Display driving circuit and display device

Abstract

The present invention discloses a display driver circuit and a display device. The display driver circuit includes a central control board and a source driver board, and the display driver circuit also includes a discharge unit circuit and a freewheeling unit circuit: the discharge unit circuit is arranged between the central control board and the source driver board. When the analog voltage output by the power management chip fluctuates upward, the discharge unit circuit is turned on and discharges the analog voltage. After the analog voltage is discharged to a standard value, the discharge unit circuit is turned off; the freewheeling unit circuit is arranged between the central control board and the source driver board. When the analog voltage output by the power management chip fluctuates downward, the freewheeling unit circuit is turned on and compensates the analog voltage. After the analog voltage is compensated to the standard value, the freewheeling unit circuit is turned off. The solution provided by the present invention can slow down the fluctuation of the circuit voltage and ensure normal image display.

Description

Technical Field

[0001] The present invention relates to the field of liquid crystal display technology, and in particular to a display driving circuit and a display device. Background Art

[0002] In the display protocol, such as Figure 2 As shown, each frame consists of a display area and a blanking area. In the display area, the transistors in the panel are turned on, and the source driver IC charges the panel through the output channels. In the blanking area, the transistors in the panel are turned off, and the source driver IC stops charging the panel through the output channels. The source driver IC's current is primarily provided by the analog voltage VAA. Since the source driver IC stops charging the panel in the blanking area, the VAA voltage in the blanking area is very low, and the corresponding VAA current is very low. In the display area, the source driver IC charges the panel, so the VAA voltage in the display area is very high, and the corresponding VAA current is very high.

[0003] like Figure 3 As shown in the figure, the VAA routing path is long from the timing control board (Control Board, abbreviated as CB) → FFC (flexible cable) → XLBoard, XR Board (source control board) → COF (chip on film), and the VAA routing path from the power management chip (Power Manage IC, abbreviated as PMIC) to the source driver chip Source Driver IC has a certain impedance, and a voltage drop is inevitable in the middle. The larger the VAA current, the greater the voltage drop.

[0004] The VAA current in the display area and the blanking area is very different, and the surge current effect caused by the filter capacitor on the VAA causes the VAA of the source driver IC to fluctuate greatly in the display area and the blanking area (here, Figure 4 If the VAA voltage fluctuates greatly, firstly, it is easy to cause damage to components. Secondly, if the VAA voltage fluctuates greatly downward and is lower than the reference voltage GM1, it will cause the voltage level of the reference voltage GM1 to decrease, resulting in abnormal display images. Summary of the Invention

[0005] In order to solve the technical problem of large voltage fluctuation of the analog voltage VAA, embodiments of the present invention provide a display driving circuit and a display device.

[0006] The technical solution of the embodiment of the present invention is achieved as follows:

[0007] An embodiment of the present invention provides a display driving circuit, which includes a central control board and a source driving board. The central control board is provided with a power management chip and a gamma chip. The source driving board is provided with a source driving chip. The central control board and the source driving board are electrically connected. The power management chip outputs an analog voltage to the source driving chip and the gamma chip, and the gamma chip outputs a gamma voltage to the source driving chip; the display driving circuit also includes a discharge unit circuit and a freewheeling unit circuit: the discharge unit circuit is arranged between the central control board and the source driving board. When the analog voltage output by the power management chip fluctuates upward, the discharge unit circuit is turned on and discharges the analog voltage. After the analog voltage is discharged to a standard value, the discharge unit circuit is turned off; the freewheeling unit circuit is arranged between the central control board and the source driving board. When the analog voltage output by the power management chip fluctuates downward, the freewheeling unit circuit is turned on and compensates the analog voltage. After the analog voltage is compensated to the standard value, the freewheeling unit circuit is turned off.

[0008] In one embodiment, the discharge unit circuit includes a discharge input terminal, a discharge reference input terminal, a voltage discharge terminal, and a first unidirectional conduction switch, wherein one terminal of the first unidirectional conduction switch is connected to the discharge input terminal, the other terminal of the first unidirectional conduction switch is connected to the voltage discharge terminal, and the discharge reference input terminal is connected to a first node connecting the first unidirectional conduction switch and the voltage discharge terminal. When the voltage difference between the analog voltage at the discharge input terminal and the discharge reference input terminal is greater than a threshold voltage, the first unidirectional conduction switch is turned on, and the analog voltage passes through the first unidirectional conduction switch and is discharged through the voltage discharge terminal. When the voltage difference between the analog voltage at the discharge input terminal and the discharge reference input terminal is less than or equal to the threshold voltage, the first unidirectional conduction switch is turned off.

