KR101576024B1 - Apparatus for supplying power and display device comprising the same - Google Patents

Abstract

The present invention relates to a power supply device capable of improving the efficiency of a power supply integrated circuit by minimizing a switching loss generated in a switching device of a power supply integrated circuit, and a display device including the power supply device. The power supply device includes an input A DC power generator for generating a DC power using a power source and outputting the generated DC power to an output terminal; And a power supply integrated circuit for selectively switching at least one switching element among a plurality of switching elements connected to the DC power generating part according to a load level to adjust the DC power to a desired voltage level .

Power supply, load level, DC power supply, power supply integrated circuit, switching element

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a power supply device and a display device including the power supply device.

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a display device, and more particularly, to a power supply device capable of minimizing a switching loss generated in a switching device of a power supply integrated circuit, thereby improving the efficiency of the power supply integrated circuit, and a display device including the same .

Currently, various flat panel display devices capable of reducing weight and volume, which are disadvantages of cathode ray tubes (CRTs), are being developed. A flat panel display device includes a liquid crystal display (LCD), a field emission display, a plasma display panel (PDP), and a light emitting diode (PDP) display device.

Among flat panel display devices, a light emitting diode display device displays a desired image by supplying a current according to image information to a light emitting element formed in pixels arranged in a matrix using at least two thin film transistors. And a power supply for supplying a DC power for driving each pixel of the LED display device.

1 is a schematic view for explaining a conventional power supply apparatus.

Referring to FIG. 1, a conventional power supply device includes an inductor L, a diode D, and a power supply integrated circuit 10.

The inductor L is connected between the input voltage Vin and the node N1.

The diode D is connected between the first node N1 and the output terminal N2.

The power supply integrated circuit 10 includes a switching element Q connected between a node N1 and a ground voltage VSS and a control section 12 for controlling switching (ON / OFF) of the switching element Q.

The switching element Q is switched according to the switching control of the controller 12 so that energy is stored in the inductor L or energy stored in the inductor L is outputted.

The control unit 12 controls the switching of the switching element Q in accordance with the load level LL of the load connected to the output terminal N2. Here, the rod may be a display panel of a flat panel display.

The conventional power supply device having such a configuration outputs energy stored in the inductor L to the output terminal N2 through the diode D in accordance with switching of the switching device Q connected to the power supply integrated circuit 10 The input voltage Vin to be input is stepped up or reduced.

However, in the conventional power supply device, since the switching element is designed to have the highest efficiency at the optimum load level regardless of the magnitude of the load level, as shown in FIG. 2, A).

Therefore, in the conventional power supply apparatus, since the ratio of the switching loss of the switching elements generated in the low load level section A is large, the efficiency of the power supply integrated circuit 10 in the low load level section A There is a problem that it can not be increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a power supply device and a display device including the same, which can improve the efficiency of a power supply integrated circuit by minimizing a switching loss generated in a switching device of the power supply integrated circuit It is a technical task.

According to an aspect of the present invention, there is provided a power supply apparatus including: a DC power generator generating a DC power using an input power supplied to an input terminal and outputting the generated DC power to an output terminal; And a power supply integrated circuit for selectively switching at least one switching element among a plurality of switching elements connected to the DC power generating part according to a load level to adjust the DC power to a desired voltage level .

Wherein the direct current power generator comprises: an inductor connected to the input terminal and the first node; A diode connected between the first node and the output terminal; And a capacitor connected between the output terminal and the base power supply.

Wherein the power supply integrated circuit includes: a load level detector for detecting the load level of the load connected to the output terminal of the DC power generator to generate a load level signal; A control unit for generating a switching control signal and a switch selection signal corresponding to the load level signal supplied from the load level detection unit; A voltage level adjuster having the plurality of switching elements electrically connected in parallel between the first node and the base power supply and selectively switching according to the switching control signal to adjust the DC power supply to a desired voltage level; And a switch selector for selecting at least one switching element among the plurality of switching elements according to the switch selection signal and supplying the switching control signal to the selected switching element.

According to an aspect of the present invention, there is provided a display device including: a DC power supply for generating a DC power using an input power supplied to an input terminal and outputting the generated DC power to an output terminal; And a power supply integrated circuit for selectively switching at least one switching element among a plurality of switching elements connected to the DC power generating part according to a load level to adjust the DC power to a desired voltage level And a power supply unit.

