Display driving device and its current bias circuit

Abstract

The present disclosure discloses a display driving device configured to process data by using a low-voltage bias current, process a source signal by using a high-voltage bias current, and provide the low-voltage bias current and the high-voltage bias current by using one bias core.

Description

[0001] Technical Area

[0002] The present disclosure relates to a display driving device, and more particularly, to a display driving device for processing data and providing a source signal for a display by using a bias current, and a current bias circuit of the display driving device for providing the bias current. Background Art

[0003] The display device includes a display panel (such as an LCD panel or an LED panel) for displaying a screen and a display driving device for driving the display panel.

[0004] Among the display panel and the display driving device, the display driving device is manufactured as an integrated circuit and is configured to process data for display provided from the outside and provide a source signal corresponding to the data to the display panel. The display panel can display a screen in response to the source signal of the display driving device.

[0005] The display driving device is designed to include a low voltage bias core for low voltage power and a high voltage bias core for high voltage power. The low voltage bias core is used to generate a low voltage bias current. The low voltage bias current is used to process data, that is, digital signals. In addition, the high voltage bias core is used to generate a high voltage bias current. The high voltage bias current is used to process source signals, that is, analog signals.

[0006] As described above, the display driving device requires two bias cores for high voltage power and low voltage power. Therefore, the display driving device has a limitation in reducing its chip area because it requires areas for two bias cores and additional components of the two bias cores.

[0007] Furthermore, it is difficult to implement a circuit for generating a high voltage bias current in a manner that accurately controls the current compared to a circuit for generating a low voltage bias current. Therefore, it is difficult for a conventional display driving device to accurately control the high voltage bias current.

[0008] Therefore, it is necessary to develop a display driving device to solve the above problems. Summary of the invention

[0009] Various embodiments are directed to providing a display driving device and a current bias circuit thereof, which can reduce the area and number of components thereof by providing a low voltage bias current and a high voltage bias current using one bias core.

[0010] Furthermore, various embodiments are directed to providing a display driving device and a current bias circuit thereof, the display driving device being capable of providing a low voltage bias current and a high voltage bias current by using a low voltage core and accurately controlling the high voltage bias current by controlling the low voltage bias current.

[0011] In addition, various embodiments relate to providing a display driving device and a current bias circuit thereof, which is used to generate a high voltage bias current by using a low voltage bias current and stably maintain protection of a low voltage device for receiving the low voltage bias current even when the voltage environment changes according to a power sequence.

[0012] In an embodiment, a display driving device may include: a bias core configured to provide a core current based on a low voltage power; a low voltage bias unit configured to generate a low voltage bias current in response to the core current; a current conversion circuit configured to generate a transfer current based on a driving voltage for a high voltage power in response to the core current; a high voltage bias unit configured to generate a high voltage bias current based on the driving voltage in response to the transfer current; and a signal driving circuit configured to output a source signal corresponding to data for a display, perform a first bias control for processing the data by using the low voltage bias current, and perform a second bias control for processing the source signal by using the high voltage bias current.

[0013] In an embodiment, a current bias circuit of a display driving device may include: a bias core configured to provide a core current based on a low voltage power; a current conversion circuit configured to generate a transfer current based on a driving voltage for a high voltage power in response to the core current; and a high voltage bias unit configured to generate a high voltage bias current based on the driving voltage in response to the transfer current, wherein the current conversion circuit is driven by the driving voltage for the high voltage power and a first ground voltage for the low voltage power.

[0014] The display driving device of the present disclosure can provide a low voltage bias current for processing data and a high voltage bias current for processing a source signal by using one bias core, thereby reducing the area and number of components used to configure the display driving device.

[0015] In addition, the display driving device of the present disclosure can provide a low voltage bias current and a high voltage bias current by using a low voltage core. Therefore, the display driving device has an advantage in that it can accurately control a high voltage bias current by controlling a low voltage bias current.

[0016] In addition, the display driving device of the present disclosure can use low voltage equipment to generate high voltage bias current by using low voltage bias current, and can prevent the low voltage equipment for receiving low voltage bias current from being damaged due to the influence of driving voltage (i.e., high voltage). Therefore, the display driving device of the present disclosure has the effect of ensuring safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1is a block diagram showing a display driving device according to a preferred embodiment of the present disclosure.

[0018] Figure 2 is a circuit diagram showing an example of a current conversion circuit.

[0019] Figure 3 is a circuit diagram showing another example of the current conversion circuit.

