Abstract:
Disclosed are a display apparatus and a power supplying method thereof. The display apparatus includes: a backlight driver configured to drive a backlight to emit light; a main power supply configured to detect connection of the backlight to the backlight driver and supply a voltage to the backlight driver in response to a control voltage; and a standby power supply configured to supply the control voltage to the main power supply, in response to determining the connection of the backlight to the backlight driver.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority from Korean Patent Application No. 10-2014-0099159, filed on Aug. 1, 2014 in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    Apparatuses and methods consistent with exemplary embodiments relate to a display apparatus and a power supplying method thereof, and more particularly to a display apparatus and a power supplying method thereof, which can prevent damage to a circuit component even though an alternating current (AC) power plug is connected without a backlight or a video circuit during assembly or a test process. 
         [0004]    2. Description of Related Art 
         [0005]    A display apparatus, such as a television (TV), operates by receiving power from an internal or external power supply. The display apparatus includes a plurality of components, such as a video circuit, a backlight driver, a backlight, an audio reproducer, and the like, to which electric power may be supplied. 
         [0006]      FIG. 6  is a circuit diagram illustrating a power supplying structure of a general display apparatus. 
         [0007]    The display apparatus includes a main power supply  10  which converts an input voltage into voltages needed for respective components and supplies the converted voltages to the respective components. The display apparatus also includes a standby power supply  30  which generates standby power while the display apparatus is in a standby mode and controls the main power supply  10  to turn on in response to a power-on signal. As shown in  FIG. 6 , if the power-on signal is input via a photo coupler  35  of the standby power supply  30 , a transistor switch Q 1  is switched on and off, so that the standby power supply  30  can supply a control voltage to a switching integrated circuit (IC)  14  in order to control the main power supply  10 . 
         [0008]    In general, assembly or testing may be performed by supplying an AC voltage to the display apparatus while the video circuit is absent. If the video circuit is absent, a power-on signal may not be transmitted from the video circuit. During assembly or testing, the main power supply  10  must operate even though the video circuit is absent. Therefore, as shown in  FIG. 6 , the output terminal of the standby power supply  30  is connected to the power-on signal input terminal of the video circuit, so that the main power supply  10  can operate whenever an AC voltage is supplied. 
         [0009]    However, as the power is supplied to the respective components of the display apparatus when the AC power is supplied without a connection between the backlight and the video circuit, the circuit may be damaged. 
         [0010]    In particular, abnormal discharge of electric charges stored in a capacitor, or similar energy storage element, may damage the circuit components. 
       SUMMARY 
       [0011]    An aspect of an exemplary embodiment provides a display apparatus and a power supplying method thereof, that can selectively supply a control voltage to a main power supply based on a connection status between a backlight and a backlight driving circuit, and to prevent damage to a circuit component from occurring when power is supplied while a backlight is disconnected. 
         [0012]    According to an exemplary embodiment, a display apparatus for displaying an image, the display apparatus includes: a backlight driver configured to drive a backlight to emit light; a main power supply configured to supply a voltage to the backlight driver in response to a control voltage; and a standby power supply configured to detect connection of the backlight to the backlight driver and supply the control voltage to the main power supply, in response to detecting the connection of the backlight to the backlight driver. 
         [0013]    The standby power supply may be further configured to determine whether a video circuit is connected to the display apparatus, and supply the control voltage in accordance with a result of the determination. 
         [0014]    The standby power supply may be further configured to determine whether a video circuit is connected to the display apparatus and supply a power-on signal to the video circuit in accordance with a result of the determination. 
         [0015]    The display apparatus may further include a wire harness including a first side and a second side configured to connect the backlight to the backlight driver. 
         [0016]    The first side of the wire harness may include a first terminal connected to an output terminal of the standby power supply and a second terminal connected to a bias control-voltage input terminal of the main power supply, the second side of the wire harness may include a third terminal configured to be coupled to the first terminal and a fourth terminal configured to be coupled to the second terminal, and the third terminal and the fourth terminal may be directly electrically connected to each other. 
