Embodiments are directed to an implantable medical device comprising stimulation circuitry for controlling delivery of a medical therapy to a patient, a processor for controlling the IMD according to executable code, and a power source. The implantable medical device may further include current regulator circuitry comprising electrode selection circuitry that is configured to select electrodes for use during a discharge mode, and a programmable current regulator configured to provide an exponentially decreasing discharge current to the selected electrodes from the power source. A current output of a programmable current regulator may be decreased in precalculated steps to create the exponentially decreasing discharge current applied to the selected electrodes.