PREDICTION AND RECOVERY OF ZERO-CROSSING INFORMATION AND SELECTIVE CONTROL SIGNAL PULSE DURATION

Operating an electrical load controller includes, in one aspect, predetermining a duration of time based at least in part on a frequency of an alternating current (AC) waveform, the alternating current (AC) waveform oscillating though full cycles, each full cycle comprising a positive half cycle and a negative half cycle; selecting a detection window of time equal in duration to the predetermined duration of time, the selected detection window extending from a selected first time to a selected second time and straddling an expected time of a next zero-crossing of the AC waveform; monitoring a zero-crossing signal for a zero-crossing indication, of the next zero-crossing, occurring within the selected detection window; ascertaining a time of the next zero-crossing based on the monitoring; and selectively controlling a supply of AC power to a load, wherein the controlling uses the ascertained time of the next zero-crossing of the AC waveform to fire a switching circuit of the electrical load controller. Additionally or alternatively, operating an electrical load controller includes, based on a desired load level setting of the electrical load controller, determining a firing angle, of an alternating current (AC) waveform, at which to fire a switching circuit of the electrical load controller to selectively control the switching circuit to conduct a supply of AC power to a load, the firing angle corresponding to a firing delay time, after zero-crossings of the AC waveform, at which to fire the switching circuit; selecting a control signal pulse duration, the control signal pulse duration being a duration of time for a control signal to be held in an ON state to latch the switching circuit to conduct the supply of AC power to the load, wherein the selecting the control signal pulse duration comprises selecting, for the control signal pulse duration, and based on the determined firing angle, between: (i) a fixed duration of time that begins at the firing delay time and ends after the fixed duration of time; and (ii) a variable duration of time that begins at the firing delay time and ends at a preset unlatch time of the AC waveform; and controlling the supply of AC power to the load based on the selected control signal pulse duration, wherein the controlling holds the control signal in the ON state for the selected control signal pulse duration in selectively controlling the switching circuit to conduct the supply of AC power to the load. Alternatively, in some