Generating a control signal based on leading edge dimming detection for maintaining input current of a power converter

A power converter, comprising:

• an energy transfer element coupled between an input and an output of the power converter;
• a power switch coupled to the energy transfer element to control a transfer of energy between the input and the output of the power converter;
• a controller coupled to control switching of the power switch to regulate an output of the power converter;
• a leading edge dimming detection circuit coupled to generate a control signal in response to detecting leading edge dimming at the input of the power converter;
• a compensator coupled to the input of the power converter;
• and
• a control switch coupled to selectively engage the compensator in response to the control signal indicating the detection of leading edge dimming, wherein, when engaged, the compensator is coupled to maintain an input current of the power converter to be equal to or greater than a minimum current,
• wherein the leading edge dimming detection circuit is coupled to detect a current spike in a rectified input current of the power converter, and to generate the control signal to engage the compensator in response thereto, wherein the current spike corresponds with the turning on of an input voltage of the power converter by a dimming circuit during leading edge dimming, and wherein the leading edge dimming detection circuit comprises a current sense resistance coupled such that the rectified input current flows through the current sense resistance to develop a first voltage across the current sense resistance.

A power converter, comprising:

• an energy transfer element coupled between an input and an output of the power converter;
• a power switch coupled to the energy transfer element to control a transfer of energy between the input and the output of the power converter;
• a controller coupled to control switching of the power switch to regulate an output of the power converter;
• a damper circuit coupled to suppress a spike in an input current of the power converter, wherein the spike in the input current corresponds with a turn-on event of an input voltage of the power converter by a leading edge dimming circuit that is to be coupled to the input of the power converter;
• and
• a leading edge dimming detection circuit coupled to generate a control signal in response to detecting leading edge dimming at the input of the power converter, wherein the leading edge dimming detection circuit further includes a spike energy reclamation circuit coupled to the damper circuit to store energy generated by the spike in the input current and to generate the control signal in response thereto.