Systems and methods for current regulation in light-emitting-diode lighting systems

A method for regulating a current flowing through one or more light emitting diodes, the method comprising:

• receiving a first voltage related to a first current flowing out of a first controller terminal;
• generating a second voltage based at least in part on the first voltage;
• receiving the second voltage;
• generating a clock signal based at least in part on the second voltage, the clock signal being associated with an operating frequency;
• generating a drive signal associated with the operating frequency;
• and
• outputting the drive signal to affect a second current flowing through one or more light emitting diodes;
• wherein generating a clock signal based at least in part on the second voltage includes:
• keeping the operating frequency unchanged at a first frequency magnitude in response to the second voltage changing if the second voltage remains smaller than a first voltage magnitude;
• keeping the operating frequency unchanged at a second frequency magnitude in response to the second voltage changing if the second voltage remains larger than a second voltage magnitude;
• and
• changing the operating frequency in response to the second voltage changing if the second voltage remains larger than the first voltage magnitude and smaller than the second voltage magnitude;
• wherein the second voltage magnitude is larger than the first voltage magnitude.