Abstract:
A plasma display device, a driving apparatus and a driving method are provided. A first transistor is coupled to a power source and electrodes of a first group. A second transistor is coupled to the power source and electrodes of a second group. A third transistor is coupled to a first diode. The fourth transistor is coupled to the electrodes of the first group and a second power source. The fifth transistor is coupled to the electrodes of the second group and the second power source. A first diode is coupled to an inductor. A second diode is coupled to the fifth transistor and the electrodes of the second group. A third diode is coupled to the electrodes of the second group and the third transistor. The fourth diode is coupled to the third transistor and the electrodes of the second group.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority to and the benefit of Korean Patent Application No. 10-2005-0104207 filed in the Korean Intellectual Property Office on Nov. 2, 2005, the entire content of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     (a) Field of the Invention  
         [0003]     The present invention relates to a plasma display device, a driving apparatus and a driving method thereof. More particularly, the present invention relates to a power recovery circuit of a plasma display device, a driving apparatus and a driving method thereof.  
         [0004]     (b) Description of the Related Art  
         [0005]     A plasma display device is a flat panel display that uses plasma generated by a gas discharge to display characters or images. The plasma display device is driven by a plurality of subfields of a frame. A turn-on discharge cell is selected among a plurality of discharge cells by performing an addressing discharge for an address period of each subfield, and the turn-on discharge cell is sustain-discharged for a sustain period of each field so as to display an image.  
         [0006]     Particularly, during the sustain period, high and low level voltages are alternately applied to the electrodes for performing a sustain discharge. In this case, capacitance exists on the panel due to a discharge space between scan and sustain electrodes performing sustain discharges and the discharge space operates as a capacitive load. Accordingly, an additional reactive power as well as power for the sustain discharge is desirable so as to apply the sustain pulses of the high and low level voltages to the two electrodes. Therefore, a typical sustain discharge driving circuit includes a power recovery circuit for recovering and reusing the reactive power. The power recovery circuit typically uses additional capacitors for generally supplying and recovering energy. Therefore, the cost is increased because this power recovery capacitor has a large capacitance.  
       SUMMARY OF THE INVENTION  
       [0007]     One exemplary embodiment of the present invention provides a plasma display device that includes a plurality of electrodes grouped into a first group and a second group. The device also includes a first transistor coupled between a first power source and electrodes of the first group wherein the first power source is supplying a first voltage. The display also includes a second transistor coupled between the first power source and electrodes of the second group. The display also includes an inductor having a first end coupled to the electrodes of the first group, a first diode having an anode coupled to a second end of the inductor and a third transistor having a first end coupled to a cathode of the first diode. The display also includes a second diode having an anode coupled to a second end of the third transistor and a cathode coupled to the electrodes of the second group, a third diode having an anode coupled to the electrodes of the second group and a cathode coupled to the first end of the third transistor. The display also includes a fourth diode having an anode coupled to the second end of the third transistor and a cathode coupled to the electrodes of the second group. The display also includes a fourth transistor coupled between the electrodes of the first group and a second power source for supplying a second voltage, and a fifth transistor coupled between the electrodes of the second group and the second power source. The electrodes of the first group may include odd numbered electrodes and the electrodes of the second group may include even numbered electrodes. The plasma display device further includes: a controller adapted to set the third transistor to be turned on during a first mode; and to set the second transistor and the fourth transistor to be turned on during a second mode. The controller is also adapted to set the third transistor to be turned on during a third mode; and to set the first transistor and the fifth transistor to be turned on during a fourth mode.  
         [0008]     Another embodiment of the present invention provides a driving method of a plasma display device having a plurality of electrodes being grouped into a first group and a second group. The driving method includes, during a first mode, applying a first voltage to electrodes of the first group and a second voltage less than the first voltage to electrodes of the second group. The method also includes, during a second mode, forming a resonance path through the electrodes of the first group, an inductor having a first end coupled to the electrodes of the first group, and a first transistor coupled between a second end of the inductor and the electrodes of the second group, and decreasing a voltage of the electrodes of the first group and increasing a voltage of the electrodes of the second group. The method also includes, during a third mode, applying the second voltage to the electrodes of the first group and applying the first voltage to the electrodes of the second group. The method also includes, during a fourth mode, forming a resonance path through the electrodes of the second group, the first transistor, the inductor and the electrodes of the first group, and increasing the voltage of the electrodes of the first group and decreasing the voltage of the electrodes of the second group.  
