Patent ID: 11870333
Assignee: LUTRON TECHNOLOGY COMPANY LLC
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 12:
13. A method of controlling a light-emitting load of an illumination device that receives power from an alternating-current (AC) mains supply through a dimmer, the method comprising:
receiving a phase-cut signal from the dimmer;
measuring a conduction angle of the phase-cut signal;
controlling the light-emitting load to emit light by causing a power supply to conduct a supply current from the AC mains supply and produce a drive current through the light-emitting load when the power supply is active;
controlling the power supply to be active for a length of an operating time period during a conduction period of a half-cycle of the phase-cut signal;
determining the length of the conduction period of the phase-cut signal based on the measured conduction angle;
determining a maximum duration of the operating time period during the half-cycle based on a length of the conduction period of the phase-cut signal;
setting the length of the operating time period of the power supply to the maximum duration when an average magnitude of the supply current to be drawn from the AC mains supply over multiple cycles is greater than a threshold;
setting the maximum duration of the operating time period equal to the length of the conduction period of the phase-cut signal minus a predetermined offset parameter; and
setting the length of the operating time period of the power supply to be less than the maximum duration when the average magnitude of the supply current to be drawn from the AC mains supply is less the threshold.