DC-DC converter

Abstract

This disclosure provides a DC-DC converter, which includes a sensing unit, a judgment unit, a reference voltage control unit, and an output voltage control unit. The sensing unit senses an output voltage and generates a sensing signal. The judgment unit judges the difference between the sensing signal and a first protection level. The reference voltage control unit generates a second reference voltage based on a first reference voltage and the output value of the judgment unit. The output voltage control unit outputs the output voltage based on an input voltage, a feedback voltage of the output voltage, and the second reference voltage.

Description

Technical Field

[0001] This disclosure relates to a DC-DC converter, a DC-DC conversion method using the same, and a display device including the same. More specifically, it relates to a DC-DC converter, a DC-DC conversion method using the same, and a display device including the same, which can stably output the output voltage by changing the level of the output voltage even when the output voltage is abnormal. Background Technology

[0002] The display device includes a DC-DC converter for converting battery voltage into DC voltage for the display panel. To protect the DC-DC converter, it can be shut down when the load increases sharply due to a short circuit or damage to its output voltage.

[0003] However, for example, when the display device is used in an automotive device, if the DC-DC converter is turned off, a dangerous situation may occur while the vehicle is in motion because the display panel is turned off.

[0004] Even if the display device is not used in the automotive device, there may be situations where the display panel needs to remain in a display state rather than being turned off. Summary of the Invention

[0005] In view of this, the technical problem of this disclosure focuses on this point, and the purpose of this disclosure is to provide a DC-DC converter that can stably output the output voltage by changing the level of the output voltage even when the output voltage is abnormal.

[0006] Another object of this disclosure is to provide a DC-DC conversion method utilizing the said DC-DC converter.

[0007] Another object of this disclosure is to provide a display device including the DC-DC converter.

[0008] A DC-DC converter according to an embodiment for achieving the above-described objectives of this disclosure includes a sensing unit, a determination unit, a reference voltage control unit, and an output voltage control unit. The sensing unit senses an output voltage and generates a sensing signal. The determination unit determines the difference between the sensing signal and a first protection level. The reference voltage control unit generates a second reference voltage based on a first reference voltage and the output value of the determination unit. The output voltage control unit outputs the output voltage based on an input voltage, a feedback voltage of the output voltage, and the second reference voltage.

[0009] In one embodiment of this disclosure, the protection state may be activated when the state in which the sensing signal is greater than or equal to the first protection level continues to be greater than the duration of the first time period.

[0010] In one embodiment of this disclosure, when the protection state is activated, the reference voltage control unit generates a second reference voltage whose sensing signal does not exceed the first protection level.

[0011] In one embodiment of this disclosure, the protection state may be deactivated when the state in which the sensing signal is less than or equal to the second protection level continues to be greater than the period of the first time period while the state in which the protection state is activated is active.

[0012] In one embodiment of this disclosure, when the protection state is activated for a period longer than the second time period, the output voltage is changed to a predetermined forced level, and the protection state is deactivated.

[0013] In one embodiment of this disclosure, the determination unit may amplify the difference between the sensing signal and the first protection level to generate an amplified signal and output the amplified signal to the reference voltage control unit.

[0014] In one embodiment of this disclosure, the DC-DC converter may further include: a comparison unit that compares the sensing signal with a first protection level indicating an active protection state or a second protection level indicating an inactive protection state to generate a comparison signal; and a counter that accumulates the comparison signal to generate a protection activation signal.

[0015] In one embodiment of this disclosure, the DC-DC converter may further include: a selection unit that outputs either the first protection level or the second protection level to the comparison unit based on the protection activation signal.

[0016] In one embodiment of this disclosure, the first protection level may be greater than the second protection level.

[0017] In one embodiment of this disclosure, the determination unit may be a first comparison unit that generates a first comparison signal by comparing the sensing signal and the first protection level.

[0018] In one embodiment of this disclosure, the DC-DC converter may further include: a second comparison unit that compares the sensing signal with a first protection level indicating an active protection state or a second protection level indicating an inactive protection state to generate a second comparison signal; and a counter that accumulates the second comparison signal to generate a protection activation signal.

[0019] In one embodiment of this disclosure, the DC-DC converter may further include: an up-down counter, which generates an up-down signal based on the first comparison signal and the protection activation signal and outputs it to the reference voltage control unit. Alternatively, the reference voltage control unit may generate a second reference voltage based on the first reference voltage, the up-down signal, and the protection activation signal.

[0020] A DC-DC conversion method according to an embodiment for achieving the above-described objectives of this disclosure includes: a step of sensing an output voltage and generating a sensing signal; a step of determining a difference between the sensing signal and a first protection level; a step of generating a second reference voltage based on a first reference voltage and the result of the determination; and a step of outputting the output voltage based on an input voltage, a feedback voltage of the output voltage, and the second reference voltage.

[0021] In one embodiment of this disclosure, the protection state may be activated when the state in which the sensing signal is greater than or equal to the first protection level continues to be greater than the duration of the first time period.

[0022] In one embodiment of this disclosure, when the protection state is activated, the second reference voltage that does not exceed the first protection level is generated as the sensing signal.

[0023] In one embodiment of this disclosure, the protection state may be deactivated when the state in which the sensing signal is less than or equal to the second protection level continues to be greater than the period of the first time period while the state in which the protection state is activated is active.

