Logah Technology Corp.

Logan Technology Corp.

Cheng-Chia Hsu

Teng-Kang Chang

Yu-Cheng Pan

Yun-Ching Wu

Yung-Chin Chou

Ho-Wen Chen

Teng-Ho Wu

Jong-Chi Tseng

Chia-Yuan Chen

An LCD backlight driving device with an isolating transformer comprises a DC power supply, a square wave generator, a square wave controller, said isolating transformer and a driver transformer; wherein said isolating transformer has a primary side connected to said square wave generator and a secondary side connected to said driver transformer, since said isolating transformer is placed between said square wave generator and said driver transformer, it helps to effectively shorten a safety distance required for setting up said driver transformer; the present invention uses said isolating transformer to shorten the safety distance required than that of using said driver transformer directly and to decrease an area in implementing a circuit board and to cut cost of said device.

LCD backlight driving device with an isolating transformer

A lamp driving structure for backlight module includes a backlight module implemented for disposing a first circuit board and a second circuit board thereon, the first circuit board couples with the second circuit board through a transmission line; the structure further includes at least a square wave controller, two square wave switches, a mutually coupled transformer, a plurality of driving transformers and a plurality of connectors disposed selectively on the first circuit board and the second circuit board, thereby reducing the number of driving transformers and connectors and the area of circuit boards to further reduce the manufacturing cost of the lamp driving device.

Lamp driving structure for backlight module

Disclosed is an improved lamp circuit of a liquid crystal device (LCD) backlight source, comprising a printed circuit board (PCB) for lamp initialization having a control circuit and a first connector thereon; a first lamp connection board disposed between the first lamp connection board and a second lamp connection board and being lamps of the LCD backlight source; a second lamp connection board having a second connector and transformers thereon, the transformers each corresponding to one of the lamps; and a low voltage wire set connected between the first connector on the PCB for lamp initialization and the second connector on the second lamp connection board, wherein a signal issued from the first connector on the PCB for lamp initialization is transmitted through the low voltage wire set to the second connector on the first PCB for lamp initialization and then to a corresponding one of the transformers so that the lamps may be driven to operate. With use of the present invention, number of the used connectors may be reduced and arrangement issue of the high voltage wires may be obviated, making volume of the PCB for lamp initialization allowed to be reduced and cost of the lamp circuit lowered.

Lamp circuit of liquid crystal device backlight source

The locked phase active power current control circuit is composed of a DC source, an electronic switch, a driving transformer, a phase detecting unit, a current intercepting unit and a square wave controller. A DC signal provided by the DC source is converted into a square wave signal by the electronic switch for the driving transformer to operate a load. The electronic switch outputs the square wave signal to the phase detecting unit whereat a phase signal of the square wave is detected and the detected signal is transmitted to the current intercepting unit whereat the detected signal is compared with the current intercepted at the electronic switch, the driving transformer, or the load, and the comparison result is fed back to the square wave controller so as to set the operation frequency of the electronic switch. The essential principle of the present invention is based on the fact that the square wave is in phase with the first harmonic wave.

Locked phase active power current control circuit

A two-end driven lamp controlling device includes a direct-current (DC) power supply, square wave switches, a square wave controller, a plurality of lamps, a plurality of starting transformers and a plurality of lamps commonly connective transformers, wherein the plurality of starting transformers or the plurality of lamps commonly connective transformers are disposed besides the plurality of lamps and the square wave switches are connected to the sides of the plurality of starting transformers or the plurality of lamps commonly connective transformers and to the DC power supply and can receive signals from the square wave controller. The present invention utilizes a circuitry design of a plurality of lamps, a plurality of starting transformers and a plurality of lamps commonly connective transformers so as to make the brightness of the plurality of lamps effectively homogenized and balanced and, moreover, to solve the problem of high cost for conventional devices, which use too many components for maintaining the brightness of the lamps.

Two-end driven lamp controlling device

An improved winding structure of a transformer, wherein the transformer comprises a winding base externally set with an isolating plate, the transformer is divided into a primary side region and a secondary side region by the isolating plate. The primary side region has a winding reel for a pre-formed wire set to sleeve on while the secondary side region is divided into a plurality of winding grooves by a plurality of partitions for placing a wire in the grooves, and an iron core set is set on the outside of the winding base and the hollow structure, which altogether form an transformer. In the present invention, an pre-formed wire set is sleeved on a primary side winding reel, therefore, the costs of traditional hand-winding will be displaced, and the manufacturing quality and usage stability of transformers will be effectively improved as well.

