Systems and methods for intelligent control related to triac dimmers by using modulation signals

A system controller for a lighting system, the system controller comprising:

• a first controller terminal configured to receive a first signal;
• a transistor including a first transistor terminal, a second transistor terminal, and a third transistor terminal;
• a second controller terminal coupled to the first transistor terminal;
• and
• a third controller terminal coupled to the third transistor terminal;
• wherein the system controller is configured to:
• determine whether the first signal is associated with a leading-edge TRIAC dimmer based at least in part on the first signal, the leading-edge TRIAC dimmer being configured to receive an AC input voltage associated with at least a first half cycle, a second half cycle, and a third half cycle, the first half cycle immediately preceding the second half cycle, the third half cycle following the first half cycle and the second half cycle;
• in response to the first signal being determined to be associated with the leading-edge TRIAC dimmer, generate a drive signal;
• and
• send the drive signal to the second transistor terminal;
• wherein the system controller is further configured to:
• within the first half cycle, determine a first time period from a first time when the first signal becomes larger than a first threshold to a second time when the first signal becomes smaller than a second threshold;
• within the second half cycle, determine a second time period from a third time when the first signal becomes larger than the first threshold to a fourth time when the first signal becomes smaller than the second threshold;
• and
• determine a third time period and a fourth time period based at least in part on the first time period and the second time period;
• wherein the system controller is further configured to:
• within the third half cycle, in response to determining that the first signal satisfies a first condition, start, at a fifth time, modulating the drive signal by changing the drive signal between a first logic level and a second logic level to turn on and off the transistor;
• keep modulating the drive signal for the third time period from the fifth time;
• within the third half cycle, in response to determining that the first signal satisfies a second condition, start, at a sixth time, modulating the drive signal by changing the drive signal between the first logic level and the second logic level to turn on and off the transistor;
• and
• keep modulating the drive signal for the fourth time period from the sixth time.

A method for a lighting system, the method comprising:

• receiving a first signal;
• determining whether the first signal is associated with a leading-edge TRIAC dimmer based at least in part on the first signal, the leading-edge TRIAC dimmer being configured to receive an AC input voltage associated with at least a first half cycle from a starting time to an ending time;
• in response to the first signal being determined to be associated with the leading-edge TRIAC dimmer, generating a drive signal;
• and
• sending the drive signal to a transistor;
• wherein the process of in response to the first signal being determined to be associated with the leading-edge TRIAC dimmer, generating a drive signal includes:
• keeping the drive signal at a first logic level to turn on the transistor from a first time, the first time being the same or after the starting time;
• in response to determining that the first signal satisfies a first condition, starting, at a second time, modulating the drive signal by changing the drive signal between the first logic level and a second logic level to turn on and off the transistor;
• keeping modulating the drive signal for a first predetermined time period from the second time to a third time;
• stopping, at the third time, modulating the drive signal to keep the drive signal at the second logic level to turn off the transistor;
• in response to determining that the first signal satisfies a second condition, starting, at a fourth time, modulating the drive signal by changing the drive signal between the first logic level and the second logic level to turn on and off the transistor, the fourth time being before the ending time;
• keeping modulating the drive signal for a second predetermined time period from the fourth time to a fifth time;
• and
• stopping, at the fifth time, modulating the drive signal to keep the drive signal at the first logic level to turn on the transistor.

A method for a lighting system, the method comprising:

• receiving a first signal;
• determining whether the first signal is associated with a leading-edge TRIAC dimmer based at least in part on the first signal, the leading-edge TRIAC dimmer being configured to receive an AC input voltage associated with at least a first half cycle, a second half cycle, and a third half cycle, the first half cycle immediately preceding the second half cycle, the third half cycle following the first half cycle and the second half cycle;
• in response to the first signal being determined to be associated with the leading-edge TRIAC dimmer, generating a drive signal;
• and
• sending the drive signal to a transistor;
• wherein the process of in response to the first signal being determined to be associated with the leading-edge TRIAC dimmer, generating a drive signal includes:
• within the first half cycle, determining a first time period from a first time when the first signal becomes larger than a first threshold to a second time when the first signal becomes smaller than a second threshold;
• within the second half cycle, determining a second time period from a third time when the first signal becomes larger than the first threshold to a fourth time when the first signal becomes smaller than the second threshold;
• determining a third time period and a fourth time period based at least in part on the first time period and the second time period;
• within the third half cycle, in response to determining that the first signal satisfies a first condition, starting, at a fifth time, modulating the drive signal by changing the drive signal between a first logic level and a second logic level to turn on and off the transistor;
• keeping modulating the drive signal for the third time period from the fifth time;
• within the third half cycle, in response to determining that the first signal satisfies a second condition, starting, at a sixth time, modulating the drive signal by changing the drive signal between the first logic level and the second logic level to turn on and off the transistor;
• and
• keeping modulating the drive signal for the fourth time period from the sixth time.