Patent ID: 6940981

Claim:
An apparatus to limit power to a load, comprising: a power source to drive the load using an input signal; a voltage monitor coupled to the power source to detect a voltage supplied by the power source and to provide a voltage signal representative of said voltage; a current monitor coupled to the power source to detect a current supplied by the power source and to provide a current signal representative of said current; a control circuit to receive said voltage signal and said current signal, said control circuit to provide a value based on said voltage signal and said current signal according to control parameters which include a power averaging time and a power threshold; and, a signal attenuator coupled to the power source and the control circuit, the signal attenuator to limit said input signal based on said value, wherein an averaging coefficient (T A ) is calculated by the control circuit using the 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.