Patent ID: 6680588
Filing Date: 2004-01-20
Classification: H05B

Abstract:
A low noise backlight system for use in a display device, the system comprising:a first and a second lamps; a control unit for receiving a vertical synchronization signal of the display, producing a first control signal which has a duty cycle controlled depending upon current flowing in the first lamp and is synchronized with the vertical synchronization signal, and producing a second control signal which has a duty cycle controlled depending upon current flowing in the second lamp, is synchronized with the vertical synchronization signal and has a predetermined time lag with respect to the first control signal; a first power supply unit for producing a first driving voltage for causing the first lamp to be driven in synchronization with the first control signal and supplying the first driving voltage to the first lamp; and, a second power supply unit for producing a second driving voltage for causing the second lamp to be driven in synchronization with the second control signal and supplying the second driving voltage to the second lamp.