Low Distortion Output Stage for Audio Amplifiers

An integrated circuit operational amplifier comprising:

• an input stage operable to receive differential input voltage signals and further operable to generate an amplified voltage signal that amplifies the difference between the input voltage signals;
• and
• an output stage operable to receive the amplified voltage signal and further operable to generate an audio output signal that modifies the amplified signal for playback by a first speaker system, the output stage comprising:
• a diamond driver circuit operable to buffer the input stage from the first speaker system;
• a boosting circuit operable to amplify the current of the amplified voltage signal, wherein the boost circuit comprises at least one complementary pair of boosting transistors, wherein the boosting circuit further comprises a pair of Miller compensation capacitors;
• and
• a biasing circuit operable to provide bias currents to the transistors of the boost circuit.

An integrated circuit operational amplifier comprising:

• an input stage operable to receive differential input voltage signals and further operable to generate an amplified voltage signal that amplifies the difference between the input voltage signals;
• and
• an output stage operable to receive the amplified voltage signal and further operable to generate an audio output signal that modifies the amplified signal for playback by a first speaker system, the output stage comprising:
• a diamond driver circuit operable to buffer the input stage from the first speaker system;
• a boosting circuit operable to amplify the current of the amplified voltage signal, wherein the boost circuit comprises at least one complementary pair of boosting transistors;
• a biasing circuit operable to provide bias currents to the transistors of the boost circuit, wherein the diamond driver circuit includes a pair of series current sources that provide a biasing current to the biasing circuit.

A method for amplifying an audio signal for playback by a speaker system, the method comprising:

• receiving, at an input stage, differential input voltage signals;
• generating, at the input stage, an amplified voltage signal that amplifies the difference between the input voltage signals;
• receiving, at an output stage, the amplified voltage signal;
• buffering the input stage from the first speaker system via a diamond driver circuit of the output stage;
• amplifying the current of the amplified voltage signal via a boost circuit of the output stage, wherein the boost circuit comprises at least one complementary pair of boosting transistors, wherein the at least one complementary pair of boosting transistors are configured to provide push-pull current amplification;
• providing bias currents to the transistors of the boost circuit via a biasing circuit;
• and
• generating an audio output signal that modifies the amplified signal for playback by the speaker system.

A method for amplifying an audio signal for playback by a speaker system, the method comprising:

• receiving, at an input stage, differential input voltage signals;
• generating, at the input stage, an amplified voltage signal that amplifies the difference between the input voltage signals;
• receiving, at an output stage, the amplified voltage signal;
• buffering the input stage from the first speaker system via a diamond driver circuit of the output stage;
• amplifying the current of the amplified voltage signal via a boosting circuit of the output stage, wherein the boosting circuit comprises at least one complementary pair of boosting transistors, wherein the boosting circuit further comprises a pair of Miller compensation capacitors;
• providing bias currents to the transistors of the boost circuit via a biasing circuit and
• generating an audio output signal that modifies the amplified signal for playback by the speaker system.

A method for amplifying an audio signal for playback by a speaker system, the method comprising:

• receiving, at an input stage, differential input voltage signals;
• generating, at the input stage, an amplified voltage signal that amplifies the difference between the input voltage signals;
• receiving, at an output stage, the amplified voltage signal;
• buffering the input stage from the first speaker system via a diamond driver circuit of the output stage;
• amplifying the current of the amplified voltage signal via a boosting circuit of the output stage, wherein the boosting circuit comprises at least one complementary pair of boosting transistors,
• providing bias currents to the transistors of the boost circuit via a biasing circuit and
• generating an audio output signal that modifies the amplified signal for playback by the speaker system, wherein the diamond driver circuit includes a pair of series current sources that provide a biasing current to the biasing circuit.