         [0017]    According to another aspect of an exemplary embodiment, a power supplying method of a display apparatus with a standby power supply and a main power supply, the power supplying method includes: by the standby power supply, generating standby power based on an input alternating current power; connecting a backlight driver to a backlight; and by the standby power supply, detecting connection of the backlight to the backlight driver and based on the detecting, supplying the generated standby power as a control voltage to the main power supply. 
         [0018]    The power supplying method may further include determining whether a video circuit is connected to the display apparatus, and supplying the control voltage in accordance with a result of the determining. 
         [0019]    The power supplying method may further include determining whether a video circuit is connected to the display apparatus and supplying the control voltage in accordance with a result of the determination. 
         [0020]    According to an aspect of another exemplary embodiment, a display apparatus includes: a backlight driver comprising a backlight connection harness, the backlight driver configured to drive a backlight connected via the backlight connection harness; a standby power supply configured to generate and output a standby voltage to the backlight connection harness. 
         [0021]    The standby power supply may be further configured to receive the standby voltage from the wiring harness. 
         [0022]    The display apparatus may further include a main power supply. The standby power supply may be further configured to activate the main power supply in response to receiving the standby voltage from the backlight connection harness. 
         [0023]    The display apparatus may further include a video circuit configured to generate an activation signal. The standby power supply may be further configured to activate the main power supply in response to receiving the activation signal received from the video circuit. 
         [0024]    The video circuit may include a remote-controller light receiver configured to generate an indicator signal in response to receiving a power command from a remote control, and the video circuit may be further configured to generate the activation signal in response to the indicator signal. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    The above and/or other aspects will become apparent and more readily appreciated from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings, in which: 
           [0026]      FIG. 1  is a block diagram schematically illustrating a display apparatus according to an exemplary embodiment; 
           [0027]      FIG. 2  is a block diagram illustrating power connections to respective components according to an exemplary embodiment; 
           [0028]      FIG. 3  is a circuit diagram illustrating power connections according to an exemplary embodiment; 
           [0029]      FIG. 4  is a diagram illustrating a wire harness according to an exemplary embodiment; 
           [0030]      FIG. 5  is a flowchart illustrating a power supplying method according to an exemplary embodiment; and 
           [0031]      FIG. 6  is a circuit diagram illustrating a conventional display apparatus. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0032]    Below, exemplary embodiments will be described in detail with reference to the accompanying drawings. The following exemplary embodiments describe configurations related to the present disclosure, and the descriptions of other configurations may be omitted. Further, like numerals refer to like elements throughout. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. In describing exemplary embodiments, the term “connected to” or “coupled to” that is used to designate a connection or coupling of one element to another element includes both a case that an element is “directly connected or coupled to” another element and a case that an element is connected or coupled to another element via still another element. In this case, the term “directly connected to” or “directly coupled to” means that an element is connected or coupled to another element without intervention of any other element. 
         [0033]    According to an exemplary embodiment, as shown in 
         [0034]      FIG. 1 , a display apparatus  100  may include an image receiver  200 , a power circuit  300 , a video circuit  400 , a backlight driver  500 , a backlight  600 , and a remote-controller light receiver  700 . In addition to the foregoing elements, the display apparatus  100  may further include a graphic processor, a storage, a user interface generator, an audio processor, a wired/wireless communicator, etc., descriptions of which will be omitted for convenience. 
         [0035]    The image receiver  200  may include a tuner connected to an external antenna. The image receiver  200  receives a television (TV) broadcast through the antenna under control of a microcomputer, performs a predetermined signal-amplification process or the like, extracts an image signal from the TV broadcast signal, and outputs the image signal to the video circuit  400 . Additionally, the image receiver  200  may receive the TV broadcast from a cable or satellite signal. 
         [0036]    The power circuit  300  may include a main power supply  310  which normally supplies a control voltage to the display apparatus  100  after receiving a power-on signal from the video circuit  400 , and a standby power supply  330  which supplies power to the display apparatus  100  while in a standby mode. 