[0020] Figure 4 Is used to describe Figure 3 Circuit diagram of the core protection operation of the current conversion circuit.

[0021] Figure 5 Is used to describe Figure 3 Circuit diagram of the sub-protection operation of the current conversion circuit. DETAILED DESCRIPTION

[0022] You can refer to Figure 1 The display driving device of the present disclosure is described below.

[0023] The display driving device includes a signal driving circuit 100 and a current bias circuit 200 .

[0024] First, the signal driving circuit 100 is configured to receive data DATA for a display screen from an external source such as a timing controller (not shown), generate a source signal Sout corresponding to the data DATA, and output the source signal Sout.

[0025] To this end, the signal driving circuit 100 may include a receiving unit 110 , a restoring unit 120 , a serial-parallel converting unit 130 , a level shifter 140 , a digital-to-analog converter (DAC) 150 , a gamma buffer 160 , and a channel buffer 170 .

[0026] In this case, the receiving unit 110 interfaces with an external transmission line (not shown) and is configured to receive data DATA and provide the received data DATA to the recovery unit 120 to recover the received data DATA. It can be understood that the receiving unit 110 defines an interface unit that receives the data DATA of the transmission line and transmits the received data DATA to the recovery unit 120.

[0027] In addition, the recovery unit 120 separates and recovers the display data, the clock signal, and the control data included in the data DATA. The clock signal and the control data recovered by the recovery unit 120 can be used to process the data DATA and the source signal, but a detailed explanation and description thereof are omitted. The recovery unit 120 is configured to provide the recovered display data for each channel in series to the series-parallel conversion unit 130.

[0028] The serial-parallel conversion unit 130 is configured to parallel-align the serial display data in the latches by sequentially latching the serial display data in the latches, and provide the parallel-latched display data to the level shifter 140 .

[0029] The level shifter 140 is configured to shift the level of display data in a low voltage power region to the level of display data in an appropriate high voltage power region to input the display data to the DAC 150 , and provide the DAC 150 with the level-shifted display data.

[0030] The low voltage power region can be defined as a region between an operating voltage VCC and a first ground voltage VSS. It is understood that the low voltage power provides an operating voltage VCC and a first ground voltage VSS. In addition, the high voltage power region can be defined as a region between a drive voltage VDDH and a second ground voltage VSSH. It is understood that the high voltage power provides a drive voltage VDDH and a second ground voltage VSSH. In this case, the high voltage power region can be set to have a voltage width wider than the low voltage power region. The drive voltage VDDH can be higher than the operating voltage VCC. The second ground voltage VSSH can be equal to or different from the first ground voltage VSS.

[0031] The DAC 150 is configured to receive the gamma voltages from the gamma buffer 160 , select the gamma voltages having a level corresponding to the display data, and output the selected gamma voltages to the channel buffer 170 as the source signal Sout.

[0032] The channel buffer 170 is configured to amplify the source signal Sout output by the DAC 150 so that the source signal has an appropriate level to be provided to a display panel (not shown), and output the amplified source signal Sout to the display panel.

[0033] The receiving unit 110, the restoring unit 120, the serial-parallel converting unit 130 and the level shifter 140 are used to process display data, ie, digital signals. The DAC 150, the gamma buffer 160 and the channel buffer 170 are used to process source signals.

[0034] The receiving unit 110, the restoring unit 120, the serial-parallel conversion unit 130 and the input end of the level shifter 140 operate in the low voltage power region, while the output end of the level shifter 140, the DAC 150, the gamma buffer 160 and the channel buffer 170 operate in the high voltage power region.

[0035] In addition, the receiving unit 110 and the recovery unit 120 perform bias control for processing data. For this purpose, the receiving unit 110 and the recovery unit 120 require a low voltage bias current. In addition, the level shifter 140, the gamma buffer 160, and the channel buffer 170 perform bias control for processing source signals. For this purpose, the level shifter 140, the gamma buffer 160, and the channel buffer 170 require a high voltage bias current.

[0036] As described above, the signal driving circuit 100 is configured to output a source signal Sout corresponding to data DATA for a display, perform a first bias control for processing the data DATA by using a low voltage bias current, and perform a second bias control for processing the source signal Sout by using a high voltage bias current.

[0037] The current bias circuit 200 is configured to generate a low voltage bias current and a high voltage bias current by using one bias core 210 , and to provide the low voltage bias current and the high voltage bias current to necessary components of the signal driving circuit 100 .

