The invention discloses an
alternating current mains supply isolation
zero crossing checking circuit combined with low-
voltage power line carrier wave communication
signal coupling, belonging to the field of low-
voltage power line carrier wave communication and control. The circuit comprises a carrier wave
signal coupling circuit, a
zero crossing checking circuit and a protective circuit, wherein the carrier wave
signal coupling circuit receives and sends the carrier wave signal in the carrier wave communication process in a mode of combining series
resonance with a
coupling transformer, and the active
power consumption and the inactive
power consumption of a
system can be effectively lowered. in the
zero crossing detection circuit, a biasing circuit is designed according to the conduction condition of a Darlington tube, the
capacitance characteristics and the optocoupling working condition, so as to accurately detect the zero crossing point time of the
alternating current mains supply; the carrier wave signal coupling circuit and the zero crossing detection circuit share one protective circuit to prevent
impact interference, such as pulse or surge and the like; and strong current and
weak current are completely isolated to guarantee
system safety. In the
alternating current mains supply isolation zero crossing checking circuit, a low-
voltage power line carrier
wave coupling circuit is combined; the characteristics of components are used for realizing the zero crossing point detection function; the coupling circuit and the detection circuit share one protective circuit, and the whole circuit is easy to realize, thereby correspondingly lowering cost, and lowering the active
power consumption and the inactive power consumption of a
system; and especially the zero crossing point detection accuracy required for carrier wave communication is guaranteed.