Patent ID: 7436967

Claim:
An apparatus to limit an average power applied to a loudspeaker comprising: a power source to drive the loudspeaker using an input signal; a voltage monitor coupled to the power source to detect a voltage of the input signal; a current monitor coupled to the power source to detect a current of the input signal; a control circuit coupled to said voltage monitor and said current monitor, said control circuit to calculate an average power being applied to the loudspeaker by the power source using said voltage and current, wherein an averaging coefficient (T A ) is calculated by the control circuit using a power averaging time according to T A = ⅇ - n t a ⁢ f s , where n is a filter order, t a is the power averaging time in seconds, and f s is a sampling frequency; and, a signal attenuator coupled to the power source and the control circuit, the signal attenuator to limit said input signal based on said average power, wherein said signal attenuator is to limit said input signal based on one or more control parameters, wherein said control parameters includes one or more of the power averaging time, a power threshold, an attack time and a release time.