[0038] To this end, the current bias circuit 200 may include a bias core 210 , a low voltage bias unit 220 , a current conversion circuit 230 , and a high voltage bias unit 240 .

[0039] The bias core 210 is configured to generate a core current through a low voltage power and provide the core current to the low voltage bias unit 220 and the current conversion circuit 230 .

[0040] The low voltage bias unit 220 may be configured to generate a low voltage bias current in response to the core current and provide the low voltage bias current to the receiving unit 110 and the recovery unit 120 .

[0041] The current conversion circuit 230 is configured to generate a low voltage bias reference current based on an operating voltage for low voltage power in response to a core current of the bias core 210 and generate a transfer current based on a driving voltage with high voltage power in response to the low voltage bias reference current.

[0042] Furthermore, the high voltage bias unit 240 is configured to generate a high voltage bias current based on the driving voltage in response to the transfer current of the current conversion circuit 230 , and provide the high voltage bias current to the level shifter 140 , the gamma buffer 160 , and the channel buffer 170 .

[0043] Among them, the bias core 210 and the low voltage bias unit 220 operate in the low voltage power area. The high voltage bias unit 240 operates in the high voltage power area. That is, it can be understood that the bias core 210 and the low voltage bias unit 220 are driven using the operating voltage VCC for low voltage power and the first ground voltage VSS. It can be understood that the high voltage bias unit 240 is driven using the driving voltage VDDH and the second ground voltage VSSH for high voltage power. In addition, in an embodiment, the current conversion circuit 230 is configured to be driven using the driving voltage VDDH and the first ground voltage VSS.

[0044] refer to Figure 2 Examples of the bias core 210 , the current conversion circuit 230 , and the high voltage bias unit 240 are described.

[0045] The bias core 210 is driven by a low voltage power supplying an operation voltage VCC and a first ground voltage VSS, and includes a low voltage core 212 and a driving device ML1 .

[0046] The low voltage core 212 may be understood as a circuit that functions as a source that provides a source current based on a low voltage power.

[0047] The driving device ML1 is configured using a PMOS transistor and is a low voltage device that operates within the range of an operating voltage VCC for low voltage power and a first ground voltage VSS. More specifically, the driving device ML1 is configured to have a drain connected to the low voltage core 212, a drain and a gate connected in common, and a source to which the operating voltage VCC is applied. Because the voltage level of the gate of the driving device ML1 drops to a low level through the source current of the low voltage core 212, the driving device ML1 is turned on and generates a core current.

[0048] The bias core 210 is configured to provide a core current to the first low voltage device ML2 of the current conversion circuit 230 through a node to which the drain and gate of the driving device ML1 are commonly connected.

[0049] Furthermore, the current conversion circuit 230 includes a reference current generator 232 and a transfer current generator 234 .

[0050] In this case, the reference current generator 232 is configured to generate a low voltage bias reference current ILV based on the operating voltage VCC in response to the core current of the bias core 210 .

[0051] More specifically, the reference current generator 232 includes low voltage devices ML2 and ML3 connected in series. The low voltage devices ML2 and ML3 are devices that operate within the range of the operating voltage VCC for low voltage power and the first ground voltage VSS. The low voltage device ML2 is configured using a PMOS transistor. The low voltage device ML3 is configured using an NMOS transistor.

[0052] The low voltage device ML2 has a gate provided with a core current for biasing the core 210, and is configured to generate a low voltage bias reference current ILV based on the operating voltage VCC in response to the core current. More specifically, since the voltage level of the gate of the low voltage device ML2 drops to a low level by the core current, the low voltage device ML2 is turned on and generates the low voltage bias reference current ILV by the operating voltage VCC applied to the source of the low voltage device ML2.

[0053] In addition, the low voltage device ML3 is turned on in response to the low voltage bias reference current ILV, and is configured to provide a turn-on voltage corresponding to the low voltage bias reference current ILV to the transfer current generator 234. More specifically, the low voltage device ML3 is configured to have a drain provided with the low voltage bias reference current ILV, a drain and a gate connected in common, and a source applied with a first ground voltage VSS. The low voltage device ML3 provides a turn-on voltage corresponding to the low voltage bias reference current ILV of the low voltage device ML2 to the low voltage device MLC of the transfer current generator 234.