[0024] In one embodiment of this disclosure, when the protection state is activated for a period longer than the second time period, the output voltage is changed to a predetermined forced level, and the protection state is deactivated.

[0025] A display device according to an embodiment for achieving another object of the present disclosure described above includes a display panel, a scan driver, a data driver, and a power generation unit. The display panel includes a plurality of scan lines, a plurality of data lines, and a plurality of pixels connected to the scan lines and the data lines. The scan driver outputs a scan signal to the scan lines. The data driver provides a data voltage to the data lines. The power generation unit provides a first power supply voltage and a second power supply voltage lower than the first power supply voltage to the display panel. The power generation unit includes a DC-DC converter that generates at least one of the first power supply voltage and the second power supply voltage. The DC-DC converter includes: a sensing unit that senses an output voltage and generates a sensing signal; a determining unit that determines the difference between the sensing signal and a first protection level; a reference voltage control unit that generates a second reference voltage based on the first reference voltage and the output value of the determining unit; and an output voltage control unit that outputs the output voltage based on an input voltage, a feedback voltage of the output voltage, and the second reference voltage.

[0026] In one embodiment of this disclosure, the output voltage may be the first power supply voltage. Alternatively, the DC-DC converter may reduce the level of the first power supply voltage when a protection state is activated.

[0027] In one embodiment of this disclosure, the output voltage may be the second power supply voltage. Alternatively, the DC-DC converter may increase the level of the second power supply voltage when a protection state is activated.

[0028] (Public impact)

[0029] According to such a DC-DC converter, the DC-DC conversion method thereusing, and the display device including the same, even in the event of an abnormal output voltage, the output voltage of the DC-DC converter can be stably output by changing the level of the output voltage, without cutting off the output voltage. Therefore, when the display device is used in an automotive device, even if the output voltage of the DC-DC converter is abnormal, the DC-DC converter will not be turned off, and the display panel will not be turned off, thus ensuring the safety of the user of the automotive device. Attached Figure Description

[0030] Figure 1 This is a block diagram illustrating a display device according to an embodiment of the present disclosure.

[0031] Figure 2 It is shown Figure 1 The circuit diagram of the pixel structure of the display panel.

[0032] Figure 3 It is shown Figure 1A block diagram of the power generation section.

[0033] Figure 4a This indicates the protected state. Figure 3 A schematic diagram of the levels of the first power supply voltage and the second power supply voltage.

[0034] Figure 4b This indicates the protected state. Figure 3 A schematic diagram of the levels of the first power supply voltage and the second power supply voltage.

[0035] Figure 5 It is shown Figure 1 The circuit diagram of the power generation section.

[0036] Figure 6 It is shown Figure 3 The circuit diagram of the second DC-DC converter.

[0037] Figure 7 It is shown Figure 6 Timing diagram of the operation of the second DC-DC converter.

[0038] Figure 8 It is shown Figure 6 Timing diagram of the operation of the second DC-DC converter.

[0039] Figure 9 It is shown Figure 6 Timing diagram of the operation of the second DC-DC converter.

[0040] Figure 10 It is shown Figure 6 The sequence diagram of the operation of the second DC-DC converter.

[0041] Figure 11 This is a circuit diagram illustrating a second DC-DC converter according to an embodiment of the present disclosure.

[0042] Figure 12 This is a circuit diagram illustrating a second DC-DC converter according to an embodiment of the present disclosure.

[0043] Explanation of reference numerals in the attached figures

[0044] 100: Display panel; 200: Drive control unit

[0045] 300: Scan driver unit; 400: Data driver unit

[0046] 500: Power generation unit; 520: First DC-DC converter

[0047] 540, 540A, 540B: ​​Second DC-DC converter Detailed Implementation

[0048] The present disclosure will now be described in more detail with reference to the accompanying drawings.

[0049] Figure 1 This is a block diagram illustrating a display device according to an embodiment of the present disclosure.

[0050] Reference Figure 1 The display device may include a display panel 100, a drive control unit 200, a scan drive unit 300, a data drive unit 400, and a power generation unit 500.

[0051] In one embodiment of this disclosure, the drive control unit 200, the scan drive unit 300, the data drive unit 400, and the power generation unit 500 can be implemented by a single integrated circuit (IC) chip.

[0052] In one embodiment of this disclosure, the scan driver unit 300 may be mounted on the display panel 100 or integrated on the display panel 100. Additionally, the data driver unit 400 may be mounted on the display panel 100 or integrated on the display panel 100.

[0053] The display panel 100 displays an image. The display panel 100 includes multiple scan lines SL1, SL2, SL3…SLN, multiple data lines DL1, DL2, DL3…DLM, and multiple pixels P connected to the scan lines SL1, SL2, SL3…SLN and the data lines DL1, DL2, DL3…DLM. For example, the pixels P can be configured in a matrix.

[0054] In one embodiment of this disclosure, the number of scan lines SL1, SL2, SL3...SLN can be N. The number of data lines DL1, DL2, DL3...DLM can be M. N and M are natural numbers. In one embodiment of this disclosure, the number of pixels P can be N×M.

[0055] The display panel 100 is connected to the scan driver unit 300 via multiple scan lines SL1, SL2, SL3...SLN, and to the data driver unit 400 via multiple data lines DL1, DL2, DL3...DLM.