[0009] In one embodiment, the discharge unit circuit further includes a voltage divider module and a first operational amplifier, the reference input terminal is connected to one end of the voltage divider module, the voltage divider module is used to divide the voltage of the reference input terminal, the other end of the voltage divider module is connected to the non-inverting input terminal of the first operational amplifier, the inverting input terminal and the output terminal of the first operational amplifier are connected, and the output terminal of the first operational amplifier is also connected to the first node.

[0010] In one embodiment, the voltage discharge terminal includes a third resistor, one end of the third resistor is connected to the first unidirectional conduction switch, and the other end of the third resistor is grounded; the voltage divider module includes a first resistor and a second resistor, one end of the first resistor is connected to the reference input terminal, one end of the second resistor is grounded, the other ends of the first resistor and the second resistor are both connected to a second node, and the second node is connected to the non-inverting input terminal of the first operational amplifier.

[0011] In one embodiment, the freewheeling unit circuit includes a freewheeling input terminal, a freewheeling reference input terminal, a second unidirectional conduction switch, and a freewheeling compensation terminal, one end of the second unidirectional conduction switch is connected to the freewheeling compensation terminal, and the other end of the second unidirectional conduction switch is connected to the freewheeling input terminal; when the voltage difference between the analog voltage of the freewheeling input terminal and the freewheeling reference input terminal is greater than a threshold voltage, the second unidirectional conduction switch is turned off; when the voltage difference between the analog voltage of the freewheeling input terminal and the freewheeling reference input terminal is less than a threshold voltage, the second unidirectional conduction switch is turned on, and the freewheeling unit circuit compensates for the analog voltage.

[0012] In one embodiment, the freewheeling unit circuit further includes a second operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor, and a seventh resistor, the freewheeling reference input terminal is connected to the non-inverting input terminal of the second operational amplifier via the fifth resistor, the inverting input terminal of the second operational amplifier is connected to the ground terminal via the fourth resistor, the second unidirectional conduction switch is connected to the output terminal of the second operational amplifier via the seventh resistor, one end of the sixth resistor is connected to the inverting input terminal of the second operational amplifier, and the other end of the sixth resistor is connected to one end of the second unidirectional conduction switch connected to the seventh resistor.

[0013] In one embodiment, the freewheeling reference input terminal and the discharge reference input terminal are both connected to the first gamma voltage output terminal of the gamma chip.

[0014] In one embodiment, when the voltage difference between the voltage at the discharge reference input terminal after passing through the first operational amplifier and the analog voltage at the discharge input terminal is greater than a threshold voltage, the first unidirectional conduction switch is turned on; when the voltage difference between the voltage at the freewheeling reference input terminal after passing through the second operational amplifier and the analog voltage at the freewheeling input terminal is greater than a threshold voltage, the second unidirectional conduction switch is turned on.

[0015] In one embodiment, the display driving circuit further includes: a filtering circuit for filtering the voltage value output by the discharge unit circuit or the freewheeling unit circuit; the filtering circuit includes a first capacitor: the first capacitor is arranged between the discharge unit circuit and the freewheeling unit circuit and the source driving board, one end of the first capacitor is respectively connected to the discharge unit circuit and the freewheeling unit circuit, and the other end of the first capacitor is grounded.

[0016] An embodiment of the present invention further provides a display device, comprising a display panel and a display driving circuit, wherein the display panel and the display driving circuit are electrically connected, and the display driving circuit adopts any of the display driving circuits described in the above embodiments.

[0017] In one embodiment, each frame of the display panel includes a display area and a blanking area. The display area corresponds to when the transistors in the display panel are turned on, and the source driver chip in the display driver circuit charges the display panel through the output channel; the blanking area corresponds to when the transistors in the display panel are turned off, and the source driver chip in the display driver circuit stops charging the display panel through the output channel.