[0054] The transfer current generator 234 includes a low voltage device MLC for receiving a low voltage bias reference current ILV, and is configured to generate a transfer current It based on a driving voltage VDDH in response to turning on the low voltage device MLC, and perform protection for reducing the driving voltage VDDH applied to the low voltage device MLC.

[0055] To this end, the transfer current generator 234 includes a low voltage device MLC, a high voltage device MH1, and a protection device MHD.

[0056] The low voltage device MLC is a device that operates within the range of the operating voltage VCC for low voltage power and the first ground voltage VSS, and is configured using an NMOS transistor. More specifically, the low voltage device MLC is configured to have a source to which the first ground voltage VSS is applied, a drain connected to the protection device MHD, and a gate to which the turn-on voltage of the low voltage device ML3 is provided. The low voltage device MLC is turned on in response to the turn-on voltage of the low voltage device ML3 applied to its gate, and controls the generation of the transfer current It by turning on the high voltage device MH1.

[0057] The protection device MHD is a device that operates within the range of a driving voltage VDDH and a first ground voltage VSS, and is configured using an NMOS transistor. More specifically, the protection device MHD is configured to have a source connected to the drain of the low voltage device MLC, a gate to which the operating voltage VCC is applied, and a drain connected to the high voltage device MH1. The protection device MHD is configured so that the first ground voltage VSS applied by the low voltage device MLC is used as a reverse bias voltage. The protection device MHD is turned on in response to the operating voltage VCC, and connects the low voltage device MLC and the high voltage device MH1, reduces the driving voltage VDDH, and transmits the reduced driving voltage VDDH to the low voltage device MLC.

[0058] In addition, the high voltage device MH1 is a device that operates within the range of the driving voltage VDDH and the first ground voltage VSS, and is configured using a PMOS transistor. More specifically, the high voltage device MH1 is configured to have a drain connected to the drain of the protection device MHD, a drain and a gate connected in common, and a source to which the driving voltage VDDH is applied. When the low voltage device MLC is turned on in response to the low voltage bias reference current ILV, since the voltage level of the gate of the high voltage device MH1 drops to a low level, the high voltage device MH1 is turned on, and a transfer current It is generated by the driving voltage VDDH applied to the source of the high voltage device MH1. In addition, the high voltage device MH1 transmits a turn-on voltage corresponding to the transfer current It to the high voltage bias unit 240.

[0059] The high voltage bias unit 240 includes high voltage devices MH9 and MH10 connected in series. The high voltage devices MH9 and MH10 are devices that operate within the range of a driving voltage VDDH having high voltage power and a second ground voltage VSSH. The high voltage device MH9 is configured using a PMOS transistor. The high voltage device MH10 is configured using an NMOS transistor.

[0060] Among them, the high voltage device MH9 is configured to have a gate provided with a turn-on voltage of the transfer current generator 234, and generates a high voltage bias current IHV based on the driving voltage VDDH by turning on the high voltage device MH9. More specifically, when the level of the turn-on voltage of the transfer current generator 234 is a low level, the high voltage device MH9 is turned on and generates a high voltage bias current IHV based on the driving voltage VDDH applied to the source of the high voltage device MH9.

[0061] In addition, the high voltage device MH10 is turned on in response to the high voltage bias current IHV and is configured to drive the high voltage bias current IHV. More specifically, the high voltage device MH10 is configured to have a drain provided with the high voltage bias current IHV, a drain and a gate connected in common, and a source applied with the second ground voltage VSSH. The high voltage device MH10 is turned on in response to the high voltage bias current IHV of the high voltage device MH9.

[0062] exist Figure 2 In the embodiment, according to the above structure, the current conversion circuit 230 can generate a low voltage bias reference current ILV in response to the core current of the bias core 210, and can generate a transfer current It corresponding to the low voltage bias reference current ILV. The high voltage bias unit 240 can generate a high voltage bias current IHV in response to the transfer current It.

[0063] Figure 2 An implementation may provide both low voltage bias current and high voltage bias current by using one bias core.

[0064] also, Figure 2 The embodiment generates a high voltage bias current by using a low voltage bias reference current that can be accurately controlled. Therefore, the high voltage bias current can be effectively controlled by accurately controlling the low voltage bias reference current.

[0065] In addition, Figure 2 In the embodiment, the driving voltage VDDH (ie, high voltage) is dropped by the protection device MHD turned on during the generation of the high voltage bias current and is applied to the low voltage device ML3. Therefore, the low voltage device ML3 can be driven in a safe voltage environment without affecting the low voltage device ML3.