         [0009]     Another embodiment of the present invention provides a driving apparatus having a plurality of electrode being grouped into a first group and a second group. The driving apparatus includes an inductor having a first end coupled to electrodes of the first group. The apparatus also includes a first path including a first transistor, wherein the first transistor is coupled between a second end of the inductor and a electrodes of the second group; and a second path including the first transistor, wherein the first transistor is coupled between the second end of the inductor and the electrodes of the second group. The apparatus also includes a second transistor coupled between the electrodes of the first group and a first power source for supplying a first voltage; and a third transistor coupled between the electrodes of the second group and the first power source. The apparatus also includes a fourth transistor coupled between the electrodes of the first group and a second power source supplying a second voltage; and a fifth transistor coupled between the electrodes of the second group and the second power source. The first path may further include: a first diode having an anode coupled to the second end of the inductor and an cathode coupled to the first end of the first transistor; and a second diode having an anode coupled to the second end of the first transistor and a cathode coupled to the electrodes of the second group. The second path may further include: a third diode having an anode coupled to the electrodes of the second group and a cathode coupled to the first end of the first transistor; and a fourth diode having an anode coupled to the second end of the first transistor and a cathode coupled to the second end of the inductor. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  shows a schematic diagram of a plasma display device according to an exemplary embodiment of the present invention.  
         [0011]      FIG. 2  shows a sustain discharge pulse waveform according to a first exemplary embodiment of the present invention.  
         [0012]      FIG. 3  shows a schematic diagram of a sustain discharge circuit according to a first exemplary embodiment of the present invention.  
         [0013]      FIG. 4  shows a signal timing diagram of a sustain discharge circuit according to a first exemplary embodiment of the present invention.  
         [0014]      FIGS. 5A, 5B ,  5 C and  5 D show current paths of a sustain discharge circuit of  FIG. 3  operated according to signal timings of  FIG. 4 .  
         [0015]      FIG. 6  shows a sustain discharge pulse according to a second exemplary embodiment of the present invention.  
         [0016]      FIG. 7  shows schematic diagram of a sustain discharge circuit according to a second exemplary embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0017]     As used herein, the phrase “maintained at a predetermined voltage” should not be understood as “maintained exactly at a predetermined voltage”. To the contrary, even if a voltage difference between two points varies, the voltage difference is “maintained at a predetermined voltage” when the variance is within a range allowed in design constraints or when the variance is caused due to a parasitic component that is usually disregarded by a person of ordinary skill in the art. A threshold voltage of a semiconductor device (e.g., a transistor, a diode or the like) may be very low in comparison with a discharge voltage, and therefore the threshold voltage may be approximated to 0V in the following description.  
         [0018]     As shown in  FIG. 1 , the plasma display device according to the exemplary embodiment of the present invention includes a plasma display device panel (PDP)  100 , a controller  200 , an address electrode driver  300 , a scan electrode driver  500 , and a sustain electrode driver  400 .  
         [0019]     The plasma panel  100  includes a plurality of address electrodes A 1 -Am (hereinafter, referred to as “A electrodes”) extending in the column direction, and scan electrodes Y 1 -Yn (hereinafter, referred to as “Y electrodes”) and sustain electrodes X 1 -Xn (hereinafter, referred to as “X electrodes”) extending in the row direction. The sustain electrodes X 1 -Xn correspond to the scan electrodes Y 1 -Yn. The address electrodes A 1 -Am cross the scan electrodes Y 1 -Yn and the sustain electrodes X 1 -Xn. Discharge spaces are formed at regions where the address electrodes A 1 -Am cross the sustain and scan electrodes X 1 -Xn and Y 1 -Yn, respectively, and such discharge spaces form discharge cells  110 .  
         [0020]     The controller  200  externally receives an image signal (e.g., video image signal) and outputs driving control signals. In addition, the controller  200  controls the plasma display device by dividing a frame into a plurality of subfields having respective brightness weight values. Each subfield includes an address period and a sustain period. The address, sustain, and scan electrode drivers  300 ,  400 ,  500 , respectively, receives the driving control signals from the controller  200  and applies driving voltages to the respective address electrodes A 1 -Am, sustain electrodes X 1 -Xn and scan electrodes Y 1 -Yn.  
