公开(公告)号：WO1981001783A1

公开(公告)日：1981-06-25

申请号：PCT/US1980001367

申请日：1980-10-14

Applicant: MOTOROLA INC

Inventor： MOTOROLA INC ,  PERKINS G

IPC: H04N05/68

CPC classification number: H04N5/141

Abstract: A peak beam current leveler for use in a television receiver system which is responsive to the magnitude of the beam current supplied to the cathode of the cathode ray tube (CRT) exceeding a predetermined peak level to adjust the cathode peak beam current accordingly. The cathode beam current is supplied by a gain controlled video amplifier (38) to the cathode through the base-emitter junction of a transistor (56) The collector electrode of the transistor is connected with a resistor (58) for providing a voltage level proportional to the peak beam cathode current. A comparator circuit (70-80) is utilized to provide a gain control signal that controls the gain of the gain controlled video amplifier such that the higher the beam current the more gain reduction that occurs. Thus, the level of the peak current is automatically reduced to maintain good focusing of the display on the CRT.