Power-Loss Detection CircuitOriginal Publication Date: 1980-Jan-01Included in the Prior Art Database: 2005-Feb-12The circuit of Fig. 1 detects a drop in the AC power being sensed on the loss of a phase input. The circuit includes three comparators 5, 6, 7 whose outputs are 0Red together at node 9. The comparators translate the amplitude of each line-to-neutral phase input voltage (Pl, P2 and to a pulse train whose pulse width is modulated by the incoming amplitude. This is accomplished by a combination of clipping and hysteresis.