Power supply voltage generator and display device having the same

Abstract

A power supply voltage generator and a display device having the power supply voltage generator are provided. The power supply voltage generator includes a booster, a voltage sensor, a constant voltage controller, and a constant current controller. The booster is configured to boost an input voltage to an output voltage based on on-off operations of switches. The voltage sensor is configured to generate a sensed voltage by sensing the output voltage. The constant voltage controller is configured to generate a first switching signal by comparing the sensed voltage with a reference voltage to control the switches. The constant current controller is configured to generate a gain based on a ratio of an electrode signal of the switch to a target signal by comparing the electrode signal of the switch with the target signal.

Description

Technical Field

[0001] Exemplary embodiments of the inventive concept relate to a power supply voltage generator and a display device including the power supply voltage generator. More specifically, exemplary embodiments of the inventive concept relate to a power supply voltage generator and a display device including the power supply voltage generator that reduce manufacturing costs and power consumption. Background Art

[0002] Generally, a display device includes a display panel and a display panel driver. The display panel includes a plurality of gate lines, a plurality of data lines, and a plurality of pixels. The display panel driver includes a gate driver that outputs a gate signal to the plurality of gate lines, a data driver that outputs a data voltage to the plurality of data lines, and a power supply voltage generator that supplies a power supply voltage to the pixels.

[0003] Constant voltage control and constant current control may be performed with respect to the power supply voltage supplied to the pixels. The constant current control module may be configured to reduce the input voltage of the power supply voltage generator when the measured current has a value higher than a predetermined current.

[0004] To measure the current in the constant current control module, a large sensing resistor and an IC must be provided. The IC detects the current caused by the voltage applied across the large sensing resistor and converts the current into a digital code.

[0005] In addition, since a large voltage is applied to the sensing resistor, problems such as heat generation, voltage drop of the power supply voltage, and increased power consumption occur. Summary of the Invention

[0006] Exemplary embodiments of the inventive concept provide a power supply voltage generator that senses a signal at an electrode of a switch of a booster to operate constant current control.

[0007] Exemplary embodiments of the inventive concept also provide a display device including the power supply voltage generator.

[0008] In an exemplary embodiment of a power supply voltage generator according to the inventive concept, the power supply voltage generator includes a booster, a voltage sensor, a constant voltage controller, and a constant current controller. The booster is configured to boost an input voltage to an output voltage based on an on-off operation of a switch. The voltage sensor is configured to generate a sensed voltage by sensing the output voltage. The constant voltage controller is configured to generate a first switch signal by comparing the sensed voltage with a reference voltage to control the switch. The constant current controller is configured to generate a gain based on a ratio of an electrode signal of the switch to a target signal by comparing the electrode signal of the switch with the target signal.

[0009] In an exemplary embodiment, the power supply voltage generator may further include: a gain operator configured to generate a second switching signal by multiplying a gain by a first switching signal. The on-off operation of the switch may be controlled by the second switching signal.

[0010] In an exemplary embodiment, the booster may include an inductor, a first diode, and a switch. The inductor may include a first terminal to which an input voltage is applied and a second terminal connected to a first electrode of the first diode. The switch may include a gate electrode, a source electrode, and a drain electrode, and the second switching signal is applied to the gate electrode, and the drain electrode is connected to the first electrode of the first diode. The first diode may include a first electrode connected to the second terminal of the inductor and a second electrode connected to a voltage sensor and outputting an output voltage to the voltage sensor.

[0011] In an exemplary embodiment, the electrode signal of the switch may be a first signal that is a signal of the gate electrode of the switch.

[0012] In an exemplary embodiment, the first signal may be a pulse width modulation signal. The power supply voltage generator may further include: a signal smoothing circuit configured to convert the first signal, which is a pulse width modulation signal, into a second signal, which is a direct current signal.

[0013] In an exemplary embodiment, the signal smoothing circuit may include a second diode, a resistor, and a capacitor. The second diode may include a first electrode to which the first signal is applied and a second electrode connected to a first terminal of the resistor. The resistor may include a first terminal connected to the second electrode of the second diode and a second terminal grounded. The capacitor may include a first electrode connected to the second electrode of the second diode and a second electrode grounded.

[0014] In an exemplary embodiment, the constant current controller may be configured to generate a gain by comparing the second signal with a target duty ratio signal, and the target duty ratio signal is used to generate a target current determined based on the load of the input image data of the display device. The target current may increase as the load of the input image data increases, and may maintain the saturation current after the target current reaches the saturation current.

[0015] In an exemplary embodiment, the constant current controller may include a second operator, and the second operator includes a first input electrode to which the target duty ratio signal is input, a second input electrode to which the second signal is applied, and an output electrode connected to the gain operator and outputting the gain to the gain operator.

[0016] In an exemplary embodiment, the constant current controller may be configured to turn off the power supply voltage generator when the difference between the target duty ratio signal and the second signal is greater than or equal to a threshold.

[0017] In an exemplary embodiment, the second arithmetic unit may be configured to output a gain of zero (0) when the difference between the target duty cycle signal and the second signal is greater than or equal to a threshold value.

[0018] In an exemplary embodiment, when the input voltage of the booster is VI, the output voltage of the booster is VO, the output current of the booster is IO, the measured duty cycle of the switch is D, the inductance of the inductor is L, and the time is t, IO can be expressed as follows:

[0019]

[0020] In an exemplary embodiment, the electrode signal of the switch is a first signal that is the signal of the source electrode of the switch.

[0021] In an exemplary embodiment, the first signal is a triangular wave signal. The power supply voltage generator may further include: a signal smoothing circuit configured to convert the first signal, which is a triangular wave signal, into a second signal, which is a DC signal.

[0022] In an exemplary embodiment, the signal smoothing circuit may include a second diode, a resistor, and a capacitor. The second diode may include a first electrode to which the first signal is applied and a second electrode connected to the first terminal of the resistor. The resistor may include a first terminal connected to the second electrode of the second diode and a second terminal grounded. The capacitor may include a first electrode connected to the second electrode of the second diode and a second electrode grounded.

[0023] In an exemplary embodiment, the constant current controller may be configured to generate a gain by comparing the second signal with a net power control signal determined by the load of the input image data of the display device. The net power control signal may increase as the load of the input image data increases and maintain a saturation level after the net power control signal reaches the saturation level.

[0024] In an exemplary embodiment, the constant current controller may include a second arithmetic unit. The second arithmetic unit includes a first input electrode to which the net power control signal is input, a second input electrode to which the second signal is applied, and an output electrode connected to the gain arithmetic unit and outputting the gain to the gain arithmetic unit.

