Amplifiers

Audio amplifier circuitry comprising:

• an amplifier module located in a signal path between an input and an output;
• a detection module for detecting a characteristic of a load electrically coupled, in use, to the output;
• a distortion setting controller for selecting one of a plurality of stored distortion settings based on the detected characteristic of the load;
• and
• a pre-distortion module configured to apply a first transfer function to a signal in the signal path prior to said amplifier module, wherein the first transfer function is based on the selected distortion setting;
• wherein for at least one of the stored distortion settings the corresponding first transfer function comprises a non-linear distortion function;
• wherein the detection module is coupled to the output of the amplifier circuitry and is configured to determine the characteristic of the load through monitoring of the electrical properties at the output when a load is connected;
• wherein the detection module is configured to detect when a load is operably connected to the output and then to determine the characteristic of the load;
• and
• wherein, in response to a detection that a load has been operably connected to the output, the amplifier circuitry is configured to apply a test stimulus to the output and the detection module is configured to monitor the electrical properties at the output in response to the test stimulus to determine the characteristic of the load.

Audio amplifier circuitry comprising:

• an amplifier module located in a signal path between an input and an output;
• a detection module for detecting a characteristic of a load electrically coupled, in use, to the output;
• a distortion setting controller for selecting one of a plurality of stored distortion settings based on the detected characteristic of the load;
• and
• a pre-distortion module configured to apply a first transfer function to a signal in the signal path prior to said amplifier module, wherein the first transfer function is based on the selected distortion setting;
• wherein for at least one of the stored distortion settings the corresponding first transfer function comprises a non-linear distortion function;
• wherein the detection module is configured to, in use, continuously or periodically monitor the characteristic of the load;
• and
• wherein, when the detection module is monitoring the characteristic of the load, the amplifier circuitry is configured to add a pilot tone at a pilot tone frequency to the signal in the signal path and the detection module monitors the electrical properties at the output at said pilot tone frequency.

Audio amplifier circuitry comprising:

• an amplifier module located in a signal path between an input and an output;
• a detection module for detecting a characteristic of a load electrically coupled, in use, to the output;
• a distortion setting controller for selecting one of a plurality of stored distortion settings based on the detected characteristic of the load;
• and
• a pre-distortion module configured to apply a first transfer function to a signal in the signal path prior to said amplifier module, wherein the first transfer function is based on the selected distortion setting;
• wherein for at least one of the stored distortion settings the corresponding first transfer function comprises a non-linear distortion function;
• and
• wherein the distortion setting controller is configured such that the selection of the one of the stored plurality of distortion settings is also based on an indication of at least one operating condition of the amplifier circuitry.

Audio amplifier circuitry comprising:

• an amplifier module located in a signal path between an input and an output;
• a detection module for detecting a characteristic of a load electrically coupled, in use, to the output;
• a distortion setting controller for selecting one of a plurality of stored distortion settings based on the detected characteristic of the load;
• and
• a pre-distortion module configured to apply a first transfer function to a signal in the signal path prior to said amplifier module, wherein the first transfer function is based on the selected distortion setting;
• wherein for at least one of the stored distortion settings the corresponding first transfer function comprises a non-linear distortion function;
• and
• wherein the distortion setting controller is configured to modify the selected distortion setting based on an indication of at least one operating condition of the amplifier circuitry.

Audio amplifier circuitry comprising:

• an amplifier module located in a signal path between an input and an output;
• a detection module for detecting a characteristic of a load electrically coupled, in use, to the output;
• a distortion setting controller for selecting one of a plurality of stored distortion settings based on the detected characteristic of the load;
• and
• a pre-distortion module configured to apply a first transfer function to a signal in the signal path prior to said amplifier module, wherein the first transfer function is based on the selected distortion setting;
• wherein for at least one of the stored distortion settings the corresponding first transfer function comprises a non-linear distortion function;
• and
• wherein the distortion setting controller is configured, such that, in the event that the selected distortion setting is changed in use, to transition from the old distortion setting to the new distortion setting via at least one intermediate setting value.

An electronic device comprising audio amplifier circuitry as claimed in any preceding claim wherein the electronic device is at least one of:

• a communications device;
• a computing device;
• a portable device;
• a battery powered device;
• a wearable device;
• a gaming device;
• a mobile telephone;
• a laptop, notebook or tablet computer.