KR20210004375A - Power supply unit and display device including the same - Google Patents

Abstract

The present invention includes: a display panel displaying an image; and a power supply unit having K switching conversionunits (K is an integer greater than or equal to 2) which charge and discharge an input voltage inputted from the outside and generate an output coltage in order to generate a voltage required to drive the display panel, a control unit which controls the K switching conversion units, and a sensing circuit unit which senses an output current through at least one output terminal among the K switching conversion units and transmits a sensing result value to the control unit. The control unit changes the driving conditions of the K switching conversion units based on the sensing result value and an external signal supplied from the outside. According to the present invention, power is efficiently changed to improve power efficiency and display quality of the display device.

Description

Power supply unit and display device including the same

The present invention relates to a power supply and a display device including the same.

With the development of information technology, the market for display devices, which is a connection medium between users and information, is growing. Accordingly, an organic light emitting display (OLED), a quantum dot display (QDD), a liquid crystal display (LCD), a plasma display panel (PDP), etc. The use of the same display device is increasing.

Some of the above-described display devices, for example, a liquid crystal display device or an organic light emitting display device, include a display panel including a plurality of sub-pixels arranged in a matrix form, a driver outputting a driving signal for driving the display panel, and a display panel or a driver. And a power supply unit that generates power to be supplied. The driver includes a scan driver that supplies a scan signal (or a gate signal) to the display panel and a data driver that supplies a data signal to the display panel.

In the above display device, when a driving signal, such as a scan signal and a data signal, is supplied to subpixels formed on the display panel, the selected subpixel transmits light or emits light directly, thereby displaying an image.

The present invention for solving the problems of the above-described background technology is based on the output current and the control signal sensed from the output terminal of the power supply in consideration of both the load change of the display panel and the occurrence of voltage ripple at the output terminal. It is variable to improve power efficiency and display quality of a display device.

The present invention is a display panel for displaying an image; And a control unit that controls K switching conversion units (K is an integer greater than or equal to 2) and K switching conversion units that charge and discharge an input voltage input from the outside and generate an output voltage to generate voltages required for driving the display panel. And a power supply unit having a sensing circuit unit that senses an output current through at least one output terminal of the K switching conversion units and transmits a sensing result value to the control unit. The control unit varies the driving conditions of the K switching conversion units based on the sensing result value and an external signal supplied from the outside.

The control unit may activate or deactivate at least one switch unit included in the K switching conversion units based on the sensing result value and the external signal.

The control unit may activate or deactivate at least one of the K switching conversion units based on the sensing result value and the external signal.

When the sensing result value satisfies the criterion and the vertical synchronization signal, which is an external signal, is in a logic low state, the controller may change the driving number of the K switching conversion units.

The K switching conversion units may include switching conversion units configured in parallel such that input terminals are connected in common and output terminals are connected in common.

The sensing circuit unit has a sensor unit that senses the output current output through one of the K switching conversion units, a non-inverting terminal is connected to the output terminal of the sensor unit, an inverting terminal is connected to the reference voltage terminal, and the first input terminal of the control unit. A comparison unit to which an output terminal is connected may be included, and a second input terminal of the controller may be connected to a signal line to which an external signal is applied.

The control unit may include a latch having a first input terminal connected to an output terminal of the comparison unit, a second input terminal connected to a signal line to which an external signal is applied, and outputting output values for controlling the K switching converters.

In another aspect, the present invention provides K switching conversion units (K is an integer of 2 or more) for charging and discharging an input voltage input from the outside and generating an output voltage, a control unit for controlling K switching conversion units, and K switching conversion units. And a sensing circuit unit that senses an output current through at least one of the output terminals and transmits a sensing result value to the controller. The control unit varies the driving conditions of the K switching conversion units based on the sensing result value and an external signal supplied from the outside.

The control unit may activate or deactivate at least one of the K switching conversion units based on the sensing result value and the external signal.

The K switching conversion units may include switching conversion units configured in parallel such that input terminals are connected in common and output terminals are connected in common.

The sensing circuit unit has a sensor unit that senses the output current output through one of the K switching conversion units, a non-inverting terminal is connected to the output terminal of the sensor unit, an inverting terminal is connected to the reference voltage terminal, and the first input terminal of the control unit. A comparison unit to which an output terminal is connected may be included, and a second input terminal of the controller may be connected to a signal line to which an external signal is applied.

The control unit may include a latch having a first input terminal connected to an output terminal of the comparison unit, a second input terminal connected to a signal line to which an external signal is applied, and outputting output values for controlling the K switching converters.

The present invention has an effect of being able to efficiently and automatically change power based on an output current and a control signal sensed from an output terminal of a power supply unit. In addition, since the present invention can take into account both the load change of the display panel and the occurrence of voltage ripple at the output terminal when the driving condition of the power supply unit is changed, not only the power efficiency but also the display quality of the display device can be improved. . In addition, the present invention has an effect of preventing a problem in that a ripple in an output voltage occurs or an abnormality (such as a flicker) occurs on a screen due to a change in the number or phase of the driving of the switching converter while the display device is being driven.

