Cochlear implants (CIs), or bionic ears, restore hearing in profoundly deaf (greater than -90 dB hearing loss) patients. They function by transforming frequency patterns in sound into corresponding spatial electrode-stimulation patterns for the auditory nerve. Over the past 20 years, improvements in sound-processing strategies, in the number of electrodes and channels, and in the rate of stimulation have yielded improved sentence and word recognition scores in patients. Next- generation implants will be fully implanted inside the patient's body. Consequently, power consumption requirements for signal processing will be very stringent.