Microphone having a digital output determined at different power consumption levels

A method of generating one or more signals to wake up an acoustically controlled device, the method comprising:

• receiving, at an input of a switch from an output of an acoustic sensor element, an output signal;
• determine, using an energy level per band detector circuit of a first channel, a respective energy level for each frequency band of a plurality of frequency bands of the output signal received from the acoustic sensor element;
• buffering, using the energy level per band detector circuit, each respective energy level for each frequency band;
• generating, using analog circuit of the first channel, a signal that causes at least a portion of the first channel to operate when at least one frequency band of the plurality of frequency bands meet a first threshold criteria;
• converting, using an analog-to-digital converter of a second channel, the output signal from the acoustic sensor element into a digitized output signal;
• receiving, at a threshold level detector, an output from the first channel;
• and
• feeding, by the switch, the output signal from the acoustic sensor element to the analog-to-digital converter when the output from the first channel meets a second threshold criteria, satisfaction of which specifies a presence of specified acoustic activity.