BM1ZxxxFJ AC Voltage Zero Cross Detection ICs ROHM Semiconductor BM1Z AC Voltage Zero Cross Detection (ZCD) ICs are voltage comparators that output the AC voltage zero-cross timing detection and the DC voltage after diode rectification. By eliminating the need for photocouplers and external components required in conventional ZCD circuits, it is possible to reduce the number of parts drastically and realize compact and highly reliable power supply applications. In addition, the BM1ZxxxFJ ICs can reduce standby power largely in comparison with an existing photocoupler control.