[0025] In an exemplary embodiment, the constant current controller may be configured to turn off the power supply voltage generator when the difference between the net power control signal and the second signal is greater than or equal to a threshold value.

[0026] In an exemplary embodiment, when the difference between the net power control signal and the second signal is greater than or equal to a threshold value, the second arithmetic unit may output a gain of zero (0).

[0027] In an exemplary embodiment, the voltage sensor may include a first sensing resistor and a second sensing resistor. The first sensing resistor may include a first terminal connected to a second electrode of a first diode and a second terminal connected to a first terminal of the second sensing resistor. The second sensing resistor may include a first terminal connected to the second terminal of the first sensing resistor and a second terminal grounded.

[0028] In an exemplary embodiment, the constant voltage controller may include a first arithmetic unit. The first arithmetic unit includes a first input electrode to which a sensed voltage is applied, a second input electrode to which a reference voltage is applied, and an output electrode connected to a gain arithmetic unit and outputting a first switching signal to the gain arithmetic unit.

[0029] In an exemplary embodiment of a display device according to the inventive concept, the display device includes a display panel, a gate driver, a data driver, and a power voltage generator. The display panel includes gate lines, data lines, and pixels connected to the gate lines and the data lines. The display panel is configured to display an image based on input image data. The gate driver is configured to output a gate signal to the gate lines. The data driver is configured to output a data voltage to the data lines. The power voltage generator is configured to apply a power voltage to the pixels. The power voltage generator includes: a booster configured to boost an input voltage to an output voltage based on an on-off operation of a switch; a voltage sensor configured to generate a sensed voltage by sensing the output voltage; a constant voltage controller configured to generate a first switching signal by comparing the sensed voltage with a reference voltage to control the switch; and a constant current controller connected to the switch to receive an electrode signal from the switch and configured to generate a gain based on a ratio of the electrode signal of the switch to a target signal by comparing the electrode signal of the switch with the target signal. The output voltage is the power voltage.

[0030] In an exemplary embodiment, the power voltage generator may further include: a gain arithmetic unit connected to the constant voltage controller to receive the first switching signal from the constant voltage controller and connected to the constant current controller to receive the gain from the constant current controller, and configured to generate a second switching signal by multiplying the gain by the first switching signal. The on-off operation of the switch may be controlled by the second switching signal.

[0031] In an exemplary embodiment of a power supply voltage generator according to the inventive concept, the power supply voltage generator includes: a booster connected between an input voltage node and an output voltage node, the booster including a switch, the switch including a gate electrode and a source electrode grounded; a voltage sensor connected to the output voltage node and outputting a sensed voltage; a constant voltage controller (e.g., a first operational amplifier) including a first input electrode receiving the sensed voltage and a second input electrode receiving a reference voltage to output a first switching signal; a constant current controller (e.g., a second operational amplifier) including a first input electrode receiving a target duty ratio signal and a second input electrode connected to the switch to output a gain; and a gain arithmetic unit connected between the switch and the constant voltage controller and between the switch and the constant current controller, the gain arithmetic unit receiving the first switching signal and the gain from the constant voltage controller and the constant current controller, respectively.

[0032] The power supply voltage generator may further include: a signal smoothing circuit connected between the second input electrode of the constant current controller and the switch.

[0033] The second input electrode of the constant current controller may be connected to the gate electrode of the switch via a diode in the signal smoothing circuit.

[0034] The second input electrode of the constant current controller may be connected to the source electrode of the switch via a diode in the signal smoothing circuit.

[0035] According to the above power supply voltage generator and a display device including the power supply voltage generator, constant current control may be operated by sensing a signal of the gate electrode or the source electrode of the switch of the booster, such that a large sensing resistor for current sensing and an IC that detects a current caused by a voltage applied across the large sensing resistor and converts the current into a digital code may be omitted. Accordingly, the manufacturing cost of the display device may be reduced.

[0036] In addition, heat generation, a voltage drop of the power supply voltage, and an increase in power consumption that may occur when a large voltage is applied to the sensing resistor may be prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and other features and advantages of the inventive concept will become more apparent by describing in detail exemplary embodiments of the inventive concept with reference to the accompanying drawings, in which:

[0038] Figure 1 is a block diagram showing a display device according to an exemplary embodiment of the present disclosure;

[0039] Figure 2 is showing Figure 1 a circuit diagram of the power supply voltage generator of;

[0040] Figure 3 is showingFigure 2 Table of target duty ratio signals;

[0041] Figure 4 shows Figure 2 Timing diagram of signals in the power supply voltage generator;

[0042] Figure 5A is Figure 2 Equivalent circuit diagram of the booster shown in Figure 2 when the switch is turned on;

[0043] Figure 5B is Figure 2 Equivalent circuit diagram of the booster shown in Figure 2 when the switch is turned off;

[0044] Figure 6 Circuit diagram showing the power supply voltage generator of a display device according to an exemplary embodiment of the present disclosure;

[0045] Figure 7 Circuit diagram showing the power supply voltage generator of a display device according to an exemplary embodiment of the present disclosure; and

[0046] Figure 8 Circuit diagram showing the power supply voltage generator of a display device according to an exemplary embodiment of the present disclosure. Detailed Description

[0047] Hereinafter, the inventive concept will be described in detail with reference to the accompanying drawings.

[0048] Figure 1 Block diagram showing a display device according to an exemplary embodiment of the present disclosure.

[0049] Referring to Figure 1 , the display device includes a display panel 100 and a display panel driver. The display panel driver includes a driving controller 200, a gate driver 300, a gamma reference voltage generator 400, a data driver 500, and a power supply voltage generator 600.

[0050] For example, the driving controller 200 and the data driver 500 may be integrally formed in one IC. For example, the driving controller 200, the gamma reference voltage generator 400, and the data driver 500 may be integrally formed in one IC. For example, the driving controller 200, the gate driver 300, the gamma reference voltage generator 400, and the data driver 500 may be integrally formed in one IC.

[0051] The display panel 100 includes a display area and a peripheral area adjacent to and surrounding the display area.

[0052] For example, the display panel 100 may be an organic light emitting diode display panel including organic light emitting diodes.

[0053] The display panel 100 includes a plurality of gate lines GL, a plurality of data lines DL, and a plurality of pixels P electrically connected to the gate lines GL and the data lines DL. The gate lines GL extend in a first direction DR1, and the data lines DL extend in a second direction DR2 intersecting the first direction DR1.

