KR20060059501A - Driving apparatus of lamp and liquid crystal display using the same - Google Patents

Abstract

The present invention relates to a lamp driving device and a liquid crystal display device using the same to package circuits to include NC pins (No Connection Pins) to facilitate component replacement and to prevent short circuits between adjacent pins.

A driving device for a lamp according to the present invention includes a lamp; An inverter for driving the lamp; A detection circuit chip for feeding back a feedback signal corresponding to the tube current of the lamp to an inverter; The detection circuit chip includes a plurality of input / output pins electrically connected to the lamp and the inverter, a detection circuit electrically connected to the plurality of input / output pins to generate the feedback signal, and the plurality of input / output pins such that there is no electrical connection. It is characterized by including a plurality of dummy pins disposed between.

By such a configuration, the present invention can package the detection circuit into one chip to prevent defects such as short between electronic components due to foreign matters in the surrounding environment, and at the same time, prevent electrical short between adjacent input / output pins due to NC pins. .

NC pin, lamp, short, packaging

Description

DRIVING APPARATUS OF LAMP AND LIQUID CRYSTAL DISPLAY USING THE SAME}

1 is a view showing a driving device of a general lamp.

2 is a view showing a driving device for a lamp according to an embodiment of the present invention.

3 is a perspective view illustrating a detection circuit chip shown in FIG. 2.

FIG. 4 is a view showing a liquid crystal display using the driving device of the lamp shown in FIG.

FIG. 5 is another view of a liquid crystal display using the driving device of the lamp shown in FIG. 2; FIG.

<Explanation of Signs of Major Parts of Drawings>

20, 120: inverter 22, 122: transformer

24, 124: switching circuit 26, 126: control unit

30, 130: detection circuit 40, 140, 240, 340: lamp

150: detection circuit chip 132: package

200, 300: liquid crystal display 210: light guide plate

220, 320: optical sheet 230, 330: liquid crystal panel

310: lamp housing 312: diffuser plate

The present invention relates to a driving device of a lamp and a liquid crystal display device using the same. In particular, a circuit is packaged to include NC pins (No Connection Pins) to facilitate component replacement and to prevent shorting between adjacent pins. A driving device of a lamp and a liquid crystal display using the same.

In general, liquid crystal displays (hereinafter referred to as "LCDs") have tended to be gradually widened due to their light weight, thinness, and low power consumption. According to this trend, LCDs are used for office automation equipment, audio / video equipment, and the like. On the other hand, the LCD displays a desired image by adjusting the transmission amount of the light beam according to the image signal.

Since the LCD is not a self-luminous display device, a light source such as a back light unit is required.

As a light source used in the backlight unit, a halogen cathode fluorescent lamp (Halogen Cathode Fluorescent tube) or a cold cathode tube (cold cathode) (hereinafter referred to as "CCFL") is used. Among the light sources, CCFL is a light source tube using the cold emission (electron emission caused by a strong electric field applied to the cathode surface), and is easy to generate low heat, high brightness, long life, and full color. These CCFLs include a light guide type, a direct type type, a reflective type plate, and the like, and an appropriate light source tube is adopted according to the requirements of the LCD.

Such a light source is classified into an internal electrode fluorescent lamp having electrodes formed inside the discharge tube and an external electrode fluorescent lamp having electrodes formed outside the discharge tube. These fluorescent lamps are driven by a high pressure AC waveform. That is, the high-voltage AC waveform for driving the fluorescent lamps is obtained by converting the DC power supplied from the DC power supply unit into an AC waveform by the inverter and then boosting it by the transformer.

Referring to FIG. 1, a general lamp driving apparatus detects a lamp 40, an inverter unit 20 for driving the lamp 40, and a tube current of the lamp 40 to feed back to the inverter unit 20. The detection circuit 30 is provided.

The inverter unit 20 converts an input voltage Vin into an AC voltage in response to the switching control signal, and converts an AC voltage supplied from the switching circuit 24 into a lamp driving voltage. And a control unit 26 for controlling the switching circuit 24 in response to the feedback signal FB and the control signal from the detection circuit 30.