1 is a block diagram schematically illustrating a liquid crystal display device, and FIG. 2 is a circuit diagram schematically illustrating a sub-pixel illustrated in FIG. 1.
3 is a block diagram schematically illustrating an organic light emitting display device, and FIG. 4 is a schematic configuration diagram of a sub-pixel shown in FIG. 3.
5 is a diagram schematically illustrating an input/output relationship of a power supply unit, FIG. 6 is a diagram schematically illustrating a configuration of a power supply unit according to a first embodiment of the present invention, and FIG. 7 is a first diagram of the present invention. It is a modified example of the power supply unit according to the embodiment.
8 is a diagram for explaining in detail the configuration of a power supply unit according to a second embodiment of the present invention.
9 is a diagram for explaining in detail the configuration of a power supply unit according to a third embodiment of the present invention, and FIG. 10 is an input/output truth table of the latch unit shown in FIG. 9.
11 is an exemplary view for explaining a driving method using the power supply shown in FIG. 9 according to a third embodiment of the present invention.
12 and 13 are diagrams illustrating a circuit configuration of a latch unit illustrated in FIG. 9.

Hereinafter, specific details for carrying out the present invention will be described with reference to the accompanying drawings.

With the development of information technology, the market for display devices, which is a connection medium between users and information, is growing. Accordingly, a quantum dot display (QDD), a liquid crystal display (LCD), an organic light emitting diode display (OLED), a plasma panel (PDP), etc. The use of the same display device is increasing.

Some of the above-described display devices, for example, a liquid crystal display device or an organic light emitting display device, include a display panel including a plurality of sub-pixels arranged in a matrix form, a driver outputting a driving signal for driving the display panel, and a display panel or a driver. And a power supply unit that generates power to be supplied. The driver includes a scan driver that supplies a scan signal (or a gate signal) to the display panel and a data driver that supplies a data signal to the display panel.

In the above display device, when a driving signal, such as a scan signal and a data signal, is supplied to the sub-pixels formed on the display panel, the selected sub-pixel transmits light or emits light directly, thereby displaying an image. . Hereinafter, the description of the present invention will be continued by taking a liquid crystal display device and an organic light emitting display device as an example. On the other hand, it goes without saying that the present invention described below can be applied to a display device based on an inorganic light emitting diode rather than an organic light emitting diode.

1 is a block diagram schematically illustrating a liquid crystal display device, and FIG. 2 is a circuit diagram schematically illustrating a sub-pixel illustrated in FIG. 1.

1 and 2, the liquid crystal display includes an image supply unit 110, a timing control unit 120, a scan driving unit 130, a data driving unit 140, a liquid crystal panel 150, a backlight unit 160, and A power supply unit 180 and the like are included.

The image supply unit 110 outputs various driving signals together with an image data signal supplied from the outside or an image data signal stored in an internal memory. The image supply unit 110 supplies data signals and various driving signals to the timing controller 120.

The timing controller 120 includes a gate timing control signal GDC for controlling the operation timing of the scan driver 130, a data timing control signal DDC for controlling the operation timing of the data driver 140, and various synchronization signals ( Vsync, a vertical synchronization signal, and Hsync, a horizontal synchronization signal, are output. The timing controller 120 supplies the data signal (or data voltage) DATA supplied from the image processing unit 110 together with the data timing control signal DDC to the data driver 140.

The scan driver 130 outputs a scan signal (or a gate signal) in response to a gate timing control signal GDC supplied from the timing controller 120. The scan driver 130 supplies scan signals to sub-pixels included in the liquid crystal panel 150 through the gate lines GL1 to GLm. The scan driver 130 is formed in the form of an integrated circuit (IC) or directly formed on the liquid crystal panel 150 in a gate-in panel method.

The data driver 140 samples and latches the data signal DATA in response to the data timing control signal DDC supplied from the timing control unit 120, and converts it into an analog signal type data voltage corresponding to the gamma reference voltage, and outputs it. do. The data driver 140 supplies a data voltage to subpixels included in the liquid crystal panel 150 through the data lines DL1 to DLn. The data driver 140 may be formed in the form of an integrated circuit (IC) and mounted on the display panel 150 or on a printed circuit board, but is not limited thereto.

The power supply unit 180 generates and outputs a common voltage VCOM based on an external input voltage supplied from the outside. The power supply unit 180 includes not only a common voltage (VCOM), but also a voltage (eg, scan high voltage, scan low voltage) required to drive the scan driver 130 or a voltage (drain voltage, half voltage) required to drive the data driver 140. Drain voltage), etc. can be generated and output.