According to an aspect of the present invention, there is provided a display device including a light emitting element formed in each region defined by a plurality of data lines and a plurality of scan lines, A display panel including a plurality of pixels each having a pixel circuit for controlling a current flowing in the device; A panel driver for driving the pixel; And a power supply unit for supplying the DC power to the pixel, wherein the power supply unit includes a DC power supply unit for generating a DC power using an input power supplied to an input terminal and outputting the generated DC power to an output terminal, ; And a power supply integrated circuit for selectively switching at least one switching element among a plurality of switching elements connected to the DC power generating part according to a load level to adjust the DC power to a desired voltage level .

As described above, the power supply apparatus and the display apparatus including the power supply apparatus according to the present invention selectively switch at least one of the plurality of switching elements for adjusting the DC power to a desired voltage level according to the load level, The following effects can be obtained.

First, there is an effect that the efficiency of a power supply integrated circuit can be increased even in a low load level interval.

Secondly, there is an effect that the overall efficiency of the power supply integrated circuit can be improved and the power consumption can be reduced.

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

3 is a schematic view for explaining a power supply apparatus according to an embodiment of the present invention.

Referring to FIG. 3, a power supply 100 according to an embodiment of the present invention includes a DC power generating unit 110; And a power supply integrated circuit (120).

The DC power generating unit 110 includes an inductor L, a diode D, and a capacitor C.

The inductor L is connected between the input power supply Vin and the first node N1 and stores a voltage corresponding to a change amount of the current input from the input power supply Vin by the power supply integrated circuit 120. [

The diode D is connected between the first node N1 and the output terminal N2 and rectifies the voltage supplied from the inductor L by the power supply integrated circuit 120 and outputs the rectified voltage. Here, the diode D is a reverse current prevention diode, and the voltage supplied from the inductor L is supplied to the output terminal N2.

The capacitor C charges the voltage supplied from the inductor L through the diode D by the power supply integrated circuit 120 or outputs the charged voltage to the output terminal N2 with the DC power supply VDD.

The direct current power generating unit 110 generates a predetermined direct current power source VDD by using the input power source Vin under the control of the power source integrated circuit 120 and outputs the generated direct current power source VDD to the output terminal N2.

The power supply integrated circuit 120 includes a load level detection unit 122, a control unit 124, a switch selection unit 126; And a voltage level adjusting unit 128.

The load level detecting section 122 detects a load level LL that is connected to the output terminal N2 and is connected to a load driven by the DC power supply VDD output from the output terminal N2, Level signal LLS corresponding to the load-level signal LL. Here, the load level detector 122 may classify the detected load level LL in units of 1 mA and generate the load level signal LLS in units of 1 mA. However, the present invention is not limited to this, The load level signal LLS can be generated on a predetermined load level basis.

The control unit 124 generates a plurality of switch selection signals SS corresponding to the load level signal LLS supplied from the load level detection unit 122 and supplies the plurality of switch selection signals SS to the switch selection unit 126. [ A specific method of generating a plurality of switch selection signals SS at the control unit 124 will be described later.

The control unit 124 outputs a switching control signal DTS for adjusting the DC power supply VDD output to the output terminal N2 to a desired voltage level in accordance with the load level signal LLS supplied from the load level detection unit 122, And supplies it to the switch selection unit 126. [

The switch selection unit 126 supplies the switching control signal DTS supplied from the control unit 124 to the voltage level adjustment unit 128 in accordance with the switch selection signal SS supplied from the control unit 124. [

The voltage level adjusting unit 128 according to the first embodiment includes n switching elements Q1 to Qn having the same size as shown in FIG.

Each of the n switching elements Q1 to Qn includes a drain terminal connected to the first node N1, a source terminal connected to the base power supply VSS, and a gate terminal connected to the switch selecting section 126 And is electrically connected in parallel between one node N1 and the base power supply VSS.

At least one switching element among the n switching elements Q1 to Qn is switched according to the switching control signal DTS supplied from the switch selection unit 126 to supply the DC power VDD outputted at the output terminal N2 Adjust to the desired voltage level.

The voltage level adjusting unit 128 according to the first embodiment switches the at least one switching element Q1 to Qn selected by the switch selecting unit 126 according to the plurality of switch selecting signals SS, The DC power supply VDD output to the node N2 is adjusted to a desired voltage level.

The voltage level adjusting unit 128 according to the second embodiment includes n switching elements Q1 to Qn having different sizes as shown in FIG.

Each of the n switching elements Q1 to Qn includes a drain terminal connected to the first node N1, a source terminal connected to the base power supply VSS, and a gate terminal connected to the switch selecting section 126 And is electrically connected in parallel between one node N1 and the base power supply VSS.

At least one switching element among the n switching elements Q1 to Qn is switched according to the switching control signal DTS supplied from the switch selection unit 126 to supply the DC power VDD outputted at the output terminal N2 Adjust to the desired voltage level.