[0066] The operating voltage VCC can be formed as a low voltage. In this case, Figure 2 In the implementation mode of the embodiment, it is difficult for the protection device MHD to maintain normal conduction. To prevent this situation, it can be implemented Figure 3 implementation method. Figure 3 In the embodiment, since the bias core 210, the high voltage bias unit 240 and the reference current generator 232 are configured to Figure 2 The components are the same, and thus redundant descriptions of the configurations and operations of these components are omitted.

[0067] exist Figure 3 , the transfer current generator 234 is configured to include a low voltage device MLC, a high voltage device MH1, a protection device MHD, and a protection control circuit 236.

[0068] Since the low voltage device MLC and the high voltage device MH1 are Figure 2The components are constructed and operated in the same manner, and thus redundant descriptions thereof are omitted.

[0069] exist Figure 3 In the embodiment, the protection device MHD is arranged between the low voltage device MLC and the high voltage device MH1, and is arranged to be maintained conductive by the protection voltage provided by the high voltage device MH3. Figure 3 As shown, the protection device MHD is configured to reduce the driving voltage VDDH and transmit the reduced driving voltage VDDH to the low voltage device MLC.

[0070] like Figure 3 As shown, the protection device MHD is a device that operates within the range of the driving voltage VDDH and the first ground voltage VSS, and is configured using an NMOS transistor. More specifically, the protection device MHD is configured to have a source connected to the drain of the low voltage device MLC, a gate provided with a protection current of the protection control circuit 236, and a drain connected to the high voltage device MH1. The protection device MHD is configured so that the first ground voltage VSS applied by the low voltage device MLC is used as a reverse bias voltage. The protection device MHD is turned on in response to the protection voltage provided by the high voltage device MH3, and connects the low voltage device MLC and the high voltage device MH1, reduces the driving voltage VDDH, and transmits the reduced driving voltage VDDH to the low voltage device MLC.

[0071] If the operating voltage VCC is not formed, the low voltage device MLC is turned off and the transfer current It is not formed. In addition, after the initial stage, the driving voltage VDDH and the operating voltage VCC may each have a normal level. In this case, the low voltage device MLC is turned on and the transfer current It is formed.

[0072] The protection control circuit 236 is configured to generate a protection voltage based on the transfer current It or the driving voltage VDDH depending on whether the transfer current It is formed, and provide the protection voltage to the gate of the protection device MHD.

[0073] To this end, the protection control circuit 236 includes a core protection circuit 237 and a sub-protection circuit 239 .

[0074] When the transfer current It flows as the low voltage device MLC is turned on due to the normal level of the operating voltage VCC, the core protection circuit 237 generates a core protection current based on the driving voltage VDDH in response to the transfer current It. To this end, the core protection circuit 237 includes a high voltage device MH2 and a high voltage device MH3. The high voltage device MH2 is configured using a PMOS transistor that operates within the range of the driving voltage VDDH and the first ground voltage VSS. The high voltage device MH3 is configured using an NMOS transistor that operates within the range of the driving voltage VDDH and the first ground voltage VSS.

[0075] More specifically, the high voltage device MH2 is configured to have a drain connected to the drain of the high voltage device MH3, a gate connected to the gate of the high voltage device MH1, and a source to which the driving voltage VDDH is applied. When the voltage level of the gate of the high voltage device MH2 drops to a low level by the transfer current It, the high voltage device MH2 is turned on, and generates a core protection current based on the driving voltage VDDH applied to its source, and provides the core protection current to the high voltage device MH3.

[0076] The high voltage device MH3 is configured to have a drain and a gate connected in common, a drain connected to the drain of the high voltage device MH2, and a source to which the first ground voltage VSS is applied. The high voltage device MH3 provides a protection voltage corresponding to the core protection current of the high voltage device MH2 to the protection device MHD.

[0077] The sub-protection circuit 239 generates a protection voltage based on the driving voltage VDDH. To this end, the sub-protection circuit 239 includes a first switching device MH6, a second switching device MH7, a first sub-protection device MH5, and a second sub-protection device MH8.

[0078] Each of the first switching device MH6 and the second switching device MH7 is configured using a PMOS transistor that operates within the range of the driving voltage VDDH and the first ground voltage VSS. The first switching device MH6 and the second switching device MH7 are configured to receive the driving voltage VDDH in parallel and act as a resistor by being turned on in response to the first ground voltage VSS for low voltage power applied to its gate.

