US Patent 10121622 Systems and methods for controlling relay activation timing

Circuitry for controlling relay activation timing is described. The circuitry includes voltage zero cross detection circuitry configured to produce a zero cross detection signal indicating a zero cross time of an alternating current (AC) signal. The circuitry also includes current measuring circuitry coupled to voltage zero cross detection circuitry. The current measuring circuitry is configured to produce a current flow detection signal indicating a current flow start time of the AC signal. The circuitry further includes relay circuitry coupled to the current measuring circuitry. The circuitry additionally includes a processor coupled to the voltage zero cross detection circuitry, to the current measuring circuitry, and to the relay circuitry. The processor is configured to determine a relay time error based on the zero cross time and the current flow start time. The processor is also configured to control relay activation signal timing to reduce the relay time error.