DEGAUSSING CIRCUIT FOR TELEVISION RECEIVER HAVING SWITCHED MODE POWER SUPPLY

摘要

A switched mode power supply (10) for a remote controlled television receiver incorporates a degaussing circuit (19) having a relay (17) that is required to be energized in order to permit operation of the degaussing circuit (19). Power to energize the relay (17) is derived from a power supply switch transistor protection circuit (76) which removes residual stored energy from the power transformer primary winding (22). This stored energy is used to charge a capacitor (80) during the time the switch transistor (65) is nonconductive. The capacitor (80) is discharged to provide current to energize the degaussing circuit relay (17) in order to permit ac mains current to flow through the degaussing coil (15).