[0079] The first sub-protection device MH5 is configured using an NMOS transistor operating within the range of the driving voltage VDDH and the first ground voltage VSS. The first sub-protection device MH5 is configured to have a drain connected to the drain of the first switching device MH6, a gate connected to the common drain of the second switching device MH7 and the second sub-protection device MH8, and a source connected to the gate of the protection device MHD in common with the high voltage device MH3.

[0080] The second sub-protection device MH8 is configured using an NMOS transistor that operates within the range of the drive voltage VDDH and the first ground voltage VSS. The second sub-protection device MH8 is configured to have a drain connected to the drain of the second switching device MH7, a gate connected to the source of the first sub-protection device MH5 and the gate of the protection device MHD, and a source to which the first ground voltage VSS is applied.

[0081] If the transfer current It flows according to the situation that the level of the operating voltage VCC is a normal level, so that the voltage level of the gate of the protection device MHD is a high level, the second sub-protection device MH8 is turned on. On the contrary, if the transfer current It does not flow due to the lack of the operating voltage VCC, so that the voltage level of the gate of the protection device MHD is a low level, the second sub-protection device MH8 is turned off.

[0082] When the second sub-protection device MH8 is turned on, the first sub-protection device MH5 maintains the off state and does not provide the protection voltage to the gate of the protection device MHD. On the contrary, when the second sub-protection device MH8 is turned off, the first sub-protection device MH5 is turned on in response to the driving voltage VDDH applied by the second switching device MH7, and applies the protection voltage to the gate of the protection device MHD based on the driving voltage VHHD. At this time, the protection device MHD can remain turned on in response to the protection voltage of the first sub-protection device MH5.

[0083] As described above, when the driving voltage VDDH and the operating voltage VCC both have a normal high level, according to Figure 3 The current conversion circuit of the embodiment of the present invention provides a high voltage bias current by forming a transfer current It. At this time, the protection device MHD can maintain conduction in response to the protection voltage based on the transfer current It and prevent the driving voltage VDDH from being directly applied to the low voltage device MLC. In addition, when the driving voltage VDDH has a normal high level and the operating voltage VCC is not formed, Figure 3 In the embodiment of the present invention, the protection device MHD may remain turned on in response to the protection voltage based on the driving voltage VDDH and prevent the driving voltage VDDH from being directly applied to the low voltage device MLC.

[0084] This will refer to Figure 4 and 5 Give a description. Figure 4 This corresponds to the case where both the driving voltage VDDH and the operating voltage VCC have a normal high level and the low voltage device MLC is turned on in response to the low voltage bias reference current ILV. Figure 5 This corresponds to the case where the level of the driving voltage VDDH is high and the operating voltage VCC is not formed. Figure 4 and Figure 5 In, with Figure 3 The same components are given the same reference numerals, and redundant descriptions thereof are omitted.

[0085] When the driving voltage VDDH and the operating voltage VCC are both at a normal high level, you can refer to Figure 4 Description based on Figure 3 Operation of the current conversion circuit of the embodiment.

[0086] Since the operating voltage VCC for the low voltage power has a normal high level, the current conversion circuit 230 normally generates the low voltage bias reference current ILV corresponding to the core current and the transfer current It corresponding to the low voltage bias reference current ILV.

[0087] That is, the transfer current generator 234 normally generates a transfer current It corresponding to the low voltage bias reference current ILV. In this case, when the transfer current It is formed, the protection control circuit 236 generates a core protection current based on the high voltage device MH2, and provides a protection voltage of the high voltage device MH3 corresponding to the core protection current. Therefore, the protection device MHD can maintain conduction in response to the protection voltage of the high voltage device MH3, and reduce the driving voltage VDDH (i.e., high voltage), and transmit the reduced driving voltage to the low voltage device MLC. Therefore, damage to the low voltage device MLC caused by the driving voltage VDDH can be prevented.

[0088] Figure 4 The sub-protection circuit 239 is not shown in FIG. 2 because the sub-protection circuit 239 does not provide a protection voltage and therefore does not affect the operation of the protection device MHD.

[0089] If the level of the driving voltage VDDH is provided as a high level and the operating voltage VCC is not formed, then the reference Figure 5 To describe according to Figure 3 The operation of the current conversion circuit of the embodiment. Figure 5 In this example, the operating voltage VCC can be assumed to be 0V.