[0018] The display driving circuit and display device provided by the embodiments of the present invention include a central control board and a source driving board, the central control board is provided with a power management chip and a gamma chip, the source driving board is provided with a source driving chip, the central control board and the source driving board are electrically connected, the power management chip outputs an analog voltage to the source driving chip and the gamma chip, and the gamma chip outputs a gamma voltage to the source driving chip; the display driving circuit also includes a discharge unit circuit and a freewheeling unit circuit: the discharge unit circuit is arranged between the central control board and the source driving board, when the analog voltage output by the power management chip fluctuates upward, the discharge unit circuit is turned on and discharges the analog voltage, and after the analog voltage is discharged to a standard value, the discharge unit circuit is turned off; the freewheeling unit circuit is arranged between the central control board and the source driving board, when the analog voltage output by the power management chip fluctuates downward, the freewheeling unit circuit is turned on and compensates the analog voltage, and after the analog voltage is compensated to the standard value, the freewheeling unit circuit is turned off. Since the analog voltage VAA fluctuates during the process of being transmitted from the power management chip to the source chip, the present application sets a discharge unit circuit and a freewheeling unit circuit between the central control board and the source driver board. Therefore, when the analog voltage fluctuates upward, the analog voltage can be discharged through the discharge unit circuit. When the analog voltage fluctuates downward, the analog voltage is compensated by the freewheeling unit circuit, thereby ensuring that the analog voltage remains stable during the transmission process, and further ensuring the stability of the analog voltage transmitted to the source driver chip and the display panel. This can avoid damage to components caused by large fluctuations in the analog voltage, and can ensure the voltage level of the first gamma voltage, avoiding display abnormalities caused by large fluctuations in the analog voltage and being lower than the first gamma voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of an LCD display system in the prior art;

[0020] Figure 2 A schematic diagram of the display panel partition in the prior art;

[0021] Figure 3 This is a schematic diagram of the structural connection of a display device in the prior art;

[0022] Figure 4 It is a schematic diagram of circuit voltage fluctuation in the prior art;

[0023] Figure 5 A schematic diagram of the structure of a display driving circuit according to an embodiment of the present invention;

[0024] Figure 6 It is a schematic diagram of a display circuit of a liquid crystal display system in the prior art;

[0025] Figure 7 A schematic diagram of the complete structure of a display driving circuit according to an embodiment of the present invention;

[0026] Figure 8 Schematic diagram of the structure of a display device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to more clearly illustrate the technical solutions in the embodiments or exemplary technologies of this application, the specific implementation methods of this application will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of this application. For those of ordinary skill in the art, other drawings and other implementation methods can be obtained based on these drawings without inventive work.

[0028] To simplify the drawings, only the parts relevant to this application are schematically shown in each figure. They do not represent the actual structure of the product. In addition, to simplify the drawings and facilitate understanding, in some figures, only one of the components with the same structure or function is schematically shown or labeled. In this document, "one" not only means "only one" but also "more than one."

[0029] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0030] In a general LCD display system, such as Figure 1 As shown, the power management chip (PMIC) on the timing control board (CB) outputs VAA (called analog voltage) and HVAA (called analog half voltage) to the source driver chip (Source Driver IC), the gamma chip (Gamma IC) on the timing control board provides grayscale reference voltages such as GM1 to GM14 to the source driver chip, the timing control chip (TCON) on the timing control board provides P2P signals (image signals) to the source driver chip, and the level shift (L / S) on the timing control board provides GOA signals to the display panel. Among them, the GOA (Gate Driven on Array) signal is integrated for the gate driver on the array substrate, which can realize the row-by-row scanning drive function of the liquid crystal panel.

[0031] See also Figure 5An embodiment of the present invention provides a display driver circuit, comprising a central control board 101 and a source driver board 102. The central control board 101 is provided with a power management chip PMIC and a gamma chip GammaIC. The source driver board 102 is provided with a source driver chip Source Driver IC. The central control board 101 and the source driver board 102 are electrically connected. The power management chip outputs an analog voltage VAA to the source driver chip and the gamma chip. The gamma chip outputs a gamma voltage to the source driver chip. The display driver circuit further comprises a discharge unit circuit 104 and a freewheeling unit circuit 103.

