Systems and methods for dimming control related to TRIAC dimmers associated with LED lighting

A system for regulating a diode current that flows through one or more light emitting diodes, the system comprising:

• a bleeder configured to receive a first bleeder control signal and a second bleeder control signal and generate a bleeder current related to a rectified voltage associated with a TRIAC dimmer based at least in part on the first bleeder control signal and the second bleeder control signal, the bleeder current being equal to or larger than zero in magnitude;
• a voltage generator configured to receive a first sensing signal representing the rectified voltage associated with the TRIAC dimmer, detect a phase range within which the TRIAC dimmer is in a conduction state based at least in part on the first sensing signal, and generate a reference voltage based at least in part on the detected phase range;
• a current regulator configured to receive the reference voltage, use the reference voltage to control the diode current flowing through the one or more light emitting diodes, and generate a second sensing signal representing the diode current;
• and
• a bleeder controller configured to receive the second sensing signal from the current regulator and generate the first bleeder control signal and the second bleeder control signal based at least in part on the second sensing signal, the first bleeder control signal indicating whether the bleeder current is allowed or not allowed to be larger than zero in magnitude;
• wherein the bleeder controller is further configured to, in response to at least the second sensing signal changing from being larger than a predetermined threshold to being smaller than the predetermined threshold:
• immediately change the first bleeder control signal from indicating the bleeder current is not allowed to be larger than zero in magnitude to indicating the bleeder current is allowed to be larger than zero in magnitude;
• immediately generate the second bleeder control signal at a first logic level;
• and
• after a predetermined delay of time, change the second bleeder control signal from the first logic level to a second logic level;
• wherein the predetermined delay of time is larger than zero.

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

• receiving a sensing signal representing a rectified voltage associated with a TRIAC dimmer;
• determining whether the rectified voltage is distorted or not based at least in part on the sensing signal;
• generating a distortion detection signal indicating whether the rectified voltage is distorted or not;
• generating a phase detection signal indicating a detected phase range within which the TRIAC dimmer is in a conduction state based at least in part on the sensing signal;
• receiving the distortion detection signal and the phase detection signal;
• generating a reference voltage based at least in part on the distortion detection signal and the phase detection signal;
• receiving the reference voltage;
• and
• using the reference voltage to control the diode current flowing through the one or more light emitting diodes;
• wherein the generating a reference voltage based at least in part on the distortion detection signal and the phase detection signal includes, if the distortion detection signal indicates that the rectified voltage is distorted:
• performing a phase compensation to the detected phase range within which the TRIAC dimmer is in the conduction state to generate a compensated phase range;
• and
• using the compensated phase range to generate the reference voltage.

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

• receiving a first bleeder control signal and a second bleeder control signal;
• generating a bleeder current related to a rectified voltage associated with a TRIAC dimmer based at least in part on the first bleeder control signal and the second bleeder control signal, the bleeder current being equal to or larger than zero in magnitude;
• receiving a first sensing signal representing the rectified voltage associated with the TRIAC dimmer;
• detecting a phase range within which the TRIAC dimmer is in a conduction state based at least in part on the first sensing signal;
• generating a reference voltage based at least in part on the detected phase range;
• receiving the reference voltage;
• using the reference voltage to control the diode current flowing through the one or more light emitting diodes;
• generating a second sensing signal representing the diode current;
• receiving the second sensing signal;
• and
• generating the first bleeder control signal and the second bleeder control signal based at least in part on the second sensing signal, the first bleeder control signal indicating whether the bleeder current is allowed or not allowed to be larger than zero in magnitude;
• wherein the generating the first bleeder control signal and the second bleeder control signal based at least in part on the second sensing signal includes, in response to at least the second sensing signal changing from being larger than a predetermined threshold to being smaller than the predetermined threshold:
• immediately changing the first bleeder control signal from indicating the bleeder current is not allowed to be larger than zero in magnitude to indicating the bleeder current is allowed to be larger than zero in magnitude;
• immediately generating the second bleeder control signal at a first logic level;
• and
• after a predetermined delay of time, changing the second bleeder control signal from the first logic level to a second logic level;
• wherein the predetermined delay of time is larger than zero.