The liquid crystal panel 150 displays an image in response to a scan signal supplied from the scan driver 130, a data voltage supplied from the data driver 140, and a common voltage VCOM supplied from the power supply unit 180. Subpixels of the liquid crystal panel 150 control light provided through the backlight unit 160.

For example, one sub-pixel SP includes a switching transistor SW, a storage capacitor Cst, and a liquid crystal layer Clc. The gate electrode of the switching transistor SW is connected to the scan line GL1 and the source electrode is connected to the data line DL1. The storage capacitor Cst has one end connected to the drain electrode of the switching transistor SW and the other end connected to the common voltage line Vcom. The liquid crystal layer Clc is formed between the pixel electrode 1 connected to the drain electrode of the switching transistor SW and the common electrode 2 connected to the common voltage line Vcom.

The liquid crystal panel 150 is a TN (Twisted Nematic) mode, VA (Vertical Alignment) mode, IPS (In Plane Switching) mode, FFS (Fringe Field Switching) mode according to the structure of the pixel electrode 1 and the common electrode 2 Alternatively, it is implemented in an ECB (Electrically Controlled Birefringence) mode.

The backlight unit 160 provides light to the liquid crystal panel 150 by using a light source that emits light. The backlight unit 160 includes a light-emitting diode (hereinafter, referred to as LED), an LED driver for driving the LED, an LED substrate on which the LED is mounted, a light guide plate for converting light emitted from the LED into a surface light source, a reflector for reflecting light from the lower portion of the light guide plate, It may include, but is not limited to, optical sheets for condensing and diffusing light emitted from the light guide plate.

3 is a block diagram schematically illustrating an organic light emitting display device, and FIG. 4 is a schematic configuration diagram of a sub-pixel shown in FIG. 3.

3 and 4, in the organic light emitting display device, an image supply unit 110, a timing control unit 120, a scan driving unit 130, a data driving unit 140, a display panel 150, and a power supply unit ( 180) and the like.

The image supply unit 110, the timing control unit 120, the scan driving unit 130, and the data driving unit 140 included in the organic light emitting display device are similar in basic configuration and operation to the liquid crystal display of FIG. Omit it. Instead, portions of the power supply unit 180 and the display panel 150 that are most distinguished from the liquid crystal display device will be described in more detail.

The power supply unit 180 generates and outputs a high-potential first driving voltage EVDD and a low-potential second driving voltage EVSS based on an external input voltage supplied from the outside. The power supply unit 180 drives not only the first and second driving voltages (EVDD, EVSS), but also a voltage (eg, scan high voltage, scan low voltage) or data driving unit 140 required for driving the scan driver 130 It is possible to generate and output voltages (drain voltage, half drain voltage), etc. necessary for the device.

The display panel 150 includes a scan signal output from a driver including a scan driver 130 and a data driver 140, a driving signal including a data voltage, and a first driving and a second driving output from the power supply unit 180. An image is displayed in response to the voltages EVDD and EVSS. Sub-pixels of the display panel 150 directly emit light.

For example, one sub-pixel SP includes a pixel circuit PC including a switching transistor SW, a driving transistor, a storage capacitor, and an organic light emitting diode. Since the sub-pixel SP used in the organic light emitting display device emits light directly, the configuration of a circuit is more complicated than that of a liquid crystal display device. In addition, a compensation circuit for compensating for deterioration of an organic light-emitting diode that emits light as well as a driving transistor that supplies a driving current to the organic light-emitting diode is complex and diverse. Therefore, it is referred to that the pixel circuit PC included in the sub-pixel SP is shown in block form.

5 is a diagram schematically illustrating an input/output relationship of a power supply unit, FIG. 6 is a diagram schematically illustrating a configuration of a power supply unit according to a first embodiment of the present invention, and FIG. 7 is a first diagram of the present invention. It is a modified example diagram of the power supply unit according to the embodiment.

As shown in FIG. 5, the power supply unit 180 rectifies the input voltage Vin of the first level, which is not rectified, converts it to an output voltage Vout of the second level, and outputs a switching converter. ) (Hereinafter referred to as a switching converter) may be implemented as a DC/DC converter.

The power supply unit 180 may generate a rectified output voltage Vout based on an input voltage Vin input from the outside, and voltages required for driving the display panel based on the output voltage Vout (e.g. : A first driving voltage, a second driving voltage, a scan high voltage, a scan low voltage, etc.) can be generated. That is, the power supply unit 180 may be implemented to output one output voltage Vout or to output voltages of various levels based on this.

6, the power supply unit 180 according to the first embodiment includes a first passive device unit 181, a first switching conversion unit 182, a second switching conversion unit 183, and a sensing circuit unit ( 184), a control unit 185, and a second passive element unit 187 may be included.

