Systems and methods for controlling currents flowing through light emitting diodes

A system for controlling one or more light emitting diodes, the system comprising:

• a phase detector configured to process information associated with a rectified voltage generated by a rectifier and related to a TRIAC dimmer, the rectified voltage corresponding to a first waveform during a first half cycle of an AC voltage and corresponding to a second waveform during a second half cycle of the AC voltage, the signal detector being further configured to generate a phase detection signal representing a first time duration during which the first waveform indicates that the rectified voltage is larger than a predetermined threshold and representing a second time duration during which the second waveform indicates that the rectified voltage is larger than the predetermined threshold;
• a mode detector configured to process information associated with the rectified voltage, determine whether the TRIAC dimmer is a leading-edge TRIAC dimmer or a trailing-edge TRIAC dimmer based on at least information associated with the rectified voltage, and generate a mode detection signal that indicates whether the TRIAC dimmer is the leading-edge TRIAC dimmer or the trailing-edge TRIAC dimmer;
• and
• a modified signal generator configured to receive the phase detection signal from the phase detector and the mode detection signal from the mode detector, the modified signal generator being further configured to generate, based at least in part on the phase detection signal and the mode detection signal, a modified signal representing a third time duration corresponding to the first half cycle of the AC voltage and a fourth time duration corresponding to the second half cycle of the AC voltage;
• wherein:
• the first time duration is smaller than the second time duration in magnitude;
• the third time duration is equal to the first time duration in magnitude;
• the fourth time duration is smaller than the second duration in magnitude;
• and
• the third time duration and the fourth time duration are equal in magnitude.

A method for controlling one or more light emitting diodes, the method comprising:

• processing information associated with a rectified voltage related to a TRIAC dimmer, the rectifed voltage corresponding to a first waveform during a first half cycle of an AC voltage and corresponding to a second waveform during a second half cycle of the AC voltage;
• generating a phase detection signal representing a first time duration during which the first waveform indicates that the rectified voltage is larger than a predetermined threshold and representing a second time duration during which the second waveform indicates that the rectified voltage is larger than the predetermined threshold;
• determining whether the TRIAC dimmer is a leading-edge TRIAC dimmer or a trailing-edge TRIAC dimmer based on at least information associated with the rectified voltage;
• generating a mode detection signal that indicates whether the TRIAC dimmer is the leading-edge TRIAC dimmer or the trailing-edge TRIAC dimmer;
• receiving the phase detection signal and the mode detection signal;
• modifying the phase detection signal based at least in part on the mode detection signal;
• generating a modified signal representing a third time duration corresponding to the first half cycle of the AC voltage and a fourth time duration corresponding to the second half cycle of the AC voltage;
• receiving the modified signal;
• and
• controlling, based at least in part of the modified signal, a first current flowing through one or more light emitting diodes configured to receive the rectified voltage;
• wherein:
• the first time duration and the second time duration are different in magnitude;
• and
• the third time duration and the fourth time duration are the same in magnitude.

A method for controlling one or more light emitting diodes, the method comprising:

• processing information associated with a rectified voltage related to a TRIAC dimmer, the rectified voltage corresponding to a first waveform during a first half cycle of an AC voltage and corresponding to a second waveform during a second half cycle of the AC voltage;
• generating a phase detection signal representing a first time duration during which the first waveform indicates that the rectified voltage is larger than a predetermined threshold and representing a second time duration during which the second waveform indicates that the rectified voltage is larger than the predetermined threshold;
• determining whether the TRIAC dimmer is a leading-edge TRIAC dimmer or a trailing-edge TRIAC dimmer based on at least information associated with the rectified voltage;
• generating a mode detection signal that indicates whether the TRIAC dimmer is the leading-edge TRIAC dimmer or the trailing-edge TRIAC dimmer;
• receiving the phase detection signal and the mode detection signal;
• and
• generating, based at least in part on the phase detection signal and the mode detection signal, a modified signal representing a third time duration corresponding to the first half cycle of the AC voltage and a fourth time duration corresponding to the second half cycle of the AC voltage;
• wherein:
• the first time duration is smaller than the second time duration in magnitude;
• the third time duration is equal to the first time duration in magnitude;
• the fourth time duration is smaller than the second duration in magnitude;
• and
• the third time duration and the fourth time duration are equal in magnitude.