KR20050011078A - Power providing apparatus - Google Patents

Abstract

PURPOSE: A power supply device is provided to protect inverters or a lamp coupled with the inverters by supplying a lamp failure signal in a reverse direction based on a lamp status detected by the inverters. CONSTITUTION: A power supply device includes a controller and a power converter(300). The controller controls a power supply. The power converter includes a plurality of inverters(INV1,INV2,INVN) which are connected to each other, converts the voltage supplied by the power source, and supplies the converted voltage to a lamp. Each of the inverters supplies a protection based on a status of the lamp to one of the previous inverters or the controller. The controller controls the power supply based on the protection signal.

Description

Power supply unit {POWER PROVIDING APPARATUS}

The present invention relates to a power supply, and more particularly, to a power supply for a liquid crystal display device having a protective function.

In general, as the liquid crystal display device becomes larger and higher in brightness, the number of lamps increases. As the number of lamps increases, the size of the inverter required for driving also increases, and various protection devices are required to be added.

In particular, the direct type backlight assembly currently employed in the liquid crystal display for TV is unifying the inverter size in order to reduce the cost and use of multiplexing, and only increases the number of inverters to cope with the increase in the size of the liquid crystal display device. For example, inverters of the same specification are cascaded to control a plurality of inverters using one main controller.

However, there is a disadvantage that the protection operation is performed only for the inverter when the lamp is not turned on due to a defective lamp fastening state or an inverter malfunction.

Accordingly, in consideration of the stability of the inverter due to the enlargement of the liquid crystal panel, consideration of the lamp lighting state is required in terms of quality control of the product in which the liquid crystal panel is adopted. In other words, when a lamp is not lit, a function of monitoring a lighting state of the entire backlight control is required at the system level.

Accordingly, the technical problem of the present invention has been made in view of the above, and an object of the present invention is to provide a power supply device that provides a protection function to a backlight assembly employed in a liquid crystal display device.

1 is a view for explaining a power supply device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating the inverter of FIG. 1.

3 is a view for explaining an example of the lamp state detection unit of FIG.

4 is a view for explaining an example of the calculation unit of FIG.

<Description of the symbols for the main parts of the drawings>

100: system control unit 200: LCD control unit

300: power conversion unit 321: connector input terminal

322: connector output terminal 323: lamp power output unit

324: lamp power feedback unit 325: lamp state detection unit

326: calculator 400: lamp unit

In order to realize the above object of the present invention, a power supply apparatus includes a control unit for controlling supply of a power voltage; And a plurality of inverters connected to each other, the power converting unit converting the power voltage and supplying the lamp to a lamp, each of the inverters providing a protection signal according to the lamp state to one of the previous inverters or the controller, The controller controls the supply of the power voltage based on the protection signal. The controller may block the supply of the power voltage when the protection signal exceeds a predetermined threshold.

In addition, the inverters are cascaded to drive one or more lamps, the current one of the inverters being compared to the previous inverter by comparing one or more protection signals detected by the current inverter with a protection signal fed back from the next inverter. Or it is preferable to provide to the control unit. Here, the inverter detects the state of the connected lamp, and outputs a protection signal through a comparison with the lamp state detection unit for outputting the detected lamp state detection signal, the protection signal provided from a later inverter, and the lamp state detection signal. It generates and includes a calculation unit for providing to the front end inverter or the control unit.

According to such a power supply device, by inverting the inverter driving the lamp and supplying the power voltage in the forward direction, detecting the lamp lighting failure detected by the inverter and supplying the detected lamp lighting failure signal in the reverse direction, It is possible to protect the lamps connected to the inverter.

Hereinafter, with reference to the accompanying drawings, it will be described in detail the present invention.

1 is a view for explaining a power supply device according to an embodiment of the present invention.

As shown in FIG. 1, the power supply apparatus according to the present invention includes a system controller 100, an LCD controller 200, a power converter 300, and a lamp unit 400.

The system controller 100 provides a power supply voltage control signal VC to the LCD controller 200, and detects whether a failure occurs based on the response protection signal PDR provided from the LCD controller 200. If it is detected as a fail, if the display operation cannot be normally performed using the liquid crystal panel, that is, the backlight assembly is not normally operated, a kind of alarm may be provided to the user.

The LCD controller 200 includes a timing controller for providing an image signal or a scan signal to a liquid crystal panel, and a DC-DC converter for boosting or stepping down a DC power supply, and is provided based on the power supply voltage control signal VC. The power supply voltage is supplied to the power conversion unit 300. At this time, the supply of the power supply voltage VC is controlled based on the first protection signal PD1 provided from the power conversion unit 300, and the response protection signal PDR is provided to the system controller 100. . If the first protection signal PDR is present in a predetermined range, the LCD controller 200 adjusts the supply of the power supply voltage VC to prevent overcurrent from being applied to the lamp, and exceeds the predetermined range. In this case, the supply of the power voltage VC is cut off to prevent the lamp unit 400 from being damaged. This is because if one of the plurality of lamps is broken, an overcurrent is applied to the remaining lamps to prevent damage even to normal lamps.