The first passive device part 181 and the second passive device part 187 may be defined as an LC filter (power noise filter) circuit that removes/improves noise during voltage rectification. The first switching conversion unit 182 and the second switching conversion unit 183 may be defined as power circuits that charge/discharge and output voltages. The control unit 185 outputs a switching control signal (SWC) for controlling the switching operation (turn-on/turn-off) and duty of the first switching conversion unit 182 and the second switching conversion unit 183. It can be defined as a control circuit. The sensing circuit unit 184 is a sensing circuit that senses the output current through one of the first switching unit 182 and the second switching unit 183 and transmits the sensing result value CSEN to the control unit 185 Can be defined as

Since the first passive element unit 181 and the second passive element unit 187 are composed of passive elements, they can be separately implemented outside the IC. The first switching conversion unit 182 and the second switching conversion unit 183 are configured in parallel and have an input terminal (input common) and an output terminal (output common) connected in common. The first switching conversion unit 182, the second switching conversion unit 183, the sensing circuit unit 184, and the control unit 185 may be implemented inside the IC. However, in the case of the sensing circuit unit 184, the first passive element unit 181 and the second passive element unit 187 may be separately implemented outside the IC.

Meanwhile, in the first embodiment, it is assumed that the power supply unit 180 includes two switching conversion units 182 and 183 as an example. However, the power supply unit 180 may include K switching conversion units 182 to 18k (K is an integer greater than or equal to 2) as shown in FIG. 7.

The power supply unit 180 generates and outputs the output voltage Vout based on the input voltage Vin as the at least two first switching conversion units 182 and the second switching conversion unit 183 are switched. , The power efficiency may be varied according to the sensing result value CSEN output from the sensing circuit unit 184.

To this end, the control unit 185 includes a first switching unit 182 and a second switching unit based on a power control signal SYNC supplied from the outside and a sensing result value CSEN output from the sensing circuit unit 184. At least one of 183 may be activated (switching operation turned on) or deactivated (switching operation turned off). For example, the control unit 185 activates the first switching conversion unit 182 when the sensing result value CSEN meets the first condition, but deactivates it when the second condition is met.

The power control signal SYNC may be input from a timing control unit or a data driving unit in a manner such as I2C communication, SPI communication, or pin to pin. The power control signal SYNC includes a signal (a synchronization signal or a control signal) necessary for controlling the amount of output current of the power supply unit 180 according to a panel load of the display panel.

Hereinafter, based on the experiment of the first embodiment, when only one switching converter is operated (1-Phase) and when both switching converters are operated (2-Phase) are compared and shown in a table as follows.

As can be seen from Table 1 below, the power supply unit 180 according to the first embodiment can vary the amount of current (change power efficiency to the optimum point) while taking into account changes in the load of the display panel and the occurrence of voltage ripple at the output terminal. You can set the possible operating conditions.

1-Phase 2-Phase Power efficiency
(Compared to display panel load) 50mA 85.4% 84.1% 250mA 87.2% 87.7% 500mA 83.5% 86.5% Output ripple Light littleness Very small Heavy greatness usually

For example, when the output current output from the power supply unit 180 is low, only the first switch unit SW1 and the second switch unit SW2 of the first switching unit 182 can operate on/off. I can. And when the output current output from the power supply unit 180 is high, the first switch unit SW1 and the second switch unit SW2 of the first switching unit 182 and the second switching unit 183 are The three switch unit SW3 and the fourth switch unit SW4 may also operate on/off together. However, the first switch unit SW1 of the first switching unit 182 and the third switch unit SW3 of the second switching unit 183 may undergo a phase shift in order to change power efficiency. have.

As described above, the first embodiment of the present invention has the effect of being able to automatically and efficiently change power based on the control signal and the output current sensed from the output terminal of the power supply unit. In addition, the first embodiment of the present invention can take into account both the load change of the display panel and the occurrence of voltage ripple at the output terminal when the driving condition of the power supply unit is changed, so that not only the power efficiency but also the display quality of the display device can be improved. It can have an effect.

8 is a diagram for explaining in detail the configuration of a power supply unit according to a second embodiment of the present invention.

As shown in FIG. 8, the power supply unit 180 according to the second embodiment includes a first passive element unit 181, a first switching conversion unit 182, a second switching conversion unit 183, and a sensing circuit unit ( 184), a control unit 185, and a second passive element unit 187 may be included.

The first passive element unit 181 may include a first capacitor Cap1, a first inductor IND1, and a second inductor IND2. One end of the first capacitor Cap1 is connected to the input terminal of the power supply unit 180 to which the input voltage Vin is applied, and the other end is connected to the ground GND. One end of the first inductor IND1 is connected to the input terminal of the power supply unit 180 to which the input voltage Vin is applied, and the other end is connected to the input terminal of the first switching converter 182. The second inductor IND2 has one end connected to the input terminal of the power supply unit 180 to which the input voltage Vin is applied, and the other end connected to the input terminal of the second switching converter 183. The second passive element part 187 may include a second capacitor Cap2. One end of the second capacitor Cap2 is connected to the output terminal of the power supply unit 180 from which the output voltage Vout is output, and the other terminal is connected to the ground GND.

