Devices and methods compensate for perturbations in a stimulation signal caused by external conditions such as a magnetic field of an MRI machine so that stimulation therapy may continue in the presence of the external condition. Compensation for the perturbations during a stimulation pulse of a stimulation phase may be provided by using feedback within a stimulation current source. Perturbations during a recharge phase may be addressed by utilizing an active recharge at least when the external condition is present. Furthermore, compensation for perturbations during a recharge pulse of the active recharge phase may be provided by using feedback within a recharge current source. Passive recharge may be used instead of active recharge when the external condition is not present to preserve battery life of the stimulation device. The stimulation device may include a sensor to detect the external condition so that an appropriate mode of recharge may be chosen.