Circuit and method independent of frequency and voltage deviations of supply voltage, and display apparatus incorporating same circuit

摘要

A degaussing circuit includes an AC mains voltage, a series arrangement of a degaussing coil (Ld) and a switching element (S1) coupled between the input terminals (it1,it2). A measuring circuit (3) continuously measures a value (Ms) representing an actual value of either the degaussing current (Id) through the degaussing coil (Ld) or the AC mains voltage (Vac). A detecting circuit (2) detects a level crossing instant (ts) at which the actual value (Ms) crosses a predetermined value (Vref2). A control circuit (1) determines a switching instant (tei,tstv) of the switching element (S1) in response to the level crossing instant (ts) for generating a peak value of the degaussing current (Id) related to the actual value of the degaussing current (Id) or the AC mains voltage (Vac) at the level crossing instant (ts).