[0054] The driving controller 200 receives input image data IMG and an input control signal CONT from an external device (e.g., a graphics controller). The input image data IMG may include red image data, green image data, and blue image data. The input image data IMG may further include white image data. The input image data IMG may further include magenta image data, yellow image data, and cyan image data. The input control signal CONT may include a main clock signal and a data enable signal. The input control signal CONT may further include a vertical synchronization signal and a horizontal synchronization signal.

[0055] The controller 200 generates a first control signal CONT1, a second control signal CONT2, a third control signal CONT3, a fourth control signal CONT4, and a data signal DATA based on the input image data IMG and the input control signal CONT.

[0056] The driving controller 200 generates a first control signal CONT1 for controlling the operation of the gate driver 300 based on the input control signal CONT, and outputs the first control signal CONT1 to the gate driver 300. The first control signal CONT1 may include a vertical start signal and a gate clock signal.

[0057] The driving controller 200 generates a second control signal CONT2 for controlling the operation of the data driver 500 based on the input control signal CONT, and outputs the second control signal CONT2 to the data driver 500. The second control signal CONT2 may include a horizontal start signal and a load signal.

[0058] The driving controller 200 generates a data signal DATA based on the input image data IMG. The driving controller 200 outputs the data signal DATA to the data driver 500.

[0059] The driving controller 200 generates a third control signal CONT3 for controlling the operation of the gamma reference voltage generator 400 based on the input control signal CONT, and outputs the third control signal CONT3 to the gamma reference voltage generator 400.

[0060] The driving controller 200 generates a fourth control signal CONT4 for controlling the operation of the power voltage generator 600 based on the input image data IMG or the input control signal CONT, and outputs the fourth control signal CONT4 to the power voltage generator 600.

[0061] The gate driver 300 generates a gate signal for driving the gate line GL in response to the first control signal CONT1 received from the driving controller 200. The gate driver 300 outputs the gate signal to the gate line GL. For example, the gate driver 300 may sequentially output the gate signal to the gate line GL. For example, the gate driver 300 may be mounted on the display panel 100. For example, the gate driver 300 may be integrated on the display panel 100.

[0062] For example, the gate line GL may include a writing gate line for transmitting a writing gate signal to the pixel P. In addition, the gate line GL may include an initialization gate line for transmitting an initialization gate signal to the pixel P.

[0063] The gamma reference voltage generator 400 generates a gamma reference voltage VGREF in response to the third control signal CONT3 received from the driving controller 200. The gamma reference voltage generator 400 provides the gamma reference voltage VGREF to the data driver 500. The gamma reference voltage VGREF has a value corresponding to the level of the data signal DATA.

[0064] In an exemplary embodiment, the gamma reference voltage generator 400 may be integrated in the driving controller 200 or integrated in the data driver 500.

[0065] The data driver 500 receives the second control signal CONT2 and the data signal DATA from the driving controller 200, and receives the gamma reference voltage VGREF from the gamma reference voltage generator 400. The data driver 500 converts the data signal DATA into a data voltage of an analog type using the gamma reference voltage VGREF provided by the gamma reference voltage generator 400. The data driver 500 outputs the data voltage to the data line DL.

[0066] The power voltage generator 600 may generate a power voltage to drive the display device. For example, the power voltage generator 600 may generate a power voltage to drive the organic light emitting diodes in the display panel 100. For example, the power voltage generator 600 may generate a high power voltage ELVDD to drive the organic light emitting diodes in the display panel 100.

[0067] For example, the power supply voltage generator 600 may also generate a low power supply voltage to drive the organic light-emitting diodes in the display panel 100. For example, the power supply voltage generator 600 may also generate a gate power supply voltage to drive the gate driver 300. For example, the power supply voltage generator 600 may also generate a data power supply voltage to drive the data driver 500. For example, the power supply voltage generator 600 may also generate a common voltage applied to the display panel 100.

[0068] Figure 2 is a circuit diagram of the power supply voltage generator 600 that shows Figure 1 . Figure 3 is a table of the target duty ratio signal (TD) that shows Figure 2 .

[0069] Referring to Figures 1 to 3 , the power supply voltage generator 600 may include a booster, a voltage sensor, a constant voltage controller, and a constant current controller.

[0070] The booster may boost the input voltage VI to the output voltage VO based on the on-off operation of the switch T. For example, the output voltage VO may be the power supply voltage. The voltage sensor may generate a sensed voltage VSE by sensing the output voltage VO. The constant voltage controller may generate a first switching signal for controlling the switch T by comparing the sensed voltage VSE with a reference voltage VREF. The constant current controller may generate a gain NPCG based on the ratio of the electrode signal of the switch T to the target signal by comparing the electrode signal of the switch T with the target signal. In this embodiment, the target signal may be the target duty ratio signal TD for generating the target current GCM, and the target current GCM is determined based on the load LOAD of the input image data IMG of the display device. In this embodiment, the electrode signal may be the signal of the gate electrode of the switch T.

[0071] The power supply voltage generator 600 may further include a gain arithmetic unit MU configured to generate a second switching signal SC by multiplying the gain NPCG by the first switching signal that is the output from the constant voltage controller. The on-off operation of the switch T may be controlled by the second switching signal SC.

[0072] The booster can include an inductor L, a first diode D1, and a switch T. The inductor L can include a first terminal to which an input voltage VI is applied and a second terminal connected to a first electrode of the first diode D1. The switch T can include a gate electrode, a source electrode, and a drain electrode. A second switching signal SC can be applied to the gate electrode of the switch T, and the drain electrode of the switch T can be connected to the first electrode of the first diode D1. The source electrode of the switch T can be grounded. The first diode D1 can include a first electrode connected to the second terminal of the inductor L and a second electrode connected to a voltage sensor to output an output voltage VO.

[0073] The voltage sensor can include a first sensing resistor RS1 and a second sensing resistor RS2 connected in series. The first sensing resistor RS1 can include a first terminal connected to the second electrode of the first diode D1 to receive the output voltage VO from the booster and a second terminal connected to a first terminal of the second sensing resistor RS2. The second sensing resistor RS2 can include a first terminal connected to the second terminal of the first sensing resistor RS1 and a second terminal grounded. The voltage sensor can sense the voltage between the first sensing resistor RS1 and the second sensing resistor RS2 according to the voltage division rule between the first sensing resistor RS1 and the second sensing resistor RS2, and this voltage is a sensed voltage VSE corresponding to the output voltage VO.

