Patent ID: 6642676
Filing Date: 2003-11-04
Classification: H04N

Abstract:
An electromagnetic quadrupole driving circuit comprising:first switching means giving a driving signal in synchronization with a horizontal synchronization signal, said first switching means being in an OFF state during a synchronization period and being in an ON state during a scanning period; a series circuit, provided in parallel to said first switching means, which resonates with a first resonance frequency by an electromagnetic quadrupole coil and a first resonance capacitor connected in series, while said first switching means is in the ON state; a second resonance capacitor, provided in parallel to the series circuit, which resonates with a second resonance frequency together with said first resonance capacitor and said electromagnetic quadupole coil when said switching means becomes to be in the OFF state; current detecting means for detecting the peak value and the bottom value of current flowing along said electromagnetic quadrupole coil; first power supply means for controlling an amplitude of current to be supplied to said electromagnetic quadrupole coil based on said peak value detected by said current detecting means; and second power supply means for controlling the superposed amount of current to be supplied to said electromagnetic quadrupole coil based on said bottom value detected by said current detecting means.