[0032] The discharge unit circuit 104 is provided between the central control board 101 and the source driver board 102. When the analog voltage output by the power management chip fluctuates upward, the discharge unit circuit 104 is turned on and discharges the analog voltage. After the analog voltage is discharged to the standard value, the discharge unit circuit 104 is turned off.

[0033] The freewheeling unit circuit 103 is arranged between the central control board 101 and the source driver board 102. When the analog voltage output by the power management chip fluctuates downward, the freewheeling unit circuit 103 is turned on and compensates the analog voltage. After the analog voltage is compensated to the standard value, the freewheeling unit circuit 103 is turned off.

[0034] Specifically, see Figure 6 , Figure 6 The figure is a schematic diagram of the display circuit of a liquid crystal display system in the prior art. In the prior art, the analog voltage VAA of a typical liquid crystal display system enters the source driver IC through a wiring. The wiring generally has an impedance R0, which causes the VAA input to the source driver IC to attenuate. In the above display circuit structure, since each frame of the display image has a display area and a blanking area, and the blanking area stops supplying power to the source driver IC, the VAA in the display area and the blanking area differ greatly. If the inrush effect caused by the filter capacitor C0 is added, the VAA voltage of the source driver IC will fluctuate significantly, which can easily cause damage to components. Moreover, if the VAA fluctuates significantly downward, when VAA is lower than the first gamma voltage GM1, the GM1 voltage level will decrease, resulting in abnormal image display.

[0035] Based on the above analysis and problems, this embodiment provides a display driving circuit. By setting a discharge unit circuit and a freewheeling unit circuit between the central control board and the source driving board, when the analog voltage fluctuates upward, the analog voltage can be discharged through the discharge unit circuit. When the analog voltage fluctuates downward, the analog voltage is compensated by the freewheeling unit circuit, thereby ensuring that the analog voltage remains stable during the transmission process, and further ensuring the stability of the analog voltage transmitted to the source driving chip and the display panel. In this way, damage and injury to components caused by large fluctuations in the analog voltage during the transmission process can be avoided, and the voltage level of the first gamma voltage can be guaranteed, thereby avoiding display abnormalities caused by large fluctuations in the analog voltage and being lower than the first gamma voltage.

[0036] First embodiment:

[0037] In this embodiment, see Figure 7 , Figure 7 This is a schematic diagram of a first embodiment of a display driver circuit according to an embodiment of the present invention. In this display driver circuit, the discharge unit circuit 104 includes a discharge input terminal, a discharge reference input terminal, a voltage discharge terminal, and a first unidirectional conduction switch D1. One end of the first unidirectional conduction switch D1 is connected to the discharge input terminal, and the other end of the first unidirectional conduction switch D1 is connected to the voltage discharge terminal. The discharge reference input terminal is connected to a first node connecting the first unidirectional conduction switch D1 and the voltage discharge terminal. In this embodiment, the discharge reference input terminal can be connected to GM1 (a first gamma voltage), that is, the discharge reference input terminal is connected to the first gamma voltage.

[0038] When the voltage difference between the analog voltage VAA at the discharge input terminal and the voltage GM1 at the discharge reference input terminal is greater than the threshold voltage, it indicates that the analog voltage VAA is floating and fluctuating. At this time, the first unidirectional conduction switch D1 is turned on, and the analog voltage VAA is discharged through the voltage discharge terminal after passing through the first unidirectional conduction switch D1. When the voltage difference between the analog voltage VAA at the discharge input terminal and the voltage GM1 at the discharge reference input terminal is less than or equal to the threshold voltage, the first unidirectional conduction switch D1 is turned off. Since the voltage value set by the analog voltage VAA is It is generally about 0.5 to 0.7V greater than GM1. Therefore, in this embodiment, the threshold voltage can be any voltage between 0.5 and 0.7V. The threshold voltage can also be set to other set values. Taking the threshold voltage of 0.7V as an example, if the first unidirectional conduction switch D1 is a diode, and its forward conduction voltage drop is just 0.7V, then if the voltage difference between VAA and GM1 is greater than 0.7V, the first unidirectional conduction switch D1 is turned on, and the discharge unit circuit performs discharge. If the voltage difference between VAA and GM1 is less than 0.7V, the first unidirectional conduction switch D1 is turned off.

