Hearing aid amplifier having feed forward bias control based on signal amplitude and frequency for reduced power consumption

A hearing aid, comprising:

• a sensor that receives ambient sound from around a patient and produces a single broadband input signal in response to the ambient sound;
• a splitter that directs portions of the broadband input signal to a plurality of narrowband amplifiers, each narrowband amplifier receiving a respective band of frequencies within the frequency range of normal human hearing;
• each narrowband amplifier applying a predetermined gain to the respective narrowband input signal to form a respective narrowband output signal,
• wherein the bands of frequencies corresponding to the plurality of narrowband input signals subtend the full frequency range of normal human hearing;
• a combiner that combines the plurality of narrowband output signals to form a broadband output signal;
• a broadband amplifier that amplifies the broadband output signal, the amplified broadband output signal being capable of driving a transducer that stimulates the anatomy of the patient;
• a plurality of monitors that form a respective plurality of narrowband volume envelopes from the plurality of narrowband output signals;
• a bias generator that receives the plurality of narrowband volume envelopes, applies a predetermined weighting to the plurality of narrowband volume envelopes, determines a dynamic bias current level from the weighted plurality of narrowband volume envelopes;
• and applies a dynamic bias current at the dynamic bias current level to the amplifier.

A method, comprising:

• providing a single broadband signal;
• splitting the broadband signal into a plurality of narrowband signals, each narrowband signal having a corresponding frequency band,
• wherein the bands of frequencies corresponding to the plurality of narrowband input signals subtend the full frequency range of normal human hearing;
• forming a volume envelope for each narrowband signal;
• weighting the volume envelopes by frequency, wherein higher frequencies are weighted more heavily than lower frequencies;
• calculating a dynamic bias current level based on the weighted volume envelopes;
• providing a dynamic bias current having the dynamic bias current level to an output amplifier;
• and
• amplifying the broadband signal with the output amplifier.