         [0021]     In more detail, during the address period of each subfield, the address, sustain, and scan electrode driver  300 ,  400 ,  500  select the turn-on and turn-off discharge cells of each subfield from among the plurality of discharge cells  110 .  
         [0022]     As shown in  FIG. 2 , during the sustain period of each subfield, the sustain electrode driver  400  applies a sustain pulse alternately having a high level voltage Vs and a low level voltage 0V to odd numbered sustain electrodes (hereinafter, referred to as “Xodd electrode”) among the plurality of sustain electrodes X 1 -Xn, and applies a sustain pulse of an inverse phase with respect to the sustain pulse of the Xodd electrodes to even numbered sustain electrodes (hereinafter, referred to as “Xeven electrode”) among the plurality of sustain electrodes X 1 -Xn. In addition, the scan electrode driver  500  applies a sustain pulse of an inverse phase with respect to the sustain pulse of the Xodd electrodes to odd numbered scan electrodes (hereinafter, referred to as, “Yodd electrode”) among the plurality of scan electrodes Y 1 -Yn, and applies a sustain pulse of inverse phases with respect to the sustain pulse of the Xeven electrodes to even numbered scan electrodes (hereinafter, referred to as “Yeven electrode”) among the plurality of scan electrodes Y 1 -Yn. Voltage differences between the Xodd and Yodd electrodes, and between the Xeven and the Yeven electrodes, have alternately the voltages Vs and −Vs. The voltage of the Xodd electrode overlaps the voltage of the Xeven electrode when the voltage of the Xodd electrode is rising to the voltage Vs and the voltage of the Xeven electrode is falling to 0V and vice versa, and also, the voltage of the Yodd electrode overlaps the voltage of the Yeven electrode when the voltage of the Yodd electrode is rising into the voltage Vs and the voltage of the Yeven electrode is falling to 0V and vice versa. The sustain period may be reduced by overlapping a part of the sustain pulse in such a manner.  
         [0023]     A sustain discharge circuit for supplying the sustain pulses of  FIG. 2  will be described in detail with reference to  FIGS. 3, 4 ,  5 A,  5 B,  5 C and  5 D.  
         [0024]      FIG. 3  shows a schematic circuit diagram of a sustain discharge circuit according to a first exemplary embodiment of the present invention. For better understanding and ease of description,  FIG. 3  shows only a sustain discharge circuit  410  coupled to the plurality of sustain electrodes X 1 -Xn. However, such a sustain discharge circuit  410  may be formed in the sustain electrode driver  400  of  FIG. 1 . In addition, a sustain discharge circuit  510  coupled to the plurality of scan electrodes Y 1 -Yn may have the same structure as the sustain discharge circuit  410  of  FIG. 3 , or may have different structures from the sustain discharge circuit  410  of  FIG. 3 .  
         [0025]     Such a sustain discharge circuit  410  may be coupled to the Xodd and Xeven electrodes, or may be coupled to some predetermined sustain electrodes among the plurality of sustain electrodes X 1 -Xn. In the sustain discharge circuit  410 , capacitive components formed between the Xodd and the Yodd electrodes and between the Xeven electrodes and the Yeven electrodes, for forming the discharge cells, is illustrated as a panel capacitor Cp.  
         [0026]     As shown in  FIG. 3 , the sustain discharge circuit  410  according to the first exemplary embodiment of the present invention includes transistors S 1 , S 2 , S 3 , S 4 , and S 5 , diodes D 1 , D 2 , D 3 , and D 4 , and an inductor L. The transistors S 1 , S 2 , S 3 , S 4 , and S 5  are each formed as an n-channel field effect transistor, particularly, an n-channel metal oxide semiconductor (NMOS) transistor. These transistors S 1 , S 2 , S 3 , S 4 , and S 5  have a body diode formed in a direction towards a drain from a source. The transistors S 1  to S 5  may be formed by other transistors having similar functions. In addition, in one embodiment, the transistors S 1 , S 2 , S 3 , S 4 , and S 5  shown in  FIG. 3  are separately formed. Accordingly, the transistors S 1 , S 2 , S 3 , S 4 , and S 5  may each be formed by a plurality of transistors coupled in parallel.  