[0039] Specifically, the discharge unit circuit 104 further includes a voltage divider module and a first operational amplifier U1. The discharge reference input terminal is connected to one end of the voltage divider module. The voltage divider module is used to divide the voltage GM1 of the discharge reference input terminal. The other end of the voltage divider module is connected to the non-inverting input terminal Vp+ of the first operational amplifier U1. The inverting input terminal Vp- of the first operational amplifier U1 is connected to the output terminal. The output terminal of the first operational amplifier U1 is also connected to the connection node.

[0040] The voltage discharge end includes a third resistor R3, one end of the third resistor R3 is connected to the first unidirectional conduction switch D1, and the other end of the third resistor R3 is grounded;

[0041] The voltage divider module includes a first resistor R1 and a second resistor R2, one end of the first resistor R1 is connected to the discharge reference input terminal, one end of the second resistor R2 is grounded, the other end of the first resistor R1 and the other end of the second resistor R2 are both connected to a second node, and the second node is connected to the non-inverting input terminal Vp+ of the first operational amplifier U1.

[0042] Due to differences in panel settings in actual situations, the voltage difference between the analog voltages VAA and GM1 may be set too high or too low. In one example, if the voltage difference between VAA and GM1 is set too low, for example, 0.2V, and the forward voltage drop of the first unidirectional conduction switch D1 is 0.7V, the voltage difference between VAA and GM1 exceeds the threshold voltage of 0.2V, and the first unidirectional conduction switch D1 cannot conduct. Therefore, the voltage divider module divides the voltage of GM1, reducing GM1 and thereby raising the voltage difference between VAA and GM1 to the forward voltage drop of the first unidirectional conduction switch D1. In other words, based on the selection of the first unidirectional conduction switch D1 (the forward voltage drop of the unidirectional conduction switch) and the voltage difference between VAA and GM1, the voltage divider module divides the voltage GM1 at the bleeder reference input.

[0043] When the voltage difference between the analog voltage at the discharge input and the first voltage is greater than a threshold voltage, the first unidirectional conduction switch D1 is turned on. The first voltage is the reference voltage of the discharge reference input after passing through the first operational amplifier U1. When the first unidirectional conduction switch is turned on, the analog voltage is discharged through the first unidirectional conduction switch and then released to the ground terminal through R3. If the voltage difference between the analog voltage and the first voltage is less than or equal to the threshold voltage, the first unidirectional conduction switch is turned off. At this time, the analog voltage does not pass through the discharge unit circuit, and the analog voltage is transmitted normally in the wiring.

[0044] In this embodiment, the discharge unit circuit 104 is provided with a first operational amplifier U1 , which isolates the discharge path from the discharge reference input terminal GM1 , thereby preventing the voltage from flowing back to GM1 when the analog voltage VAA is discharged.

[0045] Specifically, in the discharge unit circuit 104, since the analog voltage VAA is generally close to the first gamma voltage, the first gamma voltage is selected as the reference voltage, that is, GM1 is used as the discharge reference voltage. Generally speaking, the analog voltage VAA is about 0.5 to 0.7 V higher than the reference voltage GM1. The first unidirectional conduction switch D1 is set with a threshold voltage (Vth). In this embodiment, the threshold voltage is set to 0.7V. The voltage obtained by dividing the reference voltage GM1 by the first resistor R1 is Vi. By adjusting the voltage dividing resistor, the normal value of the analog voltage VAA is made to be 0.7V greater than Vi (here, the forward conduction voltage of the first unidirectional conduction switch D1 can be set to 0.7V). Vi outputs the first voltage Vo through the first operational amplifier U1, Vo=Vi. When the analog voltage VAA fluctuates upward due to interference or other reasons, VAA-Vo>0.7V. At this time, the first unidirectional conduction switch D1 is turned on, and the analog voltage VAA flows into the third resistor R3 through the first unidirectional conduction switch D1 to discharge current to the ground terminal GND, thereby lowering the VAA voltage. When VAA-Vo<0.7V, the first unidirectional conduction switch D1 is turned off.

