SmartHeaP - A High-level Programmable, Low Power, and Mixed-Signal Hearing Aid SoC in 22nm FD-SOI

To handle the advances in hearing aid algorithms, the need for high-level programmable but low-power hardware architectures arises. Therefore, this paper presents the Smart Hearing Aid Processor (SmartHeaP), a mixed-signal system on chip (SoC) fabricated in 22 nm fully-depleted silicon-on-insulator (FD-SOI) with an adaptive body biasing (ABB) unit and a total die size of 7.36 mm
²
. The proposed SoC consists of two application-specific instruction set processor (ASIP) architectures: firstly, a Cadence Tensilica Fusion G6 instruction set architecture, extended with custom instructions for audio processing, and secondly, a Cadence Tensilica LX7 for wireless interfacing, e.g., Bluetooth Low Energy. Furthermore, an analog front-end and digital audio interfaces are added. The large local memory of 2 MB and a high-level software environment enables memory-intensive algorithms to be deployed quickly. Typical hearing aid algorithms in a real-time setup are used to evaluate the power consumption of the SoC at different operating frequencies. At 50 MHz, a mean power consumption of less than 2.2 mW was measured, resulting in an efficiency of 34.8 µW/MHz.