Apparatus and method provide flexibility in generating a stimulation waveform to an electrode of an implantable medical device. The stimulation waveform comprises at least one stimulation pulse. The embodiment of the invention supports a generation of a stimulation pulse in which an amplitude and an electrical polarity of the stimulation pulse can be dynamically changed. The embodiment comprises a capacitor arrangement, a regulator and a switching array. The capacitor arrangement can be reconfigured with respect to an electrical reference through the switching array in order for the regulator to deliver the stimulation pulse to a pair of electrodes. In another embodiment, a plurality of stimulation waveforms are generated in which different stimulation waveforms are associated with different electrodes. With the embodiment, a plurality of regulators are connected and reconfigured to the capacitor arrangement in order that the different stimulation waveforms are generated by different regulators.