[0056] Additionally, the display panel 100 receives a first power supply voltage ELVDD and a second power supply voltage ELVSS from the power generation unit 500. The first power supply voltage ELVDD can be applied to the first electrode of the organic light-emitting element of the pixel P. The second power supply voltage ELVSS can be applied to the second electrode of the organic light-emitting element of the pixel P. Regarding the pixel structure of the display panel 100, refer to... Figure 2 Detailed explanation.

[0057] The drive control unit 200 generates a first control signal CONT1 for controlling the drive timing of the scan drive unit 300 and outputs it to the scan drive unit 300. The drive control unit 200 generates a second control signal CONT2 for controlling the drive timing of the data drive unit 400 and outputs it to the data drive unit 400.

[0058] The scan drive unit 300 generates scan signals to drive the scan lines SL1, SL2, SL3...SLN in response to receiving the first control signal CONT1 from the drive control unit 200. The scan drive unit 300 can sequentially output the scan signals to the scan lines SL1, SL2, SL3...SLN.

[0059] The data driving unit 400 generates data signals for driving the data wirings DL1, DL2, DL3...DLM in response to receiving the second control signal CONT2 input from the driving control unit 200. The data driving unit 400 outputs the data signals to the data wirings DL1, DL2, DL3...DLM.

[0060] The power generation unit 500 generates a first power supply voltage ELVDD and a second power supply voltage ELVSS. The power generation unit 500 provides the first power supply voltage ELVDD and the second power supply voltage ELVSS to the display panel 100.

[0061] The first power supply voltage ELVDD is applied to the first electrode of the organic light-emitting element of the pixel P, and the second power supply voltage ELVSS is applied to the second electrode of the pixel P of the organic light-emitting element. For example, the first power supply voltage ELVDD may be greater than the second power supply voltage ELVSS.

[0062] The power generation unit 500 may include a DC-DC converter for generating the first power supply voltage ELVDD and the second power supply voltage ELVSS. Regarding the power generation unit 500, see [reference needed]. Figures 3 to 9 Detailed explanation.

[0063] Figure 2It is shown Figure 1 Circuit diagram of the pixel structure of the display panel 100.

[0064] Reference Figure 1 as well as Figure 2 The pixel P includes a first pixel switching element T1, a second pixel switching element T2, a storage capacitor CS, and an organic light-emitting element OLED.

[0065] The first pixel switching element T1 may be a thin-film transistor. The first pixel switching element T1 includes a control electrode connected to the scan wiring SL1, an input electrode connected to the data wiring DL1, and an output electrode connected to the control electrode of the second pixel switching element T2.

[0066] The control electrode of the first pixel switching element T1 can be a gate electrode. The input electrode of the first pixel switching element T1 can be a source electrode. The output electrode of the first pixel switching element T1 can be a drain electrode.

[0067] The second pixel switching element T2 includes a control electrode connected to the output electrode of the first pixel switching element T1, an input electrode to which the first power supply voltage ELVDD is applied, and an output electrode connected to the first electrode of the organic light-emitting element OLED.

[0068] The second pixel switching element T2 can be a thin-film transistor. The control electrode of the second pixel switching element T2 can be a gate electrode. The input electrode of the second pixel switching element T2 can be a source electrode. The output electrode of the second pixel switching element T2 can be a drain electrode.

[0069] The first end of the storage capacitor CS is connected to the input electrode of the second pixel switching element T2, and the second end of the storage capacitor CS is connected to the output electrode of the first pixel switching element T1.

[0070] The first electrode of the organic light-emitting element (OLED) is connected to the output electrode of the second pixel switching element T2, and the second electrode of the organic light-emitting element (OLED) is subjected to a second power supply voltage ELVSS.

[0071] The first electrode of the organic light-emitting element (OLED) can be an anode electrode. The second electrode of the organic light-emitting element (OLED) can be a cathode electrode.

[0072] The pixel P receives the scan signal, the data signal, the first power supply voltage ELVDD, and the second power supply voltage ELVSS, and displays the image by emitting light from the organic light-emitting element OLED with a brightness corresponding to the data signal.

[0073] Figure 3 It is shown Figure 1 Block diagram of the power generation unit 500.

[0074] Reference Figures 1 to 3 The power generation unit 500 may include a first DC-DC converter 520 and a second DC-DC converter 540.

[0075] The first DC-DC converter 520 can generate the first power supply voltage ELVDD based on the input voltage VIN. The second DC-DC converter 540 can generate the second power supply voltage ELVSS based on the input voltage VIN.

[0076] For example, the first DC-DC converter 520 may be a boost converter. For example, the second DC-DC converter 540 may be an inverting buck-boost converter.

[0077] Figure 4a This indicates the protected state. Figure 3 A schematic diagram of the levels of the first power supply voltage ELVDD and the second power supply voltage ELVSS.

[0078] Reference Figures 1 to 4a In this embodiment, if an abnormal state of the output voltage of the first DC-DC converter 520 or the second DC-DC converter 540 occurs, the first DC-DC converter 520 or the second DC-DC converter 540 can be operated in a protection state to adjust the level of the output voltage of the first DC-DC converter 520 or the second DC-DC converter 540 without shutting down the first DC-DC converter 520 or the second DC-DC converter 540.

[0079] If an abnormal state occurs in the output voltage of the first DC-DC converter 520 or the second DC-DC converter 540, the difference between the first power supply voltage ELVDD and the second power supply voltage ELVSS can be reduced, thereby reducing the current flowing to the display panel 100.

