Circuits and methods for driving light sources

A controller for controlling a buck-boost converter that receives an input voltage and an input current and powers a light-emitting diode (LED) light source, said controller comprising:

• a first sensing pin that receives a first signal indicating a current flowing through said LED light source;
• a detection pin that receives a detection signal indicating an electrical condition of an energy storage element in said buck-boost converter, wherein a current of said energy storage element is controlled by a switch, and wherein said controller turns on said switch if a current of said detection signal decreases to a predetermined current level;
• and
• a driving pin that provides a driving signal to said switch based on said first signal and said detection signal, to control an instant current flowing through said buck-boost converter so as to adjust said current flowing through said LED light source,
• wherein said first signal is derived from a second signal indicating said instant current flowing through said buck-boost converter.