[0074] The constant voltage controller can include a first arithmetic unit (e.g., an OP AMP (operational amplifier)) AM1. The first arithmetic unit AM1 includes a first input electrode to which the sensed voltage VSE is applied, a second input electrode to which a reference voltage VREF is applied, and an output electrode that outputs a first switching signal.

[0075] The power supply voltage generator 600 can further include a signal smoothing circuit. In this embodiment, the electrode signal applied to the gate electrode of the switch T can be a first signal, which is the signal applied to the gate electrode of the switch T. The first signal can be a pulse width modulation signal. The first signal can be the second switching signal SC, which is the output signal from the gain arithmetic unit MU.

[0076] The signal smoothing circuit can convert the first signal, which is a pulse width modulation signal, into a second signal, which is a direct current signal. For example, the signal smoothing circuit can include a low-pass filter.

[0077] The signal smoothing circuit may include a second diode D2, a resistor RX, and a capacitor CX. The second diode D2 may include a first electrode to which a first signal is applied and a second electrode connected to a first terminal of the resistor RX. The resistor RX may include a first terminal connected to the second electrode of the second diode D2 and a second terminal grounded. The capacitor CX may include a first electrode connected to the second electrode of the second diode D2 and a second electrode grounded.

[0078] The constant current controller may generate a gain NPCG by comparing a second signal with a target duty ratio signal TD for generating a target current GCM, where the target current GCM is determined based on a load LOAD of input image data IMG of the display device.

[0079] The display device may have a net power control function for estimating the power consumption of the display device based on the input image data IMG. For example, the net power control function may be operated by the driving controller 200. For example, when the input image data IMG is configured to turn on 1% of the area of the display panel 100 to a set maximum brightness (e.g., 500 nits), the load LOAD of the input image data IMG may be set to 1%. In addition, when the input image data IMG is configured to turn on 10% of the area of the display panel 100 to the maximum brightness (e.g., 500 nits), the load LOAD of the input image data IMG may be set to 10%. However, due to the limitation of the maximum current, the input image data IMG cannot turn on 100% of the area of the display panel 100 to the maximum brightness (e.g., 500 nits). When the load LOAD of the input image data IMG is larger than a predetermined value, the maximum brightness may be reset to a level lower than 500 nits to control the maximum current of the display to be lower than the predetermined value. This operation is called the net power control function. In the case where the maximum current of the display is set to the current obtained when the input image data IMG turns on 30% of the area of the display panel 100 to the maximum brightness (e.g., 500 nits), if the input image data IMG that needs to turn on 60% of the area of the display panel 100 to the maximum brightness is input, then the maximum brightness may be reduced from 500 nits to 250 nits to display the image, so as to keep the maximum current of the display within the set maximum value.

[0080] As Figure 3As shown, when the load LOAD of the input image data IMG has a value lower than the saturation level of the net power control (e.g., 30%), the load LOAD of the input image data IMG can be the same as the net power control value NPC. Conversely, when the load LOAD of the input image data IMG has a value greater than the saturation level of the net power control (e.g., 30%), even when the load LOAD of the input image data IMG increases to a value greater than the saturation level (e.g., 30%), the net power control value NPC no longer increases and maintains the saturation level of the net power control (e.g., 30%).

[0081] In addition, the target current GCM is the current used to achieve the net power control value NPC, and the target current GCM can have a value proportional to the net power control value NPC. For the sake of illustration, when the target current GCM for achieving a net power control value NPC of 1% is 1A, the target current GCM for achieving a net power control value NPC of 10% can be 10A, and the target current GCM for achieving a net power control value NPC of 30% can be 30A.

[0082] Similar to the net power control value NPC, the target current GCM can increase proportionally with the load LOAD of the input image data IMG until it reaches a saturation current of, for example, 30A. When the load LOAD of the input image data IMG increases to a value greater than the saturation level (e.g., 30%), the target current GCM can remain at the saturation current (e.g., 30A).

[0083] The target duty cycle TARGET DUTY refers to the duty cycle of the switch T of the power supply voltage generator 600 used to achieve the net power control value NPC. Therefore, the target duty cycle TARGET DUTY can also generally have a value proportional to the net power control value NPC. For example, the target duty cycle TARGET DUTY for achieving a net power control value NPC of 1% can be 10%, the target duty cycle TARGET DUTY for achieving a net power control value NPC of 10% can be 30%, and the target duty cycle TARGET DUTY for achieving a net power control value NPC of 30% can be 50%.

[0084] Figure 3 The numerical values shown are for the sake of illustration, and the present disclosure is not limited to Figure 3 the numerical values shown.

[0085] The drive controller 200 can output at least one of the information of the net power control value NPC, the target current GCM, and the target duty cycle TARGET DUTY to the power supply voltage generator 600.

[0086] According to this embodiment, the constant current controller can generate a gain NPCG by comparing a second signal with a target duty ratio signal TD, and the target duty ratio signal TD is used to generate a target current GCM determined based on a load LOAD of input image data IMG of a display device. As described above, the target current GCM can increase as the load LOAD of the input image data IMG increases, and can maintain the saturation current after the target current GCM reaches the saturation current.

[0087] The constant current controller may include a second arithmetic unit (e.g., OP AMP) AM2, and the second arithmetic unit AM2 includes a first input electrode to which the target duty ratio signal TD is input, a second input electrode to which the second signal is applied, and an output electrode connected to a gain arithmetic unit MU and outputting the gain NPCG to the gain arithmetic unit MU.

[0088] For example, when the duty ratio represented by the target duty ratio signal TD is 30% and the measured duty ratio represented by the second signal is 35%, the second arithmetic unit AM2 can output a gain NPCG of 6 / 7. In addition, when the duty ratio represented by the target duty ratio signal TD is 30% and the measured duty ratio represented by the second signal is 40%, the second arithmetic unit AM2 can output a gain NPCG of 3 / 4.

[0089] When the output current of the power supply voltage generator 600 increases, the level of the second signal can increase, and when the output current of the power supply voltage generator 600 decreases, the level of the second signal can decrease. As described above, the constant current controller can indirectly determine the level of the output current of the power supply voltage generator 600 based on the electrode signal provided to the gate electrode of the switch T.

[0090] The constant current controller can perform constant current control based on the level of the output current of the power supply voltage generator 600, and the level of the output current of the power supply voltage generator 600 is indirectly determined based on the electrode signal applied to the gate electrode of the switch T. Therefore, a large sense resistor for current sensing and an IC for converting the current caused by the voltage applied across the large sense resistor into a digital code can be omitted.