The voltage level adjusting unit 128 according to the second embodiment switches the at least one switching element Q1 to Qn selected by the switch selecting unit 126 according to the plurality of switch selecting signals SS, The DC power supply VDD output to the node N2 is adjusted to a desired voltage level.

The voltage level adjusting unit 128 according to the third embodiment includes n switching units 1281 to 128n as shown in FIG.

Each of the n switching units 1281 to 128n is electrically connected in parallel between the first node N1 and the base power supply VSS and is connected to the switching power supply And a different number of switching elements (Q). Here, each of the switching elements Q includes a drain terminal connected to the first node N1, a source terminal connected to the base power supply VSS, and a gate terminal connected to the switch selecting section 126. [ At this time, each of the switching elements Q is formed to have the same gate width as each other.

For example, the first switching unit 1281 is constituted by one switching element Q switched according to the switching control signal DTS, and the second switching unit 1281 is constituted by the switching control signal DTS at the same time The third switching unit 1263 may be composed of three switching elements Q simultaneously according to the switching control signal DTS and the m th switching unit 126m May be composed of n switching elements Q simultaneously according to the switching control signal DTS. As a result, the i-th switching unit may be configured to have j switching elements Q (i is any one of 1 to n). However, the present invention is not limited to this, and the number of switching elements Q formed in each of the switching parts 1281 to 126m may be set differently depending on the efficiency of the switching element Q. [

At least one switching unit among the n switching units 1281 to 128n is switched according to the switching control signal DTS supplied from the switch selection unit 126 and outputs a DC power VDD output at the output terminal N2 Adjust to the voltage level.

In this way, the voltage level adjusting unit 128 according to the third embodiment switches the at least one switching unit 1281 to 128n selected by the switch selecting unit 126 according to the plurality of switch selecting signals SS The DC power supply VDD output to the output terminal N2 is adjusted to a desired voltage level.

The control unit 124 controls the plurality of switches corresponding to the load level signal LLS in order to minimize the switching loss of the switching device Q configured in the voltage level adjusting unit 128 and to increase the efficiency of the power supply integrated circuit 120. [ Signal SS, which will be described in detail as follows.

First, the consumption current of the switching element Q is proportional to the Q (gate capacitance) value corresponding to the size of the switching element when the gate voltage and the frequency are the same. Accordingly, the efficiency of the power supply integrated circuit 120 depends on the difference of the consumption current depending on the Q value of the switching device Q. [

7 is a graph showing a result of testing efficiency according to a load level using an A-type switching element QA having a Q value of 0.45 nC and a B-type switching element QB having a Q value of 2.6 nC, to be.

As can be seen from FIG. 7, the efficiency in the section where the current value of the load level is 22 mA or less is high when the A type switching element QA having a relatively small size is used, It can be seen that the efficiency in the section of 22 mA or more is higher when the B type switching element QB having a relatively large size is used. As a result, it can be seen that the efficiency of the power supply integrated circuit 120 can be increased by using a small-sized switching element at a low load level and by using a large-sized switching element at a high load level.

Based on these test results, the control unit 124 generates a switch selection signal SS for switching relatively small number or relatively small-sized switching elements at a low load level, while at a high load level, And generates a switch selection signal SS for switching the number of switching elements or a relatively large-sized switching element.

In the first embodiment, the voltage level adjusting unit 128 is composed of n switching elements Q1 to Qn having the same size as shown in Fig. 4, and the load level signal LLS is a load of 1 mA Level, the control unit 124 generates a switch selection signal SS for selecting and switching only one switching element among the n switching elements Q1 to Qn, while the load level signal LLS ) Corresponds to a load level of 50 mA, the control unit 124 generates a switch selection signal SS for simultaneously selecting and switching all the switching elements Q1 to Qn among the n switching elements Q1 to Qn can do. As a result, the control unit 124 generates a switch selection signal SS for switching the n switching elements Q1 to Qn according to the magnitude of the load level signal LLS by simultaneously combining at least one switching element.

5, when the voltage level adjusting unit 128 is composed of n switching elements Q1 to Qn having different sizes and the load level signal LLS is 1 mA The control unit 124 generates a switch selection signal SS for selecting and switching the first switching device Q1 among the n switching devices Q1 to Qn, When the load level signal LLS corresponds to a load level of 50 mA, the control unit 124 outputs a switch selection signal SS for selecting and switching the nth switching element Qn among the n switching elements Q1 to Qn. Can be generated. As a result, the control unit 124 generates a switch selection signal SS for switching any one of the n switching elements Q1 to Qn according to the magnitude of the load level signal LLS, It is possible to generate a switch selection signal SS for switching two or more switching elements among the elements Q1 to Qn to be switched simultaneously.