The switching circuit 24 includes at least one switching element for converting the input voltage Vin into an alternating current form in response to a switching control signal from the control unit 26.

The transformer 22 has a primary winding electrically connected to the switching circuit 24 and a secondary winding electrically connected to the first electrode of the lamp 40.

One end of the secondary winding is connected to the first electrode of the lamp 40 and the other end is connected to the ground voltage source GND. The transformer 22 boosts the voltage of the alternating current type supplied from the switching circuit 24 to the primary winding by the winding ratio of the primary winding and the secondary winding to the lamp driving voltage and supplies it to the first electrode of the lamp 40. At this time, a capacitor C1 for equalizing the balance of the current supplied to the lamp 40 is connected between one end of the secondary winding and the first electrode of the lamp 40.

The detection circuit 30 detects a feedback signal FB corresponding to a tube current flowing through the lamp 40 when the lamp 40 is driven and supplies it to the controller 26. To this end, the detection circuit 30 is connected between the first resistor R1 connected between the second electrode of the lamp 40 and the ground voltage source GND, and between the first resistor R1 and the ground voltage source GND. The variable resistor RB, the first diode D1 connected between the first node N1 and the controller 26 between the second electrode and the first resistor R1 of the lamp 40, and the first A second diode D2 is connected between the second node N2, which is between the node N1 and the first diode D1, and the ground voltage source GND.

The first resistor and the variable resistors R1 and RB detect the current from the second electrode of the lamp 40 by the voltage dividing resistor and display the current on the first node N1. The detected feedback signal FB on the first node N1 is supplied to the controller 26 via the first diode D1. At this time, the second diode D2 blocks the impulse of the negative potential to maintain the lowest potential of the feedback signal FB at zero potential.

The control unit 26 controls the switching circuit 24 in response to the feedback signal FB from the detection circuit 30. That is, the controller 26 controls the switching elements constituting the switching circuit 24 in response to the feedback signal FB to control the voltage of the AC type supplied to the transformer 22.

Such a general lamp driving device drives the lamp 40 by boosting the input voltage Vin to the lamp driving voltage using the inverter unit 20 and simultaneously uses the detection circuit 30 to operate the lamp 40. The tube current of the feedback is controlled to control the lamp driving voltage supplied to the lamp 40.

On the other hand, in the driving device of a general lamp, the inverter unit 20 and the detection circuit 30 is disposed on one printed circuit board. In the case of the inverter unit 20 and the detection circuit 30, particularly the detection circuit 30, which are formed on the substrate, defects such as a short between electronic components may occur due to foreign substances in the surrounding environment. In order to prevent this, the detection circuit 30 on the printed circuit board is molded or coated with an insulating material of silicon or the like. However, a defect such as short and open occurs between components of the detection circuit 30 due to shrinkage and heat dissipation characteristics of the insulating material or the like that protects the detection circuit 30 depending on the ambient temperature. In addition, since a change in electrical characteristics occurs during a short / open test inspection of the detection circuit 30, a general lamp driving apparatus increases the rate of defective determination due to the change of characteristics. In addition, the general driving device of the lamp has a problem in that the cost increases because the entire printed circuit board needs to be replaced when a defect occurs in the components of the inverter unit 20 and the detection circuit 30.

Accordingly, in order to solve the above problems, the present invention packages a circuit to include NC pins (No Connection Pins) to facilitate component replacement and to prevent short circuits between adjacent pins. And a liquid crystal display using the same.

Driving apparatus for a lamp according to an embodiment of the present invention for achieving the above object is a lamp; An inverter for driving the lamp; A detection circuit chip for feeding back a feedback signal corresponding to the tube current of the lamp to an inverter; The detection circuit chip includes a plurality of input / output pins electrically connected to the lamp and the inverter, a detection circuit electrically connected to the plurality of input / output pins to generate the feedback signal, and the plurality of input / output pins such that there is no electrical connection. It is characterized by including a plurality of dummy pins disposed between.