The first switching unit 182 may include a first switch unit SW1 and a second switch unit SW2. In the first switch unit SW1, a gate electrode is connected to a first switching control signal line through which the first switching control signal SWC1 is transmitted, and a first electrode is connected to the other end of the first inductor IND1, and ground (GND). The second electrode is connected to. The second switch unit SW2 has a gate electrode connected to the second switching control signal line through which the second switching control signal SWC2 is transmitted, the first electrode connected to the other end of the first inductor IND1, and the output voltage Vout. The second electrode is connected to the output terminal of the power supply unit 180 to which) is output.

The second switching conversion unit 183 may include a third switch unit SW3 and a fourth switch unit SW4. In the third switch unit SW3, a gate electrode is connected to a third switching control signal line through which the third switching control signal SWC3 is transmitted, and a first electrode is connected to the other end of the second inductor IND2, and ground (GND). The second electrode is connected to. The fourth switch unit SW4 has a gate electrode connected to the fourth switching control signal line through which the fourth switching control signal SWC4 is transmitted, the first electrode is connected to the other end of the second inductor IND2, and the output voltage Vout The second electrode is connected to the output terminal of the power supply unit 180 to which) is output.

The sensing circuit unit 184 may include a sensor unit SEN and a comparison unit CMP. The sensor unit SEN is disposed to sense an output current output through one of the first switching unit 182 and the second switching unit 183. The sensor unit SEN includes a current sensor that can directly or indirectly sense a current.

The comparison unit CMP has a non-inverting terminal (+) connected to the output terminal of the sensor unit SEN, an inverting terminal (-) connected to the reference voltage terminal REF having a reference voltage, and the control unit 185a, 185b. 1 The output terminal is connected to the input terminal. The comparison unit (CMP) compares the first value (sensing value) applied to the non-inverting terminal (+) and the second value (reference value) applied to the inverting terminal (-) (high value according to hysteresis). ) And one of a low value, for example, when the first value (refer to Vs) and the second value (refer to REF) are in a relationship Vs> REF, the comparison unit CMP is High) and when Vs <REF or Vs <REF/2, the comparator CMP may output a low value. To this end, the comparator CMP may output a hysteresis comparator. Hysteresis) can be selected.

The control units 185a and 185b include a first control unit 185a that outputs a first switching control signal SWC1 and a second switching control signal SWC2, a third switching control signal SWC3 and a fourth switching control signal SWC4. It includes a second control unit (185b) for outputting. The first control unit 185a and the second control unit 185b have a first switching control signal based on the sensing result value CSEN applied through the first input terminal and the power control signal SYNC applied through the second input terminal. SWC1) to fourth switching control signals SWC4 are generated and output. Depending on the characteristics of the first switching control signal SWC1 to the fourth switching control signal SWC4 output from the first control unit 185a and the second control unit 185b, the first switch unit SW1 to the fourth switch unit ( SW4) may be activated (switching operation turned on) or deactivated (switching operation turned off).

As described above, according to the second embodiment of the present invention, there is an effect that power can be efficiently and automatically changed based on an output current and a control signal sensed from an output terminal of the power supply unit. In addition, the second embodiment of the present invention can take into account both the load change of the display panel and the occurrence of voltage ripple at the output terminal when the driving condition of the power supply unit is changed, so that not only the power efficiency but also the display quality of the display device can be improved. It can have an effect.

9 is a diagram for explaining in detail the configuration of a power supply unit according to a third embodiment of the present invention, and FIG. 10 is an input/output truth table of the latch unit shown in FIG. 9.

9, the power supply unit 180 according to the third embodiment includes a first passive element unit 181, a first switching conversion unit 182, a second switching conversion unit 183, and a sensing circuit unit ( 184), a control unit 185, and a second passive element unit 187 may be included.

The first passive element unit 181 may include a first capacitor Cap1, a first inductor IND1, and a second inductor IND2. One end of the first capacitor Cap1 is connected to the input terminal of the power supply unit 180 to which the input voltage Vin is applied, and the other end is connected to the ground GND. One end of the first inductor IND1 is connected to the input terminal of the power supply unit 180 to which the input voltage Vin is applied, and the other end is connected to the input terminal of the first switching converter 182. The second inductor IND2 has one end connected to the input terminal of the power supply unit 180 to which the input voltage Vin is applied, and the other end connected to the input terminal of the second switching converter 183. The second passive element part 187 may include a second capacitor Cap2. One end of the second capacitor Cap2 is connected to the output terminal of the power supply unit 180 from which the output voltage Vout is output, and the other terminal is connected to the ground GND.