[0046] In this embodiment, the freewheeling unit circuit 103 includes a freewheeling input terminal, a freewheeling reference input terminal, a second unidirectional conduction switch D2, and a freewheeling compensation terminal, one end of the second unidirectional conduction switch D2 is connected to the freewheeling compensation terminal, and the other end of the second unidirectional conduction switch D2 is connected to the freewheeling input terminal; when the voltage difference between the analog voltage VAA of the freewheeling input terminal and the voltage GM1 of the freewheeling reference input terminal is greater than the threshold voltage, the second unidirectional conduction switch D2 is turned off; when the voltage difference between the analog voltage VAA of the freewheeling input terminal and the voltage GM1 of the freewheeling reference input terminal is less than the threshold voltage, the second unidirectional conduction switch D2 is turned on, and the freewheeling unit circuit compensates for the analog voltage.

[0047] The freewheeling unit circuit 103 also includes a second operational amplifier U2, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a seventh resistor R7. The freewheeling reference input terminal is connected to the non-inverting input terminal Vp+ of the second operational amplifier U2 via the fifth resistor R5, the inverting input terminal Vp- of the second operational amplifier U2 is connected to the ground terminal via the fourth resistor R4, the second unidirectional conduction switch D2 is connected to the output terminal of the second operational amplifier U2 via the seventh resistor R7, one end of the sixth resistor R6 is connected to the inverting input terminal Vp- of the second operational amplifier U2, and the other end of the sixth resistor R6 is connected to one end of the second unidirectional conduction switch D2 connected to the seventh resistor R7.

[0048] In this embodiment, Vp- is the inverting input terminal, and Vp+ is the non-inverting input terminal. Vp- and Vp+ are considered to be virtually shorted, so that the potentials of Vp- and Vp+ are both the voltage of the freewheeling reference input terminal (i.e., GM1, the first gamma voltage). Then, Vp- and Vp+ are considered to be virtually disconnected, and the currents through the fourth resistor R4 and the sixth resistor R6 are equal. GM1 generates a voltage VS through the second operational amplifier U2, where VS = GM1 * (R4 + R6) / R4. D2 is a second unidirectional conduction switch, which can be a diode. If the forward voltage drop of the diode is the threshold voltage Vth, the fourth resistor R4 and the sixth resistor R6 are adjusted so that the voltage of VS is exactly Vth greater than the analog voltage VAA. In this way, if VAA drops abnormally, Vs is supplied through D2. The fifth resistor R5 and the seventh resistor R7 both act as current limiters to prevent inrush current.

[0049] When the voltage difference between the second voltage and the analog voltage at the freewheeling input terminal is greater than a threshold voltage, the second unidirectional conduction switch D2 is turned on. The second voltage is the reference voltage of the freewheeling reference input terminal after passing through the second operational amplifier U2. In this embodiment, the reference voltage at the freewheeling reference input terminal can also be connected to the first gamma voltage GM1. In this embodiment, since the reference voltage GM1 is generated by the second operational amplifier U2 to generate Vs, the Vs voltage is 0.7V greater than the normal VAA (here, the forward conduction voltage of the second unidirectional conduction switch D2 can be set to 0.7V). When the analog voltage VAA fluctuates downward, Vs-VAA>0.7V. At this time, the second unidirectional conduction switch D2 is turned on, and Vs compensates the current for the analog voltage VAA, thereby raising the analog voltage VAA. When Vs-VAA<0.7V, the second unidirectional conduction switch D2 is turned off.

[0050] In this embodiment, the freewheeling reference input terminal and the discharge reference input terminal are both connected to the first gamma voltage GM1 output terminal of the gamma chip.

[0051] Since the analog voltage VAA inside the source driver chip is used to power the output buffer to output a different reference voltage GM, it is necessary to ensure that the analog voltage VAA is slightly higher than the reference voltage GM. If the voltage difference between the analog voltage VAA and the reference voltage GM is too high, it will cause a large heat loss inside the source driver chip. Generally, the analog voltage VAA is close to the first gamma voltage, so the first gamma voltage is selected as the reference voltage, that is, GM1 is used as the discharge reference voltage.

