Controller for a power converter and method of operating the same

A controller employable with a power converter having a transformer with a primary winding coupled to a power switch and a secondary winding coupled to an output thereof, comprising:

• a primary peak current circuit configured to produce a reference voltage corresponding to a primary peak current through said primary winding of said transformer;
• an offset corrector configured to provide an offset voltage to compensate for delays in said power converter, said offset voltage being a function of said reference voltage from said primary peak current circuit and a sense voltage from a sense resistor in series with said power switch;
• a summer configured to provide an offset reference voltage as a function of said reference voltage and said offset voltage;
• and
• a comparator configured to produce a signal to turn off said power switch as a function of said offset reference voltage.

A method of operating a controller employable with a power converter having a transformer with a primary winding coupled to a power switch and a secondary winding coupled to an output thereof, comprising:

• producing a reference voltage corresponding to a primary peak current through said primary winding of said transformer;
• providing an offset voltage to compensate for delays in said power converter, said offset voltage being a function of said reference voltage and a sense voltage from a sense resistor in series with said power switch;
• providing an offset reference voltage as a function of said reference voltage and said offset voltage;
• and
• producing a signal to turn off said power switch as a function of said offset reference voltage.

A power converter, comprising:

• a transformer having a primary winding coupled to a power switch and a secondary winding coupled to an output thereof;
• and
• a controller, including:
• a primary peak current circuit configured to produce a reference voltage corresponding to a primary peak current through said primary winding of said transformer,
• an offset corrector configured to provide an offset voltage to compensate for delays in said power converter, said offset voltage being a function of said reference voltage from said primary peak current circuit and a sense voltage from a sense resistor in series with said power switch,
• a summer configured to provide an offset reference voltage as a function of said reference voltage and said offset voltage, and
• a comparator configured to produce a signal to turn off said power switch as a function of said offset reference voltage.