Apparatus and method for activating circuits

A method of activating various circuits, comprising:

• receiving, by a first circuit driven by a first clock signal generated by a first clock generator, audio data corresponding to an audio input;
• determining, by the first circuit driven by the first clock signal, whether an energy level of the audio data exceeds a predetermined threshold;
• activating a second clock generator to generate a second clock signal when the first circuit determines that the energy level of the audio data exceeds the predetermined threshold, wherein a frequency of the first clock is lower than a frequency of the second clock;
• determining, by the second circuit driven by the second clock signal, whether the audio data matches a predetermined pattern;
• and
• activating a third circuit with a frequency of a third clock greater than the frequency of the second clock when the second circuit determines that the audio data matches the predetermined pattern.

A non-transitory computer-readable medium storing instructions that, when executed by a processing circuit, cause the processing circuit to perform operations including:

• receiving an energy detection signal from a first circuit that is driven by a first clock signal generated by a first clock generator, the energy detection signal indicating whether an energy level of audio data corresponding to an audio input exceeds a predetermined threshold, the energy detection signal being generated according to
• generation of a detected energy level by integrating derived data that is derived from the audio data, and
• generation of the energy detection signal by comparing the detected energy level with the predetermined threshold;
• activating a second clock generator to generate a second clock signal when the energy detection signal indicates that the energy level of the audio data exceeds the predetermined threshold, wherein a frequency of the first clock is lower than a frequency of the second clock;
• receiving a pattern matching signal from a second circuit that is driven by the second clock signal generated by the second clock generator, the pattern matching signal indicating whether the audio data matches a predetermined pattern;
• and
• activating a third circuit with a frequency of a third clock greater than the frequency of the second clock when the pattern matching signal indicates that the audio data matches the predetermined pattern.