[0091] The gain arithmetic unit MU can generate a second switch signal SC by multiplying the gain NPCG by a first switch signal, and the second switch signal SC can be applied as the gate signal of the switch T to perform constant current control of the power supply voltage generator 600.

[0092] Figure 4 is a timing diagram of the signals in Figure 2 the power supply voltage generator 600 shown. Figure 5A is Figure 2 the boost converter shown in Figure 2Equivalent circuit diagram when switch T is turned on. Figure 5B is Figure 2 the boost converter shown in Figure 2 Equivalent circuit diagram when switch T of the boost converter is turned off.

[0093] Referring to Figures 1 to 5B , as Figure 5A disclosed in, when switch T of the boost converter is turned on (TON duration) by the second switching signal SC, the input voltage VI is charged into inductor L such that the voltage VL of inductor L is equal to the input voltage VI (VI = VL).

[0094] As Figure 5B disclosed in, when switch T of the boost converter is turned off (TOFF duration) by the second switching signal SC, the output voltage VO is equal to the input voltage VI minus the voltage VL of inductor L (VO = VI - VL).

[0095] In Figure 4 , VS represents the voltage applied across switch T.

[0096] During the on-duration (TON duration) of switch T, the current IL flowing through inductor L can gradually increase to IMAX, and during the off-duration (TOFF duration) of switch T, the current IL flowing through inductor L can gradually decrease as Figure 4 disclosed in.

[0097] When the input voltage of the boost converter is VI, the output voltage of the boost converter is VO, the output current of the boost converter is IO, the measured duty ratio of switch T is D, the inductance of inductor L is L, and the time is t, IO can be expressed as follows:

[0098]

[0099] That is to say, the output current IO of the boost converter can be proportional to the square of the measured duty ratio D of switch T. Similarly, the amplitude of the second signal proportional to the output current IO of the boost converter can be proportional to the square of the measured duty ratio D of switch T. As described above, the constant current controller can indirectly determine the level of the output current IO of the boost converter by using the electrode signal applied to the gate electrode of switch T without directly sensing the output current IO of the boost converter.

[0100] According to this exemplary embodiment, constant current control can be performed by sensing the signal of the gate electrode of switch T of the boost converter, so that a large sensing resistor for current sensing and an IC for detecting the current caused by the voltage applied across the large sensing resistor and converting the current into a digital code can be omitted. Therefore, the manufacturing cost of the display device can be reduced.

[0101] In addition, heat generation, voltage drop of the power supply voltage, and increase in power consumption that may occur when a large voltage is applied to the sense resistor can be prevented.

[0102] Figure 6 is a circuit diagram showing a power supply voltage generator 600 of a display device according to an exemplary embodiment of the present disclosure.

[0103] Except for some structures of the power supply voltage generator 600, the power supply voltage generator 600 according to the present exemplary embodiment and the display device including the power supply voltage generator 600 are substantially the same as the power supply voltage generator 600 and the display device including the power supply voltage generator 600 of the previous exemplary embodiment described with reference to Figures 1 to 5B Therefore, the same reference numerals will be used to denote components that are the same as or similar to those described in the previous exemplary embodiment of Figures 1 to 5B and any repeated description of the above elements will be omitted.

[0104] Referring to Figure 1 and Figures 3 to 6 , the display device includes a display panel 100 and a display panel driver. The display panel driver includes a driving controller 200, a gate driver 300, a gamma reference voltage generator 400, a data driver 500, and a power supply voltage generator 600.

[0105] The power supply voltage generator 600 may include a booster, a voltage sensor, a constant voltage controller, and a constant current controller.

[0106] The booster may boost the input voltage VI to the output voltage VO based on the on-off operation of the switch T. The voltage sensor may generate a sense voltage VSE by sensing the output voltage VO. The constant voltage controller may generate a first switch signal for controlling the switch T by comparing the sense voltage VSE with a reference voltage VREF. The constant current controller may generate a gain NPCG based on the ratio of the electrode signal applied to the gate electrode of the switch T to the target signal by comparing the electrode signal applied to the gate electrode of the switch T with the target signal. In the present embodiment, the target signal may be a target duty ratio signal TD for generating a target current GCM determined based on the load LOAD of the input image data IMG of the display device. In the present embodiment, the electrode signal may be a signal applied to the gate electrode of the switch T.

[0107] The power supply voltage generator 600 may further include a gain operator MU configured to generate a second switch signal SC by multiplying the gain NPCG by the first switch signal. The on-off operation of the switch T may be controlled by the second switch signal SC.

[0108] The booster can include an inductor L, a first diode D1, and a switch T. The inductor L can include a first terminal to which an input voltage VI is applied and a second terminal connected to a first electrode of the first diode D1. The switch T can include a gate electrode, a source electrode, and a drain electrode, where a second switching signal SC can be applied to the gate electrode, and the drain electrode can be connected to the first electrode of the first diode D1. The source electrode of the switch T can be grounded. The first diode D1 can include a first electrode connected to the second terminal of the inductor L and a second electrode connected to a voltage sensor and supplying an output voltage VO to the voltage sensor.

[0109] The voltage sensor can include a first sensing resistor RS1 and a second sensing resistor RS2 connected in series. The first sensing resistor RS1 can include a first terminal connected to the second electrode of the first diode D1 to receive the output voltage VO from the booster and a second terminal connected to a first terminal of the second sensing resistor RS2. The second sensing resistor RS2 can include a first terminal connected to the second terminal of the first sensing resistor RS1 and a second terminal grounded. The voltage sensor can sense a sensed voltage VSE corresponding to the output voltage VO by using the voltage divider rule between the first sensing resistor RS1 and the second sensing resistor RS2.

[0110] The constant voltage controller can include a first arithmetic unit AM1, and the first arithmetic unit AM1 includes a first input electrode to which the sensed voltage VSE is applied, a second input electrode to which a reference voltage VREF is applied, and an output electrode outputting a first switching signal.

[0111] In this embodiment, when the difference between the target duty ratio signal TD and the second signal is greater than or equal to a threshold value, the constant current controller can turn off the power voltage generator 600, where the second signal is applied to the gate electrode of the switch T in the booster and is received through a signal smoothing circuit. For example, when the difference between the target duty ratio signal TD and the second signal is greater than or equal to the threshold value, it can be determined that a short circuit occurs in a part of the display panel 100 or the voltage application line.

[0112] That is to say, the constant current controller of this embodiment can perform a constant current control operation and a protection operation.