A liquid crystal display according to an exemplary embodiment of the present invention includes a lamp, a light guide plate to which light is irradiated from the lamp through an incident surface provided on a side surface, a plurality of optical sheets disposed on the light guide plate, and a plurality of optical sheets on the plurality of optical sheets. And a liquid crystal panel arranged to adjust an amount of light emitted from the light guide plate to display an image, wherein the lamp is driven by a driving device of the lamp.

Another liquid crystal display according to an exemplary embodiment of the present invention includes a plurality of lamps, a lamp housing accommodating the plurality of lamps, a diffusion plate covering the front surface of the lamp housing, and a plurality of optical devices disposed on the diffusion plate. And a liquid crystal panel disposed on the plurality of optical sheets and configured to display an image by adjusting a transmission amount of light irradiated from the diffusion plate, wherein the lamp is driven by a driving device of the lamp.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings and embodiments.

2 is a view showing a driving device of a lamp according to an embodiment of the present invention.

2, the lamp driving apparatus according to the embodiment of the present invention detects the lamp 140, the inverter unit 120 for driving the lamp 140, and the tube current of the lamp 140 to detect the inverter unit. The detection circuit chip 150 which feeds back to 120 is provided.

The inverter unit 120 converts an input voltage Vin into an AC voltage in response to a switching control signal, and converts an AC voltage supplied from the switching circuit 124 into a lamp driving voltage. And a control unit 126 for controlling the switching circuit 124 in response to a feedback signal FB and a control signal from the detection circuit chip 150.

The switching circuit 124 includes at least one switching element that converts the input voltage Vin into an alternating current in response to a switching control signal from the controller 126.

The transformer 122 has a primary winding electrically connected to the switching circuit 124 and a secondary winding electrically connected to the first electrode of the lamp 140.

One end of the secondary winding is connected to the first electrode of the lamp 140 and the other end is connected to the ground voltage source GND. The transformer 122 boosts a voltage of an alternating current type supplied from the switching circuit 124 to the primary winding by the winding ratio of the primary winding and the secondary winding to the lamp driving voltage and supplies it to the first electrode of the lamp 140. At this time, a capacitor C1 for equalizing the balance of the current supplied to the lamp 140 is connected between one end of the secondary winding and the first electrode of the lamp 140.

The detection circuit chip 130 detects the feedback signal FB corresponding to the tube current flowing through the lamp 140 and supplies it to the controller 126 when the lamp 140 is driven. To this end, the detection circuit chip 150 is a detection circuit 130 for detecting a feedback signal (FB) corresponding to the tube current flowing through the lamp 140 when driving the lamp 140, as shown in FIG. A package 132 that packages and wraps the circuit 130, and a plurality of input / output pins P1 to P4 that are electrically connected to the detection circuit 130, the lamp 140, and the controller 126 and protrude from the package 132. And a plurality of NC pins (No connection pins) or dummy pins Pnc provided between the input / output pins P1 to P4.

Among the plurality of input / output pins P1 to P4, the first input / output pin P1 is electrically connected to the base voltage source GND, the second input / output pin P2 is input with a variable signal from the outside, and the third input / output pin ( P3 is electrically connected to the second electrode of the lamp 140, and the fourth input / output pin P4 is electrically connected to the controller 126.

Each of the plurality of NC pins Pnc is provided between each of the plurality of input / output pins P1 to P4 and is not electrically connected to adjacent electronic components. In other words, each of the plurality of NC pins Pnc is provided between the plurality of input / output pins P1 to P4 protruding from the package 132 without any electrical connection to any signal wiring of the detection circuit 130. . The test signal is applied to each of the plurality of NC pins Pnc during the electrical characteristic inspection of the detection circuit chip 130.                     