[0080] Figure 4a The illustration shows a scenario where, if an abnormal state occurs in the output voltage of the second DC-DC converter 540, the level of the second power supply voltage ELVSS is increased, thereby reducing the current flowing to the display panel 100. In this case, the output voltage of the first DC-DC converter 520 can have a fixed value.

[0081] Figure 4b This indicates the protected state. Figure 3 A schematic diagram of the levels of the first power supply voltage ELVDD and the second power supply voltage ELVSS.

[0082] Reference Figures 1 to 4b In this embodiment, if an abnormal state of the output voltage of the first DC-DC converter 520 or the second DC-DC converter 540 occurs, the first DC-DC converter 520 or the second DC-DC converter 540 can be operated in a protection state to adjust the level of the output voltage of the first DC-DC converter 520 or the second DC-DC converter 540 without shutting down the first DC-DC converter 520 or the second DC-DC converter 540.

[0083] Figure 4b The example illustrates a scenario where, if an abnormal state occurs in the output voltage of the first DC-DC converter 520, the level of the first power supply voltage ELVDD is reduced, thereby reducing the current flowing to the display panel 100. In this case, the output voltage of the second DC-DC converter 540 can have a fixed value.

[0084] Figure 5 It is shown Figure 1 Circuit diagram of the power generation unit 500.

[0085] Reference Figures 1 to 5 The first DC-DC converter 520 may include: a reference voltage generation unit RVG1 that generates a reference voltage VREF1; an amplification unit EA1A that amplifies the difference between the reference voltage VREF1 and the feedback voltage VFB1 of the output voltage VO1 (ELVDD); an output voltage control unit CNTL1 that controls the output voltage VO1 (ELVDD) based on the output of the amplification unit EA1A; and switches SW1A and SW1B that switch based on the control signal of the output voltage control unit CNTL1 to determine the level of the output voltage VO1 (ELVDD). Additionally, the first DC-DC converter 520 may also include: an inductor L1 disposed at the node where the input voltage VIN is applied; feedback resistors RF1A and RF1B that feed back the output voltage VO1 (ELVDD) in a voltage distribution manner; and a capacitor C1 connected to the node where the output voltage VO1 (ELVDD) is output. The current flowing along the node where the output voltage VO1 (ELVDD) is output can be represented by ILOAD1.

[0086] The second DC-DC converter 540 may include: a reference voltage generation unit RVG2 that generates a reference voltage VREF2; a first amplification unit EA2A that amplifies the difference between the reference voltage VREF2 and the feedback voltage VFB2 of the output voltage VO2 (ELVSS); an output voltage control unit CNTL2 that controls the output voltage VO2 (ELVSS) based on the output of the first amplification unit EA2A; and switches SW2A and SW2B that switch based on the control signal of the output voltage control unit CNTL2 to determine the level of the output voltage VO2 (ELVSS). Additionally, the second DC-DC converter 540 may further include: an inductor L2 disposed between switches SW2A and SW2B; feedback resistors RF2A and RF2B that feed back the output voltage VO2 (ELVSS) in a voltage distribution manner; and a capacitor C2 connected to the node where the output voltage VO2 (ELVSS) is output. The current flowing along the node where the output voltage VO2 (ELVSS) is output can be represented by ILOAD2.

[0087] In this embodiment, for ease of explanation, as Figure 4a The example illustrates a situation where, if an abnormal state occurs in the output voltage VO2 (ELVSS) of the second DC-DC converter 540, the level of the second power supply voltage ELVSS is increased, thereby reducing the current flowing to the display panel 100.

[0088] Therefore, the second DC-DC converter 540 may further include: a sensing unit LS for sensing the output voltage VO2 (ELVSS); and a second amplification unit EA2B for amplifying the difference between the sensing signal generated in the sensing unit LS and the correction reference voltage VREF2B. Figure 5 The sensing unit LS and the second amplification unit EA2B are shown in a simplified diagram, see reference. Figure 6 The circuitry of the second DC-DC converter 540 will be described in more detail.

[0089] Figure 6 It is shown Figure 3 The circuit diagram of the second DC-DC converter 540.

[0090] Reference Figures 1 to 6 In this embodiment, if an abnormal state occurs in the output voltage VO2 (ELVSS) of the second DC-DC converter 540, the second DC-DC converter 540 can operate in a protection state. In the protection state, the level of the second power supply voltage ELVSS is increased, thereby reducing the current flowing to the display panel 100.

[0091] The following mainly describes the structure 545 for the second DC-DC converter 540 to operate in the protected state.

[0092] The second DC-DC converter 540 may include: a sensing unit LS that senses the output voltage VO2 (ELVSS) and generates a sensing signal VISEN; a determination unit PCLAMP (EA2B) that determines the difference between the sensing signal VISEN and the first protection level PCLLEVEL1; a reference voltage control unit VREFCON that generates a second reference voltage VREFM2 based on a first reference voltage VREFM and the output value (EA2O) of the determination unit PCLAMP (EA2B); and an output voltage control unit CNTL2 that outputs the output voltage VO2 (ELVSS) based on the input voltage VIN, the feedback voltage VFB2 of the output voltage VO2 (ELVSS), and the second reference voltage VREFM2.

[0093] The sensing signal VISEN can be the value of sensing the output current ILOAD2 flowing to the output node of the second DC-DC converter 540 and converting it into a voltage level. Therefore, the sensing signal VISEN can have a level corresponding to the value of the output voltage VO2 (ELVSS).

