Patent ID: 6972969

Claim:
A method for limiting an output current of a power supply having a primary and secondary side using pulse width modulation comprising the steps of: generating a sense voltage signal on the primary side that is proportional to an output voltage signal on the secondary side; generating a digital feedback voltage signal from a sense voltage signal; generating an error feedback signal that is a function of a difference between said digital feedback voltage signal and a nominal feedback voltage signal, generating a control signal wherein said control signal corresponds to said error feedback signal when an output current does not exceed an output current limit, and wherein said control signal corresponds to said digital feedback voltage that is offset by a first voltage when said output current exceeds the output current limit; generating a squared feed-forward signal that is proportional to the square of a direct current input voltage signal; and generating an on-time signal for pulse width modulation based upon said control signal and said squared feed-forward signal.