The first switching unit 182 may include a first switch unit SW1 and a second switch unit SW2. In the first switch unit SW1, a gate electrode is connected to a first switching control signal line through which the first switching control signal SWC1 is transmitted, and a first electrode is connected to the other end of the first inductor IND1, and ground (GND). The second electrode is connected to. The second switch unit SW2 has a gate electrode connected to the second switching control signal line through which the second switching control signal SWC2 is transmitted, the first electrode connected to the other end of the first inductor IND1, and the output voltage Vout. The second electrode is connected to the output terminal of the power supply unit 180 to which) is output.

The second switching conversion unit 183 may include a third switch unit SW3 and a fourth switch unit SW4. In the third switch unit SW3, a gate electrode is connected to a third switching control signal line through which the third switching control signal SWC3 is transmitted, and a first electrode is connected to the other end of the second inductor IND2, and ground (GND). The second electrode is connected to. The fourth switch unit SW4 has a gate electrode connected to the fourth switching control signal line through which the fourth switching control signal SWC4 is transmitted, the first electrode is connected to the other end of the second inductor IND2, and the output voltage Vout The second electrode is connected to the output terminal of the power supply unit 180 to which) is output.

The sensing circuit unit 184 may include a sensor unit SEN and a comparison unit CMP. The sensor unit SEN is disposed to sense an output current output through one of the first switching unit 182 and the second switching unit 183. The sensor unit SEN includes a current sensor that can directly or indirectly sense a current.

The comparison unit CMP has a non-inverting terminal (+) connected to the output terminal of the sensor unit SEN, an inverting terminal (-) connected to the reference voltage terminal REF having a reference voltage, and the control unit 185a, 185b. 1 The output terminal is connected to the input terminal. The comparator (CMP) is a high value and a low value according to the comparison result of the first value (sensing value) applied to the non-inverting terminal (+) and the second value (reference value) applied to the inverting terminal (-). One of the values (Low) is output. For example, when the first value (refer to Vs hereinafter) and the second value (refer to REF hereinafter) have a relationship between Vs> REF, the comparator CMP outputs a high value and Vs <REF or Vs <REF/ In the case of a relationship of 2, the comparison unit CMP may output a low value. To this end, the comparator CMP may be selected as a hysteresis comparator.

The control units 185a and 185b include a first control unit 185a that outputs a first switching control signal SWC1 and a second switching control signal SWC2, a third switching control signal SWC3 and a fourth switching control signal SWC4. It includes a second control unit (185b) for outputting. The first control unit 185a and the second control unit 185b have a first switching control signal based on the sensing result value CSEN applied through the first input terminal and the power control signal SYNC applied through the second input terminal. SWC1) to fourth switching control signals SWC4 are generated and output. Depending on the characteristics of the first switching control signal SWC1 to the fourth switching control signal SWC4 output from the first control unit 185a and the second control unit 185b, the first switch unit SW1 to the fourth switch unit ( SW4) may be activated (switching operation turned on) or deactivated (switching operation turned off).

The first control unit 185a and the second control unit 185b are configured based on a latch including a first input terminal D, a second input terminal Clk, and an output terminal Q, and an output signal output from the latch. And a control signal generator for generating the first switching control signal SWC1 to the fourth switching control signal SWC4. For example, the latches included in the first control unit 185a and the second control unit 185b may include a gate type D latch having an inverter unit INV. Since the gate type D latch has an inverter unit INV, the power control signal SYNC can be inverted and input.

The inverter unit INV has an input terminal connected to a power control signal line through which the power control signal SYNC is transmitted, and an output terminal connected to the second input terminal of the controllers 185a and 185b. When a low value is input, the inverter unit INV inverts it to a high value and outputs it. When a high value is input, the inverter unit INV inverts it to a low value and outputs it.

Referring to the input/output truth table as an example of the second control unit 185b implemented as a gate type D latch, as shown in FIG. 10. In FIG. 10, a value applied to the first input terminal D of the second control unit 185b is a second input value Vi2, and a value applied to the input terminal of the inverter unit INV connected to the second input terminal Clk Note that is defined as the first input value Vi1 and the value output through the output terminal Q as the output value Vo.

11 is an exemplary view for explaining a driving method using the power supply shown in FIG. 9 according to a third embodiment of the present invention.

9 and 11, the power supply unit 180 according to the third embodiment includes a vertical synchronization signal Vsync, which is a signal defining a blank section of the display device through a terminal to which the power control signal SYNC is input. ) Can be delivered.

As described above, when the vertical synchronization signal Vsync is applied as the power control signal SYNC, the power supply unit 180 can change the logic low signal defining the blank section into a logic high signal using the inverter unit INV. Therefore, a condition for varying the power efficiency during the blank period (or in synchronization with the blank period) is formed. As described above, the load of the display panel may be determined through sensing the output current of the power supply unit 180.

The power supply unit 180 may activate (turn on the switching operation) or deactivate (turn off the switching operation) at least one of the first switching unit 182 and the second switching unit 183 during the blank period.