[0094] In this embodiment, the determination unit PCLAMP (EA2B) may be the second amplification unit EA2B (PCLAMP) that amplifies the difference between the sensing signal VISEN and the first protection level PCLLEVEL1 to generate an amplified signal EA2O and outputs the amplified signal EA2O to the reference voltage control unit VREFCON.

[0095] The second DC-DC converter 540 may further include: a comparator PCLCOMP that generates a comparison signal by comparing the sensing signal VISEN with either an active first protection level PCLLEVEL1 representing a protection state or an inactive second protection level PCLLEVEL2 representing the protection state; and a counter CN that accumulates the comparison signal to generate a protection activation signal PCLEN. Here, the first protection level PCLLEVEL1 may be greater than the second protection level PCLLEVEL2.

[0096] The counter CN can calculate the time period during which the sensing signal VISEN is greater than or equal to the first protection level PCLLEVEL1, or the time period during which the sensing signal VISEN is less than or equal to the second protection level PCLLEVEL2.

[0097] For example, if the protection state is activated, the protection activation signal PCLEN can have a value of 1; if the protection state is deactivated, the protection activation signal PCLEN can have a value of 0.

[0098] The second DC-DC converter 540 may further include a selection unit MUX that outputs either the first protection level PCLLEVEL1 or the second protection level PCLLEVEL2 to the comparator PCLCOMP based on the protection activation signal PCLEN. For example, if the protection state is active, the selection unit MUX can output the second protection level PCLLEVEL2 to the comparator PCLCOMP to monitor the inactivity of the protection state. Conversely, if the protection state is inactive, the selection unit MUX can output the first protection level PCLLEVEL1 to the comparator PCLCOMP to monitor the activation of the protection state.

[0099] The second DC-DC converter 540 may further include a protection level generation unit PCLRG that generates the first protection level PCLLEVEL1 and the second protection level PCLLEVEL2.

[0100] The second DC-DC converter 540 may further include buffers BA and BB configured between the output voltage control unit CNTL2 and the switches SW2A and SW2B.

[0101] The second DC-DC converter 540 may further include a reference voltage generation unit RVG2 for generating the first reference voltage VREFM, which can be determined by the output voltage setting code VO2SC.

[0102] Figure 7 It is shown Figure 6 Timing diagram of the operation of the second DC-DC converter 540.

[0103] Reference Figures 1 to 7 The range in which the sensing signal VISEN, corresponding to the current IPNL (ILOAD2) flowing in the display panel 100, is less than the first protection level PCLLEVEL1 indicates that the output voltage VO2 (ELVSS) is in a normal operating state.

[0104] When the period during which the sensing signal VISEN is greater than or equal to the first protection level PCLLEVEL1 exceeds the first time period TG, the second DC-DC converter 540 may operate in protection mode (APCL OPERATION).

[0105] During the period when the second DC-DC converter 540 is operating in the protection state (APCL OPERATION), the level of the output voltage VO2 (ELVSS) is controlled to increase, and the sensing signal VISEN does not exceed the first protection level PCLLEVEL1.

[0106] In the protection state (APCL OPERATION), when the period during which the sensing signal VISEN is less than or equal to the second protection level PCLLEVEL2 exceeds the first period TG, the second DC-DC converter 540 can resume operation in the normal state (NORMALOPERATION).

[0107] In this embodiment, the first protection level PCLLEVEL1 used to enter the protection state (APCL OPERATION) can be set to be greater than the second protection level PCLLEVEL2 used to enter the normal state from the protection state (APCL OPERATION).

[0108] Furthermore, in this embodiment, in order to transition to the protection state (APCL OPERATION), the sensing signal VISEN needs to be greater than or equal to the first protection level PCLLEVEL1 during a period longer than the first time period TG. This is to prevent transition to the protection state (APCL OPERATION) when the output voltage VO2 (ELVSS) is temporarily high due to noise, glitches, etc. Similarly, in this embodiment, in order to transition from the protection state (APCL OPERATION) to the normal state (NORMAL OPERATION), the sensing signal VISEN needs to be less than or equal to the second protection level PCLLEVEL2 during a period longer than the first time period TG. This is to prevent transition from the protection state (APCL OPERATION) to the normal state (NORMAL OPERATION) when the output voltage VO2 (ELVSS) is temporarily low due to noise, glitches, etc.

[0109] Figure 8 It is shown Figure 6 Timing diagram of the operation of the second DC-DC converter 540.

[0110] Reference Figures 1 to 8 When the period during which the sensing signal VISEN is greater than or equal to the first protection level PCLLEVEL1 exceeds the first time period TG, the second DC-DC converter 540 may operate in protection mode (APCL OPERATION).

[0111] Additionally, when the protection state (APCL OPERATION) is longer than the second time period TPCL, the output voltage VO2 (ELVSS) changes to a predetermined forced level (ELVSS MAX.VOLTAGE), and the second DC-DC converter 540 can have a forced maximum voltage state (FORCED ELVSS MAX.OPERATION).

[0112] exist Figure 7 The example illustrates a situation where the output voltage VO2 (ELVSS) returns to its normal operation state during the protection state (APCLOPERATION). That is, in this case, it can be assumed that the abnormal state of the output voltage VO2 (ELVSS) was short-term.

