Patent ID: 11935719

Abstract:
A power switch controller includes a condition detector, a zero crossing detector, a retimer, and a driver. The condition detector detects a change in a sense signal towards a first or second condition. The zero crossing detector detects zero crossings in an AC powerline signal. The power switch controller drives a latching relay that connects a load to powerlines. The power switch controller activates or deactivates the latching relay based on the sensed condition, and retimes activation and deactivation pulses to align the relay contact opening and closing times to coincide with the AC powerline zero crossings, compensating for contact travel times. The activation and deactivation pulses have a duration of max 20 ms, and an amplitude of at least 110% of the maximum sustainable voltage for the relay coil(s). A power-on reset deactivates the relay, aligned with a second AC zero crossing.