Patent ID: 7525823

Claim:
A system for estimating the output current of a Switch Mode Power Supply (SMPS), the SMPS including a transformer with at least a primary winding coupled to an input of the SMPS and a secondary winding coupled to an output of the SMPS and having a power switching device to switch power to the primary winding of the transformer, the system comprising: a primary current sense input to sense a primary current in the primary winding of the transformer; a charge signal input to sense a charge signal dependent on a charging time of the transformer; a discharge signal input to sense a discharge signal dependent on a discharging time of the transformer; at least one averager; and a calculator; wherein the primary current is averaged by the averager over at least a switching cycle of the SMPS; and wherein the calculator estimates the output current of the SMPS using the averaged primary current, the charge signal and the discharge signal.