In the third embodiment, as shown in FIG. 6, the voltage level adjusting unit 128 is composed of n switching units 1281 to 128n configured such that switching elements having the same size have different numbers, When the level signal LLS corresponds to a load level of 1 mA, the control unit 124 outputs a switch selection signal SS for selecting and switching the first switching unit 1281 out of the n switching units 1281 to 128n, On the other hand, when the load level signal LLS corresponds to the load level of 50 mA, the control unit 124 selects the nth switching unit 128n from the n switching units 1281 to 128n It is possible to generate a switch selection signal SS for switching. As a result, the control unit 124 generates a switch selection signal SS for switching any one of the n switching units 1281 to 128n according to the magnitude of the load level signal LLS, It is possible to generate a switch selection signal SS for simultaneously switching two or more switching units among the units 1281 to 128n.

The power supply according to the embodiment of the present invention selectively switches at least one of the plurality of switching elements for adjusting the DC power supply voltage VDD to a desired voltage level according to the load level, By minimizing the switching loss, the efficiency of the power supply integrated circuit 120 can be improved and the power consumption can be reduced.

8 is a view for explaining a display device according to an embodiment of the present invention.

Referring to FIG. 8, a display device according to an embodiment of the present invention includes a display panel 200; A panel driving unit 300; And a power supply (400).

The display panel 200 is configured to include a plurality of pixels P formed in regions defined by intersections of a plurality of data lines DL1 to DLj and a plurality of scan lines SL1 to SLk.

Each pixel P includes, as shown in Fig. 9, a light emitting element OLED; And a pixel circuit (210).

The light emitting device OLED is formed between the pixel circuit 210 and the DC power supply line PL to which the DC power supply VDD is supplied from the power supply device 400 and is connected to the DC power supply line PL) to emit light. Here, the light emitting device OLED includes an anode terminal connected to the DC power supply line PL, a cathode terminal connected to the pixel circuit 210, and a light emitting cell formed to include a fluorescent material between the anode terminal and the cathode terminal . In the light emitting device OLED, the fluorescent material is electrically excited by the current flowing from the anode terminal to the cathode terminal, thereby emitting light and emitting light.

The pixel circuit 210 controls a current flowing from the DC power supply line PL to the base power supply line VL through the light emitting device OLED in response to the scan voltage supplied from the panel driver 300 according to the data voltage. To this end, the pixel circuit 210 includes a switching transistor ST, a driving transistor DT, and a capacitor Cst.

The switching transistor ST is switched in accordance with a scanning signal supplied to the scanning line SL to supply the driving transistor DT with the data voltage VData supplied to the data line DL. Here, the switching transistor ST includes a gate terminal connected to the scanning line SL, a source terminal connected to the data line DL, and a drain terminal commonly connected to the driving transistor DT and the capacitor Cst For example, a thin film transistor.

The driving transistor DT is switched in accordance with the data voltage VData supplied from the switching transistor ST to control the current flowing from the DC power supply line PL to the base power supply line VL through the light emitting element OLED. Here, the driving transistor DT includes a gate terminal connected to the drain terminal of the switching transistor ST, a drain terminal connected to the cathode terminal of the light emitting element OLED, and a source terminal connected to the base power line VL And may be, for example, a thin film transistor.

The capacitor Cst is connected between the gate terminal of the driving transistor DT and the base power line VL and stores a voltage corresponding to the data voltage VData supplied to the gate terminal of the driving transistor DT, The ON state of the driving transistor DT is maintained constant for one frame.

Although the pixel circuit 210 described above is composed of two transistors ST and DT and one capacitor Cst, the present invention is not limited thereto. (Not shown) and at least one compensation capacitor (not shown). The driving transistor DT may be connected between the driving transistor DT and the light emitting device OLED, And a light emission control transistor (not shown) that is switched according to a light emission control signal supplied from a control signal line (not shown).

The light emitting element OLED of each pixel P is switched according to the data voltage supplied from the data line DL through the switching transistor ST switched by the scanning signal supplied to the scanning line SL A predetermined image is displayed by emitting light corresponding to the intensity of the current (i) output by the driving transistor DT. At this time, the current i flowing in the light emitting element OLED is changed according to the voltage Vgs between the gate and source of the driving transistor DT, the threshold voltage Vth of the driving transistor DT, and the data voltage VData .

8, the panel driver 300 includes a timing controller 310, a data driver 320, and a scan driver 330.

