Dimmer-controlled leds using flyback converter with high power factor

The flyback controller of claim 20 wherein the flyback controller includes a second integrator configured to generate the desired peak input current in the primary winding.

A flyback controller configured to generate a switching signal for controlling delivery of current into a primary winding of a transformer in a flyback converter, the flyback controller being further configured to generate the switching signal with a timing that:

• causes a chopped AC voltage from a dimmer control to be converted by the flyback converter into an average output current from a secondary winding of the transformer that is DC isolated from the chopped AC voltage;
• and
• varies as a function of the setting of the dimmer control, the flyback controller further being configured not to utilize a signal from an opto-isolator that is configured to provide feedback indicative of the output current from the secondary winding.

A flyback converter comprising:

• a transformer having a primary winding and a secondary winding;
• a flyback controller configured to generate a switching signal for controlling delivery of current into the primary winding of the transformer, the flyback controller including an output current monitoring circuit configured to generate a signal representative of an average output current in the secondary winding of the transformer based on a peak input current in the primary winding and a duty cycle of current in the secondary winding.

A dimmer-controllable LED circuit comprising:

• a flyback converter configured to convert a chopped AC voltage from a dimmer control into a average output current that is DC isolated from the chopped AC voltage and that varies as a function of the setting of the dimmer control, the flyback converter including a transformer and a flyback controller configured to generate a switching signal for controlling the delivery of current into a primary winding of the transformer, the flyback controller having an output current monitoring circuit configured to generate a signal representative of an average output current delivered by the secondary winding based on a peak input current through the primary winding and a duty cycle of current flowing through the secondary winding;
• and
• one or more LEDs configured to receive the average output current.

A dimmer-controllable LED circuit comprising:

• a flyback converter configured to convert a chopped AC voltage from a dimmer control into an average output current that is DC isolated from the chopped AC voltage and that varies as a function of the setting of the dimmer control, the flyback converter not having any opto-isolator configured to provide feedback indicative of the output current;
• and
• one or more LEDs configured to receive the average output current.