[0113] For example, when the difference between the target duty ratio signal TD and the second signal is greater than or equal to the threshold value, the second arithmetic unit AM2 can output a gain NPCG of zero (0).

[0114] According to the present exemplary embodiment, constant current control can be operated by sensing a signal of a gate electrode of a switch T of a booster, such that a large sense resistor for current sensing and an IC that detects a current caused by a voltage applied across the large sense resistor and converts the current into a digital code can be omitted. Accordingly, the manufacturing cost of the display device can be reduced.

[0115] In addition, heat generation, a voltage drop of a power supply voltage, and an increase in power consumption that may occur when a large voltage is applied to the sense resistor can be prevented.

[0116] Figure 7 FIG. is a circuit diagram showing a power supply voltage generator 600 of a display device according to an exemplary embodiment of the present disclosure.

[0117] Except for some structures of the power supply voltage generator 600, the power supply voltage generator 600 according to the present exemplary embodiment and the display device including the power supply voltage generator 600 are substantially the same as the power supply voltage generator 600 and the display device including the power supply voltage generator 600 of the previous exemplary embodiment described with reference to Figures 1 to 5B Therefore, the same reference numerals will be used to denote components that are the same as or similar to the components described in the previous exemplary embodiment of Figures 1 to 5B and any repeated description of the above elements will be omitted.

[0118] Referring to Figure 1 and Figures 3 to 5B and Figure 7 , the display device includes a display panel 100 and a display panel driver. The display panel driver includes a driving controller 200, a gate driver 300, a gamma reference voltage generator 400, a data driver 500, and a power supply voltage generator 600.

[0119] The power supply voltage generator 600 may include a booster, a voltage sensor, a constant voltage controller, and a constant current controller.

[0120] The booster may boost an input voltage VI to an output voltage VO based on an on-off operation of a switch T. The voltage sensor may generate a sense voltage VSE by sensing the output voltage VO. The constant voltage controller may generate a first switching signal for controlling the switch T by comparing the sense voltage VSE with a reference voltage VREF. The constant current controller may generate a gain NPCG based on a ratio of an electrode signal of the switch T to a target signal by comparing the electrode signal of the switch T with the target signal. In the present embodiment, the target signal may be a net power control signal NPC determined based on a load LOAD of input image data IMG of the display device. In the present embodiment, the electrode signal may be a signal of a source electrode of the switch T. For example, the electrode signal may be a source current IS flowing through the source electrode of the switch T.

[0121] The power supply voltage generator 600 may further include a gain arithmetic unit MU configured to generate a second switching signal SC by multiplying a gain NPCG by a first switching signal. The on-off operation of the switch T can be controlled by the second switching signal SC.

[0122] The booster may include an inductor L, a first diode D1, and a switch T. The inductor L may include a first terminal to which an input voltage VI is applied and a second terminal connected to a first electrode of the first diode D1. The switch T may include a gate electrode, a source electrode, and a drain electrode, where the second switching signal SC may be applied to the gate electrode, and the drain electrode may be connected to the first electrode of the first diode D1. The first diode D1 may include a first electrode connected to the second terminal of the inductor L and a second electrode connected to a voltage sensor and supplying an output voltage VO to the voltage sensor.

[0123] The voltage sensor may include a first sensing resistor RS1 and a second sensing resistor RS2 connected in series. The first sensing resistor RS1 may include a first terminal connected to the second electrode of the first diode D1 to receive the output voltage VO from the booster and a second terminal connected to a first terminal of the second sensing resistor RS2. The second sensing resistor RS2 may include a first terminal connected to the second terminal of the first sensing resistor RS1 and a second terminal grounded. The voltage sensor may sense a sensing voltage VSE corresponding to the output voltage VO by using the voltage divider rule between the first sensing resistor RS1 and the second sensing resistor RS2.

[0124] The constant voltage controller may include a first arithmetic unit AM1 including a first input electrode to which the sensing voltage VSE is applied, a second input electrode to which a reference voltage VREF is applied, and an output electrode for outputting a first switching signal.

[0125] The booster may further include a current sensing resistor RIS provided between the source electrode of the switch T and the ground. A current sensing voltage VIS at a first terminal of the current sensing resistor RIS may be output to the constant current controller through a signal smoothing circuit.

[0126] The signal at the source electrode of the switch T may be a first signal. The first signal may be a triangular wave signal. The power supply voltage generator 600 may further include a signal smoothing circuit configured to convert the first signal, which is a triangular wave signal, into a second signal, which is a DC signal.

[0127] The signal smoothing circuit may include a second diode D2, a resistor RX, and a capacitor CX.

[0128] The constant current controller can generate a gain NPCG by comparing a second signal with a net power control signal NPC determined based on a load LOAD of input image data IMG of a display device. The net power control signal NPC can increase in proportion to the load LOAD of the input image data IMG and maintain a saturation level after it reaches the saturation level.

[0129] The constant current controller can include a second arithmetic unit AM2. The second arithmetic unit AM2 includes a first input electrode to which the net power control signal NPC is input, a second input electrode to which the second signal is applied, and an output electrode that outputs the gain NPCG to a gain arithmetic unit MU.

[0130] The gain arithmetic unit MU can generate a second switching signal SC by multiplying the gain NPCG by a first switching signal, and the second switching signal SC can be applied as a gate signal of a switch T to perform constant current control of a power supply voltage generator 600.

[0131] According to the present exemplary embodiment, constant current control can be performed by sensing a signal of a source electrode of a switch T in a booster, so that a large sensing resistor for current sensing and an IC that detects a current caused by a voltage applied across the large sensing resistor and converts the current into a digital code can be omitted. Therefore, the manufacturing cost of the display device can be reduced.

[0132] In addition, heat generation, voltage drop of the power supply voltage, and increase in power consumption that may occur when a large voltage is applied to the sensing resistor can be prevented.

[0133] Figure 8 is a circuit diagram showing a power supply voltage generator 600 of a display device according to an exemplary embodiment of the present disclosure.

[0134] Except for some structures of the power supply voltage generator 600, the power supply voltage generator 600 according to the present exemplary embodiment and the display device including the power supply voltage generator 600 are basically the same as the power supply voltage generator 600 and the display device including the power supply voltage generator 600 of the previous exemplary embodiment described with reference to Figure 7 Therefore, the same reference numerals will be used to denote components that are the same as or similar to the components described in the previous exemplary embodiment of Figure 7 and any repeated description of the above elements will be omitted.

