A micropower envelope detector for audio applications [hearing aid applications]

A low-power envelope-detecting circuit for analog audio applications is implemented using a wide-linear-range transconductor (WLR OTA), a class-B mirror, and a simple current-mode peak detector. A DC-offset correction loop ensures insensitivity to DC input conditions. In a 1.5 /spl mu/m BiCMOS technology, and over most of the 100 Hz-10 kHz audio frequency range, an experimental implementation yielded almost 60 dB of linear operation while consuming less than 5.3 /spl mu/W of power from a 2.8 V supply.