         [0037]    For example, the main power supply  310  may supply voltages for the backlight driver  500  and the video circuit  400 . 
         [0038]    The standby power supply  330  may supply standby power as the control voltage for controlling the main power supply  310  when the backlight  600  is connected to the backlight driver. That is, if the backlight  600  is connected to the backlight driver, the standby power output from the standby power supply  330  is used as a bias voltage, so that the standby power can be supplied as the control voltage to the main power supply  310 . 
         [0039]    The video circuit  400  may include a microcomputer for generally controlling the elements of the display apparatus  100 . The microcomputer detects a power-on signal received through the remote-controller light receiver  700 , and uses the power-on signal as a bias voltage for controlling the standby power supply  330 , so that the standby power supply  330  can supply the standby power as the control voltage to the main power supply  310 . 
         [0040]    The video circuit  400  may include one or more video processors to process display image data. The image data may be received from an external source or stored image data. For example, the video processing may include scaling for enlarging or reducing the size of image in accordance with given resolutions, decoding and encoding corresponding to various image formats, de-interlacing, frame refresh rate conversion, noise reduction for improving image quality, detail enhancement, line scanning, or any other processing. The processes may be performed individually or simultaneously. 
         [0041]    The backlight  600  emits light to the back of a liquid crystal display (LCD) panel, and may include a light emitting diode (LED), a cold cathode fluorescent lamp (CCFL), or the like. The backlight  600  may directly emit light from the back of the LCD panel or may emit light to an edge, so that the light can be guided through a light guide plate toward the back of the LCD panel. 
         [0042]    The backlight driver  500  applies driving power to the backlight  600 . The backlight driver  500  may drive the backlight  600  based on a dimming signal and a lighting signal received from a timing controller. Further, the backlight driver  500  may control the backlight  600  to emit white light. 
         [0043]    The remote-controller light receiver  700  may receive a command issued by a user through a remote controller. Alternatively, for example, a power-on signal may be received from the display apparatus  100 . A user&#39;s command received through the remote-controller light receiver  700  may be identified and processed by the microcomputer of the video circuit  400 . That is, the microcomputer of the video circuit  400  receives the power-on signal from the remote-controller light receiver  700 , provides the power-on signal as the bias control voltage to the standby power supply  330  so that the standby power supply  330  can supply the standby power to the main power supply  310  and thus the main power supply  310  can supply voltages to the respective components of the display apparatus  100 . 
         [0044]      FIG. 2  is a block diagram of illustrating power connections to respective components of the display apparatus  100 . The respective components include, for example, the backlight  600  and the video circuit  400 . The main power supply  310  may supply the control voltage to another component not shown in  FIG. 2 . 
         [0045]    As shown in  FIG. 2 , the main power supply  310  of the power circuit  300  may supply the control voltage to the backlight  600  via the backlight driver  500 , and also supply the control voltage to the video circuit  400 . The backlight driver  500  may connect to the backlight  600  through the wire harness  800 . 
         [0046]    The standby power supply  330  of the power circuit  300 , in accordance with a bias control voltage, may supply the control voltage to the main power supply  310  to control the main power supply  310 . The bias control voltage may be provided as the power-on signal from the microcomputer of the video circuit  400 , and may be provided as the standby power of the output terminal of the standby power supply  330  when the backlight  600  is connected to the backlight driver  500 . At this time, when the backlight  600  is connected to the backlight driver  500 , the wire harness  800  may be used for supplying the standby power of the output terminal of the standby power supply  330  as the bias control voltage. 
         [0047]    Below, the power supplying structure of the display apparatus  100  according to an exemplary embodiment will be described in detail with reference to  FIGS. 3 and 4 . 
         [0048]    As shown in  FIG. 3 , the main power supply  310  may include a smoothing condenser  311 , a transformer  312 , a feedback circuit  313 , and a switching circuit  314 . The transformer  312  includes secondary coils Tr 21  and Tr 22  to which diodes D 1  and D 2  are respectively connected in series and capacitors C 1  and C 2  are respectively connected in parallel, thereby constituting the output terminal for the control voltage. 
