Patent ID: 8451634

Claim:
A method of operating a flyback converter circuit, the method comprising: providing power to a transformer to operate the flyback converter in a transitional or discontinuous mode having a pre-set current for a primary winding of the transformer; determining a time-averaged voltage from a rectified voltage of a first winding of the transformer; determining a constant at least in part from the pre-set current of a primary side of the transformer, the constant being related to the magnitude of the pre-set current; multiplying the time-averaged voltage by the constant to calculate a power output utilizing an amplifier with a fixed gain operatively coupled to receive the average voltage signal wherein the fixed gain is set according to a pre-set average current for the primary winding of the transformer such that the amplifier provides a signal indicative of the DC output power level of the converter; and comparing the DC output power level to a pre-set output power limit to determine whether the DC output power level has exceeded the pre-set output power limit.