Functional electrical stimulation may be used for stimulating muscles or nerves by electrical charge. To this end, electrodes may be in direct contact with biologic tissue and a charge may be brought on the electrode for example by a current source, a voltage source or by capacitive discharge. Fields of applications comprise, for example, cardiac pacemakers, cochlear and retinal implants, peripheral nerve and muscle stimulators, deep brain stimulators and arrangements for restoring tactile sense of amputees. To guarantee safe stimulation, electrode and tissue destructions have to be prevented. Concerning safety aspects, charge balancing may be one major issue, since charge accumulation over time may harm the tissue and lead to electrolysis which may dissolve the electrode.
After a stimulating pulse, residual charge may remain at the electrode. Therefore, charge balancing may be necessary in order to keep the residual charge and the corresponding electrode voltage within a safety range. Existing concepts for charge balancing may have disadvantages as for example with respect to their power consumption, complexity, required space and response time.