A 1-V, 1.2-mA fully integrated SoC for digital hearing aids

Both power and size are very important design issues for hearing aids. This paper proposes a fully integrated low-power SoC for today's digital hearing aids. The SoC integrates all the audio processing elements on single chip, including the analog front-end, digital signal processing (DSP) platform and class-D amplifier. Also, the low-dropout voltage regulators and internal clock generator are both integrated to minimize the system overall size. The 24-bit DSP platform comprises an application-specific instruction-set processor and several dedicated accelerators to achieve a trade-off between flexibility and power efficiency. Three critical hearing-aid algorithms (wide dynamic range compression, noise reduction and feedback cancellation) are performed by the low-power accelerators. The proposed SoC has been fabricated in SMIC 130 nm CMOS technology. The measurement results show that the analog front-end has up to 88 dB signal-to-noise ratio. And the DSP platform consumes about 0.86 mA current at 8 MHz clock frequency when executing the three algorithms. The total current consumption of SoC is only 1.2 mA at 1 V supply. In addition, the acoustic test results indicate that the SoC is one promising candidate for hearing-aid manufacturers. (C) 2014 Elsevier Ltd. All rights reserved.