The driving circuit of the plasma discharge type flat backlight

摘要

An object of the present invention is to compare the signal fed back from the backlight drive circuit power transformer with a reference set value to detect an overcurrent due to a malfunction and to detect the amount of change in the current according to the change in backlight luminance value, and the duty ratio of the pulse applied to the transformer. And a plasma discharge type backlight driving circuit for driving an LCD that can stabilize the brightness of the backlight under conditions of high power and high efficiency by controlling the input of the transformer by adjusting the pulse width.;The inverter circuit of the present invention receives a voltage value corresponding to the variation of the output current feedback main unit 60 for generating a pulse for adjusting brightness by comparing it to the reference voltage value; A sub-control unit 20 receiving a luminance output pulse from the main controller to generate a driving pulse, and generating a power transistor switching pulse output using the driving pulse; A step-up inverter unit 30 driving the pulse output of the sub-control unit to generate a control signal for switching the input current of the power transformer; A line filter unit 10 for supplying power to the step-up inverter unit; An output unit 40 for outputting a high frequency high voltage for driving a backlight according to the output of the step-up inverter unit; An overcurrent detector (70) for supplying a current flowing through the step-up inverter to the main controller; And a brightness controller and a feedback unit 50 for converting the current fluctuations flowing in the step-up inverter unit into voltage components and supplying them to the main control unit.