[0052] In this embodiment, reference Figure 7 The display driving circuit further includes: a filter circuit 105, which is used to filter the voltage value output by the discharge unit circuit 104 or the freewheeling unit circuit 103; the filter circuit 105 includes a first capacitor C0: the first capacitor C0 is arranged between the discharge unit circuit 104 and the freewheeling unit circuit 103 and the source driving board 102, one end of the first capacitor C0 is respectively connected to the discharge unit circuit 104 and the freewheeling unit circuit 103, and the other end of the first capacitor C0 is grounded.

[0053] The display driving circuit provided by the embodiment of the present invention includes a central control board and a source driving board. The central control board is provided with a power management chip and a gamma chip. The source driving board is provided with a source driving chip. The central control board and the source driving board are electrically connected. The power management chip outputs an analog voltage to the source driving chip and the gamma chip. The gamma chip outputs a gamma voltage to the source driving chip. The display driving circuit also includes a discharge unit circuit and a freewheeling unit circuit: the discharge unit circuit is provided between the central control board and the source driving board. When the analog voltage output by the power management chip fluctuates upward, the discharge unit circuit is turned on and discharges the analog voltage. After the analog voltage is discharged to the standard value, the discharge unit circuit is turned off; the freewheeling unit circuit is provided between the central control board and the source driving board. When the analog voltage output by the power management chip fluctuates downward, the freewheeling unit circuit The analog voltage is turned on and compensated for. After the analog voltage is compensated to the standard value, the freewheeling unit circuit is turned off. In the process of the analog voltage VAA being transmitted from the power management chip to the source chip, the analog voltage fluctuates. The present application sets a discharge unit circuit and a freewheeling unit circuit between the central control board and the source driver board. Therefore, when the analog voltage fluctuates upward, the analog voltage can be discharged through the discharge unit circuit. When the analog voltage fluctuates downward, the analog voltage is compensated through the freewheeling unit circuit, thereby ensuring that the analog voltage remains stable during the transmission process, and then ensuring the stability of the analog voltage transmitted to the source driver chip and the display panel. In this way, the damage and damage to the components caused by large fluctuations in the analog voltage can be avoided, and the voltage level of the first gamma voltage can be guaranteed, thereby avoiding display abnormalities caused by large fluctuations in the analog voltage and being lower than the first gamma voltage.

[0054] Second embodiment:

[0055] See also Figure 8 An embodiment of the present invention provides a display device, which includes a display panel 106 and a display driving circuit. The display panel 106 and the display driving circuit are electrically connected, and the display driving circuit adopts the display driving circuit described in the first embodiment above.

[0056] In one embodiment, each frame of the display panel includes a display area and a blanking area.

[0057] The display area corresponds to the transistors in the display panel being turned on, and the source driver chip in the display driver circuit charges the display panel through the output channel;

[0058] The blanking area corresponds to when the transistors in the display panel are turned off, and the source driver chip in the display driver circuit stops charging the display panel through the output channel.

[0059] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0060] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A display driver circuit comprising a central control board and a source driver board, wherein the central control board is provided with a power management chip and a gamma chip, and the source driver board is provided with a source driver chip, the central control board and the source driver board are electrically connected, the power management chip outputs an analog voltage to the source driver chip and the gamma chip, and the gamma chip outputs a gamma voltage to the source driver chip, characterized in that: The display driving circuit further includes a discharge unit circuit and a freewheeling unit circuit: The discharge unit circuit is provided between the central control board and the source driver board. When the analog voltage output by the power management chip fluctuates upward, the discharge unit circuit is turned on and discharges the analog voltage. After the analog voltage is discharged to a standard value, the discharge unit circuit is turned off. The freewheeling unit circuit is arranged between the central control board and the source driver board. When the analog voltage output by the power management chip fluctuates downward, the freewheeling unit circuit is turned on and compensates the analog voltage. After the analog voltage is compensated to the standard value, the freewheeling unit circuit is turned off.

2. The display driving circuit according to claim 1, wherein: The discharge unit circuit includes a discharge input terminal, a discharge reference input terminal, a voltage discharge terminal, and a first unidirectional conduction switch, wherein one terminal of the first unidirectional conduction switch is connected to the discharge input terminal, the other terminal of the first unidirectional conduction switch is connected to the voltage discharge terminal, and the discharge reference input terminal is connected to a first node connecting the first unidirectional conduction switch and the voltage discharge terminal; When the voltage difference between the analog voltage at the discharge input terminal and the voltage at the discharge reference input terminal is greater than a threshold voltage, the first unidirectional conduction switch is turned on, and the analog voltage passes through the first unidirectional conduction switch and is discharged through the voltage discharge terminal; when the voltage difference between the analog voltage at the discharge input terminal and the voltage at the discharge reference input terminal is less than or equal to a threshold voltage, the first unidirectional conduction switch is turned off.