[0113] However, in Figure 8 The example illustrates a situation where the protection state (APCLOPERATION) of the output voltage VO2 (ELVSS) persists above the second period TPCL without returning to the normal state (NORMAL OPERATION). That is, in this case, the abnormal state of the output voltage VO2 (ELVSS) may be long-term. In this situation, the output voltage VO2 (ELVSS) is forcibly set to a minimum current flow to the display panel 100 such that the user can perceive the image on the display panel 100, preventing the display panel 100 from being turned off and protecting the user. Therefore, the output voltage VO2 (ELVSS) in the forced maximum voltage state (FORCED ELVSS MAX. OPERATION) can be greater than the output voltage VO2 (ELVSS) in the protection state (APCL OPERATION).

[0114] Figure 9 It is shown Figure 6 Timing diagram of the operation of the second DC-DC converter 540.

[0115] Reference Figures 1 to 9 When the period during which the sensing signal VISEN is greater than or equal to the first protection level PCLLEVEL1 exceeds the first time period TG, the second DC-DC converter 540 may operate in protection mode (APCL OPERATION).

[0116] exist Figure 9 Even if the protection state (APCL OPERATION) continues for an extended period, the second DC-DC converter 540 may not switch to a different state. Figure 8Forced maximum voltage state (FORCED ELVSS MAX.OPERATION).

[0117] exist Figure 9 Even if the protection state (APCL OPERATION) of the output voltage VO2 (ELVSS) continues for a long time, the protection state (APCL OPERATION) can be maintained and the standby can continue until the output voltage VO2 (ELVSS) returns to the normal state (NORMAL OPERATION).

[0118] observe Figure 8 as well as Figure 9 It is understood that the setting of the forced maximum voltage state (FORCED ELVSSMAX.OPERATION) described in this disclosure is selective.

[0119] Figure 10 It is shown Figure 6 The sequence diagram of the operation of the second DC-DC converter 540.

[0120] Reference Figures 1 to 10 The display device is turned on and initialized (S10). The sensing unit LS (LOAD SENSOR) of the second DC-DC converter 540 is activated (S20).

[0121] The sensing unit LS monitors the output current ILOAD2 of the display panel 100 (S30). The sensing unit LS can generate the sensing signal VISEN based on the output current ILOAD2 of the display panel 100.

[0122] Determine whether the state in which the sensing signal VISEN is greater than or equal to the first protection level PCLLEVEL1 under the normal operation of the second DC-DC converter 540 continues to be greater than the period of the first time period TG (S40).

[0123] When the state of the sensing signal VISEN being greater than or equal to the first protection level PCLLEVEL1 continues to exceed the period of the first time period TG, the protection state (APCL OPERATION) can be activated (S50). At this time, the protection activation signal PCLEN can have a value of 1.

[0124] When the state of the sensing signal VISEN being greater than or equal to the first protection level PCLLEVEL1 does not continue to be greater than the first time period TG, the sensing unit LS continues to monitor the output current ILOAD2 of the display panel 100 (S30).

[0125] When the protection state (APCL OPERATION) is activated, the reference voltage control unit VREFCON can generate the second reference voltage VREFM2 (S60) where the sensing signal VISEN does not exceed the first protection level PCLLEVEL1.

[0126] Determine whether the state in which the sensing signal VISEN is less than or equal to the second protection level PCLLEVEL2 continues to be greater than the period of the first time period TG when the protection state (APCL OPERATION) is activated (S70).

[0127] When the protection state (APCL OPERATION) is activated, if the state of the sensing signal VISEN being less than or equal to the second protection level PCLLEVEL2 continues to be greater than the period of the first time period TG, the protection state can be deactivated (S80). At this time, the protection activation signal PCLEN can have a value of 0.

[0128] If the protection state (APCL OPERATION) is inactive, the second DC-DC converter 540 operates in the normal state (NORMAL OPERATION), and the sensing unit LS continues to monitor the output current ILOAD2 of the display panel 100 (S30).

[0129] Additionally, it can be determined whether the activated state of the protection state (APCL OPERATION) continues to exceed the time period of the second time period TPCL (S90).

[0130] When the activated state of the protection state (APCL OPERATION) continues to exceed the period of the second time period TPCL, the output voltage VO2 (ELVSS) changes to a predetermined forced level (ELVSS MAX.VOLTAGE), and the protection state (APCL OPERATION) can be deactivated (S100).

[0131] According to this embodiment, even if the output voltages (ELVSS, ELVDD) are abnormal, the output voltages (ELVSS, ELVDD) of the DC-DC converters 520 and 540 can be stably output by changing the levels of the output voltages (ELVSS, ELVDD). Therefore, when the display device is used in an automotive device, even if the output voltages (ELVSS, ELVDD) of the DC-DC converters 520 and 540 are abnormal, the DC-DC converters 520 and 540 are not turned off, and the display panel 100 is not turned off, thus ensuring the safety of the user of the automotive device.

[0132] Figure 11 This is a circuit diagram showing a second DC-DC converter 540A according to an embodiment of the present disclosure.

[0133] The display device according to this embodiment, apart from the structure of the DC-DC converter, is similar to... Figures 1 to 10 The display devices are substantially the same, and the same reference numerals are used for the same or similar components, and repeated descriptions are omitted.

[0134] Reference Figures 1 to 4b as well as Figure 11 The display device may include a display panel 100, a drive control unit 200, a scan drive unit 300, a data drive unit 400, and a power generation unit 500.