The detection circuit 130 is connected between a first resistor R1 connected between the first input / output pin P1 and a third input / output pin P3 and between the first input / output pin P1 and the first resistor R1. The variable resistor RB, the first diode D1 connected between the third input / output pin P3 and the fourth input / output pin P4, and between the first diode D1 and the first input / output pin P1. And a second diode D1 connected to it.

The first resistor and the variable resistors R1 and RB detect current from the second electrode of the lamp 140 by the voltage dividing resistor. In this case, the variable resistor RB may have a different resistance value according to a variable signal input from the second input / output pin P2.

The anode electrode of the first diode D1 is electrically connected to the fourth input / output pin P4, and the cathode electrode is connected to the anode electrode of the second diode D2 and the third input / output pin P3 through the first node N1. Is electrically connected). The first diode D1 prevents a reverse voltage supplied from the fourth input / output pin P4 to the first node N1.

The anode electrode of the second diode D2 is electrically connected to the cathode electrode of the first diode D1, and the cathode electrode is electrically connected to the first input / output pin P1. The second diode D2 blocks the impulse of the negative potential to maintain the lowest potential of the feedback signal FB at zero potential.

The detection circuit 130 detects the current from the second electrode of the lamp 140 by the voltage dividing resistor so that the first resistor and the variable resistors R1 and RB appear on the first node N1. The detected feedback signal FB on the first node N1 is supplied to the controller 126 via the first diode D1 and the fourth input / output pin P4.                     

The detection circuit chip 150 is disposed on one printed circuit board (not shown). In addition, the controller 126 and the switching circuit 124 may also be packaged together with the detection circuit 130.

The controller 126 controls the switching circuit 124 in response to the feedback signal FB supplied from the detection circuit 130 of the detection circuit chip 150. That is, the controller 126 controls the switching element constituting the switching circuit 124 in response to the feedback signal (FB) to control the voltage of the AC type supplied to the transformer 122.

The driving device of the lamp according to the embodiment of the present invention drives the lamp 140 by boosting the input voltage Vin to the lamp driving voltage using the inverter unit 120, and simultaneously packaged the detection circuit chip 150. By using the detection circuit 130 of the () is fed back the tube current of the lamp 140 to control the lamp driving voltage supplied to the lamp 140.

As described above, since the detection circuit 130 is packaged by the detection circuit chip 150, the lamp driving apparatus according to the embodiment of the present invention prevents defects such as a short between electronic components due to foreign substances in the surrounding environment and at the same time, the NC Due to the pins Pnc, electrical shorts between adjacent input / output pins P1 to P4 may be prevented. In addition, according to the present invention, even when a test signal is applied to the NC pins Pnc during the short / open test inspection of the detection circuit 130, there is no change in the electrical characteristics due to the test signal. Can reduce the rate of defective judgment. In addition, in the present invention, when the electronic component in the package 132 is defective, only the detection circuit chip 150, not the entire printed circuit board, needs to be replaced, thereby reducing costs and facilitating replacement of components.                     

Meanwhile, referring to FIG. 4, the liquid crystal display 200 according to an exemplary embodiment of the present invention includes a lamp 240, a light guide plate 210 to which light from the lamp 240 is irradiated through an incident surface provided on a side surface thereof, A plurality of optical sheets 220 disposed on the light guide plate 210 and a liquid crystal panel 230 disposed on the optical sheets 220 are provided.

The lamp 240 is driven by the driving device of the lamp shown in FIG. 3 to irradiate light onto the incident surface of the light guide plate 210.

The light guide plate 210 propagates the light irradiated through the incident surface from the lamp 240 toward the liquid crystal panel 230.

The plurality of optical sheets 220 improves the efficiency of light irradiated from the light guide plate 210 and irradiates the liquid crystal panel 230.

The liquid crystal panel 230 displays an image corresponding to the data signal by adjusting a transmission amount of light emitted from the light guide plate 210 through the plurality of optical sheets 220 according to the data signal.

The liquid crystal display 200 according to the exemplary embodiment of the present invention may be used as a display device such as a monitor for a notebook computer and a computer.

