Main Content

This project provides AC voltage zero-cross timing detection and a DC voltage after diode rectification with high accuracy. Possible applications for such circuits are AC motor controllers, AC lamp controllers, AC Dimmer Controllers, Home Appliances. The circuit outputs a zero-cross signal from 90 Vac to 264 Vac input. The project is based on BM1Z102FJ chip which outputs a high precision zero-cross timing of targeted AC voltage and a DC voltage after diode rectification of high accuracy. The project also includes high voltage offline AC to DC converter chip BM2P129TF.


By monitoring the voltage between the VH_AC1 and VH_AC2 pins, this IC outputs the zero-cross point of AC voltage from the ACOUT pin. These pins have a built-in monitor circuit that tolerates 600 V and they realize high reliability and low power consumption. The ACOUT pin performs an N channel open-drain output and this makes it possible to support various applications. It is necessary for the VH_AC1 pin to be connected to the N side of the AC input and for the VH_AC2 pin to be connected to the L side of the AC input”

Link to article