The timing controller 310 aligns the input data signals RGB to be displayed on the display panel 200 and supplies the data signals R, G, and B to the data driver 320. The timing controller 310 generates a timing control signal for controlling the driving timings of the data driver 320 and the scan driver 330 using the input timing synchronization signal TSS and outputs the timing control signal to the data driver 320, Driving unit 330, respectively. Here, the timing synchronization signal TSS is a vertical synchronization signal Vsync; A horizontal synchronizing signal Hsync; A data enable signal (Data Enable); And a dot clock (DCLK). The timing control signals include a data control signal DCS for supplying a data voltage to the data line DL of the display panel 200; And a scan control signal (SCS) for scanning the scan lines (SL) of the display panel (20).

The data driver 320 receives a data voltage for one horizontal line corresponding to the data signals R, G, and B supplied from the timing controller 310 according to a data control signal DCS supplied from the timing controller 310 And supplies the generated data voltages for one horizontal line to each pixel P through each of the data lines DL1 to DLj.

The scan driver 330 generates scan signals in accordance with the scan control signals SCS supplied from the timing controller 310 and sequentially scans the generated scan signals to the scan lines SL1 to SLk.

The power supply unit 400 generates a driving voltage VCC necessary for driving the panel driving unit 300 using the input power Vin and supplies the generated driving voltage VCC to the panel driving unit 300.

The power supply 400 generates a DC power source VDD according to a load of the display panel 200 and supplies the DC power source VD to the DC power line PL formed on the display panel 200, P). To this end, the power supply device 400 is configured in the same manner as the power supply device 100 shown in FIGS. 3 to 6, and a detailed description thereof will be given with reference to FIG. 3 to FIG. 100) will be described instead.

Meanwhile, in the display device according to the embodiment of the present invention, a light emitting diode display device including a display panel 200 having a light emitting device that emits light by current is described as an example. However, the present invention is not limited to this, (100, 400). ≪ / RTI >

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

1 is a schematic view for explaining a conventional power supply apparatus.

2 is a graph showing the efficiency according to a load level in a conventional power supply apparatus.

3 is a schematic view for explaining a power supply apparatus according to an embodiment of the present invention.

4 is a diagram for explaining a first embodiment of the voltage level adjusting unit shown in FIG.

5 is a view for explaining a second embodiment of the voltage level adjusting unit shown in FIG.

6 is a view for explaining a third embodiment of the voltage level adjusting unit shown in FIG.

Fig. 7 is a graph showing the results of testing efficiency of the load level by the Q value of the switching element. Fig.

8 is a view for explaining a display device according to an embodiment of the present invention.

FIG. 9 is a view for explaining an embodiment of the pixel shown in FIG.

Description of the Related Art [0002]

100, 400: Power supply unit 110: DC power generator

120: power supply integrated circuit 122: load level detector

124: control unit 126: switch selection unit

128: voltage level adjusting units 1281 to 128m:

200: display panel 210: pixel circuit

300: panel driver 310: timing controller

320: Data driver 330:

Claims (10)

delete delete delete A DC power generator for generating a DC power using an input power supplied to an input terminal and outputting the generated DC power to an output terminal; And And a power supply integrated circuit connected to the direct current power generator and adjusting the direct current power outputted to the output terminal to a desired voltage level, The power supply integrated circuit includes: A plurality of switching units electrically connected in parallel between a first node between the input terminal and the output terminal and a base power supply and having different numbers of switching elements; A load level detector for detecting a load level of a load connected to the output terminal and generating a load level signal; And And a control unit for switching at least one of the plurality of switching units according to the load level signal. 5. The method of claim 4, The DC power generating unit includes: An inductor connected to the input terminal and the first node; A diode connected between the first node and the output terminal; And And a capacitor connected between the output terminal and the base power supply. 5. The method of claim 4, The control unit generates a switch selection signal and a switching control signal corresponding to the load level signal, Wherein the power supply integrated circuit further comprises a switch selection unit that selects at least one switching unit among the plurality of switching units in accordance with the switch selection signal and supplies the switching control signal to the selected at least one switching unit. delete A display device comprising the power supply device according to any one of claims 4 to 6. A display panel having a plurality of pixels formed in regions defined by a plurality of data lines and a plurality of scan lines; A panel driver for driving the pixel; And And a power supply device according to any one of claims 4 to 6 for supplying DC power to the pixel, The pixel includes: A light emitting element connected between the direct current power source and the base power source and emitting light by a current flowing therethrough; And And a pixel circuit connected to the at least one scan line and the data line and controlling a current flowing to the light emitting element in accordance with a data signal supplied to the data line. 10. The method of claim 9, Wherein the power supply integrated circuit adjusts the voltage level of the DC power supply according to the load level applied to the display panel.

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