Embedded speaker protection for automotive audio power amplifier

A speaker system comprising:

• a speaker;
• an amplifier with an output configured to be coupled to a speaker;
• and
• an offset comparator with an input coupled to the output of the amplifier;
• a microprocessor coupled to the amplifier;
• wherein the speaker system is configured to be controlled to:
• turn on the amplifier in a mute mode;
• after a first delay period, place the amplifier in a play mode without an input signal during a second delay period;
• and
• use the offset comparator to perform a speaker offset detection during the second delay period;
• force the amplifier into the mute mode if a speaker offset is detected;
• and
• operate the amplifier in the play mode if no speaker offset is detected.

A circuit comprising:

• means for amplifying an audio signal;
• means for providing an offset control signal based on the amplified audio signal;
• means for generating a speaker control signal based upon a play control signal and an earlier value of the offset control signal;
• and
• means for generating a force mute signal based on the offset control signal, the play control signal and the speaker control signal.