[0135] Referring to Figure 1 and Figures 3 to 5B and Figure 8, the display device includes a display panel 100 and a display panel driver. The display panel driver includes a driving controller 200, a gate driver 300, a gamma reference voltage generator 400, a data driver 500, and a power supply voltage generator 600.

[0136] The power supply voltage generator 600 may include a booster, a voltage sensor, a constant voltage controller, and a constant current controller.

[0137] The booster may boost the input voltage VI to the output voltage VO based on the on-off operation of the switch T. The voltage sensor may generate a sensed voltage VSE by sensing the output voltage VO. The constant voltage controller may generate a first switching signal for controlling the switch T by comparing the sensed voltage VSE with a reference voltage VREF. The constant current controller may generate a gain NPCG based on the ratio of the electrode signal of the switch T to the target signal by comparing the electrode signal of the switch T with the target signal. In this embodiment, the target signal may be a net power control signal NPC determined based on the load LOAD of the input image data IMG of the display device. In this embodiment, the electrode signal may be the signal of the source electrode of the switch T.

[0138] The power supply voltage generator 600 may further include a gain arithmetic unit MU configured to generate a second switching signal SC by multiplying the gain NPCG by the first switching signal. The on-off operation of the switch T may be controlled by the second switching signal SC.

[0139] The booster may include an inductor L, a first diode D1, and a switch T. The inductor L may include a first terminal to which the input voltage VI is applied and a second terminal connected to the first electrode of the first diode D1. The switch T may include a gate electrode, a source electrode, and a drain electrode, where the second switching signal SC may be applied to the gate electrode, and the drain electrode may be connected to the first electrode of the first diode D1. The first diode D1 may include a first electrode connected to the second terminal of the inductor L and a second electrode connected to the voltage sensor and outputting the output voltage VO to the voltage sensor.

[0140] The voltage sensor may include a first sensing resistor RS1 and a second sensing resistor RS2 connected in series. The first sensing resistor RS1 may include a first terminal connected to the second electrode of the first diode D1 to receive the output voltage VO from the booster and a second terminal connected to the first terminal of the second sensing resistor RS2. The second sensing resistor RS2 may include a first terminal connected to the second terminal of the first sensing resistor RS1 and a second terminal grounded. The voltage sensor may sense the sensed voltage VSE corresponding to the output voltage VO by using the voltage division rule between the first sensing resistor RS1 and the second sensing resistor RS2.

[0141] The constant voltage controller may include a first arithmetic unit AM1. The first arithmetic unit AM1 includes a first input electrode to which a sensed voltage VSE is applied, a second input electrode to which a reference voltage VREF is applied, and an output electrode that outputs a first switching signal to a gain arithmetic unit MU.

[0142] In this embodiment, when the difference between the net power control signal NPC and the second signal is greater than or equal to a threshold value, the constant current controller may turn off the power voltage generator 600, where the second signal is applied to the gate electrode of the switch T of the booster and is received through a signal smoothing circuit. For example, when the difference between the net power control signal NPC and the second signal is greater than or equal to the threshold value, it may be determined that a short circuit has occurred in a part of the display panel 100 or the voltage application line.

[0143] That is, the constant current controller of this embodiment may perform a constant current control operation and a protection operation.

[0144] For example, when the difference between the net power control signal NPC and the second signal is greater than or equal to the threshold value, the second arithmetic unit AM2 may output a gain NPCG of zero (0).

[0145] According to this exemplary embodiment, constant current control may be performed by sensing a signal of the gate electrode or the source electrode of the switch T of the booster, so that a large sensing resistor for current sensing and an IC that detects a current caused by a voltage applied across the large sensing resistor and converts the current into a digital code may be omitted. Therefore, the manufacturing cost of the display device may be reduced.

[0146] In addition, heat generation, a voltage drop of the power supply voltage, and an increase in power consumption that may occur when a large voltage is applied to the sensing resistor may be prevented.

[0147] According to the inventive concept described above, the manufacturing cost of the display device and the power consumption of the display device may be reduced.

[0148] The foregoing is a description of the inventive concept and should not be construed as limiting the inventive concept. Although some exemplary embodiments of the inventive concept have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of the inventive concept. Accordingly, all such modifications are intended to be included within the scope of the inventive concept as defined in the claims. In the claims, the means-plus-function clauses are intended to cover the structures described herein as performing the recited function and are not limited to merely structural equivalents but also cover equivalent structures. Therefore, it should be understood that the foregoing is a description of the inventive concept and should not be construed as limited to the specific exemplary embodiments disclosed, and modifications to the disclosed exemplary embodiments as well as other exemplary embodiments are intended to be included within the scope of the appended claims. The inventive concept is defined by the claims and equivalents of the claims that will be included herein.

Claims

1. A power supply voltage generator, the power supply voltage generator comprises: A booster configured to boost an input voltage to an output voltage based on on - off operation of a switch; A voltage sensor configured to generate a sensed voltage by sensing the output voltage; A constant voltage controller configured to generate a first switch signal to control the switch by comparing the sensed voltage with a reference voltage; A constant current controller configured to generate a gain based on a ratio of the electrode signal of the switch to a target signal by comparing the electrode signal of the switch with the target signal; and A gain arithmetic unit connected to the constant voltage controller to receive the first switch signal from the constant voltage controller and connected to the constant current controller to receive the gain from the constant current controller, and configured to generate a second switch signal by multiplying the gain by the first switch signal.

2. The power supply voltage generator according to claim 1, wherein, The on - off operation of the switch is controlled by the second switch signal.

3. The power supply voltage generator according to claim 2, wherein, The booster includes an inductor, a first diode, and the switch, The inductor includes a first terminal to which the input voltage is applied and a second terminal connected to a first electrode of the first diode, The switch includes a gate electrode, a source electrode, and a drain electrode, the second switch signal is applied to the gate electrode, the drain electrode is connected to the first electrode of the first diode, and The first diode includes the first electrode connected to the second terminal of the inductor and a second electrode connected to the voltage sensor and outputting the output voltage to the voltage sensor.

4. The power supply voltage generator according to claim 3, wherein, The electrode signal of the switch is a first signal which is a signal of the gate electrode of the switch.

5. The power supply voltage generator according to claim 4, wherein, The first signal is a pulse width modulation signal, and The power supply voltage generator further includes: a signal smoothing circuit configured to convert the first signal, which is the pulse width modulation signal, into a second signal, which is a DC signal.