According to the driving method of FIG. 11, the first switching control signal SWC1 and the second switching control signal SWC2 are constantly generated in an on/off form without interruption after starting the operation. As a result, the first switch unit SW1 and the second switch unit SW2 continuously operate on/off in response to the first switching control signal SWC1 and the second switching control signal SWC2. Is done. That is, the first switching conversion unit 182 is continuously activated (switching operation is turned on).

On the other hand, the third switching control signal SWC3 and the fourth switching control signal SWC4 are generated in on/off form in only a part of the section after the operation starts. As a result, the third switch unit SW3 and the fourth switch unit SW4 are turned on/off only for some sections in response to the third switching control signal SWC3 and the fourth switching control signal SWC4. It works. That is, the second switching conversion unit 183 maintains an activated state (switching operation turned on) in some sections, and maintains an inactive state (switching operation turned off) in some sections.

Since the power supply unit 180 according to the third embodiment operates based on the sensing result value CSEN and the vertical synchronization signal Vsync, it is applied to the non-inverting terminal (+) and the inverting terminal (-) of the comparator (CMP). In response to the sensed value and the reference value, it can operate in the case of FIG. 11. However, the two cases of FIG. 11 should be interpreted as examples.

[Case 1] When the sensing value is higher than (exceeds) the threshold of the reference value (REF), but the vertical synchronization signal (Vsync) is logic low, the switching converter is driven. You can change the number. [Case 2] When the sensing value is less than the threshold value of the reference value (REF), but the vertical synchronization signal (Vsync) is logic low (Low), the number of drives of the switching converter can be changed. have. That is, even if the sensing value is above or below the threshold value of the reference value (even if the sensing result value satisfies the standard), if the vertical synchronization signal (Vsync) is not in a logic low state, the switching conversion unit (Converter) Do not change the number of drives.

Referring to the above two cases, the power supply unit 180 according to the third exemplary embodiment may change the number or phase of driving of the switching converter only during a blank period in which the load of the display panel is low in consideration of ripple occurrence. In addition, referring to the above 2 cases, the present invention can prevent a problem in which a ripple occurs in the output voltage or an abnormality (such as flicker) occurs on the screen due to a change in the number or phase of the driving of the switching converter during driving of the display device. You can see that it works.

12 and 13 are diagrams illustrating a circuit configuration of a latch unit illustrated in FIG. 9.

9 and 12, the latch unit is a first inverter unit (INV1), a second inverter unit (INV2), a first NAND gate unit (NAND1), a second NAND gate unit (NAND2), a third NAND A gate part NAND3 and a fourth NAND gate part NAND4 may be included.

The first inverter unit INV1 has an input terminal connected to the power control signal line to which the first input value Vi1 is applied, and the second input terminal of the first NAND gate unit NAND1 and the second input terminal of the second NAND gate unit NAND2. Output terminal is connected to 1 input terminal. The second inverter unit INV2 has an input terminal connected to an output terminal of the comparator CMP to which the second input value Vi2 is applied, and an output terminal connected to the second input terminal of the second NAND gate unit NAND2.

The first NAND gate unit NAND1 has a first input terminal connected to the output terminal of the comparator CMP to which the second input value Vi2 is applied, and the second input terminal connected to the output terminal of the first inverter unit INV1. The output terminal is connected to the first input terminal of the third NAND gate unit NAND3. The second NAND gate unit NAND2 has a first input terminal connected to the output terminal of the first inverter unit INV1 and a second input terminal connected to the output terminal of the second inverter unit INV2.

In the third NAND gate unit NAND3, the first input terminal is connected to the output terminal of the first NAND gate unit NAND1, the second input terminal is connected to the output terminal of the fourth NAND gate unit NAND4, and the output value Vo is output. The output terminal is connected to the output terminal of the latch. The fourth NAND gate unit NAND4 has a first input terminal connected to the output terminal of the third NAND gate unit NAND3, a second input terminal connected to the output terminal of the second NAND gate unit NAND2, and the third NAND gate unit NAND3. The output terminal is connected to the second input terminal of ).

As shown in FIGS. 9 and 13, the latch part is a first interverter part INV1, a first noa gate part NOR1, a second noa gate part NOR2, a third noa gate part NOR3, and a fourth. It may include a NOA gate unit NOR4.

The input terminal of the first inverter unit INV1 is connected to the output terminal of the comparator CMP to which the second input value Vi2 is applied, and the output terminal is connected to the second input terminal of the second NAND gate unit NAND2.

The first NOR gate unit NOR1 is connected to the output terminal of the comparator CMP to which the second input value Vi2 is applied, and is connected to the power control signal line to which the first input value Vi1 is applied. The second input terminal is connected, and the output terminal is connected to the first input terminal of the third NOR gate unit NOR3. In the second NOA gate unit NOR2, a first input terminal is connected to a power control signal line to which a first input value Vi1 is applied, and a second input terminal is connected to an output terminal of the first inverter unit INV1, and the fourth NOA gate The second input terminal is connected to the negative (NOR4).