Winding structure of a transformer

Disclosed is a choke transformer used in liquid crystal display (LCD) backlight driver, comprising a winding base on which a plurality of spacers are formed and having a hollow structure, a core received within the winding base and a plurality of windings wound between two neighboring ones of the plurality of spacers as a winding set, each winding set having windings of different characteristics; and is characterized in that an air gap is provided between the winding base having the hollow structure and the core. With such devised choke transformer, a higher endurable voltage is achieved. Further, the characteristics of prolonged lifetime, reduced cost, smaller dimension and saved installation space may be achieved with the choke transformer.

Choke transformer used in liquid crystal display backlight driver

In a fixation structure for fixing a lamp on a printed circuit board (PCB), a connection end of the lamp is received within a connection hole of the PCB and a sleeve having approximately cone shape is disposed between the lamp and the PCB. When the connection end of the lamp is continuously inserted into the connection hole of the PCB, a contact area between the connection end and the connection hole is increased, thereby effectively enhancing a contact-and-on performance of the lamp and the PCB. Sleeves may be located on lamps leads or alternatively placed in the connection hole of the PCB.

Fixation structure for fixing a lamp on a printed circuit board

An improved winding base structure of a transformer is assembled by combining a primary-side winding base and a secondary-side winding base. The selection of the material of the primary-side winding base and the secondary-side winding base is dependant on the compression-resistant capability because the primary-side input and the secondary-side output of the transformer bear different voltages. The outside of the assembled winding base is disposed with grooves in which the wires are wound, and the center of the winding base is disposed with a through hole for an iron core to be put therein to form a transformer. The sectional winding base of the subject application is characterized in that the primary-side winding base is made of lower compression-resistant material and the secondary-side winding base is made of higher compression-resistant material. Therefore the production cost of the winding base is reduced.

Winding base structure of transformer

A control device for multiple lamp currents of a liquid crystal display (LCD) backlight source, comprising an electronic power switch, a transformer, an inverter and an integrated circuit (IC) feedback control module. The transformer has a primary side connected to the electronic power switch and a secondary side having two ends each connected to an end of a set of lamp composed of two lamps. The inverter has three sets of coil connected to the other end of the two sets of lamp. The IC feedback control module is connected between the inverter and the electronic power switch and through which currents flown through the two sets of lamp may be balanced. Meanwhile, the current flown through the inverter is feedback to the IC feedback control module by which a control signal is outputted to the electronic power switch by determining and processing the feedback current, thereby controlling an output signal from the electronic power switch. Therefore, luminance of the multiple lamps in the LCD backlight source may be controlled and maintained.

Control device for multiple lamp currents of liquid crystal display backlight source

A lamp current control device includes an electronic power switch, a transformer, a current transformer and a pulse width modulation (PWM) IC. The transformer has its primary side connected to the electronic power switch and a secondary side connected to a lamp. The current transformer is serially connected with the primary side of the transformer. The PWM IC is coupled between a secondary side of the current transformer and the electronic power switch and uses the current transformer to feedback a feed back signal from the primary side of the transformer. The PWM IC receives and processes the feed back signal to obtain a control signal, and then the PWM IC outputs the control signal to the electronic power switch to control a pulse width outputted by the electronic power switch, thereby controlling and maintaining a brightness of the lamp.

Lamp current control device

A lamp current balancing device comprises an electronic power switch, a transformer, a current transformer and a pulse width modulation (PWM) IC; the transformer having a primary side connected to the electronic power switch and both ends of a secondary side connected to one end of each one of two lamps respectively, with another end of each one of the two lamps connecting to one end of a primary side of the current transformer respectively, the PWM IC being coupled between a secondary side of the current transformer and the electronic power switch; since the two lamps being cascaded in series with a same current flowing through them, thus providing current balancing capability, furthermore, the current transformer being used to detect an operating current of the lamps and to feed back the operating current to the PWM IC, the PWM IC receiving and processing the operating current to obtain a control signal, then outputting the control signal to the electronic power switch to control a pulse width outputted by the electronic power switch, thereby controlling and maintaining a uniform brightness of the lamps.

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Chupei, Taiwan

Cheng-Chia Hsu