to the common sensing voltage; and an output arranged to drive the at least one output side transistor as a function of the difference between the reference voltage and the common sensing voltage.