In the third noa gate unit NOR3, the first input terminal is connected to the output terminal of the first noa gate unit NOR1, the second input terminal is connected to the output terminal of the fourth noa gate unit NOR4, and the output value Vo is output. The output terminal is connected to the output terminal of the latch. In the fourth noa gate unit NOR4, a first input terminal is connected to the output terminal of the third noa gate unit NOR3, a second input terminal is connected to the output terminal of the second noa gate unit NOR2, and the third noa gate unit NOR3 The output terminal is connected to the second input terminal of ).

As described above, according to the third embodiment of the present invention, power can be efficiently and automatically changed based on an output current and a control signal sensed from an output terminal of the power supply unit. In addition, since the third embodiment of the present invention can take into account both the load change of the display panel and the occurrence of voltage ripple at the output terminal when the driving condition of the power supply unit is changed, not only the power efficiency but also the display quality of the display device can be improved. It can have an effect. In addition, according to the third embodiment of the present invention, it is possible to prevent a problem in which a ripple occurs in the output voltage or an abnormality (such as a flicker) occurs on the screen due to a change in the number or phase of the driving of the switching converter during driving of the display device. There is.

The power supply described above in the present invention is a switching regulator such as a boost converter, a buck converter, a buck-boost converter, and a single ended primary inductor (SEPIC) converter. It can be applied to (Switching Regulator).

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention described above is in other specific forms without changing the technical spirit or essential features of the present invention by those skilled in the art. It will be appreciated that it can be implemented. Therefore, the embodiments described above are illustrative in all respects and should be understood as non-limiting. In addition, the scope of the present invention is indicated by the claims to be described later rather than the detailed description. In addition, all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

150: display panel 180: power supply
181: first passive element unit 182: first switching conversion unit
183: second switching conversion unit 184: sensing circuit unit
185: control unit 187: second passive element unit
SEN: sensor unit CMP: comparison unit

Claims (12)

A display panel that displays an image; And
In order to generate the voltage required for driving the display panel, K switching conversion units (K is an integer greater than or equal to 2) generating an output voltage by charging and discharging an input voltage input from the outside, and controlling the K switching conversion units A power supply unit having a control unit and a sensing circuit unit for sensing an output current through at least one output terminal of the K switching conversion units and transmitting a sensing result value to the control unit,
The control unit varies the driving conditions of the K switching converters based on the sensing result value and an external signal supplied from the outside. The method of claim 1,
The control unit
A display device configured to activate or deactivate at least one switch unit included in the K switching conversion units based on the sensing result value and the external signal. The method of claim 1,
The control unit
A display device that activates or deactivates at least one of the K switching converters based on the sensing result value and the external signal. The method of claim 1,
The control unit
A display device configured to change the number of driving of the K switching converters when the sensing result value satisfies the criterion and the vertical synchronization signal, which is the external signal, is in a logic low state. The method of claim 1,
The K switching conversion units
A display device including switching converters configured in parallel such that input terminals are connected in common and output terminals are connected in common. The method of claim 1,
The sensing circuit unit
A sensor unit for sensing an output current output through one of the K switching conversion units,
A comparison unit having a non-inverting terminal connected to an output terminal of the sensor unit, an inverting terminal connected to a reference voltage terminal, and an output terminal connected to a first input terminal of the control unit,
The second input terminal of the controller is connected to a signal line to which the external signal is applied. The method of claim 6,
The control unit
A display device comprising a latch having a first input terminal connected to an output terminal of the comparison unit, a second input terminal connected to a signal line to which the external signal is applied, and outputting output values for controlling the K switching converters. K switching conversion units (K is an integer greater than or equal to 2) for charging and discharging an input voltage input from the outside and generating an output voltage;
A control unit for controlling the K switching conversion units; And
And a sensing circuit unit sensing an output current through at least one output terminal of the K switching conversion units and transmitting a sensing result value to the control unit,
The control unit is a power supply unit for varying the driving conditions of the K switching conversion units based on the sensing result value and an external signal supplied from the outside. The method of claim 8,
The control unit
A power supply unit configured to activate or deactivate at least one of the K switching conversion units based on the sensing result value and the external signal. The method of claim 8,
The K switching conversion units
A power supply including switching conversion units configured in parallel so that the input terminals are connected in common and the output terminals are connected in common. The method of claim 8,
The sensing circuit unit
A sensor unit for sensing an output current output through one of the K switching conversion units,
A comparison unit having a non-inverting terminal connected to an output terminal of the sensor unit, an inverting terminal connected to a reference voltage terminal, and an output terminal connected to a first input terminal of the control unit,
The second input terminal of the controller is a power supply connected to a signal line to which the external signal is applied. The method of claim 11,
The control unit
A power supply unit including a latch having a first input terminal connected to an output terminal of the comparison unit, a second input terminal connected to a signal line to which the external signal is applied, and outputting output values for controlling the K switching converters.

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