Samsung Electronics Co., Ltd.

Osamu Sengoku

Tatsuhisa Shimura

Takashi Kinoshita

Song-Yi Han

Min-Soo Choi

Yun-Gun Lee

Jin-won Jang

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.

Brightness adjusting device and liquid crystal display having the same

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.

Inverter circuit, backlight device and liquid crystal display having the same

An inverter circuit includes a first driving transformer, a second driving transformer, a power voltage circuit, a high-side FET connected to a secondary winding of the first driving transformer, a low-side FET connected to a secondary winding of the second driving transformer and an inverter transformer connected to a driving node between the high-side FET and the low-side FET. Thus, a direct current path does not exist between a gate of the high-side FET and the driving node, so that a gate voltage of the high-side FET is biased more to a negative polarity.

Inverter circuit

An inverter circuit includes plural pairs of third coils, in which adjacent third coils are serially connected to each other so as to offset AC voltage generated from the paired third coils, one end of the paired third coils being connected to ground. Input terminals of plural diodes are connected to one end of the paired third coils so as to generate the voltage detection value by detecting voltage generated from the paired third coils. A fault detector compares the voltage detection value generated from the diodes with a predetermined threshold value to detect a fault and generates the comparison result.

Inverter circuit and backlight assembly having the same

An inverter circuit includes an inverter transformer to supply AC high voltages of opposite phases, and a plurality of balance transformers. The inverter transformer supplies AC high voltages of same phases to every n number of CCFLs, and the CCFLs are connected in series to primary windings of the balance transformers at every two CCFLs. Also, secondary windings of the balance transformers are connected in series to form a closed loop. Thus, an inverter circuit may realized for a large-sized backlight without increasing a number of the balance transformers.

Inverter circuit, backlight and liquid crystal display

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.

Inverter circuit, backlight assembly, liquid crystal display having the same, and method thereof

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.

Inverter circuit, backlight assembly and liquid crystal display with the same

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.

In an inverter circuit, inverter transformers supply AC voltage to discharge tubes. The inverter transformers are arranged such that the AC voltage at a respective first terminal of each secondary coil has an opposite polarity with respect to a corresponding second terminal of each secondary coil. Balance transformers have primary coils inserted in series between a reference terminal of the secondary coils of the inverter transformers and ground. The secondary coils of the balance transformers are connected in series to form a loop. One node of the loop is grounded and a voltage detection node is located on the loop. At least one secondary coil of the secondary coils of the balance transformers is interposed between the grounded node of the loop and the voltage detection node. Thus, an abnormal state or condition, such as an open circuit or a short circuit may be detected.

Growing community of inventors

Tokyo, Japan

Osamu Sengoku