Patent ID: 7342761

Claim:
An apparatus for limiting the power consumed by electrical equipment circuits that may be connected to power sources providing varying voltages, that apparatus comprising: load circuits having a designed power limit; input power processing circuits positioned between the load circuits and a power source, the input power processing circuits including: a current sensing circuit that detects a magnitude of electric current flowing to the load circuits and producing a first signal level that indicates the magnitude of current; a comparator connected to the current sensing circuit and having a first input to which the first signal level is applied, a second input connected to a source of a reference signal level, and a comparator output at which an output signal is produced in response to comparing the first signal level and the reference signal level; a circuit branch connected to the comparator and which alters one of the first signal level and the reference signal level in response to determination of voltage applied to the load circuits, which results in an output signal indicating when electric power consumed by the load exceeds a threshold level; and a device connected to the comparator output and disconnecting flow of electric current from the power source to the load circuits in response to the output signal whereby electrical power is blocked from entering the load circuits at a current threshold value that is dependant upon the voltage applied to the load circuits to limit power to the load circuits, wherein the circuit branch comprises: a circuit element connected to a current sensing resistor and producing a signal indicating when voltage applied to the load circuits exceeds a defined magnitude; and a second operational amplifier having an input coupled to the circuit element and having a second output connected to the second input of the comparator.