A bandwidth-adaptive sensor interface

This paper describes a bandwidth-adaptive strategy to improve the power efficiency of an audio sensor interface. In this scheme, the input signal's short-time bandwidth is estimated in real time, and the analog front end (AFE) and analog-to-digital converter (ADC) of the sensor interface adapt their power consumption in response to this short-time bandwidth. A prototype sensor interface was fabricated in a 0.35-μm complementary metal-oxide-semiconductor (CMOS) process to verify the proposed bandwidth-adaptive scheme. Measurement results show that the AFE has a signal-to-noise ratio (SNR) of 62 dB and the ADC has a quantization accuracy of 9.0 bit, and these specifications are not corrupted with the bandwidth adaptation. Compared to a conventional sensor interface, whose bandwidth is always held at the maximum (4 kHz), our adaptive sensor interface provides similar or even better performance, but at a lower average power consumption.