摘要:
An inverter circuit for a backlight device includes an inverter transformer which supplies a high AC voltage to a plurality of discharge tubes, a filter circuit connected to an output terminal of the inverter transformer, and an abnormal discharge detection circuit. The filter circuit passes a current signal having a high frequency component of the high AC voltage to the abnormal discharge detection circuit, and the abnormal discharge detection circuit detects an abnormal discharge current based on the current signal.
摘要:
A backlight assembly prevents abnormal discharge of a device using a high voltage to drive a discharge tube such as CCFL. An inverter circuit includes an inverter transformer supplying an AC high voltage to a plurality of discharge tubes, and a plurality of balance transformers. First terminals of primary coils of the balance transformers are connected to the discharge tubes, and second terminals of the primary coils are connected to a ground. Secondary coils of the balance transformers are connected in series to form a loop. A resistor has a first terminal connected to the loop and a second terminal connected to the ground. Accordingly, the backlight assembly may detect a high-voltage abnormal discharge such as a corona discharge, an arc discharge or the like.
摘要:
An inverter circuit includes a power supply which outputs an alternating current voltage, an inverter transformer having one primary coil connected to an output terminal of the power supply and pairs of secondary coils which supply an alternating current high voltage, induced by the one primary coil, to pairs of discharge tubes and a plurality of balance transformers having primary coils serially connected between respective pairs of the pairs of secondary coils of the inverter transformer, and having secondary coils corresponding to the primary coils of the plurality of balance transformers, wherein the secondary coils of the plurality of balance transformers are serially connected to form a loop.
摘要:
A brightness adjusting device includes a multiplication circuit, which multiplies a vertical signal by a predetermined multiplication ratio to output a multiplication signal, a differential circuit that distinguishes between different multiplication signals, a serrated wave generator that charges/discharges a condenser according to a signal output from the differential circuit and generates a serrated wave having constant amplitude independently of a frequency of the multiplication signal, a brightness adjusting voltage generator that generates a reference voltage to determine a pulse duty, and a comparator that outputs a pulse signal by comparing a voltage of the serrated wave with the brightness adjusting voltage. The brightness adjusting voltage generator includes a circuit that outputs a variable voltage, and the multiplication circuit includes a circuit having a variable multiplication ratio.
摘要:
A backlight module that uniformly maintains the brightness of a light emitting device, in which the number of transformers is reduced, and that is applicable for use with large cold cathode ray tubes includes cold cathode ray tubes arranged in parallel, transformers having first secondary-side terminals connected to first electrodes of the cold cathode ray tubes and whose primary side terminals are connected in series to constitute a closed loop, a first inverter circuit that applies a first sine wave voltage to second terminals on the secondary sides of the transformers, and a second inverter circuit that applies a second sine wave voltage having opposite phase to second electrodes of the cold cathode ray tubes.
摘要:
An inverter circuit, a backlight assembly and a liquid crystal display include first and second electrodes and a balance circuit. The first and second electrodes supply a voltage of opposite polarities, respectively, among an even number of cold cathode fluorescent lamps (CCFLs) disposed in one direction. The first and second electrodes supply the voltage of opposite polarities to even-numbered CCFLs and odd-numbered CCFLs, respectively. The balance circuit controls currents flowing through the CCFLs. The CCFLs are halved into a first group higher in temperature and a second group lower in temperature than the first group. The balance circuit includes primary coils directly connected between at least one CCFL of the first group and at least one CCFL of the second group and secondary coils corresponding to the primary coils that are connected to each other to form a loop.