         [0027]     As shown in  FIG. 3 , a drain of the transistor S 1  is coupled to a power source Vs for supplying the high level voltage Vs of the sustain pulse, and a source of the transistor S 1  and a drain of the transistor S 4  are coupled to the Xodd electrode. A drain of the transistor S 3  is coupled to the power source Vs, a source of the transistor S 3  and a drain of the transistor S 2  are coupled to the Xeven electrode. The sources of the transistors S 4  and S 2  are coupled to a ground terminal for supplying the low level voltage of the sustain pulse, that is, the approximate ground voltage of 0V.  
         [0028]     The inductor L has a first end coupled to the Xodd electrode and a second end coupled to an anode of the diode D 1  and a cathode of the diode D 4 . A cathode of the diode D 1  is coupled to a drain of the transistor S 5 , and an anode of the diode D 4  is coupled to a source of the transistor S 5 . An anode of the diode D 3  and a cathode of the diode D 2  are coupled to the Xeven electrode, a cathode of the diode D 3  is coupled to the drain of the transistor S 5 , and an anode of the diode D 2  is coupled to the source of the transistor S 5 . When the transistor S 5  is turned on, the diodes D 1  and D 2  form a current path from the Xodd electrode to the Xeven electrode and the diodes D 3  and D 4  form a current path from the Xeven electrode to the Xodd electrode.  
         [0029]     An operation of the sustain discharge circuit  410  of  FIG. 3  will be described in detail with reference to  FIGS. 4, 5A ,  5 B,  5 C and  5 D  
         [0030]      FIG. 4  shows a signal timing diagram of a sustain discharge circuit according to a first exemplary embodiment of the present invention.  FIGS. 5A, 5B ,  5 C and  5 D show current paths of a sustain discharge circuit of  FIG. 3  operated according to signal timings of  FIG. 4 .  
         [0031]     First, it is assumed that the Xodd electrode receives the voltage Vs and the Xeven electrode receives 0V before the mode Ml starts. When the transistors S 1  and S 2  are turned on, the voltage Vs may be applied to the Xodd electrodes and the ground voltage 0V may be applied to the Xeven electrodes.  
         [0032]     As shown in  FIG. 4  and  FIG. 5A , in the mode M 1 , the transistor S 5  is turned on. Then, as shown in  FIG. 5A , a resonance path is formed through the Xodd electrode, the inductor L, the diode D 1 , the transistor S 5 , the diode D 2  and the Xeven electrode. Energy charged in the Xodd electrode is recovered through the inductor L to the Xeven electrode. Thus the voltage Vx_odd of the Xodd electrode is decreased from the voltage Vs to the ground voltage 0V and the voltage Vx_even of the Xeven electrode is increased from the ground voltage 0V to the voltage Vs. That is, energy charged in the Xodd electrode is recovered to the Xeven electrode.  
         [0033]     In the mode M 2 , the transistor S 5  is turned off and the transistors S 3  and S 4  are turned on. Then, as shown in  FIG. 5B , the Xodd electrode receives the ground voltage 0V through the Xodd electrode, the transistor S 4 , and the ground terminal, and the Xeven electrode receives the voltage Vs through the power source Vs, the transistor S 3 , and the Xeven electrode.  
         [0034]     In the mode M 3 , the transistors S 3  and S 4  are turned off and the transistor S 5  is turned on. Then, as shown in  FIG. 5C , a resonance is generated through the Xeven electrode, the diode D 3 , the transistor S 5 , the diode D 4 , the inductor L, and the Xodd electrode. Energy charged in the Xeven electrode is recovered through the inductor L to the Xodd electrode. Thus the voltage Vx_even of the Xeven electrode is decreased from the voltage Vs to the ground voltage 0V and the voltage Vx_odd of the Xodd electrode is increased from the ground voltage 0V to the voltage Vs. That is, energy charged in the Xeven electrode is again recovered to the Xodd electrode.  