On the other hand, referring to FIG. 5, another liquid crystal display 300 according to an exemplary embodiment of the present invention may include a plurality of lamps 340, a lamp housing 310 that accommodates the plurality of lamps 340, and a lamp housing. A diffusion plate 312 covering the entire surface of the 310, a plurality of optical sheets 320 disposed on the diffusion plate 312, and a liquid crystal panel 330 disposed on the optical sheet 320.

The plurality of lamps 340 are driven by the driving device of the lamp shown in FIG. 3 to irradiate light to the rear surface of the diffusion plate 312. At this time, the plurality of lamps 340 are individually driven by each of the above-described driving device of the lamp. The plurality of lamps 340 are driven in parallel, i.e., simultaneously, by the above-described lamp driving device.

The diffusion plate 312 diffuses the light irradiated from the plurality of lamps 340 and irradiates the plurality of optical sheets 320.

The plurality of optical sheets 320 improves the efficiency of light irradiated from the diffusion plate 312 and irradiates the liquid crystal panel 330.

The liquid crystal panel 330 displays an image corresponding to the data signal by adjusting the amount of light transmitted from the diffusion plate 312 through the plurality of optical sheets 320 according to the data signal.

The liquid crystal display 300 according to the exemplary embodiment of the present invention may be used as a display device such as a computer monitor and a television.

On the other hand, the present invention described above is not limited to the above-described embodiment and the accompanying drawings, it is possible that various substitutions, modifications and changes within the scope without departing from the technical spirit of the present invention It will be apparent to those skilled in the art.

The driving device of the lamp and the liquid crystal display using the same according to the embodiment of the present invention as described above package the detection circuit into one chip to prevent defects such as short circuit between electronic components due to foreign substances in the surrounding environment and at the same time NC pins The electrical short between adjacent input and output pins can be prevented. In addition, the present invention does not change the electrical characteristics during the short / open test test of the circuit due to the NC pin. In addition, the present invention can reduce the cost and facilitate the replacement of parts, because only the detection circuit chip, not the entire printed circuit board, needs to be replaced when the electronic component in the package is defective.

Claims (5)

With a lamp; An inverter for driving the lamp; A detection circuit chip for feeding back a feedback signal corresponding to the tube current of the lamp to an inverter; The detection circuit chip includes a plurality of input / output pins electrically connected to the lamp and the inverter, a detection circuit electrically connected to the plurality of input / output pins to generate the feedback signal, and the plurality of input / output pins such that there is no electrical connection. And a plurality of dummy pins disposed therebetween. The method of claim 1, The inverter, A switching circuit for converting an input voltage into an alternating voltage, A control unit controlling the switching circuit in response to a control signal and the feedback signal; And a transformer for converting an alternating current voltage supplied from the switching circuit into a lamp driving voltage for driving the lamp. The method of claim 2, The detection circuit, A resistor connected to a first input / output pin connected to the lamp and a second input / output pin connected to a base voltage source, among a plurality of input / output pins; A variable resistor connected to the resistor and the second input / output pin and whose resistance value is changed by a variable signal supplied to a third input / output pin among a plurality of input / output pins; And a diode connected to the first input / output pin and a fourth input / output pin connected to the control unit. With lamp, A light guide plate irradiated with light from the lamp through an incident surface provided on a side surface; A plurality of optical sheets disposed on the light guide plate; A liquid crystal panel disposed on the plurality of optical sheets and configured to display an image by adjusting an amount of light transmitted from the light guide plate; The lamp is driven by the driving device of the lamp according to any one of claims 1 to 3. A liquid crystal display device. A plurality of lamps, A lamp housing accommodating the plurality of lamps; A diffusion plate covering the front surface of the lamp housing; A plurality of optical sheets disposed on the diffusion plate; A liquid crystal panel disposed on the plurality of optical sheets and configured to display an image by adjusting an amount of light transmitted from the diffusion plate; The lamp is driven by the driving device of the lamp according to any one of claims 1 to 3. A liquid crystal display device.

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