Cochlear Implant Signal Processing ICs

The Nucleus Freedom cochlear implant system enables a profoundly deaf person to hear. The system consists of a surgically implanted stimulator and a battery-powered external sound processor. The processor is based on a 0.18 μm CMOS ASIC containing four DSP cores. The signal processing includes a two-microphone adaptive beamformer, a 22-channel quadrature FFT filterbank, multi-band automatic gain control, a psycho-acoustic masking model and non-linear compression. The key design challenge was power consumption.