3. The display driving circuit according to claim 2, wherein: The discharge unit circuit further includes a voltage divider module and a first operational amplifier. The reference input terminal is connected to one end of the voltage divider module, and the voltage divider module is used to divide the voltage of the reference input terminal. The other end of the voltage divider module is connected to the non-inverting input terminal of the first operational amplifier. The inverting input terminal and the output terminal of the first operational amplifier are connected. The output terminal of the first operational amplifier is also connected to the first node.

4. The display driving circuit according to claim 3, wherein: The voltage discharge end includes a third resistor, one end of the third resistor is connected to the first unidirectional conduction switch, and the other end of the third resistor is grounded; The voltage divider module includes a first resistor and a second resistor, one end of the first resistor is connected to the reference input end, one end of the second resistor is grounded, the other end of the first resistor and the other end of the second resistor are both connected to a second node, and the second node is connected to the non-inverting input end of the first operational amplifier.

5. The display driving circuit according to claim 1, wherein: The freewheeling unit circuit includes a freewheeling input terminal, a freewheeling reference input terminal, a second unidirectional conducting switch, and a freewheeling compensation terminal, wherein one end of the second unidirectional conducting switch is connected to the freewheeling compensation terminal, and the other end of the second unidirectional conducting switch is connected to the freewheeling input terminal; When the voltage difference between the analog voltage at the freewheeling input terminal and the voltage at the freewheeling reference input terminal is greater than a threshold voltage, the second unidirectional conduction switch is turned off; When the voltage difference between the analog voltage at the freewheeling input terminal and the voltage at the freewheeling reference input terminal is smaller than a threshold voltage, the second unidirectional conduction switch is turned on, and the freewheeling unit circuit compensates the analog voltage.

6. The display driving circuit according to claim 5, wherein: The freewheeling unit circuit also includes a second operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor, and a seventh resistor. The freewheeling reference input terminal is connected to the non-inverting input terminal of the second operational amplifier via the fifth resistor, the inverting input terminal of the second operational amplifier is connected to the ground terminal via the fourth resistor, the second unidirectional conduction switch is connected to the output terminal of the second operational amplifier via the seventh resistor, one end of the sixth resistor is connected to the inverting input terminal of the second operational amplifier, and the other end of the sixth resistor is connected to one end of the second unidirectional conduction switch connected to the seventh resistor.

7. The display driving circuit according to any one of claims 4 to 6, characterized in that: The freewheeling reference input terminal and the discharge reference input terminal are both connected to the first gamma voltage output terminal of the gamma chip.

8. The display driving circuit according to claim 7, wherein: When the voltage difference between the analog voltage at the discharge input terminal and the first voltage is greater than the threshold voltage, the first unidirectional conduction switch is turned on, and the first voltage is the voltage of the reference voltage at the discharge reference input terminal after passing through the first operational amplifier; When the voltage difference between the second voltage and the analog voltage at the freewheeling input terminal is greater than the threshold voltage, the second unidirectional conduction switch is turned on. The second voltage is the voltage of the reference voltage at the freewheeling reference input terminal after passing through the second operational amplifier.

9. The display driving circuit according to claim 1, wherein: The display driving circuit also includes: a filtering circuit for filtering the voltage value output by the discharge unit circuit or the freewheeling unit circuit; the filtering circuit includes a first capacitor: the first capacitor is arranged between the discharge unit circuit and the freewheeling unit circuit and the source driving board, one end of the first capacitor is respectively connected to the discharge unit circuit and the freewheeling unit circuit, and the other end of the first capacitor is grounded.

10. A display device comprising a display panel and a display driving circuit, wherein the display panel and the display driving circuit are electrically connected, characterized in that: The display driving circuit adopts the display driving circuit according to any one of claims 1 to 9.

Images