[0090] Since the operating voltage VCC for the low voltage power is 0V, the current conversion circuit 230 does not generate the low voltage bias reference current ILV, and does not generate the transfer current It corresponding to the low voltage bias reference current ILV.

[0091] In this case, since the transfer current It is not generated, the high voltage device MH1 of the transfer current generator 234 and the high voltage device MH2 of the core protection circuit 237 are not turned on. That is, the core protection circuit 237 does not provide a protection voltage. Figure 5 The high voltage device MH1 and the high voltage device MH2 are not shown in FIG. 2 because they do not affect the operation of the protection control circuit 236 .

[0092] The protection control circuit 236 does not generate the transfer current It. Therefore, the sub-protection circuit 239 generates a protection voltage based on the driving voltage VDDH.

[0093] More specifically, in the sub-protection circuit 239, the first switching device MH6 and the second switching device MH7 are turned on in response to the first ground voltage VSS for low voltage power, thereby acting as a resistor. In addition, since the transfer current It is not formed, the voltage level of the gate of the protection device MHD drops, and the second sub-protection device MH8 is turned off in response to the voltage level of the gate of the protection device MHD. At this time, since the second sub-protection device MH8 is turned off, the driving voltage VDDH is applied to the gate of the first sub-protection device MH5 through the second switching device MH7.

[0094] The first sub-protection device MH5 of the sub-protection circuit 239 may be turned on in response to the driving voltage VDDH applied thereto, and may provide a protection voltage based on the driving voltage VDDH to the gate of the protection device MHD.

[0095] Therefore, the protection device MHD may remain turned on in response to the protection voltage provided by the first sub-protection device MH5.

[0096] like Figure 5 As shown, even if the level of the driving voltage VDDH is provided as a high level and the operating voltage VCC is not formed, the protection device MHD may be turned on and prevent the driving voltage VDDH from being applied to the low voltage device MLC.

[0097] Therefore, the display driving apparatus of the present disclosure can provide a low voltage bias current and a high voltage bias current by using a low voltage core, and can prevent a low voltage device generating a high voltage bias current from being damaged due to the influence of a high voltage by using the low voltage bias current.

[0098] In addition, the display driving device of the present disclosure can generate a high voltage bias current by using a low voltage bias current, and can maintain protection for a low voltage device receiving the low voltage bias current, regardless of whether the level of the operating voltage VCC is normal. Therefore, the display driving device of the present disclosure has the effect of ensuring safety and reliability.

Claims

1. A display driving device, comprising: a bias core configured to provide a core current based on a low-voltage power supply; a low-voltage bias unit configured to generate a low-voltage bias current in response to the core current; a current conversion circuit configured to generate a transfer current based on a driving voltage for a high-voltage power supply in response to the core current; a high-voltage bias unit configured to generate a high-voltage bias current based on the driving voltage in response to the transfer current; and a signal driving circuit configured to output a source signal corresponding to data for a display, perform a first bias control for processing the data by using the low-voltage bias current, and perform a second bias control for processing the source signal by using the high-voltage bias current, wherein the current conversion circuit includes: a reference current generator configured to generate a low-voltage bias reference current based on an operating voltage for the low-voltage power supply in response to the core current; and a transfer current generator configured to generate the transfer current based on the driving voltage in response to the low-voltage bias reference current, wherein the transfer current generator includes: a first low-voltage device configured to turn on in response to the low-voltage bias reference current; and a first high-voltage device configured to generate the transfer current based on the driving voltage in response to the turning on of the first low-voltage device.

2. The display driving device according to claim 1, wherein the transfer current generator performs protection for reducing the driving voltage applied to the first low-voltage device.

3. The display driving device according to claim 1, wherein the reference current generator includes: a second low-voltage device configured to generate the low-voltage bias reference current based on the operating voltage in response to the core current; and a third low-voltage device that turns on in response to the low-voltage bias reference current and is configured to provide the low-voltage bias reference current to the transfer current generator.

4. The display driving device according to claim 2, wherein the transfer current generator further includes: a protection device configured to maintain conduction between the first low-voltage device and the first high-voltage device and perform protection for reducing the driving voltage applied to the first low-voltage device.

5. The display driving device according to claim 4, wherein the protection device turns on in response to the operating voltage being lower than the driving voltage.

6. The display driving device according to claim 2, wherein the transfer current generator further includes: a protection device configured between the first low-voltage device and the first high-voltage device and configured to maintain conduction in response to a protection voltage and perform protection for reducing the driving voltage applied to the first low-voltage device; and a protection control circuit configured to determine whether to form the protection voltage based on the transfer current or the driving voltage depending on the transfer current.

