Dual-mode constant load control circuits and associated methods

A circuit, comprising:

• a primary winding;
• a switching transistor coupled to the primary winding, the switching transistor being configured to carry a drain-source current;
• a feedback voltage port configured to carry a feedback voltage;
• a switch coupled to the feedback voltage port;
• an amplifier having an input port coupled to the switch and an output port coupled to the switching transistor;
• and
• a comparator having a first input port configured to carry a threshold voltage, a second input port coupled to the feedback voltage port, and an output port configured to carry a signal having a first logic state and a second logic state, the output port of the comparator coupled to the switch to couple the input port of the amplifier to the feedback voltage port only if the output port voltage of the comparator is the first logic state;
• wherein the peak current limit increases with increasing feedback voltage if and only if the feedback voltage satisfies an ordered relationship with a threshold.

A system, comprising:

• a primary winding;
• a first winding magnetically coupled to the primary winding to provide a feedback voltage;
• a switching transistor coupled to the primary winding, the switching transistor to provide a drain-source current;
• and
• a feedback port coupled to the first winding, the feedback port being configured to carry the feedback voltage and being coupled to the switching transistor to switch off the switching transistor when the drain-source current reaches a peak current limit, wherein the peak current limit increases with increasing feedback voltage only if the feedback voltage satisfies a first ordered relationship with a first threshold, and wherein the peak current limit is static only if the feedback voltage satisfies a second ordered relationship with a second threshold.