[0135] The power generation unit 500 may include a first DC-DC converter 520 and a second DC-DC converter 540A.

[0136] The first DC-DC converter 520 can generate the first power supply voltage ELVDD based on the input voltage VIN. The second DC-DC converter 540A can generate the second power supply voltage ELVSS based on the input voltage VIN.

[0137] In this embodiment, if an abnormal state of the output voltage of the first DC-DC converter 520 or the second DC-DC converter 540A occurs, the first DC-DC converter 520 or the second DC-DC converter 540A can be operated in a protection state to adjust the level of the output voltage of the first DC-DC converter 520 or the second DC-DC converter 540A without shutting down the first DC-DC converter 520 or the second DC-DC converter 540A.

[0138] The following mainly describes the structure 545A for the second DC-DC converter 540A to operate in the protection state.

[0139] The second DC-DC converter 540A may include: a sensing unit LS that senses the output voltage VO2 (ELVSS) and generates a sensing signal VISEN; a determination unit PCLAMP (EA2B) that determines the difference between the sensing signal VISEN and the first protection level PCLLEVEL1; a reference voltage control unit VREFCON that generates a second reference voltage VREFM2 based on a first reference voltage VREFM and the output value (EA2O) of the determination unit PCLAMP (EA2B); and an output voltage control unit CNTL2 that outputs the output voltage VO2 (ELVSS) based on the input voltage VIN, the feedback voltage VFB2 of the output voltage VO2 (ELVSS), and the second reference voltage VREFM2.

[0140] In this embodiment, the determination unit PCLAMP (EA2B) may be the second amplification unit EA2B (PCLAMP) that amplifies the difference between the sensing signal VISEN and the first protection level PCLLEVEL1 to generate an amplified signal EA2O, and outputs the amplified signal EA2O to the reference voltage control unit VREFCON.

[0141] In this embodiment, the first protection level PCLLEVEL1, which indicates the activation of the protection state, and the second protection level PCLLEVEL2, which indicates the deactivation of the protection state, can be the same. That is, the first protection level PCLLEVEL1 used to enter the protection state and the second protection level PCLLEVEL2 used to enter the normal state from the protection state can be the same.

[0142] The second DC-DC converter 540A may also include a protection level generation unit PCLRG that generates the first protection level PCLLEVEL1.

[0143] Alternatively, in this embodiment, if the sensing signal VISEN is greater than or equal to the first protection level PCLLEVEL1, the second DC-DC converter 540A immediately enters the protection state (APCL OPERATION); if the sensing signal VISEN is less than the first protection level PCLLEVEL1, the second DC-DC converter 540A immediately enters the normal state (APCL OPERATION).

[0144] Unlike this, such as Figure 6As shown, when the comparator PCLCOMP and the counter CN are included, the anti-spiking pulse time (first time period TG) for entering the protection state (APCL OPERATION) and the anti-spiking pulse time (first time period TG) for entering the normal state (APCL OPERATION) from the protection state (APCL OPERATION) can be set.

[0145] According to this embodiment, even if the output voltages (ELVSS, ELVDD) are abnormal, the output voltages (ELVSS, ELVDD) of the DC-DC converters 520 and 540A can be maintained without cutting off the output voltages (ELVSS, ELVDD). Instead, the levels of the output voltages (ELVSS, ELVDD) are changed to stably output the output voltages (ELVSS, ELVDD). Therefore, when the display device is used in an automotive device, even if the output voltages (ELVSS, ELVDD) of the DC-DC converters 520 and 540A are abnormal, the DC-DC converters 520 and 540A are not turned off, and the display panel 100 is not turned off, thus ensuring the safety of the user of the automotive device.

[0146] Figure 12 This is a circuit diagram illustrating a second DC-DC converter 540B according to an embodiment of the present disclosure.

[0147] The display device according to this embodiment, apart from the structure of the DC-DC converter, is similar to... Figures 1 to 10 The display devices are substantially the same, and the same reference numerals are used for the same or similar components, and repeated descriptions are omitted.

[0148] Reference Figures 1 to 4b as well as Figure 12 The display device may include a display panel 100, a drive control unit 200, a scan drive unit 300, a data drive unit 400, and a power generation unit 500.

[0149] The power generation unit 500 may include a first DC-DC converter 520 and a second DC-DC converter 540B.

[0150] The first DC-DC converter 520 can generate the first power supply voltage ELVDD based on the input voltage VIN. The second DC-DC converter 540B can generate the second power supply voltage ELVSS based on the input voltage VIN.

[0151] In this embodiment, if an abnormal state of the output voltage of the first DC-DC converter 520 or the second DC-DC converter 540B occurs, the first DC-DC converter 520 or the second DC-DC converter 540B can be operated in a protection state to adjust the level of the output voltage of the first DC-DC converter 520 or the second DC-DC converter 540B without shutting down the first DC-DC converter 520 or the second DC-DC converter 540B.

[0152] The following mainly describes the structure 545B used for the second DC-DC converter 540B to operate in the protection state.

[0153] The second DC-DC converter 540B may include: a sensing unit LS that senses the output voltage VO2 (ELVSS) and generates a sensing signal VISEN; a determination unit (PCLCOMP1) that determines the difference between the sensing signal VISEN and a first protection level PCLLEVEL1; a reference voltage control unit VREFCON that generates a second reference voltage VREFM2 based on a first reference voltage VREFM and the output value (CMPO1) of the determination unit (PCLCOMP1); and an output voltage control unit CNTL2 that outputs the output voltage VO2 (ELVSS) based on the input voltage VIN, the feedback voltage VFB2 of the output voltage VO2 (ELVSS), and the second reference voltage VREFM2.