7. The display driving device according to claim 6, wherein the protection control circuit includes: A core protection circuit configured to generate and provide the protection voltage in response to the transfer current; and A sub - protection circuit configured to generate and provide the protection voltage in response to the drive voltage when the transfer current is not formed.

8. The display driving device according to claim 7, wherein, The core protection circuit includes: A second high - voltage device configured to generate a core protection current in response to the transfer current; and A third high - voltage device configured to generate the protection voltage in response to the core protection current.

9. The display driving device according to claim 7, wherein, The sub - protection circuit includes: A first switching device and a second switching device configured to receive the drive voltage in parallel and act as a resistor by being turned on in response to a first ground voltage for the low - voltage power; A first sub - protection device having a drain connected to the first switching device and a gate connected to the second switching device, and configured to generate the protection voltage corresponding to the drive voltage by being turned on when the drive voltage is applied to the second switching device; and A second sub - protection device having a drain connected to the second switching device, and configured to share the protection voltage through the gate of the second sub - protection device with the protection device, and control the application of the drive voltage to the second switching device and the generation of the protection voltage through the first sub - protection device in response to the level of the protection voltage.

10. The display driving device according to claim 1, wherein: The first low - voltage device operates within a range of the operating voltage for the low - voltage power and a first ground voltage, and The transfer current generator is driven by the drive voltage for the high - voltage power and the first ground voltage for the low - voltage power.

11. A current biasing circuit of a display driving device, comprising: A biasing core configured to provide a core current based on low - voltage power; A current conversion circuit configured to generate a transfer current based on a drive voltage for high - voltage power in response to the core current; and A high - voltage biasing unit configured to generate a high - voltage biasing current based on the drive voltage in response to the transfer current, wherein the current conversion circuit is driven by the drive voltage for the high - voltage power and a first ground voltage for the low - voltage power, wherein the current conversion circuit includes: A reference current generator configured to generate a low - voltage biasing reference current based on an operating voltage for the low - voltage power in response to the core current; and A transfer current generator configured to generate the transfer current based on the drive voltage in response to the low - voltage biasing reference current, wherein the transfer current generator includes: A first low - voltage device configured to be turned on in response to the low - voltage biasing reference current; and A first high - voltage device configured to generate the transfer current based on the drive voltage in response to the turn - on of the first low - voltage device.

12. The current biasing circuit according to claim 11, wherein, The first low-voltage device operates within a range of the operating voltage for the low-voltage power and the first ground voltage, and the transfer current generator performs protection for reducing the drive voltage applied to the first low-voltage device.

13. The current biasing circuit according to claim 12, wherein, the transfer current generator further includes: a protection device configured between the first low-voltage device and the first high-voltage device, and configured to maintain conduction in response to the operating voltage being lower than the drive voltage, and perform protection for reducing the drive voltage applied to the first low-voltage device.

14. The current biasing circuit according to claim 12, wherein, the transfer current generator further includes: a protection device configured between the first low-voltage device and the first high-voltage device, and configured to maintain conduction in response to a protection voltage, and perform protection for reducing the drive voltage applied to the first low-voltage device; and a protection control circuit configured to depend on whether the transfer current forms to provide the protection voltage based on the transfer current or the drive voltage.

15. The current biasing circuit according to claim 14, wherein: the protection control circuit includes: a core protection circuit configured to generate and provide the protection voltage in response to the transfer current, and a sub-protection circuit configured to generate and provide the protection voltage in response to the drive voltage when the transfer current is not formed; the core protection circuit includes: a second high-voltage device configured to generate a core protection current in response to the transfer current, and a third high-voltage device configured to generate the protection voltage in response to the core protection current; and the sub-protection circuit includes: a first switching device and a second switching device configured to receive the drive voltage in parallel and act as a resistor by being turned on in response to the first ground voltage, a first sub-protection device having a drain connected to the first switching device and a gate connected to the second switching device, and configured to generate the protection voltage corresponding to the drive voltage by being turned on when the drive voltage is applied to the second switching device, and a second sub-protection device having a drain connected to the second switching device, and configured to share the protection voltage through the gate of the second sub-protection device with the protection device, and control the application of the drive voltage to the second switching device and the generation of the protection voltage in response to the level of the protection voltage through the first sub-protection device.

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