A Low-Power Magnitude Detector for Analysis of Transient-Rich Signals

作者：Rumberg Brandon^*; Graham David W

来源：IEEE Journal of Solid-State Circuits, 2012, 47(3): 676-685.

DOI：10.1109/JSSC.2011.2179452

• Analog processing circuits
• CMOS integrated circuits
• continuous-time circuits
• envelope detectors
• magnitude detectors
• nonlinear dynamic circuits
• peak detectors
• ultra-low power

Magnitude detection, such as envelope detection or RMS estimation, is needed for many low-power signal-analysis applications. In such applications, the temporal accuracy of the magnitude detector is as important as its amplitude accuracy. We present a low-power audio-frequency magnitude detector that simultaneously achieves both high temporal accuracy and high amplitude accuracy. This performance is achieved by rectifying the signal with a high-ripple peak detector and then averaging this rectified signal with an adaptive-time-constant filter. The time constant of this filter decreases with increasing amplitude, enabling the filter to quickly respond on a short time scale to transients, while steady-state ripple is averaged on a longer time scale. The circuit has been fabricated in a 0.18 mu m CMOS process and consumes only 1.1 nW-1.08 mu W when tuned for operation from 20 Hz-20 kHz. It exhibits a dynamic range of 70 dB across typical speech frequencies.

• 出版日期2012-3