US 8,284,971 B2Granted

Logarithmic compression systems and methods for hearing amplification

AssigneeEnvoy Medical Corporation

InventorPeter Schiller

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Abstract

Embodiments of the invention provide an amplifier including a gain control circuit having a gain measurement circuit as part of a feedback loop. The gain measurement circuit generates an attenuated output signal, based on the gain of the amplifier circuit, which is used to generate a gain control signal. One amplifier includes a first attenuator enabling primary compression and a second attenuator as part of a gain measurement circuit. In some cases the attenuation factors of the first and second attenuators may be proportional or substantially the same. In some embodiments one or more output stages (e.g., differential amplifiers) are provided to generate the gain control signal based on differential combinations of an audio output, the attenuated output signal, and a primary threshold signal. A ratio of the gains of the two or more comparing amplifiers can set a primary compression ratio in some cases.

Claims28

Dependent claims

A hearing assistance device, comprising:

an input transducer;
an output transducer;
an audio amplifier having a gain, a gain control input, an input coupled to the input transducer and an output coupled to the output transducer, the audio amplifier generating an audio output signal on its output based on the audio amplifier gain;
and
a gain control circuit having an input coupled to the audio amplifier output and an output coupled to the audio amplifier gain control input, the gain control circuit having
a gain measurement circuit having an input coupled to the audio amplifier output, an output, and a control input, the gain measurement circuit adapted to generate an attenuated output signal based on the audio amplifier gain and
a control signal generator having a first input coupled to the audio amplifier output, a second input coupled to the gain measurement circuit output, a third input coupled to a threshold signal reference, and an output coupled to the audio amplifier gain control input and the gain measurement circuit control input, the control signal generator adapted to generate and output a gain control signal based on a threshold signal, the audio output signal and the attenuated output signal.

4 more elements

A hearing assistance device, comprising:

an audio amplifier circuit receiving as inputs an input signal and a gain control signal for adjusting a gain of the audio amplifier circuit, the audio amplifier circuit generating and outputting an audio output signal based on the input signal and the gain control signal;
and
a gain control circuit receiving as an input the audio output signal and generating and outputting the gain control signal for controlling the audio amplifier circuit, the gain control circuit comprising a first output stage outputting a first output signal, the gain control signal being based on at least the first output signal, and the gain control circuit generating the first output signal as a function of the gain of the audio amplifier circuit using the audio output signal and the gain control signal.

A hearing assistance device comprising:

an input transducer;
an output transducer;
an audio amplifier having a gain, a gain control input, an input coupled to the input transducer and an output coupled to the output transducer, the audio amplifier generating an audio output signal on its output based on the audio amplifier gain;
and
a gain control circuit having an input coupled to the audio amplifier output and an output coupled to the audio amplifier gain control input, the gain control circuit having
a gain measurement circuit having an input coupled to the audio amplifier output, an output, and a control input, the gain measurement circuit adapted to generate an attenuated output signal based on the audio amplifier gain and
a control signal generator comprising a first input coupled to the audio amplifier output, a second input coupled to the gain measurement circuit output, a third input coupled to a threshold signal reference, an output coupled to the audio amplifier gain control input and the gain measurement circuit control input, a first logarithmic converter adapted to receive the audio output signal and generate and output a transformed output signal proportional to a logarithm of the audio output signal, a second logarithmic converter adapted to receive the attenuated output signal and generate and output a transformed attenuated output signal proportional to a logarithm of the attenuated output signal, and a third logarithmic converter adapted to receive a threshold signal and generate and output a transformed threshold signal proportional to a logarithm of the threshold signal,
the control signal generator adapted to generate and output a gain control signal based on the threshold signal, the audio output signal and the attenuated output signal.

5 more elements

Dependencies are inferred from the claim text.