The power conversion unit 300 is composed of a plurality of inverters INV1, INV2, ..., INVN connected in cascade, and converts the power voltage VS provided from the LCD control unit 200 to the lamp unit 400. In addition, the first protection signal PD1 according to the driving of the lamp unit 400 is provided to the LCD controller 200. In general, considering that the power supply voltage VS supplied from the LCD control unit 200 is a DC power supply voltage, each of the inverters INV1, INV2, ..., INVN is converted into an AC power supply voltage, and converted AC The power supply voltage is supplied to both ends of the lamp groups provided in the lamp unit 400.

The lamp unit 400 includes lamp groups 410, 420, 430,..., 4N0 connected to each of the inverters, emits light based on an input voltage VI provided from the inverter, and provides feedback based on a lamp state. Provide the voltage (L) to the connected inverter. Each of the lamp groups 410, 420, 430,..., 4N0 may be formed of one lamp or a plurality of lamps. If the lamp is made of a plurality, it is preferable to be connected in parallel.

In detail, the first inverter 310 provides the power supply voltage VS provided from the LCD controller 200 to the second inverter 320, and inputs the input voltage VI stepped down or stepped up to the first lamp. The first protection is provided on one end of the lamp provided in the group 410 and based on the feedback voltage VO received through the other end of the corresponding lamp and the second protection signal PD2 provided from the second inverter 320. The signal PD1 is generated and provided to the LCD controller 200.

The second inverter 320 provides the power supply voltage VS passing through the first inverter 310 to the third inverter 330, and supplies the input voltage VI stepped down or stepped up to the second ramp group ( The second second is provided on one end of the lamp included in the 420 and is generated based on the feedback voltage V0 provided through the other end of the corresponding lamp and the third protection signal PD3 provided from the third inverter 330. The protection signal PD2 is provided to the first inverter 310.

Through this process, the power voltages provided from the LCD control unit 200 are sequentially supplied in the first direction to the first to Nth inverters 310, 320, 330,..., 3N0 to be connected to the lamp groups. The protection signals according to the lamp states, which are respectively supplied to and supplied to the lamp group, are provided to the LCD control unit 200 in a direction opposite to the first direction, so that an error such as lamp lighting failure may be fed back at the system level. I can receive it.

In the drawing, a plurality of inverters are cascaded to each other, and a current inverter drives a lamp together with a power supply voltage provided from a previous inverter to a next inverter, and a protection signal provided from a next inverter and a sensing signal according to driving the lamp. It is shown to provide the protection signal generated by comparing the previous inverter.

However, the current inverter supplies the power voltage provided from the previous inverter to the next inverter and drives the lamp, and the protection signal generated by comparing the protection signal provided from the next inverter with the detection signal according to the driving of the lamp is generated. Can also be provided to older inverters.

Of course, the protection signal output from the current inverter may be input to the LCD control unit via the connected inverter, but may also be directly input to the LCD control unit via the inverter.

As such, lamp failures can be detected at the system level, protecting the inverter or the lamps connected to the inverter. In particular, when any one of the lamps are broken and the current does not flow normally, overcurrent is applied to the remaining parallel-connected lamps.

In addition, by protecting the normal lamp, the replacement cycle of the lamp can be extended, and the reliability of the backlight assembly or the liquid crystal display device employing the lamp can be improved.

FIG. 2 is a block diagram illustrating the inverter of FIG. 1.

As shown in FIG. 2, the inverter for a liquid crystal display according to the present invention includes a connector input terminal 321, a connector output terminal 322, a lamp power output unit 323, a lamp power feedback unit 324, and a lamp state detection unit. 325 and arithmetic unit 326. Here, the second inverter 320 disposed between the first inverter 310 and the third inverter 330 is shown as an example.

The connector input terminal 321 is connected to the connector output terminal of the first inverter 310 to receive the power supply voltage VS, and the connector output terminal 322 is connected to the connector input terminal of the third inverter 330 to supply the power voltage ( Supply VS). Although only the power supply voltage VS is shown in the figure, it is preferable to further supply a power supply control signal for controlling the supply of the power supply voltage. The power supply control signal includes a horizontal synchronization signal, a PWM signal, and an on / off control signal for supplying the power supply voltage.

The lamp power output unit 323 is connected to at least one lamp end to supply a first power voltage for driving the lamp, and the lamp power feedback unit 324 is connected to at least one other end of the lamp to power the second power for driving the lamp. Supply the voltage. That is, the lamp power output unit 323 is connected to the hot electrode of the lamp, and the lamp power feedback unit 324 is connected to the cold electrode of the lamp to supply the power voltage of the first polarity and the power voltage of the second polarity. .

The lamp state detector 325 detects a state of each of the lamps connected to the lamp power feedback unit 324, and provides the detected lamp state detection signal to the calculator 326.

The calculation unit 326 defines a second protection signal PD2 by calculating and calculating a detection signal provided from the lamp state detection unit 325 and a third protection signal PD3 provided from the third inverter 330. The defined second protection signal PD2 is provided to the first inverter 310. For example, when the detection signal of the high level defining the lamp's unlit is input or the third protection signal PD3 is the high level, a second protection signal of the high level is defined and provided to the first inverter. do.

