Two-wire dimmer with improved zero-cross detention

A method to control power delivered to an electrical load, the method comprising:

• receiving, by a dimmer switch control circuit, a signal from a controllably conductive device that represents a voltage developed across the controllably conductive device during a portion of an alternating current (AC) half-cycle;
• generating, by the dimmer switch control circuit, a direct current (DC) fill signal that complements the signal received from the controllably conductive device during the remaining portion of the AC half-cycle;
• combining, by the dimmer switch control circuit, the AC signal received from the controllably conductive device and the DC fill signal to produce a combined signal, the combined signal having the same frequency as an AC supply signal to the controllably conductive device;
• and
• filtering, by the dimmer switch control circuit, the combined signal by filtering the signal received from the controllably conductive device during the portion of the AC half-cycle in which the voltage is developed across the controllably conductive device and filtering the DC fill signal during the remaining portion of the AC half-cycle.

A non-transitory, machine-readable, storage device that includes instructions that, when executed by a dimmer switch control circuit, causes the dimmer switch control circuit to:

• receive a signal from a controllably conductive device that represents a voltage developed across the controllably conductive device during a portion of an alternating current (AC) half-cycle;
• generate a direct current (DC) fill signal that complements the signal received from the controllably conductive device during the remaining portion of the AC half-cycle;
• combine the AC signal received from the controllably conductive device and the DC fill signal to produce a combined signal, the combined signal having the same frequency as an AC supply signal to the controllably conductive device;
• and
• filter the combined signal by filtering the signal received from the controllably conductive device during the portion of the AC half-cycle in which the voltage is developed across the controllably conductive device and filtering the DC fill signal during the remaining portion of the AC half-cycle.