[0154] In this embodiment, the determination unit (PCLCOMP1) may be a first comparison unit PCLCOMP1 that compares the sensing signal VISEN and the first protection level PCLLEVEL1 to generate a first comparison signal CMPO1.

[0155] In this embodiment, the second DC-DC converter 540B may further include: a second comparison unit PCLCOMP2 that compares the sensing signal VISEN with either the activated first protection level PCLLEVEL1 representing the protection state (APCL OPERATION) or the deactivated second protection level PCLLEVEL2 representing the protection state (APCL OPERATION) to generate a second comparison signal CMPO2; and a counter CN that accumulates the second comparison signal CMPO2 to generate a protection activation signal PCLEN.

[0156] The second DC-DC converter 540B may further include an add / subtract counter UDCN that generates an add / subtract signal based on the first comparison signal CMPO1 and the protection activation signal PCLEN and outputs it to the reference voltage control unit VREFCON.

[0157] The reference voltage control unit VREFCON can generate the second reference voltage VREFM2 based on the first reference voltage VREFM, the addition / subtraction signal, and the protection activation signal PCLEN.

[0158] In this embodiment, the reference voltage control unit VREFCON can operate digitally and can increase or decrease the second reference voltage VREFM2 by a predetermined increase or decrease level according to the increase or decrease signal of the increase / decrease counter UDCN.

[0159] According to this embodiment, even if the output voltages (ELVSS, ELVDD) are abnormal, the output voltages (ELVSS, ELVDD) of the DC-DC converters 520 and 540B can be maintained without cutting off the output voltages (ELVSS, ELVDD). Instead, the levels of the output voltages (ELVSS, ELVDD) are changed to stably output the output voltages (ELVSS, ELVDD). Therefore, when the display device is used in an automotive device, even if the output voltages (ELVSS, ELVDD) of the DC-DC converters 520 and 540B are abnormal, the DC-DC converters 520 and 540B are not turned off, and the display panel 100 is not turned off, thus ensuring the safety of the user of the automotive device.

[0160] (Industry availability)

[0161] Based on the above description of the DC-DC converter according to this disclosure, the DC-DC conversion method thereunder, and the display device including the present invention, when the display device is used in an automotive device, the safety of the user of the automotive device can be ensured.

[0162] The above description has been based on embodiments; however, those skilled in the art will understand that various modifications and alterations can be made to this disclosure without departing from the concept and scope of the disclosure as set forth in the following claims.

Claims

1. A DC-DC converter, wherein, include: The sensing unit senses the output voltage of the DC-DC converter and generates a sensing signal; The judgment unit determines the difference between the sensing signal and the first protection level; The reference voltage control unit generates a second reference voltage based on the first reference voltage and the output value of the determination unit; as well as The output voltage control unit outputs a control signal to control the output voltage based on the feedback voltage of the output voltage and the second reference voltage.

2. The DC-DC converter according to claim 1, characterized in that, The protection state is activated when the state of the sensing signal being greater than or equal to the first protection level continues to exceed the period of the first time period.

3. The DC-DC converter according to claim 2, characterized in that, When the protection state is activated, the reference voltage control unit generates a second reference voltage that does not exceed the first protection level when the sensing signal is activated.

4. The DC-DC converter according to claim 3, characterized in that, When the state in which the protection state is activated is less than or equal to the second protection level and continues to be greater than the period of the first time period, the protection state is deactivated.

5. The DC-DC converter according to claim 3, characterized in that, When the protection state is activated for a period of time longer than the second time period, the output voltage is changed to a predetermined forced level, and the protection state is deactivated.

6. The DC-DC converter according to claim 1, characterized in that, The determination unit is an amplification unit that amplifies the difference between the sensing signal and the first protection level to generate an amplified signal and outputs the amplified signal to the reference voltage control unit.

7. The DC-DC converter according to claim 6, characterized in that, The DC-DC converter also includes: The comparison unit compares the sensing signal with either an active first protection level indicating a protection state or an inactive second protection level indicating the protection state to generate a comparison signal; and A counter accumulates the comparison signal to generate a protection activation signal.

8. The DC-DC converter according to claim 7, characterized in that, The DC-DC converter also includes: The selection unit outputs either the first protection level or the second protection level to the comparison unit based on the protection activation signal.

9. The DC-DC converter according to claim 8, characterized in that, The first protection level is greater than the second protection level.

10. The DC-DC converter according to claim 1, characterized in that, The determination unit is a first comparison unit that generates a first comparison signal by comparing the sensing signal and the first protection level.

11. The DC-DC converter according to claim 10, characterized in that, The DC-DC converter also includes: The second comparison unit compares the sensing signal with either an activated first protection level indicating a protection state or an inactive second protection level indicating the protection state to generate a second comparison signal; and The counter accumulates the second comparison signal to generate a protection activation signal.

12. The DC-DC converter according to claim 11, characterized in that, The DC-DC converter also includes: The up / down counter generates an up / down signal based on the first comparison signal and the protection activation signal, and outputs it to the reference voltage control unit. The reference voltage control unit generates the second reference voltage based on the first reference voltage, the addition / subtraction signal, and the protection activation signal.

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