Although the second inverter 320 has been described above, if the N-th inverter 3N0 detects only the lamp state signal of the N-th inverter and provides it to the N-th inverter, and if the first inverter 310, the first inverter The lamp state signal connected to the 310 and a calculation signal provided from the second inverter 320 are calculated and provided to the LCD controller 200.

3 is a view for explaining an example of the lamp state detection unit of FIG.

Referring to FIG. 3, the lamp state detector 325 includes a first current detector 3151, a first comparator 3253, a second current detector 3255, and a second comparator 3257, and includes two lamps. Each of the flowing current levels is detected, and the first and second lamp state detection signals 325A and 325B corresponding to the detected current levels are provided to the calculator 326.

More specifically, the first current detector 3251 includes a first diode D11 having a cathode connected to the lamp power feedback unit 324 and an anode grounded, and an anode having a cathode and lamp power feedback of the first diode D11. The second diode D12 connected to the unit 324, the first resistor R1 connected to the cathode of the second diode D12 and the other end grounded, and one end connected to the first resistor R1. The first and second capacitors C1 connected to each other are grounded to detect a tube current flowing through the lamp, and provide a tube voltage corresponding to the detected tube current to the first comparator 3253. Although the second diode D12 is illustrated in the drawing, it may be omitted.

The first comparator 3253 provides the calculator 326 with a high or low level lamp state detection signal through comparison between the tube voltage detected by the first current detector 3151 and the reference voltage Vref. For example, if the tube voltage is greater than the reference voltage, a high level first lamp state detection signal 325A will be provided. If the tube voltage is less than the reference voltage, the low level first lamp state detection signal will be provided. Will provide 325A.

The second current detector 3255 may include a third diode D21 having a cathode connected to the lamp power feedback unit 324 and an anode grounded, and an anode of the cathode and lamp power feedback unit 324 of the third diode D21. A fourth diode D22 connected to the second diode, one end of which is connected to the cathode of the fourth diode D22 and the other end of which is grounded, and one end of which is connected to one end of the first resistor R2 and the other end thereof It consists of a grounded second capacitor (C2), detects the tube current flowing through the lamp, and provides a tube voltage corresponding to the detected tube current to the second comparator (3257). Although the fourth diode D42 is illustrated in the drawing, the fourth diode D42 may be omitted.

The second comparator 3257 transmits a high or low level second lamp state detection signal 325B to the calculator 326 by comparing the tube voltage detected by the first current detector 3151 with the reference voltage Vref. to provide. For example, when the tube voltage is higher than the reference voltage Vref, the second lamp state detection signal 325B of high level will be provided, and if the tube voltage is lower than the reference voltage Vref, Will provide a second lamp state detection signal 325B. The reference voltage Vref applied to the second comparator 3257 may be the same as or different from the reference voltage Vref applied to the first comparator 3251.

4 is a view for explaining an example of the calculation unit of FIG.

Referring to FIG. 4, the first or gate 3326 receives the first and second lamp state detection signals 325A and 325B from the lamp state detection unit 325 and receives the first or arithmetic signal from the lamp state detection unit 325. 3263). In particular, when either the first lamp state detection signal 325A or the second lamp state detection signal 325B is at a high level, the first OR operation signal having a high level is output to the second OR gate 3263.

The second OR gate 3263 is high or low through OR operation between a signal provided from the first OR gate 3331 and a signal provided from the third inverter 330 and level reduced by the third resistor R3. The second OR operation signal having the level is defined as the second protection signal PD2 and output to the first inverter 310.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

As described above, according to the present invention by supplying the power supply voltage in the forward direction by cascading the inverter driving the lamp, by detecting the lamp lighting failure detected by the inverter by supplying the detected lamp lighting failure signal in the reverse direction It can protect the inverter or lamps connected to the inverter.

In addition, since the inverter and the lamp can be protected, the backlight assembly employing the inverter and the lamp can be protected, and thus the reliability of the product can be secured by extending the lamp replacement cycle.

Claims (4)

A control unit controlling a supply of a power supply voltage; And Comprising a plurality of inverters connected to each other, including a power conversion unit for converting the power supply voltage to supply to the lamp, Each of the inverters provides a protection signal according to the lamp state to one of the previous inverters or the controller, And the control unit controls the supply of the power voltage based on the protection signal. The power supply device of claim 1, wherein the control unit cuts off the supply of the power voltage when the protection signal exceeds a predetermined threshold. The method of claim 1, wherein the inverters are cascaded to drive one or more lamps, A current inverter of the inverters is provided to the previous inverter or the control unit by comparing one or more protection signals sensed by the current inverter with a protection signal fed back from the next inverter. The method of claim 3, wherein the inverter, A lamp state detection unit for detecting a state of a connected lamp and outputting a detected lamp state detection signal; And And a calculation unit configured to generate a protection signal through a comparison between the protection signal provided from a rear end inverter and the lamp state detection signal and provide the protection signal to the front end inverter or the control unit.