         [0049]    Further, the main power supply  310  may additionally include a rectifier circuit anterior to the smoothing condenser  311 . The rectifier circuit may be, for example, a bridge rectifier circuit configured to rectify an external AC voltage into a direct current (DC) voltage. 
         [0050]    The smoothing condenser  311  smoothes the DC voltage output from the rectifier circuit, and the DC voltage is input to the primary coil Tr 1  of the transformer  312 . 
         [0051]    The transformer  312  transforms the DC voltage input to the primary coil Tr 1  into predetermined voltages at secondary coils Tr 21  and Tr 22 . The voltages are transformed by certain integer ratios, thereby outputting the transformed voltages to the backlight driver  600  and the video circuit  400 , respectively. 
         [0052]    The feedback circuit  313  may include a photo coupler so as to feed the voltage at the secondary side of the transformer  312  back to the primary side. 
         [0053]    The switching circuit  314  may apply pulse width modulation (PWM) to control the voltage at the primary side Tr 1  of the transformer  312  in accordance with the feedback signal of the feedback circuit  313 . The switching circuit  314  may be achieved by a pulse width control integrated circuit (IC) and a field effect transistor (FET) switch. 
         [0054]    The standby power supply  330  may include a smoothing condenser  331 , a transformer  332 , a feedback circuit  333 , a switching circuit  334 , an enabling circuit  335 , and a transistor switch Q 1 . A secondary coil Tr 4  of the transformer  332  connects with a diode D 3  in series and connects with a capacitor C 3  in parallel, thereby constituting an output terminal for a standby voltage. 
         [0055]    Further, the standby power supply  330  may additionally include a rectifier circuit anterior to the smoothing condenser  331 . The rectifier circuit may be, for example, a bridge rectifier circuit configured to rectify an external AC voltage into a DC voltage. 
         [0056]    The smoothing condenser  331  smoothes the DC voltage output from the rectifier circuit, and the DC voltage is input to the primary coil Tr 3  of the transformer  332 . 
         [0057]    The transformer  332  transforms the DC voltage input to the primary coil Tr 3  into predetermined voltages at the secondary coil Tr 4  by respective certain integer ratios, thereby outputting the standby voltage from the secondary coil Tr 4 . 
         [0058]    The feedback circuit  333  may include a photo coupler so as to feed the voltage at the secondary side of the transformer  332  back to the primary side. 
         [0059]    The switching circuit  334  may apply PWM control to the voltage at the primary side Tr 3  of the transformer  332  in accordance with the feedback signal of the feedback circuit  333 . The switching circuit  334  may be achieved by, for example, a pulse width control IC and an FET switch. 
         [0060]    The enabling circuit  335  may include a photo coupler to turn on or off the standby power of the standby power supply  330  applied to the switching circuit  314  of the main power supply  310 . 
         [0061]    The transistor switch Q 1  is arranged in between the output terminal of the standby power supply  330  and the switching circuit  314  of the main power supply  310 , so as to control switching of the switching circuit  314  with the standby power. The transistor switch Q 1  may be achieved by various semiconductor switches such as an FET switch, etc. 
         [0062]    The standby power output from the standby power supply  330  is connected to a collector C of the transistor switch Q 1 . An emitter E of the transistor switch Q 1  is connected to the switching circuit  314  of the main power supply  310 . The base B of the transistor switch Q 1  is connected to the output terminal of the enabling circuit  335 . 
         [0063]    As shown in  FIG. 4 , a first wire harness  810  of the backlight driver  500  includes terminals  811 - 816  and a second wire harness  820  of the backlight  600  includes terminals  821 - 826 . The output terminal of the transformer  332  at the secondary side is connected to a fifth terminal  815  of the first wire harness  810  connecting with the second wire harness  820 . A sixth terminal  816  of the first wire harness  810  is connected to the bias control-voltage input terminal of the enabling circuit  335 . The fifth terminal  815  and sixth terminal  816  of the first wire harness  810  may use terminals other than the terminals  811  and  812  used in connecting the backlight driver  500  and the backlight  600 . The fifth terminal  825  and sixth terminal  826  of the second wire harness  820  corresponding to the fifth terminal  815  and sixth terminal  816  of the first wire harness  810  are connected and short-circuited by a short-circuit wire  827 . 