6. The power supply voltage generator according to claim 5, wherein, The signal smoothing circuit includes a second diode, a resistor, and a capacitor, The second diode includes a first electrode to which the first signal is applied and a second electrode connected to a first terminal of the resistor, The resistor includes the first terminal connected to the second electrode of the second diode and a second terminal grounded, and The capacitor includes a first electrode connected to the second electrode of the second diode and a second electrode grounded.

7. The power supply voltage generator according to claim 5, wherein, The constant current controller is configured to generate the gain by comparing the second signal with a target duty ratio signal, the target duty ratio signal being used to generate a target current determined based on a load of input image data of a display device, and The target current increases as the load of the input image data increases, and maintains the saturation current after the target current reaches the saturation current.

8. The power supply voltage generator according to claim 7, wherein, the constant current controller includes a second arithmetic unit, the second arithmetic unit includes a first input electrode to which the target duty ratio signal is input, a second input electrode to which the second signal is applied, and an output electrode connected to the gain arithmetic unit and outputting the gain to the gain arithmetic unit.

9. The power supply voltage generator according to claim 8, wherein, the constant current controller is configured to turn off the power supply voltage generator when the difference between the target duty ratio signal and the second signal is greater than or equal to a threshold value.

10. The power supply voltage generator according to claim 9, wherein, the second arithmetic unit is configured to output a gain of zero when the difference between the target duty ratio signal and the second signal is greater than or equal to the threshold value.

11. The power supply voltage generator according to claim 7, wherein, when the input voltage of the booster is VI, the output voltage of the booster is VO, the output current of the booster is IO, the measured duty ratio of the switch is D, the inductance of the inductor is L, and the time is t, the IO is expressed as follows: 。 12. The power supply voltage generator according to claim 3, wherein, the electrode signal of the switch is a first signal which is the signal of the source electrode of the switch.

13. The power supply voltage generator according to claim 12, wherein, the first signal is a triangular wave signal, and the power supply voltage generator further includes: a signal smoothing circuit configured to convert the first signal which is the triangular wave signal into a second signal which is a DC signal.

14. The power supply voltage generator according to claim 13, wherein, the signal smoothing circuit includes a second diode, a resistor and a capacitor, the second diode includes a first electrode to which the first signal is applied and a second electrode connected to the first terminal of the resistor, the resistor includes the first terminal connected to the second electrode of the second diode and a second terminal grounded, and the capacitor includes a first electrode connected to the second electrode of the second diode and a second electrode grounded.

15. The power supply voltage generator according to claim 13, wherein, the constant current controller is configured to generate the gain by comparing the second signal with a net power control signal determined by the load of the input image data of the display device, and the net power control signal increases as the load of the input image data increases, and maintains the saturation level after the net power control signal reaches the saturation level.

16. The power supply voltage generator according to claim 15, wherein, The constant current controller includes a second arithmetic unit, and the second arithmetic unit includes a first input electrode to which the net power control signal is input, a second input electrode to which the second signal is applied, and an output electrode connected to the gain arithmetic unit and outputting the gain to the gain arithmetic unit.

17. The power supply voltage generator according to claim 16, wherein, the constant current controller is configured to turn off the power supply voltage generator when the difference between the net power control signal and the second signal is greater than or equal to a threshold value.

18. The power supply voltage generator according to claim 17, wherein, when the difference between the net power control signal and the second signal is greater than or equal to the threshold value, the second arithmetic unit outputs a gain of zero.

19. The power supply voltage generator according to claim 3, wherein, the voltage sensor includes a first sensing resistor and a second sensing resistor, the first sensing resistor includes a first terminal connected to the second electrode of the first diode and a second terminal connected to the first terminal of the second sensing resistor, and the second sensing resistor includes a first terminal connected to the second terminal of the first sensing resistor and a second terminal grounded.

20. The power supply voltage generator according to claim 3, wherein, the constant voltage controller includes a first arithmetic unit, and the first arithmetic unit includes a first input electrode to which the sensed voltage is applied, a second input electrode to which the reference voltage is applied, and an output electrode connected to the gain arithmetic unit and outputting the first switch signal to the gain arithmetic unit.

21. A display device, the display device comprising: a display panel including gate lines, data lines, and pixels connected to the gate lines and the data lines, and the display panel is configured to display an image based on input image data; a gate driver configured to output a gate signal to the gate lines; a data driver configured to output a data voltage to the data lines; and a power supply voltage generator configured to apply a power supply voltage to the pixels; wherein the power supply voltage generator includes: a booster configured to boost an input voltage to an output voltage based on on-off operations of a switch; a voltage sensor configured to generate a sensed voltage by sensing the output voltage; a constant voltage controller configured to generate a first switch signal to control the switch by comparing the sensed voltage with a reference voltage; and a constant current controller connected to the switch to receive an electrode signal from the switch, and configured to generate a gain based on a ratio of the electrode signal of the switch to a target signal by comparing the electrode signal of the switch with the target signal; A gain arithmetic unit is connected to the constant voltage controller to receive the first switching signal from the constant voltage controller and connected to the constant current controller to receive the gain, and is configured to generate a second switching signal by multiplying the gain by the first switching signal, and wherein the output voltage is the power supply voltage.

22. The display device according to claim 21, wherein, the on-off operation of the switch is controlled by the second switching signal.

23. A power supply voltage generator, the power supply voltage generator comprises: A booster connected between an input voltage node and an output voltage node, the booster includes a switch, and the switch includes a gate electrode and a grounded source electrode; A voltage sensor connected to the output voltage node and outputting a sensed voltage; A constant voltage controller including a first input electrode receiving the sensed voltage and a second input electrode receiving a reference voltage to output a first switching signal; A constant current controller including a first input electrode receiving a target duty ratio signal and a second input electrode connected to the switch to output a gain; and A gain arithmetic unit connected between the switch and the constant voltage controller and between the switch and the constant current controller, the gain arithmetic unit receives the first switching signal and the gain from the constant voltage controller and the constant current controller respectively, and is configured to generate a second switching signal by multiplying the gain by the first switching signal.

24. The power supply voltage generator according to claim 23, the power supply voltage generator further comprises: A signal smoothing circuit connected between the second input electrode of the constant current controller and the switch.

25. The power supply voltage generator according to claim 24, wherein, the second input electrode of the constant current controller is connected to the gate electrode of the switch via a diode in the signal smoothing circuit.

26. The power supply voltage generator according to claim 24, wherein, the second input electrode of the constant current controller is connected to the source electrode of the switch via a diode in the signal smoothing circuit.

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