An implantable cochlear stimulator (ICS) has eight output stages (212), each having a current source (212B) connected to a pair of electrodes, designated "A" and "B", through respective output coupling capacitors and an electrode switching matrix (212C). An indifferent electrode is connected to each output stage by way of an indifferent electrode switch (212D). The current source generates a precise stimulation current as a function of an analog control voltage. The analog control voltage, in turn, is generated by a logarithmic D/A converter. The D/A converter serially converts data words, received in a data frame from an external source, to respective analog control voltages that are applied sequentially to the current sources of each output stage. An output mode register (208) controls the switching matrix of each stage, as well as the indifferent electrode switch, to configure the electrodes for a desired stimulation configuration, e.g., bipolar stimulation (current flow between the pair of electrodes of the output stage), or monopolar stimulation (current flow between one of the electrodes of the output stage and the indifferent electrode). The voltage at the "A" and "B" electrode of each output stage may be selectively telemetered to the wearable system, as may the current flow through the indifferent electrode, thereby facilitating a measurement of the electrode impedance. The "A" and "B" electrodes of each output stage may be selectively shorted through a high or low resistance in order to discharge the output coupling capacitors.