         [0035]     In the mode M 4 , the transistor S 5  is turned off and the transistors S 1  and S 2  are turned on. Then, as shown in  FIG. 5D , the Xodd electrode receives the voltage Vs through the power source Vs, the transistor S 1 , and the Xodd electrode, and the Xeven electrode receives the ground voltage 0V through the Xeven electrode, the transistor S 2 , and the ground terminal.  
         [0036]     According to the first exemplary embodiment of the present invention, during the sustain period, the modes M 1 , M 2 , M 3  and M 4  are repeated a number of times corresponding to the weight value of the corresponding subfield. Accordingly, the Xodd electrodes and the Xeven electrodes receive a sustain pulse having different phases. In the modes M 1  and M 3 , energy is exchanged between the Xodd and Xeven electrodes, and accordingly, additional energy recovery capacitors are not used thereby reducing the cost thereof.  
         [0037]      FIG. 6  shows a sustain discharge pulse waveform according to a second exemplary embodiment of the present invention.  FIG. 7  shows a schematic diagram of a sustain discharge circuit according to a second exemplary embodiment of the present invention.  
         [0038]     As shown in  FIG. 6 , according to the second exemplary embodiment of the present invention, during the sustain period, the Xodd electrode receives the sustain pulse having alternately the voltages Vs and −Vs, and the Xeven electrode receives the sustain pulse of inverse phases. The plurality of scan electrodes Y 1  to Yn (illustrated as “Y” in  FIG. 6 ) receives the voltage 0V. The voltage of the Xeven electrode is increased from the voltage −Vs to the voltage Vs when the voltage of the Xodd electrode is decreased from the voltage Vs to the voltage −Vs, and the voltage of the Xeven electrode is decreased from the voltage Vs to the voltage −Vs when the voltage of the Xodd electrode is increased from the voltage −Vs to the voltage Vs. In the same manner as in the sustain pulse of  FIG. 2 , the voltage difference between the Xodd and Yodd electrodes may alternately have the voltages Vs and −Vs, and the voltage difference between the Xeven and Yeven electrodes may alternately have the voltages Vs and −Vs.  
         [0039]     As shown in  FIG. 7 , the sustain discharge circuit  410 ′ according to the second exemplary embodiment has the source of the transistors S 2  and the source of the transistor S 4  coupled to the power source −Vs having the voltage −Vs. In addition, in this case, energy may be exchanged between the Xodd electrodes and the Xeven electrodes, and accordingly, additional energy recovery capacitors need not be used.  
         [0040]     According to the exemplary embodiment of the present invention, the cost of the sustain discharge circuit can be reduced because the additional energy recovery capacitors are not used.  
         [0041]     It is one example that the sustain discharge circuit  410 ′ is coupled between the Xodd electrodes and the Xeven electrodes and the Y electrode receives approximately 0V in  FIG. 6  and  FIG. 7 . Accordingly, the sustain discharge circuit may be coupled between the Yodd and Yeven electrodes and the X electrode may receive approximately 0V.  
         [0042]     When the transistors S 1  and S 3  respectively have a drain coupled to a power source for supplying a voltage Vs/ 2 , and the transistors S 2  and S 4  respectively have a drain coupled to a power source for supplying a voltage Vs/ 2 , a sustain pulse alternately having the voltages Vs/ 2  and −Vs/ 2  may be applied. In the case, the sustain pulse alternately having the voltages Vs/ 2  and −Vs/ 2  may be applied to the Yodd electrode in an inverse phase with respect to the sustain pulse of the Xodd electrode. Also, the sustain pulse alternately having the voltages Vs/ 2  and −Vs/ 2  may be applied to the Yeven electrode in an inverse phase with the respect to the sustain pulse of the Xeven electrode.  
         [0043]     Meanwhile, according to the exemplary embodiment of the present invention, it is one example that the plurality of sustain electrodes X 1  to Xn are divided into the Xodd electrodes and the Xeven electrodes, the sustain discharge circuit is disposed between the Xodd electrodes and the Xeven electrodes, and thus energy is exchanged between the Xodd electrodes and the Xeven electrodes. Accordingly, the plurality of sustain electrodes X 1  to Xn may be divided into a plurality of groups including at least one sustain electrode and the sustain discharge circuit may be disposed between the divided groups.  
         [0044]     While this invention has been described in connection with exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.