         [0064]    When the first wire harness  810  of the backlight driver  500  is coupled to the second wire harness  820 , not only is the control voltage of the backlight driver  500  supplied to the backlight  600 , but the standby voltage of the standby power supply  330  is also supplied to the bias control-voltage input terminal of the enabling circuit  335  via the fifth terminal  815  of the first wire harness  810 , the fifth terminal  825  of the second wire harness  820 , the sixth terminal  826  of the second wire harness  820  and the sixth terminal  816  of the first wire harness  810 . 
         [0065]    Thus, the standby voltage of the standby power supply  330  is supplied to the bias control-voltage input terminal of the enabling circuit  335  in accordance with a connection between the backlight driver  500  and the backlight  600 . Thereby, the transistor switch Q 1  can be turned on to thereby operate the switching circuit  314  of the main power supply  310  with the standby power. 
         [0066]    Further, the video circuit  400  is connected to the bias input terminal of the enabling circuit  335 , and thus the power-on signal is supplied from the microcomputer so that the transistor switch Q 1  can be turned on to thereby operate the switching circuit  314  of the main power supply  310  with the standby power. 
         [0067]    As described above, if the video circuit  400  and the backlight  600  are not mounted in the assembling process or the test process, the transistor switch Q 1  is always turned off because the default standby power or the power-on signal is not applied to the enabling circuit  335 , thereby preventing the circuit component from damage. 
         [0068]    If only the video circuit  400  is mounted without the backlight  600 , the main power supply  310  may be operated by the power-on signal of the video circuit  400 . 
         [0069]    Below, the power supplying method of the display apparatus  100  according to an exemplary embodiment will be described with reference to  FIG. 5 . 
         [0070]    At operation S 110 , if AC power is connected, the standby power is output by the smoothing condenser  331 , the transformer  332 , the feedback circuit  333  and the switch circuit  334 . 
         [0071]    At operation S 120 , it is determined whether the backlight driver  500  is connected to the backlight  600 . 
         [0072]    If it is determined at operation S 120  that the first wire harness  810  of the backlight driver  500  is connected to the second wire harness  820  of the backlight  600 , at operation S 130 , the output standby power is supplied to the bias control-voltage input terminal of the enabling circuit  335  via the wire harness  800  of connecting the backlight driver  500  and the backlight  600  and the transistor switch Q 1  is turned on, and at operation S 140  the main power supply  310  is turned on. 
         [0073]    If it is determined at operation S 120  that the first wire harness  810  of the backlight driver  500  is not connected to the second wire harness  820  of the backlight  600 , at operation S 150  it is determined whether the power-on signal from the video circuit  400  is applied to the bias control-voltage input terminal of the enabling circuit  335 . 
         [0074]    If it is determined at operation S 150  that the power-on signal is received from the video circuit  400 , the transistor switch Q 1  is turned on, and at operation S 140  the main power supply  310  is enabled. If it is determined at operation S 150  that the power-on signal is not received from the video circuit  400 , the transistor switch Q 1  is turned off, and at operation S 160  the main power supply  310  is disabled. 
         [0075]    According to an exemplary embodiment, the display apparatus disables the main power supply, and thus prevents the circuit component, such as the capacitor, from damage even though the AC power is connected while the video circuit and the backlight are not connected. 
         [0076]    Although a few exemplary embodiments have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these exemplary embodiments without departing from the principles and spirit of the exemplary embodiments. Therefore, the foregoing has to be considered as illustrative only. The scope of the present disclosure is defined in the appended claims and their equivalents. Accordingly, all suitable modification and equivalents may fall within the scope of the present disclosure.